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Point-to-Point Protocol (PPP) over Asynchronous Transfer Mode (ATM) is now available on an ATM CES port adapter in a Cisco 7200-series router.
Also in this release, PPP over ATM is enhanced to support virtual circuit (VC) multiplexed encapsulation and complies with the Internet Engineering Task Force (IETF) draft on multiplexed encapsulation titled PPP over AAL5. The previous version of PPP over ATM supported only the Frame Forwarding data encapsulation (aal5ciscoppp).
This release of the PPP over ATM feature provides support for IETF-compliant PPP over ATM and significantly increases the maximum number of PPP over ATM sessions running on a router. The maximum number of PPP over ATM sessions supported on a platform depends on available system resources such as memory and CPU speed.
PPP over ATM is not supported on switched virtual circuits (SVCs) and can only be applied to PVCs. IETF-compliant PPP over ATM VC encapsulations can only be configured using the new ATM syntax. The Frame Forwarding PPP over ATM encapsulation can be configured using either the new command syntax or the old atm pvc command.
This release does not support NetFlow switching or optimum switching PPP over ATM traffic; however, PPP over ATM fastswitching will be supported.
This feature is supported only on the Cisco 7200 series routers with ATM CES (and NPE-200 processor recommended) for the 11.3 AA release.
The PPP over ATM feature supports both VC multiplexed and the Frame Forwarding data encapsulations. These configuration tasks are described in the following sections:
None
Decide which encapsulation method you will use, VC multiplexed or Frame Forwarding data encapsulation, then perform one of the tasks in the following sections.
To configure PPP over ATM to support the VC multiplexed PPP payloads as specified by the PPP over AAL5 Internet Draft, perform the following tasks beginning in interface configuration mode:
| Task | Command |
|---|---|
Configure a PPP over ATM PVC on a multipoint ATM interface. | interface atm number multipoint |
Configure the PVC. | pvc vpi/vci |
Configure VC multiplexed encapsulation. |
To configure PPP over ATM to support the Frame Forwarding encapsulation type, perform the following tasks beginning in interface configuration mode:
| Task | Command |
|---|---|
Configure a PPP over ATM PVC on a multipoint ATM interface. | interface atm number multipoint |
Configure the PVC. | pvc vpi/vci |
Configure 's Frame Forwarding encapsulation. | encapsulation aal5ciscoppp virtual-template number |
This section provides the following examples of how to configure IETF PPP over ATM:
Running PVCs with different PPP over ATM encapsulation types under the same subinterface is supported. In the following example, three PVCs are configured for PPP over ATM on subinterface ATM 2/0.1. PVC 0/60 is configured with VC multiplexed PPP payload encapsulation. Its traffic shaping parameter is an unspecified bit rate with peak cell rate at 500 kbps. PVC 0/70 is also configured with VC multiplexed PPP payload 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 Frame Forwarding encapsulation. Its traffic shaping parameter is an unspecified bit rate with peak cell rate at 700 kbps.
int atm 2/0.1 multipoint pvc 0/60 encapsulation aal5mux ppp virtual-template 3 ubr 500 pvc 0/70 encapsulation aal5mux ppp virtual-template 3 vbr-nrt 1000 500 64 pvc 0/80 encapsulation aal5ciscoppp virtual-template 3 ubr 700
The IETF PPP over ATM feature was designed to support installations with Asymmetric Digital Subscriber Line (ADSL) circuits. Figure 1 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 L2F 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 Dialup Networks in the Cisco IOS release 11.3 Dial Solutions Configuration Guide for details about setting up VPDN services.)
The commands that you might enter to configure this topology are very similar to those in the previous example, and follow Figure 1.
int atm 4/0.1 multipoint pvc 0/60 encapsulation aal5mux ppp virtual-template 3 ubr 500 pvc 0/70 encapsulation aal5mux ppp virtual-template 3 vbr-nrt 1000 500 64 pvc 0/80 encapsulation aal5mux ppp virtual-template 3 ubr 700
vpdn enable vpdn outgoing cisco.com dsl7200 ip 10.1.2.3 username dsl7200 password password-1 username cisco-gateway password password-2
Figure 2 illustrates an ATM interface with two PVC session connections. (See the chapter Dial-In Terminal Service and Remote Node Configuration in the Cisco IOS release 11.3 Dial Solutions Configuration Guide for details on PPP configuration.) The sample commands following Figure 2 establish the back-to-back router configuration.
