Usage Guidelines

Before you can use the echo command, you must first enter the mpls oam command to enter MPLS OAM configuration mode.

The jitter keyword specifies the jitter TLV that is encoded in the echo request to instruct the responder to delay responding by a random time between zero and the jitter value. This allows the echo replies to be spread out uniformly over the jitter duration. The configured jitter value is also used by the responder node. If the configured jitter value is smaller than the received jitter TLV, then the reply is generated after a random time between one and the configured jitter value. If the configured jitter value is larger than the received jitter TLV, then the reply is generated after a random time between one and the received jitter TLV.

Specify the revision keyword if one of the following conditions exists:

• You want to change the revision number from the default value of 4 to 3 .

• You previously entered the mpls oam command and changed the revision number to 3 and you want to change it back to 4 .

To prevent failures reported by the replying device due to TLV version issues, you can use the echo revision command to configure all devices in the core for the same version of the IEFT label-switched path (LSP) ping draft. For example, if the network is running draft RFC 4379 implementations, but one device is capable of only Version 3 (Cisco Revision 3), configure all devices in the network to operate in Revision 3 mode. Revision 3 mode is used only with Multiprotocol Label Switching (MPLS) LSP ping or traceroute. Revision 3 mode does not support MPLS multipath LSP traceroute.

The vendor-extension keyword is enabled by default in the device. If your network includes devices that are not Cisco devices, you may want to disable Cisco-extended TLVs. To disable Cisco-extended TLVs, specify the no echo vendor-extension command in MPLS OAM configuration mode. To enable Cisco-extended TLVs again, enter the echo vendor-extension command.

Usage Guidelines

In L2transport VC configuration mode, the pvc command and the encapsulation command work together. Use the commands for AToM differently than for all other applications. The table below shows the differences in how the commands are used.

Router(config-if)# pvc 1/100
Router(config-if-atm-vc)# encapsulation aal5snap

Router(config-if)# pvc 1/100 l2transport
Router(config-if-atm-l2trans-pvc)# encapsulation aal5

The following list highlights the differences:

• pvc command: For most applications, you create a permanent virtual circuit (PVC) by using the pvc vpi/vci command. For AToM, you must add the l2transport keyword to the pvc command. The l2transport keyword enables the PVC to transport Layer 2 packets.

• encapsulation command: The encapsulation command for AToM has only two keyword values: aal5 or aal0 . You cannot specify an encapsulation type, such as aal5snap . In contrast, the encapsulation aal5 command you use for most other applications requires you to specify the encapsulation type, such as aal5snap .

• You cannot create switched virtual circuits or VC bundles to transport Layer 2 packets.

When you use the aal5 keyword, incoming cells (except Operation, Administration, and Maintenance [OAM] cells) on that PVC are treated as AAL5 encapsulated packets. The router reassembles the packet from the incoming cells. The router does not check the contents of the packet, so it does not need to know the encapsulation type (such as aal5snap and aal5mux ). After imposing the Multiprotocol Label Switching (MPLS) label stack, the router sends the reassembled packet over the MPLS core network.

When you use the aal0 keyword, the router strips the header error control (HEC) byte from the cell header and adds the MPLS label stack. The router sends the cell over the MPLS core network.

Usage Guidelines

The pvc command and the encapsulation command work together. The use of these commands with Layer 2 local switching is slightly different from the use of these commands with other applications. The following list highlights the differences:

• For Layer 2 local switching, you must add the l2transport keyword to the pvc command. The l2transport keyword enables the PVC to transport Layer 2 packets.

• The Layer 2 local switching encapsulation command works only with the pvc command. You cannot create switched virtual circuits or VC bundles to transport Layer 2 packets. You can use only PVCs to transport Layer 2 packets.

The table below shows the encapsulation types supported for each transport type:

Usage Guidelines

Interface Range Configuration Mode

IEEE 802.1Q encapsulation is configurable on Fast Ethernet interfaces. IEEE 802.1Q is a standard protocol for interconnecting multiple switches and routers and for defining VLAN topologies.

