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Configuring ATM

Configuring ATM

This chapter describes how to configure ATM on the Cisco 2600 series, Cisco 3600 series, Cisco 4500, Cisco 4700, Cisco 7200 series, Cisco 7500 and Cisco 12000 series routers. For further general information about ATM, see the "Wide-Area Networking Overview" chapter at the beginning of this book.

To configure routers that use a serial interface for ATM access through an ATM data service unit (ADSU), see the section "Configuring ATM Access over a Serial Interface" later in this chapter.


Note Beginning in Cisco IOS Release 11.3, all commands supported on the Cisco 7500 series routers are also supported on Cisco 7000 series routers equipped with RSP7000.

For a complete description of the ATM commands in this chapter, refer to the "ATM Commands" chapter in the Cisco IOS Wide-Area Networking Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

For information about Switched Multimegabit Data Service (SMDS) support, refer to the "SMDS Commands" chapter in the Cisco IOS Wide-Area Networking Command Reference.

For information about configuring LAN emulation (LANE) for ATM, refer to the "Configuring LAN Emulation" chapter in the Cisco IOS Switching Services Configuration Guide. For information about LANE commands, refer to the "LAN Emulation Commands" chapter in the Cisco IOS Switching Services Command Reference.

For information about configuring IP to ATM class of service, refer to the "IP to ATM Class of Service Overview" and "Configuring IP to ATM Class of Service" chapters in the Cisco IOS Quality of Service Solutions Configuration Guide.

ATM Configuration Task List

To configure ATM, complete the tasks in the following sections. The first task is required, and then you must configure at least one PVC or SVC. The virtual circuit options you configure must match in three places: on the router, on the ATM switch, and at the remote end of the PVC or SVC connection. The remaining tasks are optional.

See the "ATM Configuration Examples" section at the end of this chapter for configuration examples.

Enabling the ATM Interface

This section describes how to configure an ATM interface. For the AIP, all ATM port adapters, and the 1-port ATM-25 network module, the port number is always 0. For example, the slot/port address of an ATM interface on an AIP installed in slot 1 is 1/0.

To configure the ATM interface, use the following commands beginning in privileged EXEC mode:

Command Purpose

Step 1

configure terminal

At the privileged EXEC prompt, enter global configuration mode from the terminal.

Step2

interface atm 
slot/0

or

interface atm slot/port-adapter/0

or

interface atm number

Specify the ATM interface using the appropriate format of the interface atm command.1

Step3

ip address 
ip-address mask

If IP routing is enabled on the system, optionally assign a source IP address and subnet mask to the interface.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

To enable the ATM interface, use the following command in interface configuration mode:

Command Purpose
no 
shutdown

Change the shutdown state to up and enable the ATM interface, thereby beginning the segmentation and reassembly (SAR) operation on the interface.

The no shutdown command passes an enable command to the ATM interface, which then begins segmentation and reassembly (SAR) operations. It also causes the ATM interface to configure itself based on the previous configuration commands sent.

Configuring PVCs

To use a permanent virtual circuit (PVC), you must configure the PVC into both the router and the ATM switch. PVCs remain active until the circuit is removed from either configuration.


NoteIf you use PVC discovery, you do not have to configure the PVC on the router. Refer to the section "Configuring PVC Discovery" for more information.

All virtual circuit characteristics listed in the "Wide-Area Networking Overview" chapter apply to these PVCs. When a PVC is configured, all the configuration options are passed on to the ATM interface. These PVCs are writable into the nonvolatile RAM (NVRAM) as part of the Route Processor (RP) configuration and are used when the RP image is reloaded.

Some ATM switches might have point-to-multipoint PVCs that do the equivalent of broadcasting. If a point-to-multipoint PVC exists, then that PVC can be used as the sole broadcast PVC for all multicast requests.

To configure a PVC, perform the tasks in the following sections. The first two tasks are required; the other tasks are optional.

Creating a PVC

To create a PVC on the ATM interface and enter interface-ATM-VC configuration mode, use the following command beginning in interface configuration mode:

Command Purpose
pvc [name] vpi/vci 
[ilmi | qsaal | smds]

Configure a new ATM PVC by assigning a name (optional) and VPI/VCI numbers. Enter interface-ATM-VC configuration mode. Optionally configure ILMI, QSAAL, or SMDS encapsulation.


NoteAfter configuring the parameters for an ATM PVC, you must exit the interface-ATM-VC configuration mode in order to create the PVC and enable the settings.

Once you specify a name for a PVC, you can reenter the interface-ATM-VC configuration mode by simply entering pvc name.


NoteThe ilmi keyword in the pvc command is used for setting up an ILMI PVC in an SVC environment. Refer to the section "Configuring Communication with the ILMI" later in this chapter for more information.

See examples of PVC configurations in the section "ATM Configuration Examples" at the end of this chapter.

Mapping a Protocol Address to a PVC

The ATM interface supports a static mapping scheme that identifies the network address of remote hosts or routers. This section describes how to map a PVC to an address, which is a required task for configuring a PVC.

To map a protocol address to a PVC, use the following command in interface-ATM-VC configuration mode:

Command Purpose
protocol protocol 
protocol-address [[no] broadcast]

Map a protocol address to a PVC.


NoteIf you enable or disable broadcasting directly on a PVC using the protocol command, this configuration will take precedence over any direct configuration using the broadcast command.

See examples of PVC configurations in the section "ATM Configuration Examples" at the end of this chapter.

Configuring the AAL and Encapsulation Type

To configure the ATM adaptation layer (AAL) and encapsulation type, use the following command beginning in interface-ATM-VC configuration mode:

Command Purpose
encapsulation 
aal5encap

Configure the ATM adaptation layer (AAL) and encapsulation type.

For a list of AAL types and encapsulations supported for the aal-encap argument, refer to the encapsulation aal5 command in the "ATM Commands" chapter of the Cisco IOS Wide-Area Networking Command Reference. The global default is AAL5 with SNAP encapsulation.

Configuring PVC Traffic Parameters

The supported traffic parameters are part of the following service categories: Available Bit Rate (ABR), Unspecified Bit Rate (UBR), UBR+, Variable Bit Rate Non Real-Time (VBR-NRT), and real-time Variable Bit Rate (VBR). Only one of these categories can be specified per PVC connection so if a new one is entered, it will replace the existing one.

To configure PVC traffic parameters, use one of the following commands beginning in interface-ATM-VC configuration mode:

Command Purpose
abr output-pcr 
output-mcr

Configure the Available Bit Rate (ABR). (ATM-CES port adapter and Multiport T1/E1 ATM Network Module only.)

ubr output-pcr

Configure the Unspecified Bit Rate (UBR).

ubr+ output-pcr 
output-mcr

Configure the UBR and a minimum guaranteed rate.

vbr-nrt output-pcr 
output-scr output-mbs

Configure the Variable Bit Rate-Non Real Time (VBR-NRT) QOS.

vbr-rt peak-rate 
average-rate burst

Configure the real-time Variable Bit Rate (VBR). (CiscoMC3810 and Multiport T1/E1 ATM Network Module only.)

The -pcr and -mcr arguments are the peak cell rate and minimum cell rate, respectively. The -scr and -mbs arguments are the sustainable cell rate and maximum burst size, respectively.

For an example of how to configure an ABR PVC, refer to the section "Configuring an ABR PVC Example" at the end of this chapter.

For a description of how to configure traffic parameters in a VC class and apply the VC class to an ATM interface or subinterface, refer to the section "Configuring VC Classes."


NoteThe commands in this section are not supported on the ATM port adapter (PA-A1 series). The ABR service class is only supported on the ATM-CES port adapter for PVCs. The 1-port ATM-25 network module only supports UBR.

For ABR VCs, you can optionally configure the amount that the cell transmission rate increases or decreases in response to flow control information from the network or destination. To configure this option, use the following command in interface-ATM-VC configuration mode:

Command Purpose
atm abr rate-factor [rate-increase-factor] 
[rate-decrease-factor]

Specify the ABR rate factors. The default increase and decrease rate factors is 1/16.

For an example of configuring an ABR PVC, see the section "Configuring an ABR PVC Example" later in this chapter.

Configuring PVC Discovery

You can configure your router to automatically discover PVCs that are configured on an attached adjacent switch. The discovered PVCs and their traffic parameters are configured on an ATM main interface or subinterface that you specify. Your router receives the PVC parameter information using Interim Local Management Interface (ILMI).

To configure PVC discovery on an ATM interface, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0

or

interface atm slot/port-adapter/0

or

interface atm number

Specify the ATM interface using the appropriate format of the interface atm command.1

Step2

pvc [name] 0/16 ilmi

Configure an ILMI PVC on the main interface.

Step3

exit

Return to interface configuration mode.

Step4

atm ilmi-pvc-discovery 
[subinterface]

Configure PVC Discovery on the main interface and optionally specify that discovered PVCs will be assigned to a subinterface.

Step5

exit

Return to global configuration mode.

Step6

interface atm slot/0[.subinterface-number
{multipoint | point-to-point}]

or

interface atm 
slot/port-adapter/0[.subinterface-number 
{multipoint | point-to-point}]

or

interface atm number[.subinterface-number 
{multipoint | point-to-point}]

Specify the ATM main interface or subinterface that discovered PVCs will be assigned to.

Step7

ip address ip-address mask

(Optional) Specify the protocol address for the subinterface.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

Use the subinterface keyword in Step4 if you want the discovered PVCs to reside on an ATM subinterface that you specify in Step6. The discovered PVCs are assigned to the subinterface number that matches the VPI number of the discovered PVC. For example, if subinterface 2/0.1 is specified using the interface atm command in Step6, then all discovered PVCs with a VPI value of1 will be assigned to this subinterface. For an example, see the section "Configuring PVC Discovery Example" later in this chapter.

Repeat Steps6 and 7 if you want discovered PVCs to be assigned to more than one subinterface. If no subinterfaces are configured, discovered PVCs will be assigned to the main interface specified in Step1.

For an example of configuring PVC discovery, refer to the section "Configuring PVC Discovery Example" at the end of this chapter.

Enabling Inverse ARP

Inverse ARP is enabled by default when you create a PVC using the pvc command. Once configured, a protocol mapping between an ATM PVC and a network address is learned dynamically as a result of the exchange of ATM Inverse ARP packets.

Inverse ARP is supported on PVCs running IP or IPX and no static map is configured. If a static map is configured, Inverse ARP will be disabled.

To enable Inverse ARP on an ATM PVC, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0[.subinterface-number 
{multipoint | point-to-point}]

or

interface atm 
slot/port-adapter/0[.subinterface-number 
{multipoint | point-to-point}]

or

interface atm number[.subinterface-number 
{multipoint | point-to-point}]

Specify the ATM interface using the appropriate format of the interfaceatm command.1

Step2

pvc [name] vpi/vci

Specify an ATM PVC by name (optional) and VPI/VCI numbers.

Step3

encapsulation aal5snap

Configure AAL5LLC-SNAP encapsulation if it is not already configured.

Step4

inarp minutes

(Optional) Adjust the Inverse ARP time period.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

When PVC discovery is enabled on an active PVC and the router terminates that PVC, the PVC will generate an ATM Inverse ARP request. This allows the PVC to resolve its own network addresses without configuring a static map.

Address mappings learned through Inverse ARP are aged out. However, mappings are refreshed periodically. This period is configurable using the inarp command, which has a default of 15minutes.

You can also enable Inverse ARP using the protocol command. This is necessary only if you disabled Inverse ARP using the no protocol command. For more information about this command, refer to the "ATMCommands" chapter in the Cisco IOS Wide-Area Networking Command Reference.

For an example of configuring Inverse ARP, see the section "Enabling Inverse ARP Example" at the end of this chapter.

Configuring Generation of End-to-End F5 OAM Loopback Cells to Verify Connectivity

You can optionally configure the PVC to generate end-to-end F5 OAM loopback cells to verify connectivity on the virtual circuit. The remote end must respond by echoing back such cells. If OAM response cells are missed (indicating the lack of connectivity), the PVC state goes down. If all the PVCs on a subinterface go down, the subinterface goes down.

To configure transmission of end-to-end F5 OAM cells on a PVC, use the following commands in interface-ATM-VC configuration mode:

Command Purpose

Step1

oam-pvc [manage] 
frequency

Configure transmission of end-to-end F5 OAM loopback cells on a PVC, specify how often loopback cells should be sent, and optionally enable OAM management of the connection.

Step2

oam retry up-count 
down-count retry-frequency

(Optional) Specify OAM management parameters for verifying connectivity of a PVC connection. This command is only supported if OAM management is enabled.

Use the up-count argument to specify the number of consecutive end-to-end F5 OAM loopback cell responses that must be received in order to change a PVC connection state to up. Use the down-count argument to specify the number of consecutive end-to-end F5 OAM loopback cell responses that are not received in order to tear down a PVC. Use the retry-frequency argument to specify the frequency (in seconds) that end-to-end F5 OAM loopback cells should be transmitted when a change in UP/DOWN state is being verified. For example, if a PVC is up and a loopback cell response is not received after the frequency (in seconds) specified using the oam-pvc command, then loopback cells are sent at the retry-frequency to verify whether or not the PVC is down.

For information about managing PVCs using OAM, see the section "Configuring OAM Management" later in this chapter.

For an example of OAM loopback cell generation, see the section "Configuring Generation of End-to-End F5 OAM Loopback Cells Example" at the end of this chapter.

Configuring Broadcast on a PVC

To send duplicate broadcast packets for all protocols configured on a PVC, use the following command in interface-ATM-VC configuration mode:

Command Purpose
broadcast

Send duplicate broadcast packets for all protocols configured on a PVC.


NoteIf you enable or disable broadcasting directly on a PVC using the protocol command, this configuration will take precedence over any direct configuration using the broadcast command.

Assigning a VC Class to a PVC

By creating a VC class, you can preconfigure a set of default parameters that you may apply to a PVC. To create a VC class, refer to the section "Configuring VC Classes" later in this chapter.

Once you have created a VC class, use the following command in interface-ATM-VC configuration mode to apply the VC class to a PVC:

Command Purpose
class-vc 
vc-class-name

Apply a VC class to a PVC.

The vc-class-name argument is the same as the name argument you specified when you created a VC class using the vc-class atm command. Refer to the section "Configuring VC Classes" later in this chapter for a description of how to create a VC class.

Configuring PVC Trap Support

You can configure the PVC to provide failure notification by sending a trap when a PVC on an ATM interface fails or leaves the UP operational state.

PVC Failure Notification

Only one trap is generated per hardware interface, within the specified interval defined by the interval atmIntPvcNotificationInterval. If other PVCs on the same interface go DOWN during this interval, traps are generated and held until the interval has elapsed. Once the interval has elapsed, the traps are sent if the PVCs are still DOWN.

No trap is generated when a PVC returns to the UP state after having been in the DOWN state. If you need to detect the recovery of PVCs, you must use the SNMP management application to regularly poll your router.

PVC Status Tables

When PVC trap support is enabled, the SNMP manager can poll the SNMP agent to get PCV status information. The table atmInterfaceExtTable provides PVC status on an ATM interface. The table atmCurrentlyFailingPVclTable provides currently failing and previously failed PVC time-stamp information.


NotePVC traps are only supported on permanent virtual circuit links (PVCLs), not permanent virtual path links (PVPLs).

Prerequisites

Before you enable PVC trap support, you must configure SNMP support and an IP routing protocol on your router. See the "ATM Configuration Examples" section later in this document. For more information about configuring SNMP support, refer to the chapter "Monitoring the Router and Network" in the Cisco IOS Configuration Fundamentals Configuration Guide for CiscoIOS Release12.1. For information about configuring IP routing protocols, refer to the section "IPRouting Protocols" in the Cisco IOS Configuration Guide for CiscoIOS Release12.1.

To receive PVC failure notification and access to PVC status tables on your router, you must have the Cisco PVC trap MIB called CISCO-IETF-ATM2-PVCTRAP-MIB.my compiled in your NMS application. You can find this MIB on the Web at Cisco's MIB website that has the URL http://www.cisco.com/public/mibs.

Enabling PVC Trap Support

When you configure PVC trap support, you must also enable OAM management on the PVC. To enable PVC trap support and OAM management, use the following commands beginning in global configuration mode:

Command Purpose

Step1

snmp-server enable traps atm 
pvc interval seconds fail-interval seconds

Enable PVC trap support.

Step2

interface atm 
slot/0[.subinterface-number {multipoint | 
point-to-point}]

or

interface atm 
slot/port-adapter/0[.subinterface-number {multipoint 
| point-to-point}]

or

interface atm number[.subinterface-number 
{multipoint | point-to-point}]

Specify the ATM interface using the appropriate form of the interface atm command.1

Step3

pvc [name] vpi/vci

Enable the PVC.

Step4

oam-pvc manage

Enable end-to-end OAM management for an ATM PVC.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

For more information on OAM management, see the section "Configuring OAM Management" later in this chapter.

The new objects in this feature are defined in the IETF draft The Definitions of Supplemental Managed Objects for ATM Management, which is an extension to the AToM MIB (RFC 1695). You can find this draft on the Web at the following URL: http://www.ietf.org/internet-drafts/.

For an example of configuring PVC trap support, see the section "Configuring PVC Trap Support Example" at the end of this chapter.

Configuring SVCs

ATM switched virtual circuit (SVC) service operates much like X.25 SVC service, although ATM allows much higher throughput. Virtual circuits are created and released dynamically, providing user bandwidth on demand. This service requires a signalling protocol between the router and the switch.

The ATM signalling software provides a method of dynamically establishing, maintaining, and clearing ATM connections at the User-Network Interface (UNI). The ATM signalling software conforms to ATM Forum UNI 3.0 or ATM Forum UNI 3.1 depending on what version is selected by ILMI or configuration.

In UNI mode, the user is the router and the network is an ATM switch. This is an important distinction. The Ciscorouter does not perform ATM-level call routing. Instead, the ATM switch does the ATM call routing, and the router routes packets through the resulting circuit. The router is viewed as the user and the LAN interconnection device at the end of the circuit, and the ATM switch is viewed as the network.

Figure 1 illustrates the router position in a basic ATM environment. The router is used primarily to interconnect LANs via an ATM network. The workstation connected directly to the destination ATM switch illustrates that you can connect not only routers to ATM switches, but also any computer with an ATM interface that conforms to the ATM Forum UNI specification.


Figure1: Basic ATM Environment


You must complete the tasks in the following sections to use SVCs:

The tasks in the following sections are optional SVC tasks for customizing your network. These tasks are considered advanced; the default values are almost always adequate. You should not have to perform these tasks unless you need to customize your particular SVC connection.


NoteSVCs are not supported on the 1-port ATM-25 network module.

Configuring Communication with the ILMI

In an SVC environment, you must configure a PVC for communication with the Integrated Local Management Interface (ILMI) so the router can receive SNMP traps and new network prefixes. The recommended vpi and vci values for the ILMI PVC are 0 and 16, respectively. To configure ILMI communication, use the following command in interface configuration mode:

Command Purpose
pvc [name] 0/16 ilmi

Create an ILMI PVC on an ATM main interface.


NoteThis ILMI PVC can be set up only on an ATM main interface, not on ATM subinterfaces.

Once you have configured an ILMI PVC, you can optionally enable the ILMI keepalive function by using the following command in interface configuration mode:

Command Purpose
atm ilmi-keepalive 
[seconds]

Optionally, enable ILMI keepalives and set the interval between keepalives.

No other configuration steps are required.

ILMI address registration for receipt of SNMP traps and new network prefixes is enabled by default. The ILMI keepalive function is disabled by default; when enabled, the default interval between keepalives is 3 seconds.

For an example of configuring ILMI, see the section "Configuring Communication with the ILMI Example" within the "ATM Configuration Examples" at the end of this chapter.

Configuring the PVC that Performs SVC Call Setup

Unlike X.25 service, which uses in-band signalling (connection establishment done on the same circuit as data transfer), ATM uses out-of-band signalling. One dedicated PVC exists between the router and the ATM switch, over which all SVC call establishment and call termination requests flow. After the call is established, data transfer occurs over the SVC, from router to router. The signalling that accomplishes the call setup and teardown is called Layer 3 signaling or the Q.2931protocol.

For out-of-band signalling, a signalling PVC must be configured before any SVCs can be set up. Figure 2 illustrates that a signalling PVC from the source router to the ATM switch is used to set up two SVCs. This is a fully meshed network; workstations A, B, and C all can communicate with each other.


Figure2: One or More SVCs Require a Signalling PVC


To configure the signalling PVC for all SVC connections, use the following command in interface configuration mode:

Command Purpose
pvc [name] vpi/vci qsaal

Configure the signalling PVC for an ATM main interface that uses SVCs.


NoteThis signalling PVC can be set up only on an ATM main interface, not on ATM subinterfaces.

The VPI and VCI values must be configured consistently with the local switch. The standard value for VPI and VCI are 0 and 5, respectively.

See the section "SVCs in a Fully Meshed Network Example" at the end of this chapter for a sample ATM signalling configuration.

