JUNOS Internet Software Network Operations Guide: Hardware
500 ! Understanding the Redundant Routing Engine Configuration
Understanding the Redundant Routing Engine Configuration
For routers with redundant Routing Engines, you can configure a master and
backup Routing Engine. By default, the Routing Engine in slot
RE0 is the master,
and the Routing Engine in slot
RE1 is the backup. Once configured, you can specify
the Routing Engine to assume mastership automatically if it detects loss of the
keepalive signal from the master. You can configure Routing Engine redundancy is
in the JUNOS software command-line interface (CLI) configuration mode at the
[edit
chassis redundancy]
hierarchy level.
You can configure redundant Routing Engine automatic failover for the backup
Routing Engine with a specified failover time. By default, automatic failover is
disabled. To enable it, include the
failover on-loss-of-keepalives statement at the [edit
chassis redundancy]
hierarchy level. By default, failover will occur after 300 seconds
(5 minutes) unless a different time is specified. The failover time is indicated by the
keepalive-timeseconds statement at the [edit chassis redundancy] hierarchy level. The
range for the keepalive time is from 2 to 10,000 seconds.
To display the current Routing Engine redundancy configuration, follow these steps:
1. Enter the CLI configuration mode using the following command:
user@host# configure
2. From the [edit chassis redundancy] hierarchy level, show the configuration using
the following command:
user@host# show
Alternative Action To display the current Routing Engine configuration, you can also use the following
CLI command:
user@host>
show chassis redundancy
Sample Output
user@host>
show chassis redundancy
routing-engine 0 master;
routing-engine 1 backup;
failover on-loss-of-keepalives;
keepalive-time 300;
NOTE: We recommend that both Routing Engines have the same configuration.
When changing the configuration on a Routing Engine, commit it to both Routing
Engines using the
commit synchronize statement at the [edit] hierarchy level. For
more information about synchronizing configurations, see “Host Redundancy
Overview” on page 463.