int atm 2/0 atm clock internal pvc 0/60 encapsulation aal5mux ppp virtual-template 1 ubr 90 ! pvc 0/70 encapsulation aal5mux ppp virtual-template 2 vbr-nrt 90 50 1024 ! interface Virtual-Template1 ip address 10.0.1.1 255.255.255.0 ! interface Virtual-Template2 ip address 10.0.2.1 255.255.255.0 !
int atm 2/0.1 multipoint pvc 0/60 encapsulation aal5mux ppp virtual-template 1 ubr 90 ! pvc 0/70 encapsulation aal5mux ppp virtual-template 2 vbr-nrt 90 50 1024 ! interface Virtual-Template1 ip address 10.0.1.2 255.255.255.0 ! interface Virtual-Template2 ip address 10.0.2.2 255.255.255.0 !
In the following example, PVC 0/60 is configured on subinterface ATM 2/0.1 with a VC class attached to it. (See the chapter New VC Configuration in the Cisco IOS 11.3(2)T release Enhanced ATM VC Configuration and Management guide for details on assigning a VC class rather than an encapsulation method.) By rule of inheritance, PVC 0/60 runs with VC multiplexed PPP encapsulation using the configuration from interface virtual-template 1. Its parameter is an unspecified bit rate with peak cell at 90 kbps.
int atm 2/0.1 pvc 0/60 class pvc-ppp vc-class atm pvc-ppp encapsulation aal5mux ppp virtual-template 1 ubr 90
This section describes enhancements to the following commands:
To configure the ATM adaptation layer (AAL) and encapsulation type for an ATM PVC, SVC, or VC class, use the encapsulation command in the appropriate command mode. Use the no form of this command to remove an encapsulation from a PVC, SVC, or VC class.
encapsulation aal-encap [virtual-template number]
aal-encap | ATM adaptation layer (AAL) and encapsulation type. When aal5mux is specified, a protocol is required. Possible values for aal-encap are as follows: aal5ciscoppp---For Cisco PPP over ATM. Supported on ATM PVCs only. Use the virtual-template number argument to establish. aal5mux apollo---For a multiplex (MUX)-type virtual circuit using the Apollo protocol. aal5mux appletalk---For a MUX-type virtual circuit using the AppleTalk protocol. aal5mux decnet---For a MUX-type virtual circuit using the DECnet protocol. aal5mux ip---For a MUX-type virtual circuit using the IP protocol. aal5mux ipx---For a MUX-type virtual circuit using the IPX protocol. aal5mux ppp---For a MUX-type virtual circuit running PPP over ATM. Use the virtual-template number argument to establish. aal5mux vines---For a MUX-type virtual circuit using the VINES protocol. |
| aal5mux xns---For a MUX-type virtual circuit using the XNS protocol. aal5nlpid---Allows ATM interfaces to interoperate with High-Speed Serial Interfaces (HSSIs) that are using an ATM data service unit (ADSU) and running ATM-Data Exchange Interface (DXI). Supported on ATM PVCs only. aal5snap---The only encapsulation supported for Inverse ARP. Logical Link Control/Subnetwork Access Protocol (LLC/SNAP) precedes the protocol datagram. |
virtual-template number | (This argument is required for aal5ciscoppp and aal5mux ppp encapsulations only). Specifies the number used to identify the virtual template. |
The global default encapsulation is aal5snap. See the "Usage Guidelines" section for other default characteristics.
Interface-ATM-VC configuration (for an ATM PVC or SVC)
VC-class configuration (for a VC class)
This command first appeared in Cisco IOS Release 11.3 T.
Use of one of the aal5mux encapsulation options to dedicate the specified PVC to a single protocol; use the aal5snap encapsulation option to multiplex two or more protocols over the same PVC. Whether you select aal5mux or aal5snap encapsulation might depend on practical considerations, such as the type of network and the pricing offered by the network. If the network's pricing depends on the number of PVCs set up, aal5snap might be the appropriate choice. If pricing depends on the number of bytes transmitted, aal5mux might be the appropriate choice because it has slightly less overhead.
When configuring Cisco PPP over ATM, specify the aal5ciscoppp encapsulation for the aal-encap argument and specify the virtual template number.
It is possible to implicitly create a virtual template when configuring PPP over ATM. In other words, if the parameters of the virtual template are not explicitly defined before configuring the ATM PVC, the PPP interface will be brought up using default values from the virtual template identified. However, some parameters (such as an IP address) take effect only if they are specified before the PPP interface comes up. Therefore, we recommend that you explicitly create and configure the virtual template before configuring the ATM PVC to ensure such parameters take effect.
