Chapter 21 Configuring Pseudowire

Hot Standby Pseudowire Support for ATM/IMA

Structure-Aware TDM Circuit Emulation Service over Packet-Switched Network

CESoPSN encapsulates structured (NxDS0) TDM signals as PWs over PSNs.

Emulation of NxDS0 circuits saves PSN bandwidth and supports DS0-level grooming and distributed cross-connect applications. It also enhances resilience of CE devices due to the effects of loss of packets in the PSN.

For instructions on how to configure CESoPSN, see Configuring Circuit Emulation Service over Packet-Switched Network, page 21-14.

For a sample CESoPSN configuration, see Configuration Examples for Pseudowire, page 21-31.

Transportation of Service Using Ethernet over MPLS

Ethernet over MPLS (EoMPLS) PWs provide a tunneling mechanism for Ethernet traffic through an MPLS-enabled Layer 3 core network. EoMPLS PWs encapsulate Ethernet protocol data units (PDUs) inside MPLS packets and use label switching to forward them across an MPLS network. EoMPLS PWs are an evolutionary technology that allows you to migrate packet networks from legacy networks while providing transport for legacy applications. EoMPLS PWs also simplify provisioning, since the provider edge equipment only requires Layer 2 connectivity to the connected customer edge (CE) equipment. The Cisco ASR 901 implementation of EoMPLS PWs is compliant with the RFC 4447 and 4448 standards.

For instructions on how to create an EoMPLS PW, see Configuring Transportation of Service Using Ethernet over MPLS.

Limitations

When configuring an EoMPLS pseudowire on the Cisco ASR 901, you cannot configure an IP address on the same interface as the pseudowire.

Layer 2 Tunneling Protocol, version 2 and 3 (L2TPv2 and L2TPv3) is not supported on the Cisco ASR 901 series routers.

Hot Standby Pseudowire Support for ATM/IMA

The Hot Standby Pseudowire Support for Inverse Multiplexing over ATM (IMA) feature improves the availability of pseudowires by detecting failures and handling them with minimal disruption to the service. This feature allows the backup pseudowire to be in a “hot standby” state, so that it can immediately take over if the primary pseudowire fails.

A backup pseudowire is provisioned and corresponding entries are populated to hardware tables. When the primary pseudowire goes down, the backup pseudowire is used to switch the packets.

This feature supports the following transport types:

ATM AAL5 in VC mode

ATM in VP mode

ATM in port mode

 

 

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Cisco Systems A9014CFD Hot Standby Pseudowire Support for ATM/IMA, Transportation of Service Using Ethernet over Mpls