Juniper ACX2000 Configuration Guide

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.
Related
Documentation
Example: Configuring Pseudowire Redundancy in a Mobile Backhaul Scenario•
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
Requirements
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
627Copyright © 2017, Juniper Networks, Inc.
Chapter 20: Configuring MPLS and Pseudowires

Juniper ACX2000 Specifications

General

Brand	Juniper
Model	ACX2000
Category	Network Router
Language	English