34-38
Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 34 Configuring MPLS, MPLS VPN, MPLS OAM, and EoMPLS
Enabling EoMPLS
L2VPNs also provide pseudowire resiliency through their routing protocols. When connectivity between
end-to-end PE routers fails, an alternative path is provided between the directed LDP session and the
user data. However, there are some parts of the network where this rerouting mechanism does not protect
against interruptions in service.
Figure 34-6
shows those parts of the network that are vulnerable to an
interruption in service.
Figure 34-6
Points of Potential Failure in an L2 VPN Network
L2VPN pseudowire redundancy provides the ability to ensure that the CE2 router in
Figure 34-6
can
always maintain network connectivity, even if one or all of the failures in the figure occur.
You can
configure a backup pseudowire so that if the primary pseudowire fails, the provider-edge router switches
to the backup pseudowire. You can configure the primary pseudowire to resume operation after it
restarts. You can also configure the network with redundant pseudowires and redundant network
elements (routers).
Figure 34-7
shows a network with redundant pseudowires and redundant attachment circuits. You can
also optionally configure the network with redundant CE routers and redundant PE routers.
Figure 34-7
L2 VPN Network with Redundant Pseudowires and Attachment Circuits
This section includes this information:
•
Configuration Guidelines, page 34-38
•
Configuring Pseudowire Redundancy, page 34-39
•
Forcing a Manual Switchover to the Backup Pseudowire VC, page 34-40
•
Monitoring L2VPN Pseudowire Redundancy, page 34-40
Configuration Guidelines
Follow these guidelines when configuring L2 VPN pseudowire redundancy:
PE1
CE1
P1
P2
PE2
CE2
X1
X2
X3
X4
X1 = End-to-end routing failure
X2 = PE hardware or software failure
X3 = Attachment circuit failure from a line break
X4 = CE hardware or software failure
135057
Primary
pseudowire
PE1
CE1
PE2
CE2
Backup
pseudowire
135058
Redundant
attachment
circuits
