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The master Routing Engine gives up control of the system bus and goes into the backup

state. The backup Routing Engine becomes master and restarts the Packet Forwarding

Engine. You can then diagnose the original master Routing Engine for problems or prepare

it for upgrade or reconfiguration. When switchover occurs, the backup Routing Engine

does not run through its full boot cycle (only the packet forwarding components run

through a full boot cycle).

When you enter the request chassis routing-engine masterrelease command on the master

Routing Engine, the system passes mastership to the backup Routing Engine. The master

Routing Engine gives up control of the system bus and goes into the backup state. The

backup Routing Engine becomes master and restarts the Packet Forwarding Engine. You

can then diagnose the original master Routing Engine for problems or prepare it for

upgrade or reconfiguration.

In all cases, once the switchover occurs, the new master Routing Engine reestablishes

routing adjacencies, populates the routing table, and transfers forwarding table

information to the Packet Forwarding Engine. When Routing Engine mastership changes,

the Packet Forwarding Engine components are rebooted to reestablish communication

links and download the microkernel to each component. When this occurs, forwarding

is interrupted and packet buffers are flushed.

Documentation

Understanding Redundancy for the Routing Engine, Host Module, and Host Subsystem

on page 565

•

Determining Why Mastership Switched

Purpose To determine why a mastership has switched.

Action Mastership can switch between the master Routing Engine and the backup Routing

Engine for the following reasons:

• Hardware problems.

• The master Routing Engine is pulled.

• Software issues, such as a Routing Engine kernel crash.

View the log file /var/log/mastership for redundancy logging. This file contains hardware

and software transitions to help debug auto-redundancy issues.

user@host> show log mastership

Table 136 on page 582 lists the event codes that can be displayed in the mastership log.

Table 136: Logging Events

DescriptionEvent Code

The event is a null event.E_NULL = 0

The Routing Engine is configured as master.E_CFG_M

The Routing Engine is configured as backup.E_CFG_B

M Series and T Series Routers Monitoring and Troubleshooting Guide

Juniper M Series User Manual

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