Configuring the NSAP Address

Every ATM interface involved with signalling must be configured with a network service access point (NSAP) address. The NSAP address is the ATM address of the interface and must be unique across the network.

To configure an NSAP address, complete the tasks described in one of the following sections:

Configuring the ESI and Selector Fields

If the switch is capable of delivering the NSAP address prefix to the router by using ILMI, and the router is configured with a PVC for communication with the switch via ILMI, you can configure the endstation ID (ESI) and selector fields using the atm esi-address command. The atmesi-address command allows you to configure the ATM address by entering the ESI (12hexadecimal characters) and the selector byte (2 hexadecimal characters). The NSAP prefix (26hexadecimal characters) is provided by the ATM switch.

To configure the router to get the NSAP prefix from the switch and use locally entered values for the remaining fields of the address, use the following commands beginning in interface configuration mode:

Command Purpose

Step1

pvc [name] 0/16 ilmi

Configure an ILMI PVC on an ATM main interface for communicating with the switch by using ILMI.

Step2

exit

Return to interface configuration mode.

Step3

atm 
esi-address_(_IREFOBJ:1025077_
)_ esi.selector

Enter the ESI and selector fields of the NSAP address.

The recommended vpi and vci values for the ILMI PVC are 0 and 16, respectively.

You can also specify a keepalive interval for the ILMI PVC. See the "Configuring Communication with the ILMI" section earlier in this chapter for more information.

To see an example of setting up the ILMI PVC and assigning the ESI and selector fields of an NSAP address, see the section "SVCs with Multipoint Signalling Example" at the end of this chapter.

Configuring the Complete NSAP Address

When you configure the ATM NSAP address manually, you must enter the entire address in hexadecimal format because each digit entered represents a hexadecimal digit. To represent the complete NSAP address, you must enter 40 hexadecimal digits in the following format:

XX.XXXX.XX.XXXXXX.XXXX.XXXX.XXXX.XXXX.XXXX.XXXX.XX

Note All ATM NSAP addresses may be entered in the dotted hexadecimal format shown, which conforms to the UNI specification. The dotted method provides some validation that the address is a legal value. If you know your address format is correct, the dots may be omitted.

Because the interface has no default NSAP address, you must configure the NSAP address for SVCs. To set the ATM interface's source NSAP address, use the following command in interface configuration mode:

Command Purpose
atm nsap-address 
nsap-address

Configure the ATM NSAP address for an interface.

The atmnsap-address and atmesi-address commands are mutually exclusive. Configuring the router with the atmnsap-address command negates the atmesi-address setting, and vice versa. For information about using the atmesi-address command, see the preceding section "Configuring the ESI and Selector Fields."

See an example of assigning an NSAP address to an ATM interface in the section "ATM NSAP Address Example" at the end of this chapter.

Creating an SVC

To create an SVC, use the following commands beginning in interface configuration mode:

Command Purpose

Step1

svc [name] nsap address

Create an SVC and specify the destination NSAP address.

Step2

encapsulation aal5encap

(Optional) Configure the ATM adaptation layer (AAL) and encapsulation type.

Step3

protocol protocol 
protocol-address [[no] broadcast]

Map a protocol address to an SVC.

Once you specify a name for an SVC, you can reenter interface-ATM-VC configuration mode by simply entering the svc name command; you can remove an SVC configuration by entering the no svc name command.

For a list of AAL types and encapsulations supported for the aal-encap argument, refer to the encapsulation aal5 command in the "ATM Commands" chapter of the Cisco IOS Wide-Area Networking Command Reference. The default is AAL5 with SNAP encapsulation.

Configuring ATM UNI Version Override

Normally, when ILMI link autodetermination is enabled on the interface and is successful, the router takes the user-network interface (UNI) version returned by ILMI. If the ILMI link autodetermination process is unsuccessful or ILMI is disabled, the UNI version defaults to 3.0. You can override this default by using the atm uni-version command. The no form of the command sets the UNI version to the one returned by ILMI if ILMI is enabled and the link autodetermination is successful. Otherwise, the UNI version will revert to 3.0. To override the ATM UNI version used by the router, use the following command in interface configuration mode:

Command Purpose
atm uni-version 
version-number

Override UNI version used by router.

No other configuration steps are required.

Configuring the Idle Timeout Interval

You can specify an interval of inactivity after which any idle SVC on an interface is torn down. This timeout interval might help control costs and free router memory and other resources for other uses.

To change the idle timeout interval, use the following command in interface-ATM-VC configuration mode:

Command Purpose
idle-timeout seconds 
[minimum-rate]

Configure the interval of inactivity after which an idle SVC will be torn down.

In addition to configuring the interval of inactivity, you can optionally specify the minimum-rate in kilobits per second (kbps). This is the minimum traffic rate required on an ATM SVC to maintain the connection.

Configuring Point-to-Multipoint Signalling

Point-to-multipoint signalling (or multicasting) allows the router to send one packet to the ATM switch and have the switch replicate the packet to the destinations. It replaces pseudobroadcasting on specified virtual circuits for protocols configured for broadcasting.

You can configure multipoint signalling on an ATM interface after you have mapped protocol addresses to NSAPs and configured one or more protocols for broadcasting.

After multipoint signalling is set, the router uses the SVC configurations that have the broadcast keyword set to establish multipoint calls. The call is established to the first destination with a Setup message. Additional parties are added to the call with AddParty messages each time a multicast packet is sent. One multipoint call will be established for each logical subnet of each protocol that has the broadcast keyword set.

To configure multipoint signalling on an ATM interface, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0

or

interface atm slot/port-adapter/0

or

interface atm number

Specify the ATM interface using the appropriate format of the interface atm command.1

Step2

pvc [name] 0/5 qsaal

Configure the signalling PVC for an ATM main interface that uses SVCs.

Step3

exit

Return to interface configuration mode.

Step4

pvc [name] 0/16 ilmi

and

exit

(Optional) Configure an ILMI PVC on an ATM main interface and return to interface configuration mode. This task is required if you configure the ATM NSAP address in Step 5 by configuring the ESI and selector fields.

Step5

atm nsap-address 
nsap-address

or

atm esi-address 
esi.selector

Configure the complete NSAP address manually.

or

Configure the ESI and selector fields. To use this method, you must configure Step4 first.

Step6

svc [name] nsap address

Create an SVC and specify the destination NSAP address. Enter interface-ATM-VC mode.

Step7

protocol protocol 
protocol-address broadcast

Provide a protocol address for the interface and enable broadcasting.

Step8

exit

Return to interface configuration mode.

Step9

atm multipoint-signalling 

Enable multipoint signalling to the ATM switch.

Step10

atm multipoint-interval 
interval 

(Optional) Limit the frequency of sending AddParty messages.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

If multipoint virtual circuits are closed, they are reopened with the next multicast packet. Once the call is established, additional parties are added to the call when additional multicast packets are sent. If a destination never comes up, the router constantly attempts to add it to the call by means of multipoint signalling.

For an example of configuring multipoint signalling on an interface that is configured for SVCs, see the section "SVCs with Multipoint Signalling Example" at the end of this chapter.

Configuring IP Multicast over ATM Point-to-Multipoint Virtual Circuits

This task is documented in the "ConfiguringIPMulticast Routing" chapter of the CiscoIOSIP and IP RoutingConfigurationGuide.

Configuring SVC Traffic Parameters

The tasks in this section are optional and advanced. The ATM signalling software can specify to the ATM interface on the router and the switch a limit on how much traffic the source router will be sending. It provides this information in the form of traffic parameters. (These parameters have default values.) The ATM switch in turn sends these values as requested by the source to the ATM destination node. If the destination cannot provide such capacity levels, the call may fail. (For Ciscorouter series behavior, see the per-interface atm sig-traffic-shaping strict command in the Cisco IOS Wide-Area Networking Command Reference.) There is a single attempt to match traffic values.

The supported traffic parameters are part of the following service categories: Unspecified Bit Rate (UBR), UBR+, and Variable Bit Rate Non Real-Time (VBR-NRT). Only one of these categories can be specified per SVC connection so if a new one is entered, it will replace the existing one. The commands used to specify the service category and traffic values are identical to those used when you create a PVC.

To configure traffic parameters on an SVC, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0[.subinterface-number
{multipoint | point-to-point}]

or

interface atm 
slot/port-adapter/0[.subinterface-number {multipoint 
| point-to-point}]

or

interface atm number[.subinterface-number 
{multipoint | point-to-point}]

Specify the ATM interface using the appropriate format of the interface atm command.1

Step2

svc [name] nsap address

Create an SVC and specify the destination NSAP address.

Step3

protocol protocol 
protocol-address [[no] broadcast]

Map a destination protocol address to an SVC.

Step4

ubr output-pcr [input-pcr]

or

ubr+ output-pcr output-mcr 
[input-pcr] [input-mcr]

or

vbr-nrt output-pcr output-scr 
output-mbs [input-pcr] [input-scr] [input-mbs]

Configure the UBR

or

Configure the UBR and a minimum guaranteed rate

or

Configure the VBR-NRT QOS.

Step5

exit

Return to interface configuration mode and enable the traffic parameters on the SVC.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.


NoteThe commands in this section are not supported on the ATM port adapter (PA-A1 series). The 1-port ATM-25 network module only supports UBR.

The -pcr and -mcr arguments are the peak cell rate and minimum cell rate, respectively. The -scr and -mbs arguments are the sustainable cell rate and maximum burst size, respectively.

For an example of configuring traffic parameters on an SVC, see the section "Configuring SVC Traffic Parameters Example" at the end of this chapter.

For a description of how to configure traffic parameters in a VC class and apply the VC class to an ATM interface or subinterface, refer to the section "Configuring VC Classes."

Configuring Strict Traffic Shaping

You can configure strict traffic shaping on an ATM interface to specify that an SVC be established using only signaled traffic parameters. If such shaping cannot be provided, the SVC is released.

To specify that an SVC be established on an ATM interface using only signaled traffic parameters, use the following command in interface configuration mode:

Command Purpose
atm sig-traffic-shaping 
strict

Specify that an SVC be established on an ATM interface using only signaled traffic parameters.

If you do not configure strict traffic shaping on the router ATM interface, an attempt is made to establish an SVC with traffic shaping for the transmit cell flow per the signaled traffic parameters. If such shaping cannot be provided, the SVC is installed with default shaping parameters; that is, it behaves as though a PVC were created without specifying traffic parameters.

Configuring Generation of End-to-End F5 OAM Loopback Cells toVerifyConnectivity

You can optionally configure the SVC to generate end-to-end F5 OAM loopback cells to verify connectivity on the virtual circuit. The remote end must respond by echoing back such cells. If OAM response cells are missed (indicating the lack of connectivity), the SVC is torn down. For more information, refer to the "Configuring OAM Management" section later in this chapter.

To configure transmission of end-to-end F5 OAM loopback cells on an SVC, use the following commands in interface-ATM-VC configuration mode:

Command Purpose

Step1

oam-svc [manage] 
frequency

Configure transmission of end-to-end F5 OAM loopback cells on an SVC, specify how often loopback cells should be sent, and optionally enable OAM management of the connection.

Step2

oam retry up-count 
down-count retry-frequency

(Optional) Specify OAM management parameters for verifying connectivity of an SVC connection. This command is only supported if OAM management is enabled.

The up-count argument does not apply to SVCs, but it must be specified in order to configure the down-count and retry-frequency. Use the down-count argument to specify the number of consecutive end-to-end F5 OAM loopback cell responses that are not received in order to tear down an SVC. Use the retry-frequency argument to specify the frequency (in seconds) that end-to-end F5 OAM loopback cells should be transmitted when a change in UP/DOWN state is being verified. For example, if an SVC is up and a loopback cell response is not received after the frequency (in seconds) specified using the oam-svc command, then loopback cells are sent at the retry-frequency to verify whether or not the SVC is down.


NoteGenerally, ATM signalling manages ATM SVCs. Configuring the oam-svc command on an SVC verifies the inband integrity of the SVC.

Configuring Broadcast on an SVC

To send duplicate broadcast packets or send a single broadcast packet using multipoint signalling for all protocols configured on an SVC, use the following command in interface-ATM-VC configuration mode:

Command Purpose
broadcast

Send duplicate broadcast packets for all protocols configured on an SVC.


NoteIf you enable or disable broadcasting directly on an SVC using the protocol command, this configuration will take precedence over any direct configuration using the broadcast command.

Assigning a VC Class to an SVC

By creating a VC class, you can preconfigure a set of default parameters that you may apply to an SVC. To create a VC class, refer to the section "Configuring VC Classes" later in this chapter.

Once you have created a VC class, use the following command in interface-ATM-VC configuration mode to apply the VC class to an SVC:

Command Purpose
class-vc 
vc-class-name

Apply a VC class to an SVC.

The vc-class-name argument is the same as the name argument you specified when you created a VC class using the vc-class atm command. Refer to the section "Configuring VC Classes" later in this chapter for a description of how to create a VC class.

Configuring SSCOP

The Service-Specific Connection-Oriented Protocol (SSCOP) resides in the service-specific convergence sublayer (SSCS) of the ATM adaptation layer (AAL). SSCOP is used to transfer variable-length service data units (SDUs) between users of SSCOP. SSCOP provides for the recovery of lost or corrupted SDUs.


NoteThe tasks in this section customize the SSCOP feature to a particular network or environment and are optional. The features have default values and are valid in most installations. Before customizing these features, you should have a good understanding of SSCOP and the network involved.

Setting the Poll Timer

The poll timer controls the maximum time between transmission of a POLL PDU when sequential data (SD) or SDP PDUs are queued for transmission or are outstanding pending acknowledgments. To change the poll timer from the default value of 100seconds, use the following command in interface configuration mode:

Command Purpose
sscop poll-timer 
seconds

Set the poll timer.

Setting the Keepalive Timer

The keepalive timer controls the maximum time between transmission of a POLL PDU when no SD or SDP PDUs are queued for transmission or are outstanding pending acknowledgments. To change the keepalive timer from the default value of 5seconds, use the following command in interface configuration mode:

Command Purpose
sscop 
keepalive-timer 
seconds

Set the keepalive timer.

Setting the Connection Control Timer

The connection control timer determines the time between transmission of BGN, END, or RS (resynchronization) PDUs as long as an acknowledgment has not been received. Connection control performs the establishment, release, and resynchronization of an SSCOP connection.

To change the connection control timer from the default value of 1seconds, use the following command in interface configuration mode:

Command Purpose
sscop cc-timer 
seconds

Set the connection control timer.

To change the retry count of the connection control timer from the default value of 10, use the following command in interface configuration mode:

Command Purpose
sscop max-cc 
retries

Set the number of times that SSCOP will retry to transmit BGN, END, or RS PDUs when they have not been acknowledged.

Setting the Transmitter and Receiver Windows

A transmitter window controls how many packets can be transmitted before an acknowledgment is required. To change the transmitter's window from the default value of 7, use the following command in interface configuration mode:

Command Purpose
sscop 
send-window 
packets

Set the transmitter's window.

A receiver window controls how many packets can be received before an acknowledgment is required. To change the receiver's window from the default value of 7, use the following command in interface configuration mode:

Command Purpose
sscop 
receive-window 
packets

Set the receiver's window.

Closing an SVC

You can disconnect an idle SVC by using the following command in EXEC mode:

Command Purpose
atmsig close 
atm slot/0 
vcd

(Optional) Close the signalling PVC for an SVC.

Configuring VC Classes

A VC class is a set of preconfigured VC parameters that you configure and apply to a particular VC or ATM interface. You may apply a VC class to an ATM main interface, subinterface, PVC, or SVC. For example, you can create a VC class that contains VC parameter configurations that you will apply to a particular PVC or SVC. You might create another VC class that contains VC parameter configurations that you will apply to all VCs configured on a particular ATM main interface or subinterface. Refer to the "ATM Configuration Examples" section later in this chapter for examples of VC class configurations.

To create and use a VC class, complete the tasks in the following sections:

Creating a VC Class

To create a VC class, use the following command in global configuration mode:

Command Purpose
vc-class atm 
name

Create a VC class and enter vc-class configuration mode.

For examples of creating VC classes, see the section "Creating a VC Class Examples" at the end of this chapter.

Configuring VC Parameters

After you create a VC class and enter vc-class configuration mode, configure VC parameters using one or more of the following commands:

Refer to the sections "Configuring PVCs" and "Configuring PVC Trap Support" for descriptions of how to configure these commands for PVCs and SVCs.

If an SVC command (for example, idle-timeout or oam-svc) is configured in a VC class, but the VCclass is applied on a PVC, the SVC command is ignored. This is also true if a PVC command is applied to an SVC.

For examples of creating VC classes, see the section "Creating a VC Class Examples" at the end of this chapter.

Applying a VC Class

Once you have created and configured a VC class, you can apply it directly on an ATM PVC or SVC, or you can apply it on an ATM interface or subinterface.

To apply a VC class directly on an ATM PVC or SVC use the following commands beginning in interface configuration mode:

Command Purpose

Step1

pvc [name] vpi/vci

or

svc [name] nsap address

Specify an ATM PVC,

or

specify an ATM SVC.

Step2

class-vc 
vc-class-name

Apply a VC class directly on the PVC or SVC.

To apply a VC class on an ATM main interface or subinterface, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0[.subinterface-number 
{multipoint | point-to-point}]

or

interface atm 
slot/port-adapter/0[.subinterface-number 
{multipoint | point-to-point}]

or

interface atm number[.subinterface-number
{multipoint | point-to-point}]

Specify the ATM interface using the appropriate format of the interface atm command.1

Step2

class-int vc-class-name

Apply a VC class on an the ATM main interface or subinterface.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

For examples of applying a VC class to an ATM interface, see the section "Applying a VC Class Examples" later in this chapter.

Configuring VC Management

When you configure VC management, you enable the router to detect VC connections and disconnections automatically. This notifies protocols to reroute packets immediately, preventing protocols from waiting for unpredictable and relatively long timeout periods.

You may use Integrated Local Management Interface (ILMI) or operation, administration, and maintenance (OAM) or both for managing your PVCs, and OAM for managing your SVCs. For PVCs, you must decide which method is reliable in your particular network.

When ILMI and OAM management methods are both configured to manage a PVC, both must indicate that a PVC is up in order for that PVC to be determined as up. If either ILMI or OAM is not configured, a PVC will be managed by the method that is configured.

When a PVC goes down, route caches for protocols configured on that PVC are cleared (or flushed) so that new routes may be learned. The route cache flush is applied on the PVC's interface. When all PVCs on a subinterface go down, VC management shuts down the subinterface in addition to flushing route caches. ATM hardware must keep the PVC active, however, so that OAM and ILMIcells may flow. When any PVC on a subinterface comes up, the subinterface is brought up.

VC management using ILMI is referred to as ILMI management. VC management using OAM is referred to as OAM management. To configure either management method or both, perform the tasks in one or both of the following sections:

Configuring ILMI Management

ILMI management applies to PVCs only. To configure ILMI management, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0[.subinterface-number
{multipoint | point-to-point}]

or

interface atm 
slot/port-adapter/0[.subinterface-number {multipoint 
| point-to-point}]

or

interface atm number[.subinterface-number 
{multipoint | point-to-point}]

Specify the ATM interface using the appropriate format of the interfaceatm command.1

Step2

pvc [name] 0/16 ilmi

Configure a PVC for communication with the ILMI.

Step3

interface atm slot/0.subinterface-number multipoint

or

interface atm 
slot/port-adapter/0.subinterface-number multipoint

or

interface atm number.subinterface-number multipoint

(Optional) Specify the ATM subinterface of the PVC you want to manage.

Step4

pvc [name] vpi/vci

Specify the PVC to be managed.

Step5

ilmi manage

Enable ILMI management on the PVC.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

Repeat Steps 4 and 5 for each PVC you want to manage. Step 3 is necessary only if you want to configure a PVC on a subinterface and not just on the main ATM interface.

The PVC comes up only if ILMI indicates the PVC is up. The PVC comes down when ILMI indicates that the PVC is down. If OAM management is also configured for the same PVC, the PVC comes up only if both ILMI and OAM indicate that the PVC is up.

For an example of configuring ILMI management on a PVC, see the section "ILMI Management on an ATM PVC Example" at the end of this chapter.

Configuring OAM Management

OAM management may be enabled for both PVCs and SVCs. To configure OAM management, perform the tasks in one or both of the following sections:

Configuring OAM Management for PVCs

To configure OAM management for an ATM PVC, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0[.subinterface-number 
{multipoint | point-to-point}]

or

interface atm 
slot/port-adapter/0[.subinterface-number {multipoint 
| point-to-point}]

or

interface atm number[.subinterface-number 
{multipoint | point-to-point}]

Specify the ATM interface using the appropriate format of the interfaceatm command.1

Step2

pvc [name] vpi/vci

Specify the ATM PVC.

Step3

oam-pvc manage [frequency]

Enable OAM management on the PVC.

