Control Word Processing; L2Vpn Nonstop Routing; How To Implement Point To Point Layer 2 Services; Configuring An Interface Or Connection For Point To Point Layer 2 Services - Cisco CRS Configuration Manual

Implementing Point to Point Layer 2 services
The successful transmission of the Layer 2 frames between PE routers is due to the configuration of the PE
routers. You set up a connection, called a pseudowire, between the routers. You specify this information on
each PE router:
• The type of Layer 2 data that will be transported across the pseudowire, such as Ethernet, or ATM
• The IP address of the loopback interface of the peer PE router, which enables the PE routers to
• A unique combination of peer PE IP address and VC ID that identifies the pseudowire.
These topics describe the AToM feature:
•

Control Word Processing

The control word contains forward explicit congestion notification (FECN), backward explicit congestion
notification (BECN) and DE bits in case of frame relay connection.
Control word is mandatory for:
• ATM AAL5

L2VPN Nonstop Routing

The L2VPN Nonstop Routing (NSR) feature avoids label distribution path (LDP) sessions from flapping on
events such as process failures (crash) and route processor failover (RP FO). NSR on process failure (crash)
is supported by performing RP FO, if you have enabled NSR using NSR process failure switchover.
NSR enables the router (where failure has occurred) to maintain the control plane states without a graceful
restart (GR). NSR, by definition, does not require any protocol extension and typically uses Stateful Switch
Over (SSO) to maintain it's control plane states.

How to Implement Point to Point Layer 2 Services

This section describes the tasks required to implement Point to Point Layer 2 Services:

Configuring an Interface or Connection for Point to Point Layer 2 Services

Perform this task to configure an interface or a connection for Point to Point Layer 2 Services.
communicate.
Control Word Processing
Cisco IOS XR Virtual Private Network Configuration Guide for the Cisco CRS Router, Release 6.1.x
L2VPN Nonstop Routing
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