If you specify virtual template parameters after the ATM PVC is configured, you should issue a shutdown command followed by a no shutdown command on the ATM subinterface to restart the interface, causing the newly configured parameters (such as an IP address) to take effect.
If the encapsulation command is not explicitly configured on an ATM PVC or SVC, the VC inherits the following default configuration (listed in order of next highest precedence):
The following example configures an ATM PVC with VPI 0 and VCI 33 for a MUX-type encapsulation using IP:
pvc 0/33 encapsulation aal5mux ip
To configure an ATM interface type and enter interface configuration mode, use the interface atm global configuration command.
interface atm number (for the NPM on Cisco 4500 and 4700 routers)To configure a subinterface, use the interface atm global configuration command.
interface atm number.subinterface-number {multipoint | point-to-point} (for the NPM on
number | On Cisco 4500 and Cisco 4700 routers, specifies the NPM number. The numbers are assigned at the factory at the time of installation or when added to a system, and can be displayed with the show interfaces command. |
port-adapter | ATM port adapter number for the ATM port adapter on Cisco 7500 series routers. The value can be 0 or 1. |
slot | On the Cisco 7000 series routers with RSP7000 and Cisco 7200 series, specifies the backplane slot number. On the 7000, the slot number can be 0, 1, 2, 3, or 4. |
.subinterface-number | Subinterface number in the range 1 to 4294967293. |
multipoint | point-to-point | Specifies a multipoint or point-to-point subinterface. There is no default. |
None
Global configuration
This command first appeared in Cisco IOS Release 10.0 for the Cisco 7000 family routers.
This command first appeared in Cisco IOS Release 11.0 for the Cisco 4500 and 4700 routers.
The following example assigns an IP network address and network mask to the ATM interface in slot 1 on port 0 of a Cisco 7500 series router:
interface atm 1/0
ip address 1.1.1.1.255.255.255.0
show interfaces atm
To display all ATM PVCs and traffic information, use the show atm pvc privileged EXEC command.
show atm pvc [vpi/vci | name | interface atm interface_number | ppp]
vpi/vci | (Optional) The ATM VPI and VCI numbers. The absence of the slash character (/) and a vpi value defaults the vpi value to 0. |
name | (Optional) Name of the PVC. |
interface atm interface_number | (Optional) Interface number or subinterface number of the PVC. Displays all PVCs on the specified interface or subinterface. The interface_number uses one of the following formats, depending on what router platform you are using: slot/0[.subinterface-number multipoint] (for the AIP on Cisco 7500 series routers and ATM port adapter on the Cisco 7200 series routers) number[.subinterface-number multipoint] (for the NPM on Cisco 4500 and 4700 routers) slot/port-adapter/0[.subinterface-number multipoint] (for the ATM port adapter on Cisco 7500 series routers) For a description of these arguments, refer to the interface atm command. |
Privileged EXEC
This command first appeared in Cisco IOS Release 11.3 T.
If the vpi/vci or name is not specified, the output of this command is the same as that of the show atm vc command but only the configured PVCs are displayed. See the first sample output below.
If the vpi/vci or name is specified, the output of this command is the same as the show atm vc vcd command, plus extra information related to PVC management including connection name, detailed states, and OAM counters. See the second sample output below.
If the interface atm interface-number option is included in the command, all PVCs under that interface or subinterface are displayed. See the third sample output below.