Step4

oam retry up-count down-count 
retry-frequency

(Optional) Specify OAM management parameters for re-establishing and removing a PVC connection.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

Use the up-count argument to specify the number of consecutive end-to-end F5 OAM loopback cell responses that must be received in order to change a PVC connection state to up. Use the down-count argument to specify the number of consecutive end-to-end F5 OAM loopback cell responses that are not received in order to tear down a PVC. Use the retry-frequency argument to specify the frequency (in seconds) that end-to-end F5 OAM loopback cells should be transmitted when a change in UP/DOWN state is being verified. For example, if a PVC is up and a loopback cell response is not received after the frequency (in seconds) specified using the oam-pvc command, then loopback cells are sent at the retry-frequency to verify whether or not the PVC is down.

By default, end-to-end F5 OAM loopback cell generation is turned off for each PVC. A PVC is determined as down when any of the following is true on that PVC:

A PVC is determined as up when all of the following are true on that PVC:

For an example of configuring OAM management on a PVC, see the section "OAM Management on an ATM SVC Example" at the end of this chapter.

Configuring OAM Management for SVCs

To configure OAM management for an ATM SVC, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0[.subinterface-number 
{multipoint | point-to-point}]

or

interface atm 
slot/port-adapter/0[.subinterface-number 
{multipoint | point-to-point}]

or

interface atm number[.subinterface-number 
{multipoint | point-to-point}]

Specify the ATM interface using the appropriate format of the interfaceatm command.1

Step2

svc [name] nsap address

Specify the ATM SVC.

Step3

oam-svc manage 
[frequency]

Enable OAM management on the SVC.

Step4

oam retry up-count 
down-count retry-frequency

(Optional) Specify OAM management parameters for re-establishing and removing an SVC connection.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

If OAM management is enabled on SVCs and detects disconnection on an SVC, that SVC is torn down.

The up-count argument does not apply to SVCs, but it must be specified in order to configure the down-count and retry-frequency. Use the down-count argument to specify the number of consecutive end-to-end F5 OAM loopback cell responses that are not received in order to tear down an SVC. Use the retry-frequency argument to specify the frequency (in seconds) that end-to-end F5 OAM loopback cells should be transmitted when a change in UP/DOWN state is being verified. For example, if an SVC is up and a loopback cell response is not received after the frequency (in seconds) specified using the oam-svc command, then loopback cells are sent at the retry-frequency to verify whether or not the SVC is down.

For an example of configuring OAM management on an SVC, see the section "OAM Management on an ATM SVC Example" at the end of this chapter.

Configuring Classical IP and ARP over ATM

Ciscoimplements both the ATM Address Resolution Protocol (ARP) server and ATM ARP client functions described in RFC1577. RFC 1577 models an ATM network as a logical IP subnetwork on a LAN.

The tasks required to configure classical IP and ARP over ATM depend on whether the environment uses SVCs or PVCs.

Configuring Classical IP and ARP in an SVC Environment

The ATM ARP mechanism is applicable to networks that use SVCs. It requires a network administrator to configure only the device's own ATM address and that of a single ATM ARP server into each client device. When the client makes a connection to the ATM ARP server, the server sends ATM Inverse ARP requests to learn the IP network address and ATM address of the client on the network. It uses the addresses to resolve future ATM ARP requests from clients. Static configuration of the server is not required or needed.

In Cisco's implementation, the ATM ARP client tries to maintain a connection to the ATM ARP server. The ATM ARP server can tear down the connection, but the client attempts once each minute to bring the connection back up. No error messages are generated for a failed connection, but the client will not route packets until the ATM ARP server is connected and translates IP network addresses.

For each packet with an unknown IP address, the client sends an ATM ARP request to the server. Until that address is resolved, any IP packet routed to the ATM interface will cause the client to send another ATM ARP request. When the ARP server responds, the client opens a connection to the new destination so that any additional packets can be routed to it.

Ciscorouters may be configured as ATM ARP clients to work with any ATM ARP server conforming to RFC 1577. Alternatively, one of the Ciscorouters in a logical IP subnet (LIS) may be configured to act as the ATM ARP server itself. In this case, it automatically acts as a client as well. To configure classical IP and ARP in an SVC environment, perform the tasks in one of the following sections:

Configuring the Router as an ATM ARP Client

In an SVC environment, configure the ATM ARP mechanism on the interface by using the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0

or

interface atm slot/port-adapter/0

or

interface atm number

Specify the ATM interface using the appropriate format of the interfaceatmcommand.1

Step2

atm esi-address esi.selector

Specify the ATM address of the interface.

Step3

ip address address mask

Specify the IP address of the interface.

Step4

atm arp-server 
nsap nsap-address

Specify the ATM address of the ATM ARP server.

Step5

no shutdown

Enable the ATM interface.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

You can designate the current router interface as the ATM ARP server in Step 4 by typing self in place of nsap nsap-address.

To configure the ESI and selector fields in Step 2, the switch must be capable of delivering the NSAP address prefix to the router via ILMI and the router must be configured with a PVC for communication with the switch via ILMI. For a description of how to configure an ILMI PVC, refer to the section "Configuring Communication with the ILMI" earlier in this chapter.

For an example of configuring the ATM ARP client, see the section "Configuring ATM ARP Client in an SVC Environment Example" at the end of this chapter.

Configuring the Router as an ATM ARP Server

Cisco's implementation of the ATM ARP server supports a single, nonredundant server per logical IP subnetwork (LIS) and supports one ATM ARP server per subinterface. Thus, a single card can support multiple ARP servers by using multiple subinterfaces.

To configure the ATM ARP server, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0

or

interface atm slot/port-adapter/0

or

interface atm number

Specify the ATM interface using the appropriate format of the interfaceatmcommand.1

Step2

atm esi-address esi.selector

Specify the ATM address of the interface.

Step3

ip address address mask

Specify the IP address of the interface.

Step4

atm arp-server self

Identify the ATM ARP server for the IP subnetwork network.

Step5

no shutdown

Enable the ATM interface.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

To configure the ESI and selector fields in Step 2, the switch must be capable of delivering the NSAP address prefix to the router via ILMI and the router must be configured with a PVC for communication with the switch via ILMI. For a description of how to configure an ILMI PVC, refer to the section "Configuring Communication with the ILMI" earlier in this chapter.

For an example of configuring the ATM ARP server, see the section "Configuring ATM ARP Client in an SVC Environment Example" at the end of this chapter.

Configuring Classical IP and Inverse ARP in a PVC Environment

The ATM Inverse ARP mechanism is applicable to networks that use PVCs, where connections are established but the network addresses of the remote ends are not known. A server function is not used in this mode of operation.

In a PVC environment, the ATM Inverse ARP mechanism is enabled by default for IP and IPX when you use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0

or

interface atm slot/port-adapter/0

or

interface atm number

Specify the ATM interface using the appropriate format of the interface atm command.1

Step2

ip address address mask

Specify the IP address of the interface.

Step3

pvc [name] vpi/vci 

Create a PVC.

Step4

no shutdown

Enable the ATM interface.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

Repeat Step3 for each PVC you want to create.

By default, Inverse ARP datagrams will be sent on this virtual circuit every 15 minutes. To adjust the Inverse ARP time period, use the inarp minutes command in interface-ATM-VC configuration mode.


NoteThe ATM ARP mechanism works with IP only. The Inverse ATM ARP mechanism works with IP and IPX only. For all other protocols, the destination address must be specified.

For an example of configuring the ATM Inverse ARP mechanism, see the section "Configuring ATM Inverse ARP in a PVC Environment Example" at the end of this chapter.

Customizing the ATM Interface

You can customize the ATM interface. The features you can customize have default values that will most likely suit your environment and probably need not be changed. However, you might need to enter configuration commands, depending upon the requirements for your system configuration and the protocols you plan to route on the interface. To customize the ATM interface, perform the tasks in the following sections:

Configuring the Rate Queue

A rate queue defines the speed at which individual virtual circuits will transmit data to the remote end. You can configure permanent rate queues, allow the software to set up dynamic rate queues, or perform some combination of the two. The software dynamically creates rate queues when you create a VC with a peak rate that does not match any user-configured rate queue. The software dynamically creates all rate queues if you have not configured any.


NoteYou can only configure the rate queue for the AIP and NPM.

Using Dynamic Rate Queues

The CiscoIOS software automatically creates rate queues as necessary when you create a VC. If you do not configure traffic shaping on a VC, the peak rate of the VC is set to the UBR at the maximum peak rate that the physical layer interface module (PLIM) will allow. A rate queue is then dynamically created for the peak rate of that VC.

If dynamic rate queues do not satisfy your traffic shaping needs, you can configure permanent rate queues. Refer to the section "Configuring a Permanent Rate Queue" for more information.

See the section "Dynamic Rate Queue Examples" for example configurations of different rate queues.

Configuring Rate Queue Tolerance

To improve rate queue usage, you can configure a peak cell rate tolerance range for dynamically created rate queues. A PVC or SVC requesting a particular rate queue speed will be assigned to a rate queue that is within the range of the peak cell rate tolerance. If no such rate queue exists, a new rate queue is dynamically created on the ATM interface.

To configure a rate queue tolerance range for VCs on an ATM interface, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0

or

interface atm slot/port-adapter/0

or

interface atm number

Specify the ATM interface using the appropriate format of the interface atm command.1

Step2

atm rate-queue tolerance 
svc [pvc] tolerance-value 
[strict]

Configure a rate queue tolerance.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

The value for the tolerance-value argument is expressed as a percentage used for assigning rate queues for each VC with a requested peak rate. This value is applied to SVCs, discovered VCs, and PVCs (when the pvc keyword is used). This value can be 0 or 5 through 99. For SVCs and discovered VCs, the default value is 10. If the pvc keyword is not specified, the rate queue tolerance for PVCs will default to 0.

Configuring a Permanent Rate Queue

The supports up to eight different peak rates. The peak rate is the maximum rate, in kilobits per second, at which a virtual circuit can transmit. Once attached to this rate queue, the virtual circuit is assumed to have its peak rate set to that of the rate queue. The rate queues are broken into a high-priority (0 through 3) and low-priority (4 through 7) bank.

You can configure each permanent rate queue independently to a portion of the overall bandwidth available on the ATM link. The combined bandwidths of all rate queues should not exceed the total bandwidth available. The total bandwidth depends on the PLIM (see the "Interface Types" section in the "Wide-Area Networking Overview" chapter.)

To set a permanent rate queue, use the following command in interface configuration mode:

Command Purpose
atm rate-queue 
queue-number speed 

Configure a permanent rate queue, which defines the maximum speed at which an individual virtual circuit transmits data to a remote ATM host.

Configuring MTU Size

Each interface has a default maximum packet size or maximum transmission unit (MTU) size. For ATM interfaces, this number defaults to 4470 bytes. The maximum is 9188 bytes for the AIP and NPM, 17969 for the ATM port adapter, and 17998 for the ATM-CES port adapter. The MTU can be set on a per-sub-interface basis as long as the interface MTU is as large or larger than the largest subinterface MTU.

To set the maximum MTU size, use the following command in interface configuration mode:

Command Purpose
mtu bytes

Set the maximum MTU size.

Setting the SONET PLIM

The default SONET PLIM is STS-3C. To set the SONET PLIM to STM-1 or to set the PLIM framing for E3 or DS3, use one of the following commands in interface configuration mode:

Command Purpose
atm sonet stm-1

Set the OC-3c SONET PLIM to STM-1.

atm framing [cbitadm | 
cbitplcp | m23adm | m23plcp]

Set DS3 framing mode.

atm framing [g751adm | g832 adm | g751plcp]

Set E3 framing mode.

The default for DS3 is C-Bit ADM framing; the default for E3 is G.751 with PLCP framing.

Setting Loopback Mode

To loop all packets back to your ATM interface instead of the network, use the following command in interface configuration mode:

Command Purpose
loopback

Set loopback mode.

To loop the incoming network packets back to the ATM network, use the following command in interface configuration mode:

Command Purpose
loopback line

Set line loopback mode.

Setting the Exception Queue Length

The exception queue is used for reporting ATM events, such as CRC errors. By default, it holds 32entries; the range is 8 to 256. It is unlikely that you will need to configure the exception queue length; if you do, use the following command in interface configuration mode:

Command Purpose
atm exception-queue 
number

Set the exception queue length.


NoteThis command is supported only on the AIP.

Configuring the Maximum Number of Channels

The atm max-channels command, available if you are using the ATM-CES port adapter, can be used to divide the available number (fixed) of transmit descriptors across the configured number of transmit channels. Typically, you think of a one-to-one association between a transmit channel and a VC; however, the ATM-CES port adapter supports types of VCs other than data VCs (for example CES VCs). Also, the ATM-CES port adapter can multiplex one or more VCs over a single virtual path (VP) that is shaped, and the VP only requires a single transmit channel. Therefore, the term transmit channel is used rather than virtual circuit.

The maximum burst of packets that are allowed per VC is limited by the number of transmit descriptors allocated per VC. Because the total number of transmit descriptors available is limited by the available SRAM space, configuration of the number of transmit channels for the interface determines the number of transmit descriptors for each transmit channel. Hence the burst size for each transmit channel is determined by the atm max-channels command. For example, for 64 (default) numbers of transmit channels for the interface, 255 transmit descriptors are associated per transmit channel and for 512 numbers of transmit channels for the interface, 31 transmit descriptors are associated per transmit channel.

To configure the maximum number of transmit channels for the interface, use the following command in interface configuration mode:

Command Purpose
atm max-channels 
number

Configure the maximum number of transmit channels.


NoteThis command is available only on the ATM-CES port adapter.

Limiting the Number of Virtual Circuits

By default, the ATM interface allows the maximum of 2048 virtual circuits. However, you can configure a lower number, thereby limiting the number of virtual circuits on which your ATM interface allows segmentation and reassembly to occur. Limiting the number of virtual circuits does not affect the VPI-VCI pair of each virtual circuit.

To set the maximum number of virtual circuits supported (including PVCs and SVCs), use the following command in interface configuration mode:

Command Purpose
atm maxvc number

Limit the number of virtual circuits.


NoteThis command is not supported on the ATM-CES port adapter or the NPM.

Setting the Raw-Queue Size

The raw queue is used for raw ATM cells, which include operation, administration, and maintenance (OAM) and Interim Local Management Interface (ILMI) cells. ILMI is a means of passing information to the router, including information about virtual connections and addresses.The raw-queue size is in the range of 8 to 256 cells; the default is 32 cells.

To set the raw-queue size, use the following command in interface configuration mode:

Command Purpose
atm rawq-size 
number

Set the raw-queue size.


NoteThis command is supported only on the AIP.

Configuring Buffer Size

The number of receive buffers determines the maximum number of reassemblies that your ATM interface can perform simultaneously. The number of buffers defaults to 256, although it can be in the range from 0 to 512.

To set the number of receive buffers, use the following command in interface configuration mode:

Command Purpose
atm rxbuff 
number

Set the number of receive buffers.

The number of transmit buffers determines the maximum number of fragmentations that your ATM interface can perform simultaneously. The number of buffers defaults to 256, although it can be in the range from 0 to 512.

To set the number of transmit buffers, use the following command in interface configuration mode:

Command Purpose
atm txbuff 
number

Set the number of transmit buffers.


NoteThe commands in this section are not supported on the ATM-CES port adapter or NPM.

Setting the VCI-to-VPI Ratio

By default, the ATM interface supports 1024 VCIs per VPI. Depending on what ATM interface card or port adapter you are using, this value can be any power of 2 in the range of 16 to 8192. (See the atm vc-per-vp command in the Cisco IOS Wide-Area Networking Command Reference for the exact values that apply to your configuration.) This value controls the memory allocation on your ATM interface that deals with the VCI table. It defines only the maximum number of VCIs to support per VPI.

To set the maximum number of VCIs to support per VPI and limit the highest VCI accordingly, use the following command in interface configuration mode:

Command Purpose
atm vc-per-vp 
number

Set the number of VCIs per VPI.

Setting the Source of the Transmit Clock

By default, your ATM interface expects the ATM switch to provide transmit clocking. To specify that the ATM interface generates the transmit clock internally for SONET and E3 PLIM operation, use the following command in interface configuration mode:

Command Purpose
atm clock 
internal

Specify that the generate the transmit clock internally.

Configuring ATM Subinterfaces for SMDS Networks

An ATM adaptation layer (AAL) defines the conversion of user information into cells by segmenting upper-layer information into cells at the transmitter and reassembling them at the receiver. AAL1 and AAL2 handle isochronous traffic, such as voice and video, and are not relevant to the router. AAL3/4 and AAL5 support data communications by segmenting and reassembling packets. Beginning in CiscoIOS Release10.2, we support both AAL3/4 and AAL5.

Our implementation of the AAL3/4 encapsulates each AAL3/4 packet in a Switched Multimegabit Data Service (SMDS) header and trailer. This feature supports both unicast and multicast addressing, and provides subinterfaces for multiple AAL3/4 connections over the same physical interface.


NoteEach subinterface configured to support AAL3/4 is allowed only one SMDS E.164 unicast address and one E.164 multicast address. The multicast address is used for all broadcast operations. In addition, only one virtual circuit is allowed on each subinterface that is being used for AAL3/4 processing, and it must be an AAL3/4 virtual circuit.

Support for AAL3/4 on an ATM interface requires static mapping of all protocols except IP. However, dynamic routing of IP can coexist with static mapping of other protocols on the same ATM interface.

To configure an ATM interface for SMDS networks, use the following commands in interface configuration mode:

Command Purpose

Step1

atm aal aal3/4

Enable AAL3/4 support on the affected ATM subinterface.

Step2

atm smds-address address

Provide an SMDS E.164 unicast address for the subinterface.

Step3

atm multicast address

Provide an SMDS E.164 multicast address.

Step4

atm vp-filter hexvalue

Configure a virtual path filter for the affected ATM subinterface.

Step5

pvc [name] vpi/vci smds

Create an AAL3/4 PVC.


NoteATM subinterfaces for SMDS networks are only supported on the AIP and NPM.

The virtual path filter provides a mechanism for specifying which VPIs (or a range of VPIs) will be used for AAL3/4 processing during datagram reassembly. All other VPIs are mapped to AAL5 processing. For more information about the way the atm vp-filter command works and the effect of selecting specific values, refer to the Cisco IOS Wide-Area Networking Command Reference.

After configuring the ATM interface for SMDS networks, configure the interface for standard protocol configurations, as needed. For more information about protocol configuration, refer to the relevant chapters of the CiscoIOSIPandIPRoutingConfigurationGuide, the CiscoIOSAppletalkandNovellIPXConfigurationGuide, and the CiscoIOSApolloDomain,BanyanVINES,DECnet,ISOCLNS,andXNSConfiguration Guide, for CiscoIOS Release12.1.

For examples of configuring an ATM interface for AAL3/4 support, see the section "PVC with AAL3/4 and SMDS Encapsulation Examples" at the end of this chapter.

Limiting the Message Identifiers Allowed on Virtual Circuits

Message identifier (MID) numbers are used by receiving devices to reassemble cells from multiple sources into packets.

To ensure that the message identifiers are unique at the receiving end and, therefore, that messages can be reassembled correctly, you can limit the number of message identifiers allowed on a virtual circuit and assign different ranges of message identifiers to different PVCs.

To limit the number of message identifier numbers allowed on each virtual circuit and to assign different ranges of message identifiers to different PVCs, use the following commands beginning in interface configuration mode:

Command Purpose

Step1

atm 
mid-per-vc 
maximum

Limit the number of message identifiers allowed per virtual circuit.

Step2

pvc [name] vpi/vci smds

Create an ATM PVC with SMDS encapsulation.

Step3

mid midlow 
midhigh

Limit the range of message identifier values used on the PVC.

The maximum number of message identifiers per virtual circuit is set at 16 by default; valid values are 16, 32, 64, 128, 256, 512, or 1024.

The default value for both the midlow and the midhigh arguments is zero.

Setting the Virtual Path Filter Register

The virtual path filter allows you to specify which VPI or range of VPIs will be used for AAL3/4 processing. The default value of the's virtual path filter register is 0x7B. To set the virtual path filter register, use the following command in interface configuration mode:

Command Purpose
atm vp-filter 
hexvalue

Set the virtual path filter register.

Configuring Fast-Switched Transparent Bridging for SNAP PVCs

The implementation of transparent bridging over ATM allows the spanning tree for an interface to support virtual circuit descriptors (VCDs) for AAL5-LLC Subnetwork Access Protocol (SNAP) encapsulations.

If the relevant interface or subinterface is explicitly put into a bridge group, as described in the task table below, AAL5-SNAP encapsulated bridge packets on a PVC are fast-switched.

The bridging implementation supports IEEE 802.3 frame formats and IEEE 802.10 frame formats. The router can accept IEEE802.3 frames with or without frame check sequence (FCS). When the router receives frames with FCS (RFC1483 bridge frame formats with 0x0001 in the PID field of the SNAP header), it strips off the FCS and forwards the frame as necessary. All IEEE 802.3 frames that originate at or are forwarded by the router are sent as 802.3 bridge frames without FCS (bridge frame formats with 0x0007 in the PID field of the SNAP header).


