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N:1 PVC Mapping to PWE with Non Unique VPIs
First Published: November 1, 2011Last Updated: November 18, 2011
The N:1 PVC Mapping to PWE with Non Unique VPIs feature maps one or more ATM permanent virtual circuits (PVCs) to a single pseudowire. Benefits of this feature include the following:
•Aggregate quality of service (QoS) can be applied to related PVCs.
•Bandwidth is conserved with the reduction in the number of pseudowires that are used.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Restrictions for N:1 PVC Mapping to PWE with Non Unique VPIs
•N:1 PVC mapping configuration is supported only on multipoint subinterfaces; it is not supported on main interfaces or point-to-point subinterfaces.
•N:1 PVC mapping mode is not supported on Access Circuit Redundancy subinterfaces.
•Preconfigured PVCs cannot exist on the multipoint subinterface on which you want to configure N:1 PVC mapping.
•An attachment circuit that has been bound to a pseudowire cannot be removed unless all Layer 2 VCs have been removed.
•Layer 3 PVCs cannot be configured on N:1 subinterfaces.
•Cell packing values configured under a virtual circuit (VC) class attached to the PVC, main interface, or subinterface will not be inherited by N:1 PVCs.
•Operation, Administration, and Maintenance (OAM) functionality is not supported on N:1 Layer 2 PVCs. OAM cells coming from the customer edge network will be treated as normal data traffic and traverse the pseudowire.
•Only ATM adaptation layer type 0 (AAL-0) encapsulation is supported for N:1 PVCs.
•Service policy configuration can be configured only at the subinterface level for N:1 PVCs.
Information About N:1 PVC Mapping to PWE with Non Unique VPIs
N:1 PVC Mapping to PWE with Non Unique VPIs Feature Description
To transport ATM cells over Multiprotocol Label Switching (MPLS), a virtual circuit is established between the provider edge (PE) routers on both ends of the MPLS backbone. With the N:1 PVC Mapping to PWE with Non Unique VPIs feature, multiple PVCs irrespective of their VPIs, are transported over a single pseudowire configured on a subinterface. ("N:1" refers to the number of PVCs transported over one pseudowire). ATM cells are packed together on a single frame and sent over the single pseudowire. The ATM cell header information is packed together with the cell payload on a per-cell basis in the packets so that packets received at the egress end are unpacked and the ATM cells are mapped to the respective PVCs.
In N:1 PVC mapping mode, the router can pack cells only from a single PVC in an MPLS packet to transmit over a pseudowire; cells from multiple PVCs cannot be packed in a single MPLS packet and mapped to a single pseudowire for transmission. However, if an MPLS packet packed with cells from multiple PVCs is received, then those cells will be unpacked and sent to the respective PVCs.
How to Configure N:1 PVC Mapping to PWE with Non Unique VPIs
Configuring N:1 PVC Mapping to PWE with Non Unique VPIs
2. configure terminal
3. interface atm slot/subslot/port.subinterface
4. atm mcpt-timers timer-1 timer-2 timer-3
6. interface atm slot/subslot/port.subinterface multipoint
7. no ip address
8. atm enable-ilmi-trap
9. cell-packing cells mcpt-timer timer-number
10. xconnect peer-address vc-id encapsulation mpls
11. pvc vpi/vci l2transport
12. Repeat Step 11 for the number of PVCs you want to configure.
Configuration Examples for N:1 PVC Mapping to PWE with Non Unique VPIs
Example: Configuring N:1 PVC Mapping to PWE with Non Unique VPIs
The following example shows how to configure the N:1 ATM PVC mapping to pseudowires with non unique VPIs:Router> enableRouter# configure terminalRouter(config)# interface atm 9/1/1Router(config-if)# atm mcpt-timers 20 30 40Router(config-if)# exitRouter(config)# interface atm 9/1/1.1 multipointRouter(config-subif)# no ip addressRouter(config-subif)# atm enable-ilmi-trapRouter(config-subif)# cell packing 20 mcpt-timer 2Router(config-subif)# xconnect 10.1.1.1 100 encapsulation mplsRouter(config-subif)# pvc 10/100 l2transportRouter(config-subif)# pvc 11/122 l2transportRouter(config-subif)# pvc 19/231 l2transportRouter(config-subif)# exitRouter(config)# end
Related Topic Document Title
Cisco IOS commands
Feature Information for N:1 PVC Mapping to PWE with Non Unique VPIs
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Note Table 1 lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
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