The following is sample output from the show atm pvc command:
Router# show atm pvc VCD/ Peak Avg/Min Burst Interface Name VPI VCI Type Encaps Kbps Kbps Cells Sts 2/0 1 0 5 PVC SAAL 155000 155000 UP 2/0 2 0 16 PVC ILMI 155000 155000 UP 2/0.2 101 0 50 PVC SNAP 155000 155000 UP 2/0.2 102 0 60 PVC SNAP 155000 155000 DOWN 2/0.2 104 0 80 PVC SNAP 155000 155000 UP 2/0 hello 0 99 PVC SNAP 1000 UP
The following is sample output from the show atm pvc command with the vpi/vci specified:
Router# show atm pvc 0/99 ATM 2/0.2: VCD 102, VPI: 0, VCI: 60 UBR, PeakRate: 155000 AAL5-LLC/SNAP, etype:0x0, Flags: 0xC20, VCmode: 0x1 OAM frequency: 3 second(s), OAM retry frequency: 1 second(s) OAM up retry count: 3, OAM down retry count: 5 OAM Loopback status: OAM Sent OAM VC state: Not Verified ILMI VC state: Not Managed VC is managed by OAM InARP frequency: 15 minute(s) InPkts: 1, OutPkts: 1, InBytes: 32, OutBytes: 32 InPRoc: 1, OutPRoc: 0, Broadcasts: 0 InFast: 0, OutFast:0, InAS: 0, OutAS: 0 OAM cells received: 14 F5 InEndloop: 14, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0 F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0 OAM cells sent: 25 F5 OutEndloop: 25, F5 OutSegloop: 0, F5 OutRDI: 0 OAM cell drops: 0 PVC Discovery: NOT_VERIFIED Status: DOWN, State: NOT_VERIFIED
The following is sample output from the show atm pvc command with the ATM subinterface specified:
Router# show atm pvc interface atm 2/0.2 VCD/ Peak Avg/Min Burst Interface Name VPI VCI Type Encaps Kbps Kbps Cells Sts 2/0.2 101 0 50 PVC SNAP 155000 155000 UP 2/0.2 102 0 60 PVC SNAP 155000 155000 DOWN 2/0.2 104 0 80 PVC SNAP 155000 155000 UP
The following is sample output from the show atm pvc command with PPP specified:
Router# show atm pvc ppp VCD/ ATM Int. Name VPI VCI Type VCSt VA VASt 2/0.1 10 0 60 PVC UP 1 UP
The following is sample output from the show atm pvc command that shows the virtual access state:
stirling#sh atm pvc 0/100 ATM2/0.100: VCD: 100, VPI: 0, VCI: 100 PeakRate: 155000, Average Rate: 155000 AAL5-CISCOPPP, etype:0x9, Flags: 0xC29, VCmode: 0xE000 OAM frequency: 0 second(s), OAM retry frequency: 0 second(s) OAM up retry count: 0, OAM down retry count: 0 OAM Loopback status: OAM Disabled OAM VC state: Not Managed ILMI VC state: Not Managed InARP DISABLED InPkts: 0, OutPkts: 22, InBytes: 0, OutBytes: 308 InPRoc: 0, OutPRoc: 22, Broadcasts: 0 InFast: 0, OutFast: 0, InAS: 0, OutAS: 0 OAM cells received: 0 F5 InEndloop: 0, F5 InSegloop: 0, F5 InAIS: 0, F5 InRDI: 0 F4 InEndloop: 0, F4 InSegloop: 0, F4 InAIS: 0, F4 InRDI: 0 OAM cells sent: 0 F5 OutEndloop: 0, F5 OutSegloop: 0, F5 OutRDI: 0 OAM cell drops: 0 Status: UP virtual-access: 1 virtual-access state: UP virtual-template: 3
Table 1 describes significant fields shown in the displays.
| Field | Description |
|---|---|
ATM Int | ATM interface on which the PVC is configured. |
Interface | Interface and subinterface slot and port. |
VCD/Name | Virtual circuit descriptor (virtual circuit number). The connection name is displayed if a name for the VC was configured using the pvc command. |
VPI | Virtual path identifier. |
VCI | Virtual channel identifier. |
Type | Type of PVC detected from PVC discovery, either PVC-D, PVC-L, or PVC-M.
|
Type of ATM adaptation layer (AAL) and encapsulation. | |
Peak or PeakRate | Kilobits per second transmitted at the peak rate. |
Avg/Min or Average Rate | Kilobits per second transmitted at the average rate. |
Burst Cells | Value that equals the maximum number of ATM cells the virtual circuit can transmit at peak rate. |
Sts or Status | Status of the VC connection.
