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This feature module describes the Frame Relay-to-ATM Network Interworking (FRF.5) feature. It includes information on the benefits, supported platforms, related documents, and so on.
This feature module includes the following sections:
To communicate over WANs, end-user stations and the network cloud typically must use the same type of transmission protocol. This limitation has prevented differing networks such as Frame Relay and ATM from being linked. However, the Frame Relay-to-ATM Network Interworking (FRF.5) feature allows Frame Relay and ATM networks to exchange data, despite differing network protocols. The functional requirements for linking Frame Relay and ATM networks are provided by the Frame Relay/ATM PVC Network Interworking Implementation Agreement specified in Frame Relay Forum (FRF) document number FRF.5.
FRF.5 provides network interworking functionality that allows Frame Relay end users to communicate over an intermediate ATM network that supports FRF.5. Multiprotocol encapsulation and other higher-layer procedures are transported transparently, just as they would be over leased lines. Figure 1 illustrates this concept.
FRF.5 describes network interworking requirements between Frame Relay Bearer Services and Broadband ISDN (BISDN) permanent virtual circuit (PVC) services.
The Frame Relay-to-ATM Network Interworking (FRF.5) feature benefits Internet service providers that need to link Frame Relay and ATM networks, especially those networks with ATM backbones and Frame Relay end users.
Some network interworking functions defined by FRF.5 are not supported or are not implemented in Cisco IOS Release 12.1(2)T. See the "Supported Standards, MIBs, and RFCs" section for a summary of the FRF.5 standards and Cisco support for these standards in Release 12.1(2)T.
The Frame Relay-to-ATM Network Interworking (FRF.5) feature is supported on the following platforms and interfaces:
Standards
This section compares the networking standards defined in Frame Relay Forum Document Number FRF.5: Frame Relay/ATM PVC Network Interworking Implementation Agreement with those defined for the Cisco Frame Relay-to-ATM Network Interworking (FRF.5) feature.
The following sections and subsections in this agreement are supported as follows:
MIBs
None
For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
RFCs
None
See the following sections for configuration tasks for the Frame Relay-to-ATM Network Interworking (FRF.5) feature. Each task in the list is identified as either optional or required.
To configure FRF.5 encapsulation for a one-to-one connection between two Frame Relay end users over an intermediate ATM network, use the following commands beginning in global configuration command mode:
| Command | Purpose | |
|---|---|---|
Step 1 | Router(config)#interface serialnumber | Configures the Frame Relay interface and enters interface configuration mode. |
Step2 | Router(config-if)# | Configures a switched Frame Relay DLCI. |
Step3 | Router(config)#interface atmnumber | Configures the ATM interface and enters interface configuration mode. |
Step4 | Router(config-if)# | Creates the ATM PVC and virtual path identifier/virtual channel identifier (VPI/VCI). The VCI is a 16-bit field in the header of the ATM cell. |
Step5 | Router(config-if-atm-vc)# | Configures the ATM adaption layer (AAL) and encapsulation type for the ATM PVC. |
Step6 | Router(config)#connect connection-name FR-interface FR-DLCI ATM-interface ATM-PVC network-interworking | Creates a connection to connect the Frame Relay DLCI to the ATM PVC and configures FRF.5 encapsulation. |
Step7 | Router(config-frf5)#clp-bit {0 | 1 | map-de}
| Sets the ATM cell loss priority (CLP) field in the ATM cell header.
Sets discard eligible (DE) bit mapping from ATM to Frame Relay. |
Step8 | Router( | Ends configuration mode and enters EXEC mode. Use the exit command to exit a submode and reenter global configuration command mode. |
To disconnect the FRF.5 interworking connection, use the shutdown connect subcommand.
To configure FRF.5 encapsulation for a many-to-one connection between two Frame Relay end users over an intermediate ATM network, use the following commands beginning in global configuration command mode:
| Command | Purpose | |
|---|---|---|
Step1 | Router(config)#interface serialnumber | Configures the Frame Relay interface and enters interface configuration mode. |
Step2 | Router(config-if)# | Configures a switched Frame Relay DLCI. |
Step3 | Router(config)#vc-group group-name | Assigns multiple Frame Relay DLCIs to a VC group. |
Step4 | Router(config-vc-group)#FR-interface-name FR-DLCI [FR-SSCS-DLCI] | Specifies the Frame Relay DLCIs in the VC group and maps them to the Frame Relay-SSCS DLCIs. If the optional Frame Relay-SSCS DLCI value is not specified, its value is the same as the Frame Relay DLCI. |
Step5 | Router(config)#interface atmnumber | Configures the ATM interface and enters interface configuration mode. |
Step6 | Router(config-if)# | Creates the ATM PVC and VPI/VCI. The VCI is a 16-bit field in the header of the ATM cell. |
Step7 | Router(config-if-atm-vc)# | Configures the AAL and encapsulation type for the ATM PVC. |
Step8 | Router(config)#connect connection-name vc-group group-name ATM-interface ATM-vpi/vci | Creates a connection to connect the VC group to the ATM PVC. |
Step9 | Router(config-frf5)#clp-bit {0 | 1 | map-de}
| Sets the ATM CLP field in the ATM cell header.