NoteTransparent bridging for the ATM works only on AAL5-LLC/SNAP PVCs (fast-switched). AAL3/4-SMDS, AAL5-MUX, and AAL5-NLPID bridging are not yet supported. Transparent bridging for ATM also does not operate in a switched virtual circuit (SVC) environment.

To configure transparent bridging for LLC/SNAP PVCs, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0[.subinterface-number 
{multipoint | point-to-point}

or

interface atm 
slot/port-adapter/0[.subinterface-number {multipoint 
| point-to-point}]

or

interface atm number[.subinterface-number 
{multipoint | point-to-point}]

Specify the ATM interface using the appropriate format of the interfaceatmcommand.1

Step2

pvc [name] vpi/vci

Create one or more PVCs using AAL5-SNAP encapsulation. Repeat this command as needed.

Step3

exit

Return to interface configuration mode.

Step4

bridge-group group

Assign the interface to a bridge group.

Step5

exit

Return to global configuration mode.

Step6

bridge group protocol dec

Define the type of spanning tree protocol as DEC.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

No other configuration is required. Spanning tree updates are broadcast to all AAL5-SNAP virtual circuits that exist on the ATM interface. Only the AAL5-SNAP virtual circuits on the specific subinterface receive the updates. The router does not send spanning tree updates to AAL5-MUX and AAL5-NLPID virtual circuits.

For an example of transparent bridging for an AAL5-SNAP PVC, see the section "Transparent Bridging on an AAL5-SNAP PVC Example" at the end of this chapter.

Configuring Inverse Multiplexing over ATM

Inverse multiplexing provides the capability to transmit and receive a single high-speed data stream over multiple slower-speed physical links. In inverse multiplexing over ATM (IMA), the originating stream of ATM cells is divided so that complete ATM cells are transmitted in round-robin order across the set of ATM links.

ATM T1 and E1 IMA network modules provide four or eight T1 or E1 ports with inverse multiplexing capability. These modules allow wide-area networking (WAN) uplinks at speeds ranging from 1.536Mbps to 12.288 Mbps for T1, and from 1.92 Mbps to 15.36 Mbps for E1. See the "Bandwidth Considerations".

Cisco's scalable ATM IMA solution means that you can deploy just the bandwidth you need by using multiple E1 or T1 connections instead of a more expensive E3, T3, or OC-3 to bridge between LANs and ATM WAN applications. Enterprises and branch offices can aggregate traffic from multiple low-bandwidth digital physical transmission media, such as T1 pipes, to transmit voice and data at high-bandwidth connection speeds. For example, Figure 3 illustrates a scenario where an organization must transport a mission-critical application among headquarters and branch offices at6 Mbps.


Figure3: LAN-to-WAN Application Connectivity with T1 and IMA


The following sections provide more specific information about IMA and how to configure it:

IMA Protocol Overview

In the transmit direction, IMA takes cells from the ATM layer and sends them in a round-robin order over the individual links that make up a logical link group called an IMA group (links can also be used individually instead of being the member or a group). The IMA group performance is approximately the sum of the links, although some overhead is required for ATM control cells. At the receiving end, the cells are recombined to form the original cell stream and are passed up to the ATM layer.

Filler cells are used to ensure a steady stream on the receiving side. IMA control protocol (ICP) cells control the operation of the inverse multiplexing function. Using a frame length of 128, one out of every 128 cells on each link is an ICP cell. The inverse multiplexing operation is transparent to the ATM layer protocols; therefore, the ATM layer can operate normally as if only a single physical interface were being used.

Figure 4 illustrates inverse multiplexing and demultiplexing with four bundled links, providing 6.144Mbps of bandwidth for T1s and 7.68 Mbps of bandwidth for E1 for packet traffic. The transmit side, where cells are distributed across the links, is referred to as Tx, and the receive side, where cells are recombined, is called Rx.


Figure4: Inverse Multiplexing and Demultiplexing


General Description of ATM T1/E1 IMA

ATM networks were designed to handle the demanding performance needs of voice, video, and data at broadband speeds of 34 Mbps and above. However, the high cost and spotty availability of long-distance broadband links limits broadband ATM WANs, preventing many organizations from taking advantage of ATM's power. In response to these issues, the ATM Forum defined lower-speed ATM interface options for T1 and E1. However, this was not a complete solution because a single T1 or E1 link often does not provide enough bandwidth to support either traffic among different router and switch locations or heavy end-user demand.

For this reason, many organizations find themselves caught between the bandwidth limitations of a narrowband T1 or E1 line and the much higher costs of moving to broadband links. In response to this dilemma, the ATM Forum, with Cisco as an active member, defined Inverse Multiplexing for ATM (IMA). Using Cisco 2600 and 3600 series routers to provide ATM access gives branch offices and enterprises an affordable LAN-to-ATM interface.

For a list of ATM features that are supported on the Cisco 2600 and 3600 series routers when you use IMA, see the "Cisco ATM Features" section of the "Wide-Area Networking Overview" chapter in this book.

Configuring IMA

The following sections describe the configuration and verification tasks required to set up ATM IMA groups. You can also configure ATM links individually, but these sections only include the steps for configuring IMA groups. To configure and verify IMA groups on an ATM interface, complete the tasks described in the following sections:

Configuring an ATM Interface for IMA Operation

To configure an ATM interface for IMA operation, use the following commands beginning in global configuration mode:

Command Purpose

Step1

Router(config)# interface atm slot/port

Enters interface configuration mode and specifies the location of the interface.

Step2

Router(config-if)# clock source {line | internal |
loop-timed}

Sets the clock source for a link.

Step3

Router(config-if)# cablelength long {gain26 | 
gain36} {-15db | -22.5db | -7.5db | 0db}

or

Router(config-if)# cablelength short {133 | 266 | 
399 | 533 | 655}

(T1 interfaces only) Sets a cable length longer than 655feet.

(T1 interfaces only) Sets the cable length shorter than 655feet.

Step4

Router(config-if)# no ip address

Disables ip address configuration for the physical layer interface. This and other protocol parameters should be configured on the IMA interface instead of the T1/E1 interface.

Step5

Router(config-if)# no scrambling payload

Randomizes the ATM cell payload frames to avoid continuous non-variable bit patterns and improves the efficiency of ATM's cell delineation algorithms. By default, payload scrambling is on for E1 links and off for T1 links. Normally, the default setting for this command is sufficient.

Step6

Router(config-if)# impedance {75-ohm |120-ohm}

(E1 interfaces only) Specifies the impedance (amount of wire resistance and reactivity to current) for the E1 link. The impedance is determined by the dongle-type cable that you plug in to the IMA module.

Step7

Router(config-if)# loopback [line | local | payload 
| remote]

(For testing only) Loops all packets from the ATM interface back to the interface and directs the packets to the network.

Step8

Router(config-if)# fdl {att | ansi | all | none}

(Optional, T1 only) Sets the Facility Data Link (FDL) exchange standard for the CSU controllers. The FDL is a 4-Kpbs channel used with the Extended SuperFrame (ESF) framing format to provide out-of-band messaging for error-checking on a T1 link.


NoteFor T1, ESF framing and binary eight zero substitution (B8ZS) line encoding are set. For E1, CRC4 multiframe framing and HDB3 line encoding are set. These are the parameters specified by the ATM Forum, and they cannot be changed.

You should generally leave this setting at the default, ansi, which follows the ANSI T1.403 standard for extended superframe facilities data link exchange support. Changing it allows improved management in some cases but can cause problems if your setting is not compatible with that of your service provider.

Step9

Router(config-if)# ima-group 
group-number

Specifies that the link is included in an IMA group. Enter an IMA group number from 0 to 3. You can specify up to four groups for each IMA network module. IMA groups usually span multiple ports on a module.

Step10

Router(config-if)# no shutdown

Ensures that the link is active at the IMA level. If shut down, the link is added to the group but put in an inhibited state.

Verifying an ATM Interface Configured for IMA Operation

Follow the steps below to verify the configuration of an ATM interface.


Step 1 Enter the show interface atm command to verify the configuration of an ATM interface. In the examples below, important information appears in bold. Notice that the total count of configured virtual circuits (VCs) is shown.

router# show interface atm 0/1
ATM0/1 is up, line protocol is up
  Hardware is ATM T1
  Internet address is 21.1.1.2/8
  MTU 4470 bytes, sub MTU 4470, BW 1500 Kbit, DLY 20000 usec,
     reliability 0/255, txload 1/255, rxload 1/255
  Encapsulation ATM, loopback not set
  Keepalive not supported
  Encapsulation(s): AAL5
256 maximum active VCs, 3 current VCCs
  VC idle disconnect time: 300 seconds
  Last input never, output never, output hang never
  Last clearing of "show interface" counters never
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 collisions, 3 interface resets
     0 output buffer failures, 0 output buffers swapped out
 

Step 2 To get information about the physical link, enter the show controller atm command.

router# show controller atm0/2
Interface ATM0/2 is administratively down
  Hardware is ATM T1
LANE client MAC address is 0050.0f0c.1482
  hwidb=0x617BEE9C, ds=0x617D498C
  slot 0, unit 2, subunit 2
  rs8234 base 0x3C000000, slave base 0x3C000000
  rs8234 ds 0x617D498C
  SBDs - avail 2048, guaranteed 2, unguaranteed 2046, starved 0
 Seg VCC table 3C00B800, Shadow Seg VCC Table 617EF76C, VCD Table 61805798
 Schedule table 3C016800, Shadow Schedule table 618087C4, Size 63D
 RSM VCC Table 3C02ED80, Shadow RSM VCC Table 6180C994
 VPI Index Table 3C02C300, VCI Index Table 3C02E980
 Bucket2 Table 3C01E500, Shadow Bucket2 Table 6180A0E4
 MCR Limit Table 3C01E900, Shadow MCR Table 617D2160
 ABR template 3C01EB00, Shadow template 614DEEAC
 RM Cell RS Queue 3C02C980
 Queue           TXQ Addr  Pos  StQ Addr  Pos
 0  UBR CHN0     3C028B00  0    03118540  0
 1  UBR CHN1     3C028F00  0    03118D40  0
 2  UBR CHN2     3C029300  0    03119540  0
 3  UBR CHN3     3C029700  0    03119D40  0
 4  VBR/ABR CHN0 3C029B00  0    0311A540  0
 5  VBR/ABR CHN1 3C029F00  0    0311AD40  0
 6  VBR/ABR CHN2 3C02A300  0    0311B540  0
 7  VBR/ABR CHN3 3C02A700  0    0311BD40  0
 8  VBR-RT CHN0  3C02AB00  0    0311C540  0
 9  VBR-RT CHN1  3C02AF00  0    0311CD40  0
 10 VBR-RT CHN2  3C02B300  0    0311D540  0
 11 VBR-RT CHN3  3C02B700  0    0311DD40  0
 12 SIG          3C02BB00  0    0311E540  0
 13 VPD          3C02BF00  0    0311ED40  0
 
 Queue           FBQ Addr  Pos  RSQ Addr  Pos
 0  OAM          3C0EED80  255  0311F600  0
 1  UBR CHN0     3C0EFD80  0    03120600  0
 2  UBR CHN1     3C0F0D80  0    03121600  0
 3  UBR CHN2     3C0F1D80  0    03122600  0
 4  UBR CHN3     3C0F2D80  0    03123600  0
 5  VBR/ABR CHN0 3C0F3D80  0    03124600  0
 6  VBR/ABR CHN1 3C0F4D80  0    03125600  0
 7  VBR/ABR CHN2 3C0F5D80  0    03126600  0
 8  VBR/ABR CHN3 3C0F6D80  0    03127600  0
 9  VBR-RT CHN0  3C0F7D80  0    03128600  0
 10 VBR-RT CHN1  3C0F8D80  0    03129600  0
 11 VBR-RT CHN2  3C0F9D80  0    0312A600  0
 12 VBR-RT CHN3  3C0FAD80  0    0312B600  0
 13 SIG          3C0FBD80  255  0312C600  0
SAR Scheduling channels:  -1 -1 -1 -1 -1 -1 -1 -1
Part of IMA group 3
Link 2 IMA Info:
   group index is 1
   Tx link id is 2, Tx link state is unusableNoGivenReason
   Rx link id is 99, Rx link state is unusableFault
    Rx link failure status is fault,
    0 tx failures, 3 rx failures
Link 2 Framer Info:
    framing is ESF, line code is B8ZS, fdl is ANSI
    cable-length is long, Rcv gain is 26db and Tx gain is 0db,
    clock src is line, payload-scrambling is disabled, no loopback
    line status is 0x1064; or Tx RAI, Rx LOF, Rx LOS, Rx LCD.
    port is active, link is unavailable
    0 idle rx, 0 correctable hec rx, 0 uncorrectable hec rx
    0 cells rx, 599708004 cells tx, 0 rx fifo overrun.
Link (2):DS1 MIB DATA:
  Data in current interval (518 seconds elapsed):
     0 Line Code Violations, 0 Path Code Violations
     0 Slip Secs, 518 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 519 Unavail Secs
  Total Data (last 24 hours)
     0 Line Code Violations, 0 Path Code Violations,
     0 Slip Secs, 86400 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 86400 Unavail Secs
SAR counter totals across all links and groups:
   0 cells output, 0 cells stripped
   0 cells input, 0 cells discarded, 0 AAL5 frames discarded
   0 pci bus err, 0 dma fifo full err, 0 rsm parity err
   0 rsm syn err, 0 rsm/seg q full err, 0 rsm overflow err
   0 hs q full err, 0 no free buff q err, 0 seg underflow err
   0 host seg stat q full err

Configuring IMA Groups

As shown in the previous section, the ima-group command configures links on an ATM interface as IMA group members. When IMA groups have been set up in this way, you can configure settings for each group. To configure IMA groups and settings for each group, use the following commands beginning in global configuration mode:

Command Purpose

Step1

Router(config)# interface atm slot/imagroup-number

Enters interface configuration mode and specifies the slot location of the interface and IMA group number.

Step2

Router(config-if)# ip address ip-address

Sets protocol parameters for the whole group.

Step3

Router(config-if)# no atm oversubscribe

Enables the ATM bandwidth manager which keeps track of bandwidth used by virtual circuits on a per-interface basis. This is useful because many services, such as ABR and VBR-RT, require guaranteed bandwidth. When you specify the no form of the command, a check determines whether the ATM link is already oversubscribed. If it is, the command is rejected. Otherwise, the total bandwidth available on the link is recorded and all future connection setup requests are monitored to ensure that the link is not oversubscribed.

Step4

Router(config-if)# pvc [name] vpi/vci ilmi

Creates an ATM PVC for ILMI management purposes and enters Interface-ATM-VC configuration mode.

Step5

Router(config-if-atm-vc)# exit

Exits Interface-ATM-VC configuration mode.

Step6

Router(config-if)# pvc [name] vpi/vci

Enables a PVC.

Step7

Router(config-if-atm-vc)# protocol ip address 
broadcast

Specifies a protocol address for the PVC.


NoteThe default AAL5 layer and SNAP encapsulation is used in this example, so the encapsulation aal5encap command is unnecessary.

Step8

Router(config-if-atm-vc)# vbr-rt peak-rate 
average-rate burst

Configures a type of ATM service on the PVC. This example uses Variable Bit Rate, real-time, for AAL5 communications, allowing you to set different cell rate parameters for connections where there is a fixed timing relationship among samples. (VBR is generally used with AAL5 and IP over ATM.) The command configures traffic shaping, so that the carrier does not discard calls. Configures the burst value if the PVC will carry bursty traffic.

Step9

Router(config-if-atm-vc)# exit

Exits Interface-ATM-VC configuration mode and returns to interface configuration mode.

Step10

Router(config-if)# ima 
clock-mode {common [port] |
independent}

Sets the transmit clock mode for the group.

Step11

Router(config-if)# ima 
active-links-minimum number

Specifies how many transmit links must be active in order for the IMA group to be operational.

Step12

Router(config-if)# ima 
differential-delay-maximum msec

Specifies the maximum allowed differential timing delay that can exist among the active links in an IMA group.

Step13

Router(config-if)# ima test 
[link port]
[pattern pattern-id]

Starts the IMA link test procedure with the specified link and pattern.

For examples of configuring IMA groups, see the sections "E1 Inverse Multiplexing over ATM Example" and "T1 Inverse Multiplexing over ATM Example" at the end of this chapter.

Verifying IMA Group Configuration


Step 1 Enter the show ima interface atm command to get information about IMA group interfaces. In the examples below, important information is shown in bold. The first example shows the command output without the detail keyword; the second example shows the detailed information.

Router# show ima interface atm2/ima2
Interface ATM2/IMA2 is up
        Group index is 2
        Ne state is operational, failure status is noFailure
        active links bitmap 0x30
    IMA Group Current Configuration:
        Tx/Rx configured links bitmap 0x30/0x30
        Tx/Rx minimum required links 1/1
        Maximum allowed diff delay is 25ms, Tx frame length 128
        Ne Tx clock mode CTC, configured timing reference link ATM2/4
        Test pattern procedure is disabled
    IMA Group Current Counters (time elapsed 12 seconds):
        3 Ne Failures, 3 Fe Failures, 4 Unavail Secs
    IMA Group Total Counters (last 0 15 minute intervals):
        0 Ne Failures, 0 Fe Failures, 0 Unavail Secs
    IMA link Information:
        Link     Physical Status        NearEnd Rx Status      Test Status 
        ----     ---------------        -----------------      ----------- 
        ATM2/4   up                     active                 disabled    
        ATM2/5   up                     active                 disabled    
 
router# show ima interface atm2/ima2 detail 
Interface ATM2/IMA2 is up
        Group index is 2
        Ne state is operational, failure status is noFailure
        active links bitmap 0x30
    IMA Group Current Configuration:
        Tx/Rx configured links bitmap 0x30/0x30
        Tx/Rx minimum required links 1/1
        Maximum allowed diff delay is 25ms, Tx frame length 128
        Ne Tx clock mode CTC, configured timing reference link ATM2/4
        Test pattern procedure is disabled
    Detailed group Information:
        Tx/Rx Ima_id 0x22/0x40, symmetry symmetricOperation
        Number of Tx/Rx configured links 2/2
        Number of Tx/Rx active links 2/2
        Fe Tx clock mode ctc, Rx frame length 128
        Tx/Rx timing reference link 4/4
        Maximum observed diff delay 0ms, least delayed link 5
        Running seconds 32
        GTSM last changed 10:14:41 UTC Wed Jun 16 1999
    IMA Group Current Counters (time elapsed 33 seconds):
        3 Ne Failures, 3 Fe Failures, 4 Unavail Secs
    IMA Group Total Counters (last 0 15 minute intervals):
        0 Ne Failures, 0 Fe Failures, 0 Unavail Secs
    Detailed IMA link Information:
 
Interface ATM2/4 is up
        ifIndex 13, Group Index 2, Row Status is active
        Tx/Rx Lid 4/4, relative delay 0ms
        Ne Tx/Rx state active/active
        Fe Tx/Rx state active/active
        Ne Rx failure status is noFailure
        Fe Rx failure status is noFailure
        Rx test pattern 0x41, test procedure disabled
    IMA Link Current Counters (time elapsed 35 seconds):
        1 Ima Violations, 0 Oif Anomalies
        1 Ne Severely Err Secs, 2 Fe Severely Err Secs
        0 Ne Unavail Secs, 0 Fe Unavail Secs
        2 Ne Tx Unusable Secs, 2 Ne Rx Unusable Secs
        0 Fe Tx Unusable Secs, 2 Fe Rx Unusable Secs
        0 Ne Tx Failures, 0 Ne Rx Failures
        0 Fe Tx Failures, 0 Fe Rx Failures
    IMA Link Total Counters (last 0 15 minute intervals):
        0 Ima Violations, 0 Oif Anomalies
        0 Ne Severely Err Secs, 0 Fe Severely Err Secs
        0 Ne Unavail Secs, 0 Fe Unavail Secs
        0 Ne Tx Unusable Secs, 0 Ne Rx Unusable Secs
        0 Fe Tx Unusable Secs, 0 Fe Rx Unusable Secs
        0 Ne Tx Failures, 0 Ne Rx Failures
        0 Fe Tx Failures, 0 Fe Rx Failures
 
Interface ATM2/5 is up
        ifIndex 14, Group Index 2, Row Status is active
        Tx/Rx Lid 5/5, relative delay 0ms
        Ne Tx/Rx state active/active
        Fe Tx/Rx state active/active
        Ne Rx failure status is noFailure
        Fe Rx failure status is noFailure
        Rx test pattern 0x41, test procedure disabled
    IMA Link Current Counters (time elapsed 46 seconds):
        1 Ima Violations, 0 Oif Anomalies
        1 Ne Severely Err Secs, 2 Fe Severely Err Secs
        0 Ne Unavail Secs, 0 Fe Unavail Secs
        2 Ne Tx Unusable Secs, 2 Ne Rx Unusable Secs
        0 Fe Tx Unusable Secs, 2 Fe Rx Unusable Secs
        0 Ne Tx Failures, 0 Ne Rx Failures
        0 Fe Tx Failures, 0 Fe Rx Failures
    IMA Link Total Counters (last 0 15 minute intervals):
        0 Ima Violations, 0 Oif Anomalies
        0 Ne Severely Err Secs, 0 Fe Severely Err Secs
        0 Ne Unavail Secs, 0 Fe Unavail Secs
        0 Ne Tx Unusable Secs, 0 Ne Rx Unusable Secs
        0 Fe Tx Unusable Secs, 0 Fe Rx Unusable Secs
        0 Ne Tx Failures, 0 Ne Rx Failures
        0 Fe Tx Failures, 0 Fe Rx Failures
 