Use the encapsulationdot1q command in interface range configuration mode to apply a VLAN ID to each subinterface within the range specified by theinterfacerange command. The VLAN ID specified by the vlan-id argument is applied to the first subinterface in the range. Each subsequent interface is assigned a VLAN ID, which is the specified vlan-id value plus the subinterface number minus the first subinterface number (VLAN ID + subinterface number - first subinterface number).

Note	The Cisco 10000 series router does not support the interfacerange command nor the interface range configuration mode.

Do not configure encapsulation on the native VLAN of an IEEE 802.1Q trunk without using the native keyword. (Always use the native keyword when vlan-id is the ID of the IEEE 802.1Q native VLAN.)

Subinterface Configuration Mode

Use the second-dot1q keyword to configure the IEEE 802.1Q-in-Q VLAN Tag Termination feature. 802.1Q in 802.1Q (Q-in-Q) VLAN tag termination adds another layer of 802.1Q tag (called “metro tag” or “PE-VLAN”) to the 802.1Q tagged packets that enter the network. Double tagging expands the VLAN space, allowing service providers to offer certain services such as Internet access on specific VLANs for some customers and other types of services on other VLANs for other customers.

After a subinterface is defined, use the encapsulationdot1q command to add outer and inner VLAN ID tags to allow one VLAN to support multiple VLANs. You can assign a specific inner VLAN ID to the subinterface; that subinterface is unambiguous. Or you can assign a range or ranges of inner VLAN IDs to the subinterface; that subinterface is ambiguous.

Usage Guidelines

The following error message is displayed if you use the no encapsulation mpls or encapsulation (l2tpv3) command to change encapsulation on an existing pseudowire:

Encapsulation changes are not allowed on an existing pw-class.

You must configure the ip local interface command on the same pseudowire class to define the local IP address. All existing time-to-live (TTL) and type of service (TOS) setting values configured by the ip ttl and ip tos (L2TP) commands are allowed in the pseudowire class. The ip local interface command is applicable only when L2TP and UDP data encapsulation methods are used.

Note	The l2tpv2 , l2tpv3 , and udp keywords are not available in interface configuration and template configuration modes.

Usage Guidelines

An IP explicit path is a list of IP addresses, each representing a node or link in the explicit path. If you enter the exclude-address command and specify the IP address of a link, the constraint-based Shortest Path First (SPF) routine does not consider that link when it sets up Multiprotocol Label Switching (MPLS) traffic engineering paths. If the excluded address is a flooded MPLS traffic engineering router ID, the constraint-based SPF routine does not consider that entire node. The person performing the configuration must know the router IDs of the routers because it will not be apparent whether the specified number is for a link or for a node.

Note	MPLS traffic engineering will accept an IP explicit path that comprises either all excluded addresses configured by the exclude-address command or all included addresses configured by the next-address command, but not a combination of both.

Usage Guidelines

Use this command after you have configured LSP-related attributes for a traffic engineering (TE) tunnel to exit the LSP attribute list and the LSP Attributes configuration mode.

Usage Guidelines

Use the exit-address-family command to exit address-family configuration mode and return to router configuration mode.

This command can be abbreviated to exit .

Usage Guidelines

Assignment of MPLS EXP levels to Frame Relay PVC bundle members lets you create differentiated services, because you can distribute the levels over the various PVC bundle members. You can map a single level or a range of levels to each discrete PVC in the bundle, which enables PVCs in the bundle to carry packets marked with different levels.

Use the exp other command to indicate that a PVC can carry traffic marked with EXP levels not specifically configured for other PVCs. Only one PVC in the bundle can be configured using the exp other command.

