Discussion

1.30 Managing Redundant Routing Engines
Problem
Your router has two Routing Engines, and you want them both to have the same
configuration.
Solution
Configure a hostname for each Routing Engine and an IP address for each fxp0
interface:
[edit groups]
aviva@router1# set re0 system host-name router1
aviva@router1# set re0 interfaces fxp0 unit 0 family inet address 192.168.15.1/24
aviva@router1# set re1 system host-name router1-a
aviva@router1# set re1 interfaces fxp0 unit 0 family inet address 192.168.15.2/24
[edit]
aviva@router1# set apply-groups [re0 re1]
Commit the same configuration on both Routing Engines:
aviva@router1# commit synchronize
re0:
configuration check succeeds
re1:
configuration check succeeds
Discussion
Most routers, especially those used by network providers, have redundant hardware
components, such as fans, power supplies, and Routing Engines, so that if one of
them fails, a backup component takes over immediately and router operation continues.
You can replace most redundant components without having to power down
the router; this is called hot swapping. For most hardware components, no software
configuration is required. They are simply present in the router, which you can verify
with the show chassis hardware command, and if any problems occur, a message
or alarm is logged by the system logging facility (described in Chapter 5). Redundant
Routing Engines, however, require some configuration.
By default, the Routing Engine in slot 0 is the master (RE0) and is used when the
router boots. The one Routing Engine in slot 1 (RE1) is the backup. You configure
hostnames and addresses for the two Routing Engines using configuration groups (in
the [edit groups] hierarchy level). Specifically, you must use the special configuration
group re0 (for the Routing Engine in slot 0) and re1 (for the Routing Engine in
slot 1) to define properties specific to the individual Routing Engines. Configuring
the re0 and re1 groups lets both Routing Engines use the same configuration file.
Then use the apply-groups statement to propagate the configuration group information
to the main part of the configuration.
66 | Chapter 1: Router Configuration and File Management
This is the Title of the Book, eMatter Edition
Copyright © 2008 O’Reilly & Associates, Inc. All rights reserved.