|
Connection Name | The name of the PVC. |
UBR, UBR+, or VBR-NRT | UBR---Unspecified Bit Rate QOS is specified for this PVC. See the ubr command for further information. UBR+---Unspecified Bit Rate QOS is specified for this PVC. See the ubr+ command for further information. VBR-NRT---Variable Bit Rate-Non Real Time QOS rates are specified for this PVC. See the vbr-nrt command for further information. |
etype | Encapsulation type. |
Flags | Bit mask describing virtual circuit information. The flag values are summed to result in the displayed value. 0x40---SVC 0x20---PVC 0x10---ACTIVE 0x0---AAL5-SNAP 0x2---AAL5-FRNLPID 0x3---AAL5-MUX 0x4---AAL3/4-SMDS 0x5---QSAAL 0x6---ILMI 0x7---AAL5-LANE 0x9---AAL5-CISCOPPP |
virtual-access | Virtual access interface identifier. |
virtual-template | Virtual template identifier. |
VCmode | AIP-specific or NPM-specific register describing the usage of the virtual circuit. This register contains values such as rate queue, peak rate, and AAL mode, which are also displayed in other fields. |
OAM frequency | Number of seconds between sending OAM loopback cells. |
OAM retry frequency | The frequency (in seconds) that end-to-end F5 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. |
OAM up retry count | Number of consecutive end-to-end F5 OAM loopback cell responses that must be received in order to change a PVC state to up. Does not apply to SVCs. |
OAM down retry count | Number of consecutive end-to-end F5 OAM loopback cell responses that are not received in order to change a PVC state to down or tear down an SVC. |
OAM Loopback status | Status of end-to-end F5 OAM loopback cell generation for this VC. This field will have one of the following values:
|
OAM VC state | This field will have one of the following states for this VC:
|
ILMI VC state | |This field will have one of the following states for this VC:
|
VC is managed by OAM/ILMI | VC is managed by OAM and/or ILMI. |
InARP frequency | Number of minutes for the Inverse ARP time period. |
InPkts | Total number of packets received on this virtual circuit. This number includes all fast-switched and process-switched packets. |
OutPkts | Total number of packets sent on this virtual circuit. This number includes all fast-switched and process-switched packets. |
InBytes | Total number of bytes received on this virtual circuit. This number includes all fast-switched and process-switched bytes. |
OutBytes | Total number of bytes sent on this virtual circuit. This number includes all fast-switched and process-switched bytes. |
InPRoc | Number of process-switched input packets. |
OutPRoc | Number of process-switched output packets. |
Broadcasts | Number of process-switched broadcast packets. |
InFast | Number of fast-switched input packets. |
OutFast | Number of fast-switched output packets. |
InAS | Number of autonomous-switched or silicon-switched input packets. |
OutAS | Number of autonomous-switched or silicon-switched output packets. |
OAM cells received | Total number of OAM cells received on this virtual circuit. |
F5 InEndloop | Number of end-to-end F5 OAM loopback cells received. |
F5 InSegloop | Number of segment F5 OAM loopback cells received. |
F5 InAIS | Number of F5 OAM AIS cells received. |
F5 InRDI | Number of F5 OAM RDI cells received. |
F4 InEndloop | Number of end-to-end F4 OAM loopback cells received. |
F4 InSegloop | Number of segment F4 OAM loopback cells received. |
F4 InAIS | Number of F4 OAM AIS cells received. |
F4 InRDI | Number of F4 OAM RDI cells received. |
OAM cells sent | Total number of OAM cells sent on this virtual circuit. |
F5 OutEndloop | Number of end-to-end F5 OAM loopback cells sent. |
F5 OutSegloop | Number of segment F5 OAM loopback cells sent. |
F5 OutRDI | Number of F5 OAM RDI cells sent. |
OAM cell drops | Number of OAM cells dropped (or flushed). |
PVC Discovery | NOT_VERIFIED---This PVC is manually configured on the router and not yet verified with the attached adjacent switch. WELL_KNOWN---This PVC has a VCI value of 0 through 31. DISCOVERED---This PVC is learned from the attached adjacent switch via ILMI. MIXED---Some of the traffic parameters for this PVC were learned from the switch via ILMI. MATCHED---This PVC is manually configured on the router and the local traffic shaping parameters match the parameters learned from the switch. MISMATCHED---This PVC is manually configured on the router and the local traffic shaping parameters do not match the parameters learned from the switch. LOCAL_ONLY---This PVC is configured locally on the router and not on the remote switch. |
State | When the Status field is UP, this field does not appear. When the Status field is DOWN or INACTIVE, the State field will appear with one of the following values: NOT_VERIFIED---The VC has been established successfully; Waiting for OAM (if enabled) and ILMI (if enabled) to verify that the VC is up. NOT_EXIST---VC has not been created. HASHING_IN---VC has been hashed into a hash table. ESTABLISHING---Ready to establish VC connection. MODIFYING---VC parameters have been modified. DELETING---VC is being deleted. DELETED---VC has been deleted. NOT_IN_SERVICE---ATM interface is shut down. |
VCSt | Virtual circuit state |
VA | Virtual Access Interface number |
VASt | Virtual Access Interface State |
Posted: Thu Feb 25 21:46:30 PST 1999
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