All EXP levels must be accounted for in the PVC bundle configuration, or the bundle will not come up. However, a PVC can be a bundle member but have no EXP level associated with it. As long as all valid EXP levels are handled by other PVCs in the bundle, the bundle can come up, but the PVC that has no EXP level configured will not participate in it.

The exp command is available only when MPLS is configured on the interface with the mpls ip command.

You can overwrite the EXP level configuration on a PVC by reentering the exp command with a new value.

The MPLS experimental bits are a bit-by-bit copy of the IP precedence bits. When Frame Relay PVC bundles are configured for IP precedence and MPLS is enabled, the precedence command is replaced by the exp command. When MPLS is disabled, the exp command is replaced by the precedence command.

Usage Guidelines

The export map command is used to associate a route map with the specified VRF. The export map is used to filter routes that are eligible for export out of a VRF, based on the route target extended community attributes of the route. Only one export route map can be configured for a VRF.

An export route map can be used when an application requires finer control over the routes that are exported out of a VRF than the control that is provided by import and export extended communities configured for the importing and exporting VRFs.

You can access the export map command by using the ip vrf global configuration command. You can also access the export map command by using the vrf definition global configuration command followed by the address-family VRF configuration command.

Usage Guidelines

The extended-port interface configuration command associates an XTagATM interface with a particular external interface on the remotely controlled ATM switch. The three alternate forms of the command permit the external interface on the controlled ATM switch to be specified in three different ways.

Usage Guidelines

This command enables flow labels. MPLS adds flow labels to the label stack because they contain the flow information of a VC.

Usage Guidelines

Use the l2vpn vfi context command or l2 vfi command to enter L2 VFI configuration mode. Only one pseudowire between the two N-PE routers is allowed.

Usage Guidelines

Use an import route map when an application requires finer control over the routes imported into a VRF than provided by the import and export extended communities configured for the importing and exporting VRF. You can also use the import map command to implement the BGP Support for IP Prefix Import from Global Table into a VRF Table feature.

The import map command associates a route map with the specified VRF. You can use a route map to filter routes that are eligible for import into a VRF, based on the route target extended community attributes of the route. The route map might deny access to selected routes from a community that is on the import list.

The import map command does not replace the need for a route-target import in the VRF configuration. You use the import map command to further filter prefixes that match a route-target import statement in that VRF.

You can access the import map command by using the ip vrf global configuration command. You can also access the import map command by using the vrf definition global configuration command followed by the address-family VRF configuration command.

Usage Guidelines

The vlans vlan-range is entered as a single value or a range.

The mapping is incremental, not absolute. When you enter a range of VLANs, this range is added or removed to the existing instances.

Any unmapped VLAN is mapped to the CIST instance.

Usage Guidelines

Routes imported to this VRF can be advertised to Option AB or Option AB+ peers and VPNv4 Interior Border Gateway Protocol (iBGP) peers. When routes are received from Option AB or Option AB+ peers and imported into the VRF, the next-hop table ID of the route is set to the table ID of the VRF.

The following usage guidelines apply to the csc keyword:

• If the csc keyword is not used, a per-VRF label is allocated for imported routes. For routes received from Option AB+ peers that are imported into the VRF, the learned out label is not installed in forwarding.

• If the csc keyword is used, when routes are received from Option AB or Option AB+ peers and are imported into the VRF, the learned out label is installed in forwarding..

• The csc and the global keywords are mutually exclusive.

Usage Guidelines

The space before the interface-num argument is optional.

Use the shutdown command to disable mesh tunnel interface creation when creating a template.

Usage Guidelines

Use this command on endpoint routers to specify the parameters of the MPLS-TP tunnel.

This command also enters interface configuration mode (config-if). From that mode, you can configure the following MPLS-TP parameters:

Usage Guidelines

This command allows several ethernet virtual circuits (EVCs) to be bundled over a single pseudowire. The pseudowire terminating at this virtual Ethernet interface acts like a virtual ethernet trunk port. This allows Layer 2 protocols to be run over the pseudowire. Similar to a physical Ethernet interface, a virtual Ethernet interface allows configuration of Ethernet flow points.