Step 2 To review physical level information about the IMA group, enter the show controllers atm command in privileged EXEC mode, as shown in the following example:

router# show controllers atm0/ima3
Interface ATM0/IMA3 is up
  Hardware is ATM IMA
  LANE client MAC address is 0050.0f0c.148b
  hwidb=0x61C2E990, ds=0x617D498C
  slot 0, unit 3, subunit 3
  rs8234 base 0x3C000000, slave base 0x3C000000
  rs8234 ds 0x617D498C
  SBDs - avail 2048, guaranteed 3, unguaranteed 2045, starved 0
 Seg VCC table 3C00B800, Shadow Seg VCC Table 617EF76C, VCD Table 61805798
 Schedule table 3C016800, Shadow Schedule table 618087C4, Size 63D
 RSM VCC Table 3C02ED80, Shadow RSM VCC Table 6180C994
 VPI Index Table 3C02C300, VCI Index Table 3C02E980
 Bucket2 Table 3C01E500, Shadow Bucket2 Table 6180A0E4
 MCR Limit Table 3C01E900, Shadow MCR Table 617D2160
 ABR template 3C01EB00, Shadow template 614DEEAC
 RM Cell RS Queue 3C02C980
 Queue           TXQ Addr  Pos  StQ Addr  Pos
 0  UBR CHN0     3C028B00  0    03118540  0
 1  UBR CHN1     3C028F00  0    03118D40  0
 2  UBR CHN2     3C029300  0    03119540  0
 3  UBR CHN3     3C029700  0    03119D40  0
 4  VBR/ABR CHN0 3C029B00  0    0311A540  0
 5  VBR/ABR CHN1 3C029F00  0    0311AD40  0
 6  VBR/ABR CHN2 3C02A300  0    0311B540  0
 7  VBR/ABR CHN3 3C02A700  0    0311BD40  0
 8  VBR-RT CHN0  3C02AB00  0    0311C540  0
 9  VBR-RT CHN1  3C02AF00  0    0311CD40  0
 10 VBR-RT CHN2  3C02B300  0    0311D540  0
 11 VBR-RT CHN3  3C02B700  0    0311DD40  0
 12 SIG          3C02BB00  0    0311E540  0
 13 VPD          3C02BF00  0    0311ED40  0
 
 Queue           FBQ Addr  Pos  RSQ Addr  Pos
 0  OAM          3C0EED80  255  0311F600  0
 1  UBR CHN0     3C0EFD80  0    03120600  0
 2  UBR CHN1     3C0F0D80  0    03121600  0
 3  UBR CHN2     3C0F1D80  0    03122600  0
 4  UBR CHN3     3C0F2D80  0    03123600  0
 5  VBR/ABR CHN0 3C0F3D80  0    03124600  0
 6  VBR/ABR CHN1 3C0F4D80  0    03125600  0
 7  VBR/ABR CHN2 3C0F5D80  0    03126600  0
 8  VBR/ABR CHN3 3C0F6D80  0    03127600  0
 9  VBR-RT CHN0  3C0F7D80  0    03128600  0
 10 VBR-RT CHN1  3C0F8D80  255  03129600  0
 11 VBR-RT CHN2  3C0F9D80  0    0312A600  0
 12 VBR-RT CHN3  3C0FAD80  0    0312B600  0
 13 SIG          3C0FBD80  255  0312C600  0
SAR Scheduling channels:  -1 -1 -1 -1 -1 -1 -1 -1
ATM channel number is 1
link members are 0x7, active links are 0x0
Group status is blockedNe, 3 links configured,
Group Info: Configured links bitmap 0x7, Active links bitmap 0x0,
    Tx/Rx IMA_id 0x3/0x63,
    NE Group status is startUp,
    frame length 0x80, Max Diff Delay 0,
    1 min links, clock mode ctc, symmetry symmetricOperation, trl 0,
    Group Failure status is startUpNe.
    Test pattern procedure is disabled
SAR counter totals across all links and groups:
   0 cells output, 0 cells stripped
   0 cells input, 0 cells discarded, 0 AAL5 frames discarded
   0 pci bus err, 0 dma fifo full err, 0 rsm parity err
   0 rsm syn err, 0 rsm/seg q full err, 0 rsm overflow err
   0 hs q full err, 0 no free buff q err, 0 seg underflow err
   0 host seg stat q full err
 

Step 3 Enter the privileged EXEC show atm vc command to see how SVCs and PVCs are set up.

 VCD /                                      Peak  Avg/Min Burst
Interface   Name       VPI   VCI  Type   Encaps   SC   Kbps   Kbps   Cells  Sts
0/1        1            0    50   PVC    SNAP     UBR    1000              INAC
0/IMA3     2            0     5   PVC    SAAL     UBR    4000                UP
0/IMA3     3            0    16   PVC    ILMI     UBR    4000                UP
0/IMA3     first        1    13   PVC    MUX      VBR     640    320   80    UP
0/IMA3     4            0    34   SVC    SNAP     VBR-RT  768    768 UP

Troubleshooting Tips

To troubleshoot the ATM and IMA group configuration, enter the ping command that checks host reachability and network connectivity. This command can confirm basic network connectivity on AppleTalk, ISO CLNS, IP, Novell, Apollo, VINES, DECnet, or XNS networks.

For IP, the ping command sends ICMP (Internet Control Message Protocol) Echo messages. If a station receives an ICMP Echo message, it sends an ICMP Echo Reply message back to the source.

The extended command mode of the ping command permits you to specify the supported IP header options, so that the router can perform a more extensive range of test options. To enter ping extended command mode, enter yes at the extended commands prompt of the ping command.

For detailed information on using the ping and extended ping commands, see the Cisco IOS Configuration Fundamentals Command Reference.

If a ping command fails, check the following possible reasons for the connectivity problem:


TipsUse the ping command when the network is functioning properly to see how the command works under normal conditions and so that you can compare the results when troubleshooting.

If a communication session is closing when it should not be, an end-to-end connection problem can be the cause. The debug ip packet command is useful for analyzing the messages traveling between the local and remote hosts. IP debugging information includes packets received, generated, and forwarded. Because the debug ip packet command generates a significant amount of output, use it only when traffic on the IP network is low, so other activity on the system is not adversely affected.

Bandwidth Considerations

When planning IMA groups and payload bandwidth requirements, consider the overhead required for ATM cell headers, service-layer encapsulation such as RFC 1483, AAL5 encapsulation, and ICP cells. Table 3 and Table 4 show approximate values for T1 and E1 IMA groups, respectively with a frame length of 128, estimating ATM overhead at about 10 percent. The effective payload bandwidth varies based on packet size because the packets must be divided into an integer number of ATM cells leaving the last cell padded with filler bytes.


NoteControl the bandwidth threshold to activate an IMA group by using the ima active-links-minimum command.


Table3: T1 IMA AAL5 Payload Bandwidth with IMA Frame Size 128
Number of Links in the Group Total Bandwidth Payload Bandwidth

1

1.536

1.38

2

3.072

2.76

3

4.608

4.14

4

6.144

5.52

5

7.68

6.91

6

9.216

8.28

7

10.752

9.66

8

12.288

11.04


Table4: E1 IMA AAL5 Payload Bandwidth with IMA Frame Size 128
Number of Links in the Group Total Bandwidth Payload Bandwidth

1

1.92

1.74

2

3.84

3.47

3

5.76

5.21

4

7.68

6.95

5

9.60

8.69

6

11.52

10.43

7

13.44

12.17

8

15.36

13.90

Related Documents

For information about the physical characteristics of the ATM T1/E1 IMA network modules, or for instructions on how to install the network or modem modules, either see the Cisco 2600 or 3600 series Network Module Hardware Installation Guidethat came with your ATM T1/E1 IMA network module or view the up-to-date information on CCO.

Configuring PPP over ATM

All forms of PPP over ATM can be configured on all platforms running Cisco IOS Release 12.1, except for the IETF-compliant LLC encapsulated version, which is not available for the CiscoMC3810series platform. Figure 5 shows a typical scenario for using Cisco proprietary PPP over ATM.


NoteAll forms of PPP over ATM are now supported on the ATM port adapters, except for the PA-A1 ATM port adapter for CiscoIOSRelease12.1. All forms of PPP over ATM are now supported on the enhanced ATM port adapter for CiscoIOS Release12.1.


Figure5: PPP-over-ATM Network Environment



NoteIf you need to configure the Cisco StrataCom AXIS shelf for frame forwarding at the remote sites, refer to the AXIS 4 Command Supplement for command line instructions or the StrataView Plus Operations Guide for StrataView Plus instructions. If you configure the AXIS using the command line interface, use the addport and addchan commands and select frame forwarding for the port_type and chan_type arguments, respectively.

When you configure PPP over ATM, a logical interface known as a virtual access interface associates each PPP connection to an ATM permanent virtual circuit (PVC). You can create this logical interface by configuring an ATM PVC. This configuration encapsulates each PPP connection in a separate PVC, allowing each PPP connection to terminate at the router ATM interface as if received from a typical PPP serial interface.

The virtual access interface for each PVC obtains its configuration from a virtual interface template (virtual template) when the PVC is created. Before creating the ATM PVC, it is recommended that you create and configure a virtual template as described in the "Creating and Configuring a Virtual Template" section.

Once you have configured the router for PPP over ATM, the PPP subsystem starts and the router attempts to send a PPP configure request to the remote peer. If the peer does not respond, the router periodically goes into a "listen" state and waits for a configuration request from the peer. After a timeout (typically 45seconds), the router again attempts to reach the remote router by sending configuration requests.

The virtual access interface remains associated with a PVC as long as the PVC is configured. If you deconfigure the PVC, the virtual access interface is marked as deleted. If you shut down the associated ATM interface, you will also cause the virtual access interface to be marked as down (within 10seconds), and you will bring the PPP connection down. If you set a keepalive timer of the virtual template on the interface, the virtual access interface uses the PPP echo mechanism to verify the existence of the remote peer.

The following three types of PPP over ATM connections are supported:

To configure PPP over ATM, complete the tasks described in the following sections. The tasks in the first section are optional, but recommended. The tasks in the last three sections are specific to the type of PPP over ATM that you are configuring:

Creating and Configuring a Virtual Template

Prior to configuring the ATM PVC for PPP over ATM, you typically create and configure a virtual template. To create and configure a virtual template, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface 
virtual-template 
number

Create a virtual template, and enter interface configuration mode.

Step2

encapsulation 
ppp

Enable PPP encapsulation on the virtual template.

Step3

ip unnumbered 
ethernet number

(Optional) Enable IP without assigning a specific IP address on the LAN.

Other optional configuration commands can be added to the virtual template configuration. For example, you can enable the PPP authentication on the virtual template using the pppauthenticationchap command. Refer to the "Configuring Virtual Template Interfaces" chapter in the Cisco IOS Dial Services Configuration Guide: Network Services for additional information about configuring the virtual template.

All PPP parameters are managed within the virtual template configuration. Configuration changes made to the virtual template are automatically propagated to the individual virtual access interfaces. Multiple virtual access interfaces can originate from a single virtual template; therefore, multiple PVCs can use a single virtual template.

Cisco IOS software supports up to 25 virtual template configurations. If greater numbers of tailored configurations are required, an authentication, authorization, and accounting (AAA) server may be employed. Refer to the "Configuring Per-User Configuration" chapter in the Cisco IOS Dial Services Configuration Guide: Network Services for additional information on configuring an AAA server.

If the parameters of the virtual template are not explicitly defined before configuring the ATM PVC, the PPP interface is brought up using default values from the virtual template identified. Some parameters (such as an IP address) take effect only if specified before the PPP interface comes up. Therefore, it is recommended that you explicitly create and configure the virtual template before configuring the ATM PVC to ensure such parameters take effect. Alternatively, if parameters are specified after the ATM PVC has already been configured, use the shutdown command followed by a no shutdown command on the ATM subinterface to restart the interface; this restart will cause the newly configured parameters (such as an IP address) to take effect.

Network addresses for the PPP-over-ATM connections are not configured on the main ATM interface or subinterface. Instead, these are configured on the appropriate virtual template or obtained via AAA.

The virtual templates support all standard PPP configuration commands; however, not all configurations are supported by the PPP-over-ATM virtual access interfaces. These restrictions are enforced at the time the virtual template configuration is applied (cloned) to the virtual access interface. These restrictions are described in the following paragraphs.

Only standard first-in, first-out (FIFO) queuing is supported when applied to PPP-over-ATM virtual access interfaces. Other types of queuing which are typically configured on the main interface are not (for example, fair-queuing). If configured, these configuration lines are ignored when applied to a PPP-over-ATM interface.

While fast switching is supported, flow and optimum switching are not; these configurations are ignored on the PPP-over-ATM virtual access interface. Fast switching is enabled by default for the virtual template configuration. If fast switching is not desired, use the no ip route-cache command to disable it.

The PPP reliable link that uses Link Access Procedure, Balanced (LAPB) is not supported.

Because an ATM PVC is configured for this feature, the following standard PPP features are not applicable and should not be configured:

Configuring IETF-Compliant MUX Encapsulated PPP over ATM

IETF-compliant MUX encapsulated PPP over ATM allows you to configure PPP over ATM using a VC multiplexed encapsulation mode. This feature complies with IETF RF 2364 entitled PPPoverAAL5.

You can configure ATM PVCs for IETF-compliant MUX encapsulated PPP over ATM on either point-to-point or multipoint subinterfaces. Multiple PVCs on multipoint subinterfaces significantly increase the maximum number of PPP-over-ATM sessions running on a router.

To configure IETF-compliant MUX PPP over ATM, also known as null encapsulation, that supports VC multiplexed PPP payloads, use the following commands starting in global configuration mode:

Command Purpose

Step1

interface atm slot/0.subinterface-number 
point-to-point

or

interface atm number.subinterface-number 
point-to-point

or

interface atm slot/0.subinterface-number multipoint

or

interface atm number.subinterface-number multipoint

Specify an ATM point-to-point or multipoint subinterface using the appropriate format of the interface atm command.1

Step2

pvc [name] vpi/vci

Configure the PVC.

Step3

encapsulation aal5mux ppp virtual-template number 

Configure VC multiplexed encapsulation.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

IETF-Compliant PPP over ATM is not supported on ATM SVCs and can only be applied to PVCs.

The IETF-Compliant PPP over ATM feature was designed to support installations with ADSL circuits. For an example of using ADSL termination, see the section "ADSL Termination Example" at the end of this chapter.

Configuring IETF-Compliant LLC Encapsulated PPP Over ATM

IETF-compliant LLC encapsulated PPP over ATM LLC Encapsulation allows you to configure PPP over ATM with LLC encapsulation. It accommodates Frame Relay-to-ATM service interworking (Frame Relay forum standard FRF.8). There is no equivalent VC multiplexed encapsulation mode for Frame Relay; therefore, LLC encapsulation is required for Frame Relay-to-ATM networking. This version of OOO over ATM also enables you to carry multiprotocol traffic. For example, a VC will carry both PPP and IPX traffic.

Figure 6 illustrates Frame Relay-to-ATM interworking.


Figure6: Frame Relay-to-ATM Interworking


You can configure ATM PVCs for IETF-compliant LLC encapsulated PPP over ATM on either point-to-point or multipoint subinterfaces. Multiple PVCs on multipoint subinterfaces significantly increase the maximum number of PPP-over-ATM sessions running on a router. To configure IETF-compliant LLC encapsulated PPP over ATM, use the following commands starting in global configuration mode:

Command Purpose

Step1

interface atm slot/0.subinterface-number 
point-to-point

or

interface atm number.subinterface-number 
point-to-point

or

interface atm slot/0.subinterface-number multipoint

or

interface atm number.subinterface-number multipoint

Specify an ATM point-to-point or multipoint subinterface using the appropriate format of the interface atm command.1

Step2

pvc [name] vpi/vci

Configure the PVC.

Step3

encapsulation aal5snap2

Configure LLC SNAP encapsulation.

Step4

protocol ppp virtual-template number 

Configure IETF PPP over ATM LLC Encapsulation.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.
2The snap encapsulation is a misnomer here, since this encapsulation configures both LLC and SNAP encapsulation on the VC. If snap encapsulation is not configured at a lower inheritance level, or another type of encapsulation is configured at a lower inheritance level, you will have to configure both snap and the protocol ppp command to ensure that PPP over ATM with LLC encapsulation is configured on your VC.

You can also configure IETF-compliant LLC encapsulated PPP over ATM in a VC class and apply this VC class to an ATM VC, subinterface, or interface. For information about configuring a VC class, refer to the section "Configuring VC Classes" earlier in this chapter.


NoteDepending on whether you configure IETF-compliant LLC encapsulated PPP over ATM directly on a PVC or interface, your PVC will inherit the configuration that takes highest precedence. For a description of the inheritance hierarchy, see the protocol command in the Cisco IOS Wide-Area Networking Command Reference Guide for CiscoIOS Release12.1.

Configuring Cisco Proprietary PPP over ATM

You can configure ATM PVCs for Cisco proprietary PPP over ATM on either point-to-point or multipoint subinterfaces. Multiple PVCs on multiple subinterfaces significantly increases the maximum number of PPP-over-ATM sessions running on a router. Remote branch offices must have Cisco proprietary PPP over ATM configured on PPP-compatible devices interconnecting directly to Cisco's ATM Switch Interface Shelf (AXIS) equipment through a leased-line connection. The shelves provide frame forwarding encapsulation and are terminated on BPX cores prior to connecting to a Cisco7500 series router.

To configure Cisco proprietary PPP over ATM, use the following commands starting in global configuration mode:

Command Purpose

Step1

interface atm slot/0.subinterface-number 
point-to-point

or

interface atm number.subinterface-number 
point-to-point

or

interface atm slot/0.subinterface-number multipoint

or

interface atm number.subinterface-number multipoint

Specify an ATM point-to-point or multipoint subinterface using the appropriate format of the interface atm command.1

Step2

pvc [name] vpi/vci

Configure the PVC.

Step3

encapsulation aal5ciscoppp virtual-template number

Configure Cisco Proprietary PPP over ATM encapsulation.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

The peak rate value is typically identical to the average rate or some suitable multiple thereof (up to 64 times for the Cisco7500 series routers).

The average rate value should be set to the line rate available at the remote site, because the remote line rate will typically have the lowest speed of the connection. For example, if the remote site has a T1 link, set the line rate to 1.536 Mbps. Because the average rate calculation on the ATM PVC includes the cell headers, a line rate value plus 10 or 15 percent may result in better remote line utilization.

The burst size depends on the number of cells that can be buffered by receiving ATM switches and is coordinated with the ATM network connection provider. If this value is not specified, the default, which is the equivalent to one maximum length frame on the interface, is used.

Operations, administration, and maintenance (OAM) F5 cell loopback is provided by the remote AXIS shelf so OAM may be enabled. However, Cisco Proprietary PPP over ATM is not typically an end-to-end ATM connection, and therefore enabling OAM is not recommended.

For an example of configuring Cisco proprietary PPP over ATM, see the section "Cisco Proprietary PPP-over-ATM Example" at the end of this chapter.

Configuring ATM E.164 Auto Conversion

E.164 is an International Telecommunications Union (ITU) specification for the ISDN international telephone numbering plan, which has traditionally only been used in telephone networks. The ATM Forum has defined three different 20-byte ATM End System Address (AESA) formats, along with the native E.164 format, for use in ATM networks. One of these 20-byte formats is the embedded E.164 AESA (E164_AESA) format.

With ATM E.164 auto conversion enabled, networks that operate based on ATM addressing formats can internetwork with networks based on E.164 addressing formats. The conversion requires components from addressing, routing, and signalling to perform properly.

For more information about E.164 and ATM address formats, see ATM Forum UNI 3.0, 3.1, and 4.0, and ITU E.164. Table 5 lists the ATM and E.164 address formats supported by ATM E.164 auto conversion.


Table5: ATM and E1.64 Address Formats
Address Type Example

Native E.164
A minimum of 7 and maximum of 15 ASCII-encoded decimal numbers.

1-800-555-1212

E164_AESA
E.164 ATM End System Address is an ATM address that contains an embedded E.164number.
Format |AFI | E164 | HO-DSP | ESI | SEL|
AFI = 45

45.000018005551212F00000000.112233445566.00

E164_ZDSP
E.164 Zero Domain Specific Part is an ATM address that contains all zeros in the Domain Specific Part of the address.
Format |AFI | E164 | HO-DSP | ESI | SEL|
AFI = 45
The remaining bytes in HO-DSP, ESI, and SEL are0.