|
Step10 | Router( | Ends configuration mode and enters EXEC mode. Use the exit command to exit a submode and reenter global configuration command mode. |
To disconnect the FRF.5 interworking connection, use the shutdown connect subcommand.
To verify correct configuration of the Frame Relay-to-ATM Network Interworking (FRF.5) feature, perform the following tasks:
Step 1 Enter the show connect id EXEC command to view information, including interworking parameters set, for the specified connection identifier:
C3640# show connect id 5
FR/ATM Network Interworking Connection: network-1
Status - UP
Segment 1 - VC-Group network-1
Segment 2 - ATM3/0 VPI 1 VCI 34
Interworking Parameters -
de-bit map-clp
clp-bit map-de
Step 2 Enter the show connect port EXEC command to view information about the connection on a specific interface:
C3640# show connect port atm3/0 ID Name Segment 1 Segment 2 State ======================================================================== 5 network-1 VC-Group network-1 ATM3/0 1/34 UP
Step 3 Enter the show frame-relay pvc EXEC command to view statistics about Frame Relay interfaces:
C3640# show frame-relay pvc
PVC Statistics for interface Serial1/0 (Frame Relay DCE)
Active Inactive Deleted Static
Local 0 0 0 0
Switched 1 0 0 0
Unused 0 0 0 0
DLCI = 18, DLCI USAGE = FRF.5, PVC STATUS = ACTIVE, INTERFACE =
Serial1/0
input pkts 22 output pkts 21 in bytes 2140
out bytes 2110 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 0 out bcast bytes 0 Num Pkts
Switched 22
pvc create time 02:02:49, last time pvc status changed 02:02:42
Step 4 Enter the show atm pvc EXEC command to view ATM PVCs and statistics:
C3640# show atm pvc
VCD / Peak Avg/Min Burst Interface Name VPI VCI Type Encaps SC Kbps Kbps Cells Sts 3/0 10 1 32 PVC FRATMSRV UBR 155000 UP
To display status of the virtual circuits and the Frame Relay-to-ATM interworking connections, use any of the following commands in EXEC mode:
| Command | Purpose |
|---|---|
Router#show atm pvc [signalling | interface | vcd] | Displays all ATM PVCs, switched virtual circuits (SVCs), and traffic information. Use the signalling keyword to display ATM interface signalling information for all interfaces. Use the interface keyword to display all PVCs and SVCs on the interface or subinterface. Use the vcd argument to specify the ATM VCD number (1-1023) about which to display information. |
Router#show connect [all | element | ID | name | port] | Displays connection statistics. Use the optional all keyword to display statistics about all connections. Use the optional element, ID, name, or port arguments to display particular connection details. |
Router#show frame-relay pvc | Displays statistics about Frame Relay interfaces. |
Router#show vc-group | Displays the names of all VC groups. |
This section provides the following configuration examples:
The following example shows how to configure an FRF.5 one-to-one connection:
;
; Configure a switched Frame Relay DLCI
;
interface serial0
frame-relay interface-dlci 100 switched
;
; Configure ATM PVC with FRF.5 encapsulation
;
interface atm3/0
pvc 0/32
encapsulation aal5mux frame-relay
;
; Create a connection to connect Frame Relay DLCI 100 to ATM PVC 0/32
;
connect serial0 100 atm3/0 0/32 network-interworking
clp-bit 1
de-bit map-clp
The following example shows how to configure an FRF.5 many-to-one connection:
;
; Configure Frame Relay VC group
;
; The vc-group command assigns Frame Relay DLCI 16, 17, 18,
; and 19 to a VC group named 'friends'.