Usage Guidelines

XTagATM interfaces are virtual interfaces that are created on reference-like tunnel interfaces. An XTagATM interface is created the first time the interface xtagatm command is issued for a particular interface number. These interfaces are similar to ATM interfaces, except that the former only supports LC- ATM encapsulation.

Usage Guidelines

The table below shows which L2VPN interworking features support Ethernet, IP, and VLAN types of interworking.

Usage Guidelines

The interval command allows you to configure the session parameters for a BFD template.

Usage Guidelines

You must have NetFlow accounting configured on your router before you can use this command.

Use this command to configure the MPLS-aware NetFlow feature on a label switch router (LSR) and to specify labels of interest in the incoming label stack. Label positions are counted from the top of the stack, starting with 1. The position of the top label is 1, the position of the second label is 2, and so forth.

With MPLS-aware NetFlow enabled on the router, NetFlow collects data for incoming IP packets and for incoming MPLS packets on all interfaces where NetFlow is enabled in full or in sampled mode.

Caution

When you enter the ip flow-cache mpls label-positions command on a Cisco 12000 series Internet router, NetFlow will stop collecting data for incoming IP packets on any Engine 4P line cards installed in the router on which NetFlow is enabled in full or in sampled mode. Engine 4P line cards in a Cisco 12000 series Internet router do not support NetFlow data collection of incoming IP packets and MPLS packets concurrently.

Tip	MPLS-aware NetFlow is enabled in global configuration mode. NetFlow is enabled per interface.

Usage Guidelines

You configure this command on the tailend routers in an MPLS TE P2MP topology.

Usage Guidelines

• The ip path-option command is supported at a sublabel switched path (sub-LSP) level.

• Point-to-multipoint traffic engineering supports only one path option per destination.

Usage Guidelines

The ip route static inter-vrf command is turned on by default. The no ip route static inter-vrf command causes the respective routing table (global or VRF) to reject the installation of static routes if the outgoing interface belongs to a different VRF than the static route being configured. This prevents security problems that can occur when static routes that point to a VRF interface in a different VRF are misconfigured. You are notified when a static route is rejected, then you can reconfigure it.

For example, a static route is defined on a provider edge (PE) router to forward Internet traffic to a customer on the interface pos1/0, as follows:

Router(config)# ip route 10.1.1.1 255.255.255.255 pos 1/0

The same route is mistakenly configured with the next hop as the VRF interface pos10/0:

Router(config)# ip route 10.1.1.1 255.255.255.255 pos 10/0

By default, Cisco IOS software accepts the command and starts forwarding the traffic to both pos1/0 (Internet) and pos10/0 (VPN) interfaces.

If the static route is already configured that points to a VRF other than the one to which the route belongs when you issue the no ip route static inter-vrf command, the offending route is uninstalled from the routing table and a message similar to the following is sent to the console:

01:00:06: %IPRT-3-STATICROUTESACROSSVRF: Un-installing static route x.x.x.x/32
 from global routing table with outgoing interface intx/x

If you enter the no ip route static inter-vrf command before a static route is configured that points to a VRF interface in a different VRF, the static route is not installed in the routing table and a message is sent to the console.

Configuring the no ip route static inter-vrf command prevents traffic from following an unwanted path. A VRF static route points to a global interface or any other VRF interface as shown in the following ip route vrf commands:

• Interface serial 1/0.0 is a global interface:

Router(config)# no ip route static inter-vrf
Router(config)# ip route vrf vpn1 10.10.1.1 255.255.255.255 serial 1/0.0 

• Interface serial 1/0.1 is in vpn2:

Router(config)# no ip route static inter-vrf
Router(config)# ip route vrf vpn1 10.10.1.1 255.255.255.255 serial 1/0.1

With the no ip route static inter-vrf command configured, these static routes are not installed into the vpn1 routing table because the static routes point to an interface that is not in the same VRF.