45.000018005551212F00000000.000000000000.00

When ATM E.164 auto conversion is enabled, a Ciscorouter sets up ATM SVC connections based on E.164 addresses. The router uses ATM E164_AESA addresses to set up E.164 calls in a way similar to using ATM AESA addresses to set up ATM SVCs. The ATM AESA address on an interface and the ATM AESA address of a static map must be in E164_AESA format.

To configure ATM E.164 auto conversion, you must configure the ATM interface using E164_AESA or E164_ZDSP format. To enable E.164 auto conversion, use the following commands beginning in interface configuration mode:

Command Purpose

Step1

interface atm slot/0

or

interface atm 
slot/port-adapter/0

or

interface atm number

Specify the ATM interface using the appropriate format of the interface atm command.1

Step2

ip address ip-address mask

If IP routing is enabled on the system, optionally assign a source IP address and subnet mask to the interface.

Step3

pvc 0/5 qsaal

Configure the signalling PVC for the ATM main interface that uses SVCs.

Step4

exit

Return to interface configuration mode.

Step5

atm nsap-address 
nsap-address

Set the AESA address for the ATM interface using E164_AESA or E164_ZDSP address format.

Step6

atm e164 
auto-conversion

Enable E.164 auto conversion on the interface.

Step7

exit

Return to interface configuration mode.

Step8

svc [name] nsap address

Specify the destination NSAP address using E164_AESA or E164_ZDSP address format.

Step9

protocol ip protocol-address

Specify the destination IP address of the SVC.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

Use the show interfaces atm command to verify that ATM E.164 auto conversion is running.

For an example of configuring ATM E.164 auto conversion, refer to the section "Configuring ATM E.164 Auto Conversion Example" at the end of this chapter.

Configuring Circuit Emulation Services

This section includes an overview of Circuit Emulation Services (CES) for ATM and a description of the configuration tasks.

CES Overview

Circuit emulation service internetworking function (CES-IWF) is a service based on ATM Forum standards that allows communications to occur between CBR and ATM UNI interfaces, that is, between non-ATM telephony devices (such as classic PBXs or TDMs) and ATM devices (such as Cisco 7200 series routers). Thus, a Cisco 7200 series router equipped with an ATM-CES port adapter offers a migration path from classic T1/E1 CBR data communications services to emulated CES T1/E1 unstructured (clear channel) services or structured (Nx 64) services in an ATM network.

Figure 7 shows a simplified representation of CES-IWF functions in an ATM network.


Figure7: Typical CES-IWF Operations in an ATM Network


Voice and video services (circuit emulation) allow you to interconnect existing T1 or E1 interfaces and other kinds of constant bit rate (CBR) equipment. CBR services include such features as PBX interconnect, consolidated voice and data traffic, and video conferencing.

With circuit emulation, data received from an external device at the edge of an ATM network is converted to ATM cells, sent through the network, reassembled into a bit stream, and passed out of the ATM network to its destination. T1/E1 circuit emulation does not interpret the contents of the data stream. All the bits flowing into the input edge port of the ATM network are reproduced at one corresponding output edge port.

An emulated circuit is carried across the ATM network on a PVC, which is configured through the network management system.

The ATM-CES port adapter offers two types of services:

The target application of the ATM-CES port adapter is access to a broadband public or private ATM network where multiservice consolidation of voice, video, and data traffic over a single ATM link is a requirement.

CES Configuration Task List

To configure the T1/E1 interfaces on the ATM-CES port adapter for unstructured CES services, use the commands described in the first section listed below. To configure structured CES services, use the commands described in the second section. The third section is optional if structured CES services are already configured.


NoteThe configuration tasks in these sections are only supported on the ATM-CES port adapter.

For an example of configuring CES, see the section "Configuring Circuit Emulation Services Example" at the end of this chapter.

Configuring Unstructured (Clear Channel) CES Services

A circuit that you set up on a CBR port for unstructured service is always identified as "circuit 0", because only one such circuit can be established on any given CBR port. Such a circuit consumes the entire bandwidth of the port, which is provisioned manually at the time you set up the unstructured circuit and remains dedicated to that port, whether that port is actively transmitting CBR data or not.

A CES module converts CBR traffic into ATM cells for propagation through an ATM network. The ATM cell stream is directed to an outgoing ATM port or CBR port. If the outgoing port is an ATM port on the same Cisco 7200 series router, the PVC is called a "hard PVC". As a general rule when setting up a hard PVC, you must interconnect a CBR port and the ATM port in the same ATM-CES port adapter. Only hard PVCs are supported in the Cisco 7200 series router.

To configure the T1/E1 port on the ATM-CES port adapter for unstructured (clear channel) CES services, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface cbr slot/port

Specify the ATM-CES port adapter interface.

Step2

ces aal1 service [structured | 
unstructured]

Configure the port to perform unstructured CES services. The default is unstructured.

Step3

ces aal1 clock {adaptive | srts 
| synchronous}

Optionally, select the clock method. The default is synchronous.

Step4

ces dsx1 clock source 
{loop-timed | network-derived}

If synchronous clocking is selected, configure the clock source.

Step5

ces circuit 0 [circuit-name 
name]

Specify the circuit number for unstructured services and optionally specify the logical name of the PVC. If you do not specify a circuit name, the default is CBRx/x:x.

Step6

ces pvc 0 interface atm 
slot/port vci number vpi number

Define the particular ATM destination port for the PVC.

Step7

no shutdown 

Change the shutdown state to up and enable the ATM interface, thereby beginning the segmentation and reassembly (SAR) operation on the interface.

Step8

no ces circuit 0 shutdown

Enable the PVC.

Configuring Structured (N x 64) CES Services

Structured (N x 64 kbps) CES services differ from unstructured CES services in that the structured services allow you to allocate the bandwidth in a highly flexible and efficient manner. With the structured services, you use only the bandwidth actually required to support the active structured circuit that you configure.

For example, in configuring an ATM-CES port adapter for structured service, you can define multiple hard PVCs for any given ATM-CES port adapter's T1/E1 port. The ATM-CES port adapter provides up to 24 time slots per T1 port and up to 31 time slots per E1 for defining structured CES circuits. To see the bandwidth that is required on an ATM link for this particular circuit, use the show ces circuit command.


NoteIn the ATM-CES port adapter, any bits not available for structured CES services are used for framing and out-of-band control.

For simplicity in demonstrating configuration tasks for structured CES services, the procedures in this section are directed primarily at setting up a single CES circuit per T1/E1 port. However, these procedures outline the essential steps and command syntax that you would use if you were to set up multiple CES circuits on a T1/E1 port.

Structured CES services require network clock synchronization by means of the synchronous clocking mode. You must select the clock source and define its priority locally for each Cisco 7200 series router in your network. You do this by means of the network-clock-select command.

To configure the T1/E1 port on the ATM-CES port adapter for structured (N x 64 kbps) CES services without CAS, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface cbr slot/port

Specify the ATM-CES port adapter interface.

Step2

ces aal1 service 
[structured | unstructured]

Configure the port to perform structured CES services. The default is unstructured.

Step3

ces aal1 clock {adaptive | 
srts | synchronous}

Optionally, select the clock method. The default is synchronous. Adaptive and SRTS are only available for unstructured mode.

Step4

ces dsx1 clock source 
{loop-timed | network-derived}

If synchronous clocking is selected, configure the clock source.

Step5

ces dsx1 linecode {ami | 
b8zs} (for T1)
ces dsx1 linecode {ami | hdb3} (for E1)

Specify the line code format used for the physical layer. The default is AMI.

Step6

ces dsx1 framing {esf | sf} 
(for T1)
ces dsx1 framing {e1_crc_mfCASlt | e1_crc_mf_lt 
| e1_lt | e1_mfCAS_lt} (forE1)

Specify the framing format The default for T1 is ESF and for E1is E1_LT.

Step7

ces dsx1 lbo length

Optionally, specify the line build out (cable length). Values are (in feet): 0_110, 110_220, 220_330, 330_440, 440_550, 550_660, 660_above, and square_pulse. The default is 0_110feet.

Step8

ces circuit circuit-number 
[circuit-name name]

Specify the circuit number for structured services and optionally specify the logical name of the PVC. For T1 structured service the range is 1 through 24. For E1 structured service the range is 1 through 31. If you do not specify a circuit name, the default is CBRx/x:x.

Step9

ces circuit circuit-number 
timeslots range

Specify the timeslots to be used by the PVC. For T1 the range is 1 through 24. For E1 structured service the range is 1 through 31. Use a dash to indicate a range (for example 1-24). Use a comma to separate the timeslot (for example, 1,3,5).

Step10

ces circuit circuit-number 
cdv range

Optionally, configure the circuit cell delay variation. Range is 1 through 65535 milliseconds. The default range is 2000 milliseconds.

Step11

ces pvc circuit-number 
interface atm slot/port vpi number vci number

Define the particular ATM destination port for the PVC.

Step12

no shutdown 

Change the shutdown state to up and enable the ATM interface, thereby beginning the segmentation and reassembly (SAR) operation on the interface.

Step13

no ces circuit circuit-number shutdown

Enable the PVC.


NoteYou need not specify individual circuit options on a separate command line, even though that is done in and above. If you want, you can specify all the desired circuit options on the same command line, provided that you observe the following rules: (1) specify the DS0 time slots as the first option; (2) specify each desired option thereafter in strict alphabetic order; and, (3) separate consecutive command line options with a space. You can display the options available for any structured CES circuit by typing the ces circuit circuit-number? command, which displays in alphabetic order all the options available for use in the command line.

Configuring Channel-Associated Signalling (for Structured CES Services Only)

Because the ATM-CES port adapter emulates constant bit rate services over ATM networks, it must be capable of providing support for handling channel-associated signalling (CAS) information introduced into structured CES circuits by PBXs and time-division multiplexing (TDM) devices. The ces circuit cas interface command provides this feature.

With respect to the CAS information carried in a CBR bit stream, an ATM-CES port adapter can be configured to operate as follows:

In this case, the ATM-CES port adapter does not sense the CAS information (carried as so-called "ABCD" bits in the CBR bit stream) and provides no support for CAS functions.
In this case, in addition to packaging incoming CBR data into ATM AAL1 cells in the usual manner for transport through the network, the ATM-CES port adapter in the ingress node senses the ABCD bit patterns in the incoming data, incorporates these patterns in the ATM cell stream, and propagates the cells to the next node in the network. The ATM cells are transported across the network from link to link until the egress node is reached.
At the egress node, the ATM-CES port adapter strips off the ABCD bit patterns carried by the ATM cells, reassembles the CAS ABCD bits and the user's CBR data into original form, and passes the frames out of the ATM network in the proper DS0 time slot.
All these processes occur transparently without user intervention.
In this case, the CAS and on-hook detection features work together to enable an ingress node in an ATM network to monitor on-hook and off-hook conditions for a specified 1 x 64 structured CES circuit. As implied by the notation "1 x 64," the on-hook detection (or bandwidth-release) feature is supported only in a structured CES circuit that involves a single time slot at each end of the connection.
The time slot configured for the structured CES circuit at the ingress node (time slot 2) can be different from the DS0 time slot configured at the egress node (time slot 4). Only one such time slot can be configured at each end of the circuit when the on-hook detection feature is used.
When you invoke this feature, the ingress ATM-CES port adapter monitors the ABCD bits in the incoming CBR bit stream to detect on-hook and off-hook conditions in the circuit. In an "off-hook" condition, all the bandwidth provisioned for the specified CES circuit is used for transporting ATM AAL1 cells across the network from the ingress node to the egress node.
In an on-hook condition, the network periodically sends dummy ATM cells from the ingress node to the egress node to maintain the connection. However, these dummy cells consume only a fraction of the circuit's reserved bandwidth, leaving the rest of the bandwidth available for use by other AAL5 network traffic. This bandwidth-release feature enables the network to make more efficient use of its resources.

When the CAS feature is enabled for a CES circuit, the bandwidth of the DS0 channel is limited to 56kbps for user data, because CAS functions consume 8 kbps of channel bandwidth for transporting the ABCD signalling bits. These signalling bits are passed transparently from the ingress node to the egress node as part of the ATM AAL1 cell stream.

In summary, when the optional CAS and on-hook detection features are enabled, the following conditions apply:

To configure the T1/E1 port on the ATM-CES port adapter for channel associated signalling, first use the commands in the "Configuring Structured (N x 64) CES Services" section and then use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface 
cbr slot/port

Specify the ATM-CES port adapter interface.

Step2

ces circuit 
circuit-number cas

Enable channel associated signalling.

Step3

ces dsx1 
signalmode robbedbit

Optionally, enable the signal mode as robbed bit.

Step4

ces circuit 
circuit-number on-hook-detection 
hex-number

Optionally, enable on-hook detection.

Configuring Network Clock Source and Priorities

You can specify up to four network clock sources for a Cisco 7200 series router. The highest priority active port in the chassis supplies primary reference source to all other chassis interfaces that require network clock synchronization services. The fifth network clock source is always the local oscillator on the ATM-CES port adapter.

To direct a CBR port to use the network-derived clock, you must configure the CBR port with the ces dsx1 clock source network-derived interface command. For information on configuring the CBR port, refer to the section "Configuring Unstructured (Clear Channel) CES Services" earlier in this chapter.

To establish the sources and priorities of the requisite clocking signals for an ATM-CES port adapter in a Cisco 7200 series router, use the following commands beginning in global configuration mode:

Command Purpose

Step1

network-clock-select 1 {atm | 
cbr} slot/port

Establish a priority 1 clock source.

Step2

network-clock-select 2 {atm | cbr} slot/port

Establish a priority 2 clock source.

Step3

network-clock-select 3 {atm | cbr} slot/port

Establish a priority 3 clock source.

Step4

network-clock-select 4 {atm | cbr} slot/port

Establish a priority 4 clock source.

To verify the clock signal sources and priorities that you established in the previous procedure for your ATM-CES port adapter, use the show network-clocks privileged EXEC command.


NoteThe commands in this section are only supported on the ATM-CES port adapter.

For an example of configuring the network clock source and priority, see the section "Configuring Network Clock Source Priority Example" at the end of this chapter.

Configuring Virtual Path Shaping

The ATM-CES port adapter supports multiplexing of one or more PVCs over a virtual path (VP) that is shaped at a constant bandwidth. To use this feature, you configure a permanent virtual path (PVP) with a specific virtual path identifier (VPI). Any PVCs that are created subsequently with the same VPI are multiplexed onto this VP; the traffic parameters of individual PVCs are ignored.

The traffic shaping conforms to the peak rate that is specified when you create the VP. Any number of data PVCs can be multiplexed onto a VP.


NoteThe number of CES PVCs that are multiplexed depends on the bandwidth requirement. Because of this requirement, the CES PVCs cannot be oversubscribed. The CES PVC will fail if there is no bandwidth available. Data PVCs use the bandwidth that is unused by the CES PVCs.

To create a PVP, use the following commands beginning in interface configuration mode:

Command Purpose

Step1

atm pvp vpi [peak-rate]

Create a PVP and optionally specify the peak rate.

Step2

pvc [name] vpi/vci

Optionally, create a PVC with a VPI that matches the VPI specified in Step 1.

Step3

exit

Exit interface configuration mode.

Step4

interface cbr slot/port

ces circuit circuit-number

ces pvc circuit-number 
interface atm slot/port vpi number vci number

Optionally, create a CES PVC with a VPI that matches the VPI specified in Step 1.


NoteVirtual path shaping is only available on the ATM-CES port adapter.

The value of the vpi argument is the virtual path identifier to be associated with the PVP (valid values are in the range 0 to 255 inclusive). The peak-rate argument is the maximum rate (in kbps) at which the PVP is allowed to transmit data. Valid values are in the range 84 kbps to line rate. The default peak rate is the line rate.

When you create a PVP, two PVCs are created (with VCI 3 and 4) by default. These PVCs are created for VP end-to-end loopback and segment loopback OAM support.

The pvc command is rejected if a non-multiplexed PVC with the specified VPI value already exists. This could happen if you first create a PVC with a given VPI value and then you subsequently enter this command.

To display information about the PVP, use the show atm vp EXEC command.


NoteIf you change the peak rate online, the ATM port will go down and then back up.

For an example of virtual path shaping, see the section "Configuring Virtual Path Shaping Example" at the end of this chapter.

Configuring ATM Access over a Serial Interface

This section describes how to configure routers that use a serial interface for ATM access through an ATM data service unit (ADSU). The configuration tasks include the steps necessary to enable Asynchronous Transfer Mode-Data Exchange Interface (ATM-DXI) encapsulation, select a multiprotocol encapsulation method using ATM-DXI, and set up a PVC for the selected encapsulation.

In routers with a serial interface, an ADSU is required to provide the ATM interface to the network, convert outgoing packets into ATM cells, and reassemble incoming ATM cells into packets.

Any serial interface can be configured for multiprotocol encapsulation over ATM-DXI, as specified by RFC 1483. At the ADSU, the DXI header is stripped off, and the protocol data is segmented into cells for transport over the ATM network.

RFC 1483 describes two methods of transporting multiprotocol connectionless network interconnect traffic over an ATM network. One method allows multiplexing of multiple protocols over a single PVC. The other method uses different virtual circuits to carry different protocols. Cisco's implementation of RFC 1483 supports both methods and supports transport of Apollo Domain, AppleTalk, Banyan VINES, DECnet, IP, Novell IPX, ISO CLNS, and XNS traffic.

To configure ATM access over a serial interface, complete the tasks in the following sections. The first four tasks are required.

For an example of configuring ATM access over a serial interface, see the section "ATM Access over a Serial Interface Example" at the end of this chapter.

Enabling the Serial Interface

To configure the serial interface for ATM access, enable the serial interface by using the following commands beginning in global configuration mode:

Command Purpose

Step1

interface 
serial 
number

Enable the serial interface.

Step2

appletalk 
address 
network.node
ip address address mask
ipx network
number

For each protocol to be carried, assign a protocol address to the interface. (The commands shown are a partial list for the supported protocols.)

The supported protocols are Apollo Domain, AppleTalk, Banyan VINES, DECnet, IP, Novell IPX, ISO CLNS, and XNS.

For information about the addressing requirements of a protocol, see the relevant protocol configuration chapter in the Cisco IOS IP and IP Routing Configuration Guide, the CiscoIOS Appletalk and Novell IPX Configuration Guide, or the CiscoIOSApollo Domain, Banyan VINES, DECnet, ISO CLNS, and XNSConfiguration Guide, for Cisco IOS Release 12.1.

Enabling ATM-DXI Encapsulation

To enable ATM-DXI encapsulation on a serial or High-Speed Serial Interface (HSSI), use the following command in interface configuration mode:

Command Purpose
encapsulation 
atm-dxi

Enable ATM-DXI encapsulation.

Setting Up the ATM-DXI PVC

An ATM-DXI PVC can be defined to carry one or more protocols as described by RFC1483, or multiple protocols as described by RFC1490.

To set up the ATM-DXI PVC and select an encapsulation method, use the following command in interface configuration mode:

Command Purpose
dxi pvc vpi vci [snap | nlpid | 
mux]

Define the ATM-DXI PVC and the encapsulation method.

The multiplex (MUX) option defines the PVC to carry one protocol only; each protocol must be carried over a different PVC. The Subnetwork Access Protocol (SNAP) option is LLC/SNAP multiprotocol encapsulation, compatible with RFC1483; SNAP is the current default option. The network layer protocol identification (NLPID) option is multiprotocol encapsulation, compatible with RFC 1490; this option is provided for backward compatibility with the default setting in earlier versions in the CiscoIOS software.


NoteThe default encapsulation was NLPID in software earlier than Release 10.3. Beginning in that release, the default encapsulation is SNAP. Select the nlpid keyword now if you had previously selected the default.

Mapping Protocol Addresses to the ATM-DXI PVC

This section describes how to map protocol addresses to the VCI and the VPI of a PVC that can carry multiprotocol traffic. The protocol addresses belong to the host at the other end of the link. To map a protocol address to an ATM-DXI PVC, use the following command in interface configuration mode:

Command Purpose
dxi map protocol protocol-address 
vpi vci [broadcast]

Map a protocol address to the ATM-DXI PVC's VPI and VCI.

Repeat this task for each protocol to be carried on the PVC.

The supported protocols are Apollo Domain, AppleTalk, Banyan VINES, DECnet, IP, Novell IPX, ISO CLNS, and XNS.

For an example of configuring a serial interface for ATM, see the section "ATM Access over a Serial Interface Example" later in this chapter.

Monitoring and Maintaining the ATM-DXI Serial Interface

After configuring the serial interface for ATM, you can display the status of the interface, the ATM-DXI PVC, or the ATM-DXI map. To display interface, PVC, or map information, use the following commands in EXEC mode:

Command Purpose
show interfaces atm 
[slot/port]

Display the serial ATM interface status.

show dxi pvc

Display the ATM-DXI PVC information.

show dxi map

Display the ATM-DXI map information.

