Scenario - Juniper ACX1000 Configuration Manual

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Example: Configuring Pseudowire Redundancy in a Mobile Backhaul Scenario
Requirements
Copyright © 2017, Juniper Networks, Inc.
Resiliency in the Layer 2 domain is provided through plain pseudowire redundancy for
back-to-back connections. For other topologies, pseudowire virtual circuit connectivity
verification (VCCV) is used.
Resiliency in the Layer 3 domain is provided by MPLS fast reroute and end-to-end service
restoration. A restoration timer prevents having VCs in the secondary path from being
switched back to the primary path immediately after the master PE device is restored.
Access routers can indicate to the aggregation routers which Layer 2 VC is considered to
be active. Upon arrival at LT(x) of a status TLV message communicating a standby state,
the routing process decreases the BGP's local preference value of the direct subnet
represented by the LT(y) IPv4 address. At this point, BGP proceeds to advertise this local
preference change to the rest of the members within the Layer 3 domain, which will then
reelect the designated forwarder PE device by relying on BGP's path selection
mechanisms.
A similar behavior occurs upon arrival of a status TLV message indicating a Layer 2 VC
active state. In this case, the receiving PE device changes the local preference
corresponding to the LT(y)'s subnet. The value to be used to either decrease or increase
the subnet's local preference value is manually configured using a policy.
Example: Configuring Pseudowire Redundancy in a Mobile Backhaul Scenario
This example shows how to configure pseudowire redundancy where Layer 2 and Layer
3 segments are interconnected in a mobile backhaul scenario.
Requirements on page 627
Overview on page 628
Configuration on page 628
Verification on page 646
This example can be configured using the following software and hardware components:
Junos OS Release 15.1X54–D60 or later
ACX5000 routers as the access (A) routers
MX Series routers acting as PE routers and transit label-switched routers
T Series routers as the core routers
Chapter 20: Configuring MPLS and Pseudowires
627