;
vc-group friends
serial0 16 16
serial0 17 17
serial0 18 18
serial0 19 19
;
; Configure ATM PVC with FRF.5 encapsulation
;
interface atm3/0
pvc 0/32
encapsulation aal5mux frame-relay
;
; Create a connection which connects VC group 'friends' to ATM PVC 0/32
; and configure FR DE field mapping to match ATM CLP field
;
connect vc-group friends atm3/0 0/32
de-bit map-clp
This section documents the following new and modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.1 command reference publications.
To set the ATM cell loss priority (CLP) field in the ATM cell header, use the clp-bit connect submode command. To disable ATM CLP bit mapping, use the no form of this command.
clp-bit {0 | 1 | map-de}
Syntax Description
0 The CLP field in the ATM cell header is always set to 0. 1 The CLP field in the ATM cell header is always set to 1. map-de The discard eligible (DE) field in the Frame Relay header is mapped to the CLP field in the ATM cell header.
Defaults
The default is set to map-de.
Command Modes
FRF.5 connect submode
Command History
12.1(2)T This command was introduced.
Release
Modification
Usage Guidelines
This command maps from Frame Relay to ATM.
Examples
The following example sets the CLP field in the ATM header to 1 for FRF.5:
C3640(config)# connect network-1 vc-group network-1 ATM3/0 1/35 C3640(config-frf5)# clp-bit 1
Related Commands
Connects a Frame Relay DLCI or VC group to an ATM PVC. Sets the Frame Relay DE bit field in the Frame Relay cell header.
Command
Description
To configure an FRF.5 one-to-one connection between two Frame Relay end users over an intermediate ATM network, or an FRF.5 many-to-one connection between two Frame Relay end users over an intermediate ATM network, use the connect global configuration command. To remove a connection, use the no form of this command.
connect connection-name {vc-group group-name | FR-interface FR-DLCI} ATM-interface ATM-VPI/VCI network-interworking
Syntax Description
connection-name Specifies a connection name. Enter as a 15-byte maximum character string. vc-group group-name Specifies a VC group name for a many-to-one FRF.5 connection. Enter as an 11-byte maximum character string. FR-interface Specifies the Frame Relay interface type and number, for example, serial1/0. FR-DLCI Specifies the Frame Relay data-link connection identifier (DLCI) in the range 16 to 991. ATM-interface Specifies the ATM interface type and number, for example, atm1/0. ATM-VPI/VCI Specifies the ATM virtual path identifier/virtual channel identifier (VPI/VCI). If a VPI is not specified, the default VPI is 0. network-interworking Specifies FRF.5 network interworking. Not a valid keyword if the vc-group keyword is specified.
Defaults
No default behavior or values.
Command Modes
Global configuration
Command History
12.1(2)T This command was introduced.
Release
Modification
Usage Guidelines
Use the connect command to connect a VC group to an ATM PVC or Frame Relay DLCI.
To disconnect the FRF.5 interworking connection, use the shutdown connect subcommand.
Examples
The following example shows how to create an FRF.5 one-to-one connection:
router(config)#interface serial0 router(config-if)# frame-relay interface-dlci 100 switched router(config-if)# interface atm3/0 router(config-if)# pvc 0/32 router(config-if-atm-vc)# encapsulation aal5mux frame-relayrouter(config)#connect serial0 100 atm3/0 0/32 network-interworking router(config-frf5)# clp-bit 1 router(config-frf5)# de-bit map-clp
The following example shows how to create an FRF.5 many-to-one connection:
router(config)#interface serial0 router(config-if)# frame-relay interface-dlci 100 switchedrouter(config)#vc-group friendsrouter(config-vc-group)#serial0 16 16router(config-vc-group)#serial0 17 17router(config-vc-group)#serial0 18 18router(config-vc-group)#serial0 19 19router(config)#interface atm3/0 router(config-if)# pvc 0/32 router(config-if-atm-vc)# encapsulation aal5mux frame-relayrouter(config)#connect vc-group friends atm3/0 0/32 router(config-frf5)# de-bit map-clp
Related Commands
encapsulation Configures the AAL and encapsulation type for an ATM PVC, SVC, or VC class. pvc Creates an ATM PVC on a main interface or subinterface; enters interface-ATM-VC configuration mode. Assigns multiple Frame Relay DLCIs to a VC group.
Command
Description
To set Frame Relay discard eligible (DE) bit mapping for FRF.5 network interworking, use the de-bit map-clp connect submode command. To disable or reset Frame Relay DE bit mapping, use the no form of this command.
de-bit map-clpSyntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values.
Command Modes
FRF.5 connect submode
Command History
12.1(2)T This command was introduced.