Troubleshooting the ATM Interface

The atm oam flush command is a diagnostic tool that drops all OAM cells that are received on an ATM interface. To drop all incoming OAM cells on an ATM interface, use the following commands beginning in global configuration mode:

Command Purpose

Step1

interface atm slot/0

or

interface atm slot/port-adapter/0

or

interface atm number

Specify the ATM interface using the appropriate format of the interface atm command.1

Step2

atm oam flush

Specify that incoming OAM cells be dropped on the ATM interface.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

Monitoring and Maintaining the ATM Interface

After configuring an ATM interface, you can display its status. You can also display the current state of the ATM network and connected virtual circuits. To show current virtual circuits and traffic information, use the following commands in EXEC mode:

Command Purpose
show arp

Display entries in the ARP table.

show atm class-links {vpi/vci 
| name}

Display PVC and SVC parameter configurations and where the parameter values are inherited from.

show atm interface atm slot/0

show atm interface atm slot/port-adapter/0

show atm interface atm number

Display ATM-specific information about the ATM interface using the appropriate format of the show atm interface atm command.1

show atm map

Display the list of all configured ATM static maps to remote hosts on an ATM network.

show atm pvc [vpi/vci | name | 
interface atm interface_number]

Display all active ATM PVCs and traffic information.

show atm svc [vpi/vci | name | 
interface atm interface_number]

Display all active ATM SVCs and traffic information.

show atm traffic

Display global traffic information to and from all ATM networks connected to the router, OAM statistics, and a list of counters of all ATM traffic on this router.

show atm vc [vcd]

Display all active ATM virtual circuits (PVCs and SVCs) and traffic information.

show controllers atm [slot/ima 
group-number]

Display information about current settings and performance at the physical level.

show ima interface atm 
[slot]/ima [group-number] [detail]

Display general or detailed information about IMA groups and the links in those groups.

show interfaces atm

show interfaces atm slot/0

show interfaces atm slot/port-adapter/0

Display statistics for the ATM interface using the appropriate format of the show interfaces atm command.

show network-clocks

Display the clock signal sources and priorities that you established on the router.

show sscop

Display SSCOP details for the ATM interface.

1To determine the correct form of the interface atm command, consult your ATM network module, port adapter, or router documentation.

ATM Configuration Examples

The examples in the following sections illustrate how to configure ATM for the features described in this chapter. The examples below are presented in the same order as the corresponding configuration task sections presented earlier in this chapter:

Creating a PVC Example

The following example shows how to create a PVC on an ATM main interface with AAL5/MUX encapsulation configured and a VBR-NRT QOS specified. For further information, refer to the sections "Creating a PVC" and "Configuring PVC Traffic Parameters" earlier in this chapter.

interface 2/0
pvc cisco 1/40
encapsulation aal5mux ip
vbr-nrt 100000 50000 20
exit

PVC with AAL5 and LLC/SNAP Encapsulation Examples

The following example shows how to create a PVC 0/50 on ATM interface 3/0. It uses the global default LLC/SNAP encapsulation over AAL5. The interface is at IP address 1.1.1.1 with 1.1.1.5 at the other end of the connection. For further information, refer to the sections "Creating a PVC" and "Mapping a Protocol Address to a PVC" earlier in this chapter.

interface atm 3/0
ip address 1.1.1.1 255.255.255.0
pvc 0/50
protocol ip 1.1.1.5 broadcast
exit
!
ip route-cache cbus
 

The following example is a typical ATM configuration for a PVC:

interface atm 4/0
ip address 172.21.168.112 255.255.255.0
atm maxvc 512
pvc 1/51
protocol ip 171.21.168.110
exit
!
pvc 2/52
protocol decnet 10.1 broadcast
exit
!
pvc 3/53
protocol clns 47.004.001.0000.0c00.6e26.00 broadcast
exit
!
decnet cost 1
clns router iso-igrp comet
exit
!
router iso-igrp comet
net 47.0004.0001.0000.0c00.6666.00
exit
!
router igrp 109
network 172.21.0.0
exit
!
ip domain-name CISCO.COM

PVCs in a Fully Meshed Network Example

Figure 8 illustrates a fully meshed network. The configurations for Routers A, B, and C follow the figure. In this example, the routers are configured to use PVCs. Fully meshed indicates that any workstation can communicate with any other workstation. Note that the two protocol statements configured in RouterA identify the ATM addresses of Routers B and C. The two protocol statements in Router B identify the ATM addresses of Routers A and C. The two protocol statements in RouterC identify the ATM addresses of Routers A and B. For further information, refer to the sections "Creating a PVC" and "Mapping a Protocol Address to a PVC" earlier in this chapter.


Figure8: Fully Meshed ATM Configuration Example


Router A

ip routing
!
interface atm 4/0
ip address 131.108.168.1 255.255.255.0
pvc 0/32
protocol ip 131.108.168.2 broadcast
exit
!
pvc 0/33
protocol ip 131.108.168.3 broadcast
exit

Router B

ip routing
!
interface atm 2/0
ip address 131.108.168.2 255.255.255.0
pvc test-b-1 0/32
protocol ip 131.108.168.1 broadcast
exit
!
pvc test-b-2 0/34
protocol ip 131.108.168.3 broadcast
exit

Router C

ip routing
!
interface atm 4/0
ip address 131.108.168.3 255.255.255.0
pvc 0/33 
protocol ip 131.108.168.1 broadcast
exit
!
pvc 0/34
protocol ip 131.108.168.2 broadcast
exit
 

Configuring an ABR PVC Example

The following example shows a typical ABR PVC configuration for the ATM-CES port adapter on a Cisco 7200 series router. In this example, the default peak cell rate and minimum cell rate is used (default PCR is the line rate and MCR is 0), and the ABR rate increase and decrease factor is set to32. For further information, refer to the section "Configuring PVC Traffic Parameters" earlier in this chapter.

interface atm 4/0
ip address 1.1.1.1 255.255.255.0
pvc 0/34
atm abr rate-factor 32 32
no shutdown
exit

Configuring PVC Discovery Example

The following example shows how to enable PVC Discovery on an ATM main interface 2/0. The keyword subinterface is used so that all discovered PVCs with a VPI value of 1 will be assigned to the subinterface 2/0.1. For further information, refer to the section "Configuring PVC Discovery" earlier in this chapter.

interface atm 2/0
pvc RouterA 0/16 ilmi
exit
atm ilmi-pvc-discovery subinterface
exit
!
interface atm 2/0.1 multipoint
ip address 172.21.51.5 255.255.255.0

Enabling Inverse ARP Example

The following example shows how to enable Inverse ARP on an ATM interface and specifies an Inverse ARP time period of 10 minutes. For further information, refer to the section "Enabling Inverse ARP" earlier in this chapter.

interface atm 2/0
pvc 1/32
inarp 10
exit

Configuring Generation of End-to-End F5 OAM Loopback Cells Example

The following example shows how to enable OAM management on an ATM PVC. The PVC is assigned the name routerA and the VPI and VCI are 0 and 32, respectively. OAM management is enabled with a frequency of 3 seconds between OAM cell transmissions. For further information, refer to the section "Configuring Generation of End-to-End F5 OAM Loopback Cells to Verify Connectivity" earlier in this chapter.

interface atm 2/0
pvc routerA 0/32
oam-pvc manage 3
oam retry 5 5 10

Configuring PVC Trap Support Example

The following example shows how to configure PVC trap support on your Cisco router:

!For PVC trap support to work on your router, you must first have SNMP support and !an IP routing protocol configured on your router:
Router(config)# snmp-server community public ro
Router(config)# snmp-server host 171.69.61.90 public 
Router(config)# ip routing
Router(config)# router igrp 109
Router(config-router)# network 172.21.0.0
!
!Enable PVC trap support and OAM management:
Router(config)# snmp-server enable traps atm pvc interval 40 fail-interval 10
Router(config)# interface atm 1/0.1 
Router(config-if)# pvc 0/1
Router(config-if-atm-vc)# oam-pvc manage
!
! Now if PVC 0/1 goes down, host 171.69.61.90 will receive traps.
 

For further information, refer to the "Configuring PVC Trap Support" section earlier in this chapter.

Configuring Communication with the ILMI Example

The following example shows how to configure the ILMI protocol on an ATM main interface. For further information, refer to the section "Configuring Communication with the ILMI" earlier in this chapter.

interface 2/0
pvc cisco 0/16 ilmi
exit

SVCs in a Fully Meshed Network Example

The following example is also a configuration for the fully meshed network shown in Figure 8, but this example uses SVCs. PVC 0/5 is the signalling PVC. For further information, refer to the following sections earlier in this chapter:

Router A

interface atm 4/0
ip address 131.108.168.1 255.255.255.0
atm nsap-address AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12
atm maxvc 1024
pvc 0/5 qsaal
exit
!
svc svc-1 nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.13
protocol ip 131.108.168.2
exit
!
svc svc-2 nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.12
protocol ip 131.108.168.3
exit

Router B

interface atm 2/0
ip address 131.108.168.2 255.255.255.0
atm nsap-address BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.13
atm maxvc 1024
pvc 0/5 qsaal
exit
!
svc svc-1 nsap AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12
protocol ip 131.108.168.1
exit
!
svc svc-2 nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.12
protocol ip 131.108.168.3
exit

Router C

interface atm 4/0
ip address 131.108.168.3 255.255.255.0
atm nsap-address BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.12
atm maxvc 1024
pvc 0/5 qsaal
exit
!
svc nsap AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12
protocol ip 131.108.168.1
exit
!
svc nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.13
protocol ip 131.108.168.2
exit

ATM ESI Address Example

The following example shows how to set up the ILMI PVC and how to assign the ESI and selector field values on a Cisco7500 series router. For further information, refer to the section "Configuring the ESI and Selector Fields" earlier in this chapter.

interface atm 4/0
pvc 0/16 ilmi
atm esi-address 345678901234.12

ATM NSAP Address Example

The following example shows how to assign NSAP address AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12 to ATM interface 4/0. For further information, refer to the section "Configuring the Complete NSAP Address" earlier in this chapter.

interface atm 4/0
atm nsap-address AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12
 

You can display the ATM address for the interface by executing the show interface atm command.

SVCs with Multipoint Signalling Example

The following example shows how to configure an ATM interface for SVCs using multipoint signalling. For further information, refer to the section "Configuring Point-to-Multipoint Signalling" earlier in this chapter.

interface atm 2/0
ip address 4.4.4.6 255.255.255.0
pvc 0/5 qsaal
exit
!
pvc 0/16 ilmi
exit
!
atm esi-address 3456.7890.1234.12
!
svc mcast-1 nsap cd.cdef.01.234566.890a.bcde.f012.3456.7890.1234.12 broadcast
protocol ip 4.4.4.4 broadcast
exit
!
svc mcast-2 nsap 31.3233.34.352637.3839.3031.3233.3435.3637.3839.30 broadcast
protocol ip 4.4.4.7 broadcast
exit
!
atm multipoint-signalling
atm maxvc 1024
 

Configuring SVC Traffic Parameters Example

Figure 9 illustrates a source and destination router implementing traffic settings that correspond end-to-end. The output values for the source router correspond to the input values for the destination router. The following example shows how to specify VBR-NRT traffic parameters on the source router. For further information, refer to the section "Configuring SVC Traffic Parameters" earlier in this chapter.

interface atm 4/0
svc svc-1 nsap 47.0091.81.000000.0041.0B0A.1581.0040.0B0A.1585.00
vbr-nrt 1000 500 64 800 400 64
exit

Figure9: Source and Destination Routers with Corresponding Traffic Settings


Creating a VC Class Examples

The following example shows how to create a VC class named main and how to configure UBR and encapsulation parameters. For further information, refer to the sections "Creating a VC Class" and "Configuring VC Parameters" earlier in this chapter.

vc-class atm main
ubr 10000
encapsulation aal5mux ip
 

The following example shows how to create a VC class named sub and how to configure UBR and PVC management parameters. For further information, refer to the sections "Creating a VC Class" and "Configuring VC Parameters" earlier in this chapter.

vc-class atm sub
ubr 15000
oam-pvc manage 3
 

The following example shows how to create a VC class named pvc and how to configure VBR-NRT and encapsulation parameters. For further information, refer to the sections "Creating a VC Class" and "Configuring VC Parameters" earlier in this chapter.

vc-class atm pvc
vbr-nrt 10000 5000 64
encapsulation aal5snap

Applying a VC Class Examples

The following example shows how to apply the VC class named main to the ATM main interface 4/0. For further information, refer to the section "Applying a VC Class" earlier in this chapter.

interface atm 4/0
class-int main
exit
 

The following example shows how to apply the VC class named sub to the ATM subinterface 4/0.5:

interface atm 4/0.5 multipoint
class-int sub
exit
 

The following example shows how to apply the VC class named pvc directly on the PVC 0/56:

interface atm 4/0.5 multipoint
pvc 0/56
class-vc pvc
exit

ILMI Management on an ATM PVC Example

The following example first shows how to configure an ILMI PVC on the main ATM interface 0/0. ILMI management is then configured on the ATM subinterface 0/0.1. For further information, refer to the section "Configuring ILMI Management" earlier in this chapter.

interface atm 0/0
pvc routerA 0/16 ilmi
exit
!
interface atm 0/0.1 multipoint
pvc 0/60
ilmi manage

OAM Management on an ATM PVC Example

The following example shows how to enable OAM management on an ATM PVC. The PVC is assigned the name routerA and the VPI and VCI are 0 and 32, respectively. OAM management is enabled with a frequency of 3 seconds between OAM cell transmissions. For further information, refer to the section "Configuring OAM Management for PVCs" earlier in this chapter.

interface atm 2/0
pvc routerA 0/32
oam-pvc manage 3
oam retry 5 5 10

OAM Management on an ATM SVC Example

The following example shows how to enable OAM management on an ATM SVC. The SVC is assigned the name routerZ and the destination NSAP address is specified. OAM management is enabled with a frequency of 3 seconds between OAM cell transmissions. For further information, refer to the section "Configuring OAM Management for SVCs" earlier in this chapter.

interface atm 1/0
svc routerZ nsap 47.0091.81.000000.0040.0B0A.2501.ABC1.3333.3333.05
oam-svc manage 3
oam retry 5 5 10

Classical IP and ARP Examples

This section provides three examples of classical IP and ARP configuration, one each for a client and a server in an SVC environment, and one for ATM Inverse ARP in a PVC environment.

Configuring ATM ARP Client in an SVC Environment Example

This example shows how to configure an ATM ARP client in an SVC environment. Note that the client in this example and the ATM ARP server in the next example are configured to be on the same IP network. For further information, refer to the section "Configuring the Router as an ATM ARP Client" earlier in this chapter.

interface atm 2/0.5
atm nsap-address ac.2456.78.040000.0000.0000.0000.0000.0000.0000.00
ip address 10.0.0.2 255.0.0.0
pvc 0/5 qsaal
atm arp-server nsap ac.1533.66.020000.0000.0000.0000.0000.0000.0000.00

Configuring ATM ARP Server in an SVC Environment Example

The following example shows how to configure ATM on an interface and configures the interface to function as the ATM ARP server for the IP subnetwork. For further information, refer to the section "Configuring the Router as an ATM ARP Server" earlier in this chapter.

interface atm 0/0
ip address 10.0.0.1 255.0.0.0
atm nsap-address ac.1533.66.020000.0000.0000.0000.0000.0000.0000.00
atm rate-queue 1 100
atm maxvc 1024
pvc 0/5 qsaal
atm arp-server self

Configuring ATM Inverse ARP in a PVC Environment Example

The following example shows how to configure ATM on an interface and then configures the ATM Inverse ARP mechanism on the PVCs on the interface, with Inverse ARP datagrams sent every 5 minutes on three of the PVCs. The fourth PVC will not send Inverse ATM ARP datagrams, but will receive and respond to Inverse ATM ARP requests. For further information, refer to the section "Configuring Classical IP and ARP in an SVC Environment" earlier in this chapter.

interface atm 4/0
ip address 172.21.1.111 255.255.255.0
pvc 0/32
inarp 5
exit
!
pvc 0/33
inarp 5
exit
!
pvc 0/34
inarp 5
exit
 

No map-group and map-list commands are needed for IP.

Dynamic Rate Queue Examples

The following examples assume that no permanent rate queues have been configured. The software dynamically creates rate queues when a pvc command creates a new PVC that does not match any user-configured rate queue. For further information, refer to the section "Using Dynamic Rate Queues" earlier in this chapter.

The following example shows how to set the peak rate to the maximum that the PLIM will allow. Then it creates a rate queue for the peak rate of this VC.

interface 2/0
pvc 1/41
exit
 

The following example shows how to create a 100-Mbps rate queue with an average rate of 50Mbps and a burst size of 64 cells:

interface 2/0
pvc 2/42
vbr-nrt 100000 50000 64
exit
 

The following example shows how to create a 15-Mbps rate queue and set the average rate to the peak rate:

interface 2/0
pvc 3/43
ubr 15000
exit
 

The following example shows how to configure a rate queue tolerance on the ATM interface with slot 2 and port 0. A tolerance-value of 20 is specified, which will apply to SVCs, discovered VCs, and PVCs.

interface atm 2/0
atm rate-queue tolerance svc pvc 20

PVC with AAL3/4 and SMDS Encapsulation Examples

The following example shows how to create a minimal configuration of an ATM interface to support AAL3/4 and SMDS encapsulation; no protocol configuration is shown. For further information, refer to the section "Configuring ATM Subinterfaces for SMDS Networks" earlier in this chapter.

interface atm 3/0
atm aal aal3/4
atm smds-address c140.888.9999
atm vp-filter 0
atm multicast e180.0999.9999
atm pvc 30 0 30 aal34smds
 

The following example shows how IP dynamic routing might coexist with static routing of another protocol:

interface atm 3/0
ip address 172.21.168.112 255.255.255.0
atm aal aal3/4
atm smds-address c140.888.9999
atm multicast e180.0999.9999
atm vp-filter 0
atm pvc 30 0 30 aal34smds
map-group atm
appletalk address 10.1
appletalk zone atm
!
map-group atm 
atalk 10.2 smds c140.8111.1111 broadcast
 

This example shows that IP configured is dynamically routed, but that AppleTalk is statically routed. An AppleTalk remote host is configured at address 10.2 and is associated with SMDS addressc140.8111.1111.

AAL3/4 associates a protocol address with an SMDS address, as shown in the last line of this example. In contrast, AAL5 static maps associate a protocol address with a PVC number.

Transparent Bridging on an AAL5-SNAP PVC Example

In the following example, three AAL5-SNAP PVCs are created on the same ATM interface. The router will broadcast all spanning tree updates to these AAL5-SNAP PVCs. No other virtual circuits will receive spanning tree updates. For further information, refer to the section "Configuring Fast-Switched Transparent Bridging for SNAP PVCs" earlier in this chapter.

interface atm 4/0
ip address 1.1.1.1 255.0.0.0
pvc 1/33
pvc 1/34
pvc 1/35
bridge-group 1
!
bridge 1 protocol dec
 

E1 Inverse Multiplexing over ATM Example

The following example shows the setup of ATM interfaces, IMA groups, PVCs, and SVCs for E1 IMA.

version 12.0
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname IMARouter
!
logging buffered 4096 debugging
!
ip subnet-zero
no ip domain-lookup
ip host 10.11.16.2
ip host 10.11.16.3
ip host 10.11.55.192
ip host 10.11.55.193
ip host 10.11.55.195
ip host 10.11.55.196
!
!
!
!
interface Ethernet0/0
 ip address 10.17.12.100 255.255.255.192
 no ip directed-broadcast
!

ATM interface 1/0 includes a PVC, but the specified link is not included in an IMA group. In this example, impedance and scrambling are set at their default values for E1 links and must match the far-end setting. The broadcast setting on the PVC takes precedence (addresses are fictional).

interface ATM1/0
 ip address 10.1.1.26 255.255.255.1
 no ip directed-broadcast
 no atm oversubscribe
 pvc 1/40 
  protocol ip 10.10.10.10 broadcast
 !
 scrambling-payload
 impedance 120-ohm
 no fair-queue
!

The eight-port ATM IMA E1 network module is in slot 1, and the interface commands below specify three links as members of IMA group 0.

interface ATM1/1
 no ip address
 no ip directed-broadcast
 no atm oversubscribe
 ima-group 0
 scrambling-payload
 impedance 120-ohm
 no fair-queue
!
interface ATM1/2
 no ip address
 no ip directed-broadcast
 no atm oversubscribe
 ima-group 0
 scrambling-payload
 impedance 120-ohm
 no fair-queue
!
interface ATM1/3
 no ip address
 no ip directed-broadcast
 no atm oversubscribe
 ima-group 0
 scrambling-payload
 impedance 120-ohm
 no fair-queue
!
 