If you require a VRF static route to point to a global interface, you can use the global keyword with the ip route vrf command:

Router(config)# ip route vrf vpn1 10.12.1.1 255.255.255.255 serial 1/0.0 10.0.0.1 global 

The global keyword allows the VRF static route to point to a global interface even when the no ip route static inter-vrf command is configured.

Usage Guidelines

Use a static route when the Cisco IOS software cannot dynamically build a route to the destination.

If you specify an administrative distance when you set up a route, you are flagging a static route that can be overridden by dynamic information. For example, Interior Gateway Routing Protocol (IGRP)-derived routes have a default administrative distance of 100. To set a static route to be overridden by an IGRP dynamic route, specify an administrative distance greater than 100. Static routes each have a default administrative distance of 1.

Static routes that point to an interface are advertised through the Routing Information Protocol (RIP), IGRP, and other dynamic routing protocols, regardless of whether the routes are redistributed into those routing protocols. That is, static routes configured by specifying an interface lose their static nature when installed into the routing table.

However, if you define a static route to an interface not defined in a network command, no dynamic routing protocols advertise the route unless a redistribute static command is specified for these protocols.

If a VPNv4 prefix in a given VRF is added to the global routing table, and there is recirculation on the corresponding VPN label due to egress features (ACL, Netflow, or QoS) configured on the outgoing interface, the traffic is not routed inside the VRF routing table, but inside the global routing table. If the same prefix exists in the global table, it results in a Layer 3 loop. To avoid this occurrence, use the mls mpls recir-agg command to switch off the VPN-CAM used for the VRF lookups, and to allocate the reserved VLAN for every VRF instance configured on the Cisco 7600 series routers.

Supported Static Route Configurations

When you configure static routes in a Multiprotocol Label Switching (MPLS) or MPLS VPN environment, note that some variations of the ip route and ip route vrf commands are not supported. These variations of the commands are not supported in Cisco IOS releases that support the Tag Forwarding Information Base (TFIB), specifically Cisco IOS releases 12.x T, 12.x M, and 12.0S. The TFIB cannot resolve prefixes when the recursive route over which the prefixes travel disappears and then reappears. However, the command variations are supported in Cisco IOS releases that support the MPLS Forwarding Infrastructure (MFI), specifically Cisco IOS release 12.2(25)S and later releases. Use the following guidelines when configuring static routes.

Supported Static Routes in an MPLS Environment

The following ip route command is supported when you configure static routes in an MPLS environment:

ip route destination-prefix mask interface next-hop-address

The following ip route commands are supported when you configure static routes in an MPLS environment and configure load sharing with static nonrecursive routes and a specific outbound interface:

ip route destination-prefix mask interface1 next-hop1 ip route destination-prefix mask interface2 next-hop2

Unsupported Static Routes in an MPLS Environment That Uses the TFIB

The following ip route command is not supported when you configure static routes in an MPLS environment:

ip route destination-prefix mask next-hop-address

The following ip route command is not supported when you configure static routes in an MPLS environment and enable load sharing where the next hop can be reached through two paths:

ip route destination-prefix mask next-hop-address

The following ip route command is not supported when you configure static routes in an MPLS environment and enable load sharing where the destination can be reached through two next hops:

ip route destination-prefix mask next-hop1 ip route destination-prefix mask next-hop2

Use the interface and next-hop arguments when specifying static routes.

Supported Static Routes in an MPLS VPN Environment

The following ip route vrf commands are supported when you configure static routes in an MPLS VPN environment, and the next hop and interface are in the same VRF:

• • ip route vrf vrf-name destination-prefix mask next-hop-address
  • ip route vrf vrf-name destination-prefix mask interface next-hop-address
  • ip route vrf vrf-name destination-prefix mask interface1 next-hop1 ip route vrf vrf-name destination-prefix ma sk interface2 next-hop2

The following ip route vrf commands are supported when you configure static routes in an MPLS VPN environment, and the next hop is in the global table in the MPLS cloud in the global routing table. For example, these commands are supported when the next hop is pointing to the Internet gateway.