Release
Modification
Usage Guidelines
In the default state, the DE bit in the Frame Relay header is set to 1 when one or more ATM cells belonging to a frame has its cell loss priority (CLP) field set to 1, or when the DE field of the Frame Relay service specific convergence sublayer (FR-SSCS) protocol data unit (PDU) is set to 1.
When the no de-bit map-clp command is entered, the FR-SSCS PDU DE field is copied unchanged to the Q.922 core frame DE field, independent of CLP indications received at the ATM layer.
Examples
The following example creates a connection that connects the virtual circuit (VC) group named friends to ATM PVC 0/32 and configures FR DE field mapping to match the ATM CLP field:
router(config)#vc-group friendsrouter(config-vc-group)#serial0 16 16router(config-vc-group)#serial0 17 17router(config-vc-group)#serial0 18 18router(config-vc-group)#serial0 19 19router(config)#interface atm3/0 router(config-if)# pvc 0/32 router(config-if-atm-vc)# encapsulation aal5mux frame-relayrouter(config)#connect vc-group friends atm3/0 0/32 router(config-frf5)# de-bit map-clp
Related Commands
Sets the ATM CLP field in the ATM cell header. Connects a Frame Relay DLCI or VC group to an ATM PVC. Assigns multiple Frame Relay DLCIs to a VC group.
Command
Description
To indicate that a Frame Relay data-link connection identifier (DLCI) is switched, use the frame-relay interface-dlci switched interface configuration command. To remove this assignment, use the no form of this command.
frame-relay interface-dlci dlci switched
Syntax Description
dlci Specifies the Frame Relay DLCI number.
Defaults
No DLCI is assigned.
Command Modes
Interface configuration
Command History
10.0 This command was introduced. 12.1(2)T The switched keyword was added for the Frame Relay-to-ATM Network Interworking (FRF.5) feature.
Release
Modification
Usage Guidelines
This command creates an FRF.5 Frame Relay DLCI.
Examples
The following example configures serial interface 0 as a switched Frame Relay DLCI:
router(config)# interface serial0
router(config-if)# frame-relay interface-dlci 100 switched
router(config-fr-dlci)#
Related Commands
show frame-relay pvc Displays statistics about Frame Relay interfaces. show interface Displays interface information.
Command
Description
To display statistics and other information about Frame Relay-to-ATM Network Interworking (FRF.5) connections, use the show connect EXEC mode command.
show connect [all | element | ID | name | port]
Syntax Description
all (Optional) Displays information about all Frame Relay-to-ATM Network Interworking (FRF.5) connections. element (Optional) Displays information about the specified connection element. ID (Optional) Displays information about the specified connection identifier. name (Optional) Displays information about the specified connection name. port (Optional) Displays information about all connections on an interface.
Defaults
Default state is show connect all.
Command Modes
EXEC
Command History
12.1(2)T This command was introduced.
Release
Modification
Examples
The following example displays information about all FRF.5 connections:
C3640# show connect all ID Name Segment 1 Segment 2 State ======================================================================== 5 network-1 VC-Group network-1 ATM3/0 1/34 UP
The following example displays information about the specified FRF.5 connection identifier:
C3640# show connect id 5
FR/ATM Network Interworking Connection: network-1
Status - UP
Segment 1 - VC-Group network-1
Segment 2 - ATM3/0 VPI 1 VCI 34
Interworking Parameters -
de-bit map-clp
clp-bit map-de
Table 1 describes the fields seen in these displays.
| Display | Description |
|---|---|
ID | Arbitrary connection identifier assigned by the operating system. |
Name | Assigned connection name. |
Segment 1 or 2 | Frame Relay or ATM interworking segments. |
State or Status | Status of the connection, UP, DOWN, or ADMIN DOWN. |
Related Commands
Connects a Frame Relay DLCI or VC group to an ATM PVC. show atm pvc Displays all ATM PVCs, SVCs, and traffic information. show frame-relay pvc Displays statistics about Frame Relay interfaces. Displays the names of all VC groups.
Command
Description
To display the names of all virtual circuit (VC) groups, use the show vc-group EXEC command.
show vc-group [group-name]
Syntax Description
group-name (Optional) Name defined by the vc-group command. If this argument is not specified, the names of all VC groups in the system are displayed.
Defaults
The names of all VC groups in the system are displayed.
Command Modes
EXEC
Command History
12.1(2)T This command was introduced.