Four links are members of IMA group 1.

interface ATM1/4
 no ip address
 no ip directed-broadcast
 no atm oversubscribe
 ima-group 1
 scrambling-payload
 impedance 120-ohm
 no fair-queue
!
interface ATM1/5
 no ip address
 no ip directed-broadcast
 no atm oversubscribe
 ima-group 1
 scrambling-payload
 impedance 120-ohm
 no fair-queue
!
interface ATM1/6
 no ip address
 no ip directed-broadcast
 no atm oversubscribe
 ima-group 1
 scrambling-payload
 impedance 120-ohm
 no fair-queue
!
interface ATM1/7
 no ip address
 no ip directed-broadcast
 no atm oversubscribe
 ima-group 1
 scrambling-payload
 impedance 120-ohm
 no fair-queue
!

The following commands specify parameters for the two IMA groups. For each group, a PVC is created and assigned an IP address.

interface ATM1/IMA0
 ip address 10.18.16.123 255.255.255.192
 no ip directed-broadcast
 ima clock-mode common port 2
 no atm oversubscribe
 pvc 1/42 
  protocol ip 10.10.10.10 broadcast
 !
!
interface ATM1/IMA1
 ip address 10.19.16.123 255.255.255.192
 no ip directed-broadcast
 no atm oversubscribe
 ima active-links-minimum 3
 pvc 1/99 
  protocol ip 10.10.10.10 broadcast
 !
!
ip classless
ip route 0.0.0.0 0.0.0.0 10.18.16.193
ip route 10.91.0.1 255.255.255.255 10.1.0.2
no ip http server
!
!
!
line con 0
 exec-timeout 0 0
 history size 100
 transport input none
line aux 0
line vty 0 4
 exec-timeout 0 0
 password lab
 login
 history size 100
!
end

T1 Inverse Multiplexing over ATM Example

The following example shows the setup of ATM interfaces, IMA groups, PVCs, and SVCs for T1 IMA.

version 12.0
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
no service dhcp
!
hostname router
!
ip subnet-zero
!
 

There are four links in IMA group 3. The no scrambling-payload command is actually unnecessary, because this is the default for T1 links. The T1 automatic B8ZS line encoding is normally sufficient for proper cell delineation, so no scrambling-payload is the usual setting for T1 links, The scrambling setting must match the far end.

interface ATM0/0
 no ip address
 no ip directed-broadcast
 no atm ilmi-keepalive
 ima-group 3
 no scrambling-payload
 no fair-queue
!
interface ATM0/1
 ip address 10.18.16.121 255.255.255.192
 no ip directed-broadcast
 no atm ilmi-keepalive
  !
 ima-group 3
 no scrambling-payload
 no fair-queue
!
interface ATM0/2
 no ip address
 no ip directed-broadcast
 no atm ilmi-keepalive
 ima-group 3
 no scrambling-payload
 no fair-queue
!
interface ATM0/3
 no ip address
 no ip directed-broadcast
 no atm ilmi-keepalive
 ima-group 3
 no scrambling-payload
 no fair-queue
!
!
 

IMA group 3 has PVCs that are set up for SVC management and signalling. Two SVCs and a communications PVC are also set up on the group interface.

interface ATM0/IMA3
 no ip address
 no ip directed-broadcast
 no atm ilmi-keepalive
 pvc 0/16 ilmi
 !
 pvc 0/5 qsaal
 !
 !
 pvc first 1/43
  vbr-rt 640 320 80
  encapsulation aal5mux ip
 !
 !
 
 svc second nsap 47.0091810000000050E201B101.00107B09C6ED.FE
  abr 4000 3000
 !
 !
 svc nsap 47.0091810000000002F26D4901.444444444444.01
 !
 

The IMA subcommands below specify that three links must be active in order for the group to be operational. The common clock source is the first link, ATM 0/1, and ATM 0/2 is the test link. The differential delay maximum is set to 50 milliseconds.

 ima active-links-minimum 3
 ima clock-mode common 1
 ima differential-delay-maximum 50
 ima test link 2                 
!
interface Ethernet1/0
 no ip address
 no ip directed-broadcast
 shutdown
!
interface Ethernet1/1
 no ip address
 no ip directed-broadcast
 shutdown
!
ip classless
no ip http server
!
!
!
line con 0
 exec-timeout 0 0
 transport input none
line aux 0
line vty 0 4
 login
!
!
end
 

IETF-Compliant MUX Encapsulated PPP over ATM Configuration Examples

This section provides the following examples for configuring IETF-compliant PPP over ATM:

IETF-Compliant PPP over ATM with Different Traffic Shaping Parameters Example

PVCs with different PPP-over-ATM traffic shaping parameters can be configured on the same subinterface. In the following example, three PVCs are configured for PPP over ATM on subinterface ATM 2/0.1. PVC 0/60 is configured with IETF-Compliant PPP over ATM encapsulation. Its traffic shaping parameter is an unspecified bit rate with peak cell rate at 500 kbps. PVC 0/70 is also configured with IETF-Compliant PPP over ATM encapsulation, but its traffic shaping parameter is non-real-time variable bit rate, with peak cell rate at 1 Mbps, sustainable cell rate at 500 kbps, and burst cell size of 64 cells. PVC 0/80 is configured with the Cisco's proprietary PPP over ATM encapsulation. Its traffic shaping parameter is an unspecified bit rate with peak cell rate at 700 kbps. For further information, refer to the section "Configuring IETF-Compliant MUX Encapsulated PPP over ATM" earlier in this chapter.

Router(config)# interface atm 2/0.1 multipoint
Router(config-if)# pvc 0/60
Router(config-if-atm-vc)# encapsulation aal5mux ppp virtual-template 3
Router(config-if-atm-vc)# ubr 500
Router(config-if-atm-vc)# exit
 
Router(config-if)# pvc 0/70
Router(config-if-atm-vc)# encapsulation aal5mux ppp virtual-template 3
Router(config-if-atm-vc)# vbr-nrt 1000 500 64
Router(config-if-atm-vc)# exit
 
Router(config-if)# pvc 0/80
Router(config-if-atm-vc)# encapsulation aal5ciscoppp virtual-template 3
Router(config-if-atm-vc)# ubr 700
Router(config-if-atm-vc)# exit
Router(config-if)#

ADSL Termination Example

The IETF-Compliant PPP over ATM feature was designed to support installations with ADSL circuits. Figure9 illustrates a topology for ADSL termination. This topology allows you to establish a PPP connection to a Cisco 7200 series router.

The example also illustrates the use of PPP tunneling using L2TP to provide VPDN services, in this case for the domain cisco.com. Thus, a user who logs in as bob@cisco.com is automatically tunneled to IP address 10.1.2.3. (See the chapter "Configuring Virtual Private Networks" in the CiscoIOS Release12.0 Cisco IOS Dial Services Configuration Guide: Network Services for details about setting up VPDN services.)

An example of the commands that you might enter for the user_router, dsl7200, and cisco-gateway (as shown in Figure 10) are described below. For further information, refer to the section "Configuring IETF-Compliant MUX Encapsulated PPP over ATM" earlier in this chapter.


Figure10: ADSL Termination


user_router Configuration

user_router(config)# interface virtual-template 1
user_router(config-if)# ip address negotiated
user_router(config-if)# ppp chap hostname user_router@cisco.com
user_router(config-if)# ppp chap password 0 cisco
user_router(config-if)# exit
 
user_router(config)# interface atm 0
user_router(config-if)# pvc 0/40
user_router(config-if-atm-vc)# encapsulation aal5mux ppp virtual-template 1
user_router(config-if-atm-vc)# exit
user_router(config-if)# exit
user_router(config)#

dsl7200 Configuration

dsl7200(config)# username user_router@cisco.com password 0 cisco
dsl7200(config)# username dsl7200 password 0 cisco
 
dsl7200(config)# vpdn enable
 
dsl7200(config)# vpdn-group 1
dsl7200(config)# request dialin l2tp ip 10.2.1.1 domain cisco.com
 
dsl7200(config)# interface virtual-template 1
dsl7200(config-if)# ppp authentication chap
dsl7200(config-if)# exit
 
dsl7200(config)# interface atm 2/0
dsl7200(config-if)# pvc 0/40
dsl7200(config-if-atm-vc)# encapsulation aal5mux ppp virtual-template 1
dsl7200(config-if-atm-vc)# exit
dsl7200(config-if)# exit
dsl7200(config)# 

cisco-gateway Configuration

cisco_gateway(config)# username cisco_gateway password 0 cisco
cisco_gateway(config)# username user_router@cisco.com password 0 cisco
 
cisco_gateway(config)# vpdn enable
 
cisco_gateway(config)# vpdn-group 1
cisco_gateway(config)# accept dialin l2tp virtual-template 1 remote dsl7200
 
cisco_gateway(config)# interface loopback 0
cisco_gateway(config-if)# ip address 10.0.1.1 255.255.255.0
cisco_gateway(config-if)# exit
 
cisco_gateway(config)# interface virtual-template 1
cisco_gateway(config-if)# ip unnumbered loopback 0
cisco_gateway(config-if)# peer default ip address pool pool-1
cisco_gateway(config-if)# exit
 
cisco_gateway(config)# ip local pool pool-1 10.1.2.1 10.1.2.254

Two Routers with Back-to-Back PVCs Example

Figure 11 illustrates an ATM interface with two PPP sessions over two PVC session connections. (See the chapter "PPP Configuration" in the CiscoIOS Dial Solutions Configuration Guide: Terminal Services for details on PPP configuration.) The sample commands following Figure 11 establish the back-to-back router configuration. For further information, refer to the section "Configuring IETF-Compliant MUX Encapsulated PPP over ATM" earlier in this chapter.


Figure11: Two Routers with Back-to-Back PVCs


R1 Configuration

Router1(config)# interface atm 2/0
Router1(config-if)# atm clock internal
Router1(config-if)# pvc 0/60
Router1(config-if-atm-vc)# encapsulation aal5mux ppp virtual-template 1
Router1(config-if-atm-vc)# ubr 90
Router1(config-if-atm-vc)# exit
 
Router1(config-if)# pvc 0/70
Router1(config-if-atm-vc)# encapsulation aal5mux ppp virtual-template 2
Router1(config-if-atm-vc)# vbr-nrt 90 50 1024
Router1(config-if-atm-vc)# exit
 
Router1(config-if)# interface virtual-template 1
Router1(config-if)# ip address 10.0.1.1 255.255.255.0
 
Router1(config-if)# interface virtual-template 2
Router1(config-if)# ip address 10.0.2.1 255.255.255.0
Router1(config-if)# exit
Router1(config)#

R2 Configuration

Router2(config)# interface atm 2/0.1 multipoint
Router2(config-if)# pvc 0/60
Router2(config-if-atm-vc)# encapsulation aal5mux ppp virtual-template 1
Router2(config-if-atm-vc)# ubr 90
Router2(config-if-atm-vc)# exit
 
Router2(config-if)# pvc 0/70
Router2(config-if-atm-vc)# encapsulation aal5mux ppp virtual-template 2
Router2(config-if-atm-vc)# vbr-nrt 90 50 1024
Router2(config-if-atm-vc)# exit
Router2(config-if)# exit
 
Router2(config)# interface virtual-template 1
Router2(config-if)# ip address 10.0.1.2 255.255.255.0
Router2(config-if)# exit
 
Router2(config)# interface virtual-template 2
Router2(config-if)# ip address 10.0.2.2 255.255.255.0

Multiplexed Encapsulation Using VC Class Example

In the following example, PVC 0/60 is configured on subinterface ATM 2/0.1 with a VC class attached to it. For details on creating and applying a VC class, see the section "Configuring VC Classes" earlier in this chapter. By rule of inheritance, PVC 0/60 runs with IETF-Compliant PPP over ATM encapsulation using the configuration from interface virtual-template 1. Its parameter is an unspecified bit rate with peak cell at 90 kbps.

Router(config)# interface atm 2/0.1
Router(config-if)# pvc 0/60
Router(config-if-atm-vc)# class-vc pvc-ppp
Router(config-if-atm-vc)# exit
Router(config-if)# exit
 
Router(config)# vc-class atm pvc-ppp
Router(config-vc-class)# encapsulation aal5mux ppp virtual-template 1
Router(config-vc-class)# ubr 90
Router(config-vc-class)# exit
Router(config)#
 

IETF-Compliant LLC Encapsulated PPP over ATM Configuration Examples

This section provides the following examples for configuring IETF-compliant LLC encapsulated PPP over ATM:

Configuring IETF-Compliant PPP over ATM LLC Encapsulation Example

This example shows how to configure IETF PPP over ATM LLC Encapsulation in the VC class called ppp-default. The VC class specifies virtual template 1 from which to spawn PPP interfaces, snap encapsulation (the default), and a UBR class traffic type at 256 kbps. When ppp-default is configured on interface 0.1, PVC 0/70 inherits these properties. PVC 0/80 overrides virtual template 1 in the VC class and uses virtual template 2 instead. PVC 0/90 also overrides virtual template 1 and uses virtual template 3 instead. In addition, PVC 0/90 uses a VC multiplexed encapsulation and a UBR class traffic type at 500 kbps. For further information, refer to the section "Configuring IETF-Compliant LLC Encapsulated PPP Over ATM" earlier in this chapter.

Router(config)# interface atm 0.1 multipoint
Router(config-if)# class-int ppp-default
!
Router(config-if)# pvc 0/70
Router(config-if-atm-vc)# exit
!
Router(config-if)# pvc 0/80
Router(config-if-atm-vc)# protocol ppp virtual-template 2
Router(config-if-atm-vc)# exit
!
Router(config-if)# pvc 0/90
Router(config-if-atm-vc)# encapsulation aal5mux ppp virtual-template 3
Router(config-if-atm-vc)# ubr 500
Router(config-if-atm-vc)# exit
Router(config-if)# exit
!
Router(config)# vc-class atm ppp-default
Router(config-vc-class)# protocol ppp virtual-template 1
Router(config-vc-class)# ubr 256
Router(config-vc-class)# exit
Router(config)#
 

Overriding a Virtual Template for IETF-Compliant PPP over ATM Example

This example illustrates how to use inheritance to override a virtual template configuration for mux ppp or ciscoppp encapsulations. For PVC 5/505, since the encapsulation at that level is ciscoppp virtual template 1, as specified in the VC class called muxppp, the protocol ppp virtual-template2 command overrides only the virtual-template configuration. For further information, refer to the section "Configuring IETF-Compliant LLC Encapsulated PPP Over ATM" earlier in this chapter.

Router(config)# interface atm 2/0
Router(config-if)# class-int muxppp
!
Router(config-if)# pvc 5/505
Router(config-if-atm-vc)# protocol ppp virtual-template 2
Router(config-if-atm-vc)# exit
!
Router(config)# vc-class muxppp
Router(config-vc-class)# encapsulation aal5ciscoppp virtual-template 1
Router(config-vc-class)# exit
Router(config)#

Disabling IETF-Compliant PPP over ATM LLC Encapsulation onaSpecificVCExample

This example shows how to limit the configuration of a particular LLC encapsulated protocol to a particular VC. First, we see that the VC class called ppp is configured with IETF PPP over ATM with LLC encapsulation and virtual template 1. This VC class is then applied to ATM interface 1/0/0. By configuring snap encapsulation by itself on PVC 0/32, you disable IETF PPP over ATM with LLC encapsulation on this particular PVC; PVC 0/32 will only carry IP. For further information, refer to the section "Configuring IETF-Compliant LLC Encapsulated PPP Over ATM" earlier in this chapter.

Router(config)# interface atm 1/0/0
Router(config-if)# class-int ppp
Router(config-if)# exit
!
Router(config)# interface atm 1/0/0.100 point-to-point
Router(config-if)# description IP only VC
Router(config-if)# ip address 10.1.1.1 255.255.255.0
Router(config-if)# pvc 0/32
Router(config-if-atm-vc)# encapsulation aal5snap
Router(config-if-atm-vc)# exit
Router(config-if)# exit
!
Router(config)# vc-class atm ppp
Router(config-vc-class)# encapsulation aal5snap
Router(config-vc-class)# protocol ppp virtual-template 1
Router(config-vc-class)# exit
Router(config)#

Cisco Proprietary PPP-over-ATM Example

The following example shows how to configure Cisco Proprietary PPP over ATM to use PPP unnumbered link and Challenge Handshake Authentication Protocol (CHAP) authentication. For further information, refer to the sections "Configuring PPP over ATM" and "Configuring Cisco Proprietary PPP over ATM" earlier in this chapter.

configure terminal
!
interface virtual-template 2
encapsulation ppp
ip unnumbered ethernet 0/0
ppp authentication chap
!
interface atm 2/0.2 point-to-point
pvc 0/34
encapsulation aal5ciscoppp virtual-template 2
exit
 

Configuring ATM E.164 Auto Conversion Example

The following example shows how to configure ATM E.164 auto conversion on an ATM interface. Figure 12 illustrates this example. For further information, refer to the section "Configuring ATM E.164 Auto Conversion Example" earlier in this chapter.

interface atm 0 multipoint
ip address 120.45.20.81 255.255.255.0
pvc 0/5 qsaal
exit
!
atm nsap-address 45.000120045020081F00000000.112233445566.00
atm e164 auto-conversion
svc nsap 45.000120045020071F00000000.665544332211.00
protocol ip 120.45.20.71
exit

Figure12: E164_AESA Address Auto Conversion Example


Upon entering an E.164 network at Router A, the destination E.164 address, extracted from the E164_AESA of the static map, is signaled in the Called Party Address. The destination E164_AESA address from the E164_AESA of the static map is signaled in the Called Party Subaddress.

The source E.164 address, extracted from the E164_AESA of the interface, is signaled in the Calling Party Address. The source E164_AESA address from the E164_AESA of the interface is signaled in the Calling Party Subaddress.

Upon leaving the E.164 network, the original Called and Calling Party addresses are extracted from the subaddresses and moved into the Called and Calling Parties. The call is then forwarded.

E164_ZDSP addresses are simply converted to E.164 addresses upon entering the E.164 network, and converted back to E164_ZDSP addresses upon leaving the network.

Configuring Circuit Emulation Services Example

The following example shows how to configure the T1 port on the ATM-CES port adapter for unstructured (clear channel) CES services. In this example, the T1 port uses adaptive clocking and the circuit name "CBR-PVC-A." For further information, refer to the section "Configuring Circuit Emulation Services" earlier in this chapter.

interface cbr 6/0
ces aal1 service unstructured
ces aal1 clock adaptive
atm clock internal
ces dsx1 clock network-derived
ces circuit 0 circuit-name CBR-PVC-A
ces pvc 0 interface atm 6/0 vpi 0 vci 512
no shutdown
no ces circuit 0 shutdown
exit

Configuring Network Clock Source Priority Example

The following example shows how to establish the T1 port on the ATM-CES port adapter as the first clocking priority and the ATM port as the second clocking priority. For further information, refer to the section "Configuring Network Clock Source and Priorities" earlier in this chapter.

network-clock-select 1 cbr 6/0
network-clock-select 2 atm 6/0
exit

Configuring Virtual Path Shaping Example

The following example shows a typical configuration for the ATM-CES port adapter with VP shaping on a Cisco 7200 series router. In this example, a VP is created with the VPI value of 1 and with a peak rate of 2000 kbps. The subsequent VCs created, one data VC and one CES VC, are multiplexed onto this VP. For further information, refer to the section "Configuring Virtual Path Shaping" earlier in this chapter.

interface atm 6/0
ip address 2.2.2.2 255.255.255.0
atm pvp 1 2000
pvc 1/33
no shutdown
exit
interface cbr 6/1
ces circuit 0
ces pvc 0 interface atm6/0 vpi 1 vci 100
exit

ATM Access over a Serial Interface Example

The following example shows how to configure a serial interface for ATM access.

In the following example, serial interface 0 is configured for ATM-DXI with MUX encapsulation. Because MUX encapsulation is used, only one protocol is carried on the PVC. This protocol is explicitly identified by a dxi map command, which also identifies the protocol address of the remote node. This PVC can carry IP broadcast traffic.

interface serial 0
ip address 172.21.178.48
encapsulation atm-dxi
dxi pvc 10 10 mux
dxi map ip 172.21.178.4 10 10 broadcast

ATM Port Adapters Connected Back-to-Back Example

The following example shows how to connect two ATM port adapters back to back. Two routers, each containing an ATM port adapter, is connected directly with a standard cable, that allows you to verify the operation of the ATM port or to directly link the routers to build a larger node.

By default, the ATM port adapter expects a connected ATM switch to provide transmit clocking. To specify that the ATM port adapter generates the transmit clock internally for SONET PLIM operation, add the atm clock internal command to your configuration.

Router A

interface atm 3/0
ip address 192.168.1.10 255.0.0.0
no keepalive
atm clock internal
pvc 1/35
!
protocol ip 192.168.1.20 broadcast

Router B

interface atm 3/0
ip address 192.168.1.20 255.0.0.0
no keepalive
atm clock internal
pvc 1/35
!
protocol ip 192.168.1.10 broadcast


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Posted: Wed Jul 19 15:49:32 PDT 2000
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