• • ip route vrf vrf-name destination-prefix mask next-hop-address global
  • ip route vrf vrf-name destination-prefix mask interface next-hop-address (This command is supported when the next hop and interface are in the core.)

The following ip route commands are supported when you configure static routes in an MPLS VPN environment and enable load sharing with static nonrecursive routes and a specific outbound interface:

ip route destination-prefix mask interface1 next-hop1 ip route destination-prefix mask interface2 next-hop2

Unsupported Static Routes in an MPLS VPN Environment That Uses the TFIB

The following ip route command is not supported when you configure static routes in an MPLS VPN environment, the next hop is in the global table in the MPLS cloud within the core, and you enable load sharing where the next hop can be reached through two paths:

ip route vrf destination-prefix mask next-hop-address global

The following ip route commands are not supported when you configure static routes in an MPLS VPN environment, the next hop is in the global table in the MPLS cloud within the core, and you enable load sharing where the destination can be reached through two next hops:

ip route vrf destination-prefix mask next-hop1 global ip route vrf destination-prefix mask next-hop2 global

The following ip route vrf commands are not supported when you configure static routes in an MPLS VPN environment, and the next hop and interface are in the same VRF:

ip route vrf vrf-name destination-prefix mask next-hop1 ip route vrf vrf-name destination-prefix mask next-hop2

Supported Static Routes in an MPLS VPN Environment Where the Next Hop Resides in the Global Table on the CE Router

The following ip route vrf command is supported when you configure static routes in an MPLS VPN environment, and the next hop is in the global table on the customer equipment (CE) side. For example, the following command is supported when the destination prefix is the CE router’s loopback address, as in external BGP (EBGP) multihop cases.

ip route vrf vrf-name destination-prefix mask interface next-hop-address

The following ip route commands are supported when you configure static routes in an MPLS VPN environment, the next hop is in the global table on the CE side, and you enable load sharing with static nonrecursive routes and a specific outbound interfaces:

ip route destination-prefix mask interface1 nexthop1 ip route destination-prefix mask interface2 nexthop2

Usage Guidelines

You can use this command to prevent a burst of RSVP traffic engineering signaling messages from overflowing the input queue of a receiving router. Overflowing the input queue with signaling messages results in the router dropping some messages. Dropped messages substantially delay the completion of signaling for LSPs for which messages have been dropped.

If you enter the ip rsvp msg-pacing command without the optional burst keyword, the transmission rate for RSVP messages is limited to 200 messages per second per outgoing interface. The default output queue size, specified in the maxsize keyword, is 500.

Usage Guidelines

To enable Hello globally on the router, you must enter this command. You also must enable Hello on the interface.

Usage Guidelines

You must configure hello globally on a router and on the specific interface.

Usage Guidelines

To enable the BFD protocol on the router, you must enter this command. You also must enter the ip rsvp signalling hello bfd command on the interface.

Usage Guidelines

You must enter the ip rsvp signalling hello bfd command on the router and on the specific interface.

Usage Guidelines

If a link is congested, it is recommended that you set the DSCP to a value higher than 0 to reduce the likelihood that hello messages will be dropped.

You configure the DSCP per interface, not per flow.

The DSCP applies to the RSVP hellos created on a specific interface. You can configure each interface independently for DSCP.

If you issue the iprsvpsignallinghellodscp command without the optional fast-reroute keyword, the command applies to Fast Reroute hellos. This command is provided for backward compatibility; however, we recommend that you use the iprsvpsignallinghellofast-reroutedscp command.

Usage Guidelines

You can configure the hello request interval on a per-interface basis. A node periodically generates a hello message containing a Hello Request object for each neighbor whose status is being tracked. The frequency of those hello messages is determined by the hello interval.