Release
Modification
Examples
The following example shows the default display of the show vc-group EXEC command:
C3640# show vc-group Name of All VC Groups: ====================== network-1
Related Commands
show atm pvc Displays all ATM PVCs, SVCs, and traffic information. show frame-relay pvc Displays statistics about Frame Relay interfaces. Assigns multiple Frame Relay DLCIs to a VC group.
Command
Description
To shut down a Frame Relay-to-ATM Network Interworking (FRF.5) connection, use the shutdown connect submode command. To disable disconnection, use the no form of this command.
shutdownSyntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values.
Command Modes
FRF.5 connect submode
Command History
12.1(2)T This command was introduced.
Release
Modification
Usage Guidelines
The FRF.5 connection must be manually shut down once the interworking connection is created by use of the shutdown connect subcommand.
Examples
The following example shows how to shut down an FRF.5 connection:
C3640(config)# connect network-2 interface serial0/1 16 atm3/0 0/32 network-interworking . . . C3640(config-frf5)# shutdown
Related Commands
Connects a Frame Relay DLCI or VC group to an ATM PVC.
Command
Description
To assign multiple Frame Relay data-link connection identifiers (DLCIs) to a virtual circuit (VC) group for Frame Relay-to-ATM Network Interworking (FRF.5), use the vc-group global configuration mode command. To disable the VC group assignments, use the no form of this command.
vc-group group-nameThis command requires the use of the following VC group subcommands to provide a map between Frame Relay DLCIs and Frame Relay-SSCS DLCIs:
VC Group Subcommands
FR-interface-name FR-DLCI [FR-SSCS-DLCI]
Syntax Description
group-name A VC group name entered as an 11-character maximum string.
vc-group Subcommands Syntax Description
FR-interface-name | Frame Relay interface, for example, serial0/0. |
FR-DLCI | Frame Relay DLCI number in the range 16 to 991. |
FR-SSCS-DLCI | (Optional) Frame Relay SSCS DLCI number. Default is 1022. |
Defaults
No default behavior or values.
Command Modes
Global configuration
Command History
12.1(2)T This command was introduced.
Release
Modification
Usage Guidelines
This command specifies the Frame Relay DLCIs in the VC group and maps them to the Frame Relay-SSCS DLCIs. If the optional FR-SSCS DLCI value is not specified, its value is the same as the Frame Relay DLCI.
Examples
The following example shows how to configure an FRF.5 many-to-one connection. The vc-group command maps Frame Relay DLCI 16, 17, 18, and 19 to a VC group named friends:
Router(config)#vc-group friends Router(config-vc-group)#serial0 16 16 Router(config-vc-group)#serial0 17 17 Router(config-vc-group)#serial0 18 18 Router(config-vc-group)#serial0 19 19
Related Commands
Displays the names of all VC groups.
Command
Description
Asynchronous Transfer Mode---See ATM.
ATM---Asynchronous Transfer Mode. International standard for cell relay in which multiple service types (such as voice, video, or data) are conveyed in fixed-length (53-byte) cells. Fixed-length cells allow cell processing to occur in hardware, thereby reducing transit delays. ATM is designed to take advantage of high-speed transmission media such as E3, SONET, and T3.
data-link connection identifier---See DLCI.
DLCI---data-link connection identifier. Value that specifies a permanent virtual circuit or switched virtual circuit in a Frame Relay network. In the basic Frame Relay specification, DLCIs are locally significant (connected devices might use different values to specify the same connection).
Frame Relay---Industry-standard, switched data link layer protocol that handles multiple virtual circuits using High-Level Data Link Control encapsulation between connected devices.
IMA---inverse multiplexing over ATM. Standard protocol defined by the ATM Forum in 1997.
inverse multiplexing over ATM---See IMA.
OC-3---optical carrier signal level 3. One of a series of physical protocols defined for SONET optical signal transmissions.
optical carrier signal level 3---See OC-3.
permanent virtual circuit---See PVC.
PVC---permanent virtual circuit. Virtual circuit that is permanently established. PVCs save bandwidth associated with circuit establishment and tear down in situations where certain virtual circuits must exist all the time. In ATM terminology, called a permanent virtual connection.
service specific convergence sublayer---See SSCS.
SSCS---service specific convergence sublayer. One of the two sublayers of any ATM adaption layer (AAL). SSCS, which is service-dependent, offers assured data transmission.
SVC---switched virtual circuit. Virtual circuit that is dynamically established on demand and is torn down when transmission is complete. SVCs are used in situations where data transmission is sporadic. In ATM terminology, called a switched virtual connection.
switched virtual circuit---See SVC.
Posted: Fri Jun 9 10:18:50 PDT 2000
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