If you issue the iprsvpsignallinghellorefreshinterval command without the optional fast-reroute keyword, the command applies to Fast Reroute hellos. This command is provided for backward compatibility; however, we recommend that you use the iprsvpsignallinghellofast-rerouterefreshinterval command.

Usage Guidelines

A hello comprises a hello message, a Hello Request object, and a Hello ACK object. Each request is answered by an acknowledgment. If a link is very congested or a router has a very heavy load, set this number to a value higher than the default value to ensure that hello does not falsely declare that a neighbor is down.

If you issue the iprsvpsignallinghellorefreshmisses command without the optional fast-reroute keyword, the command applies to Fast Reroute hellos and Fast Reroute capability is enabled by default. This command is provided for backward compatibility; however, we recommend that you use the iprsvpsignallinghellofast-rerouterefreshmisses command.

Usage Guidelines

The ip vrf vrf-name command creates a VRF instance named vrf-name . To make the VRF functional, a route distinguisher (RD) must be created using the rd route-distinguisher command in VRF configuration mode. The rd route-distinguisher command creates the routing and forwarding tables and associates the RD with the VRF instance named vrf-name .

The ip vrf default command can be used to configure a VRF instance that is a NULL value until a default VRF name can be configured. This is typically before any VRF related AAA commands are configured.

Usage Guidelines

Use this command to associate an interface with a VRF. Executing this command on an interface removes the IP address. The IP address should be reconfigured. The downstream keyword is available on supported platforms with virtual interfaces. The downstream keyword associates the interfaces with a downstream VRF, which enables half duplex VRF functionality on the interface. Some functions operate in the upstream VRFs, and others operate in the downstream VRFs. The following functions operate in the downstream VRFs:

• • PPP peer routes are installed in the downstream VRFs.
  • Authentication, authorization, and accounting (AAA) per-user routes are installed in the downstream VRFs.
  • A Reverse Path Forwarding (RPF) check is performed in the downstream VRFs.

Forwarding Between X.25 Interfaces and Interfaces Configured for MPLS

This command enables IP forwarding between X.25 interfaces and interfaces configured for MPLS, which lets you connect customer premises equipment (CPE) devices to a provider edge (PE) router via an X.25 network by forwarding IP traffic between the CPE devices and the MPLS network. You must configure MPLS on the PE and provider routers in the network.

This command lets you perform an X.25 aggregation function on a PE router for several CPE devices with X.25 VCs into an MPLS network. The PE router performs the aggregation function of terminating X25 VCs and also performs the mapping function (in which VCs are mapped to the appropriate MPLS VRF domains).

Distributed CEF switching, CEF switching, and fast switching are not supported (only process switching is supported). Forwarding of IPv6 traffic is not supported.

Note

Configuring IP VRF forwarding on an interface or subinterface that already has an IP address causes that IP address to be deleted from the running configuration. On an X.25 interface or subinterface, it does not cause any existing x25 map ip or x25 pvc ip statements to be deleted. Configuring an x25 map ip or x25 pvc ip statement with an IP address that matches an IP address configured on the same interface (or any subinterface of the same interface) might be rejected, even when the conflicting address is in another VRF instance.

For additional references, see CCITT 1988 Recommendation X.25 (Interface Between Data Terminal Equipment (DTE) and Data Circuit-Terminating Equipment (DCE) for Terminals Operating in the Packet Mode and Connected to Public Data Networks by Dedicated Circuit) , RFC 1356 (Multiprotocol Interconnect on X.25 and ISDN in the Packet Mode) , and RFC 1461 (SNMP MIB extension for Multiprotocol Interconnect over X.25) .

Usage Guidelines

The ip vrf receive command supports VRF route selection for the following features:

• MPLS VPN: VRF Selection Based on Source IP Address

• MPLS VPN: VRF Selection Using Policy-Based Routing