Routing Engine; Routing Engine Components; Figure 5: Routing Engine - Juniper M10i Hardware Manual

M10i Internet Router Hardware Guide

Routing Engine

The Routing Engine is an Intel-based PCI platform that runs JUNOS Internet software.
Software processes that run on the Routing Engine maintain the routing tables,
manage the routing protocols used on the router, control the router's interfaces,
control some chassis components, and provide the interface for system management
and user access to the router.
For a description of the Routing Engine's role in router architecture, see
Engine Architecture"
One or two Routing Engines can be installed into the midplane from the front of the
chassis, as shown in
Chassis Manager (HCM) determines which is the master and which is in standby
mode (and so performs no functions). By default, the Routing Engine in the slot
labeled
To change the default master Routing Engine, include the appropriate
[edit chassis redundancy routing-engine]
in the section about Routing Engine redundancy in the JUNOS System Basics
Configuration Guide.
The Routing Engine is hot-pluggable, as described in
(FRUs)"
router function. If the master Routing Engine is removed from the chassis, the effect
depends on whether two Routing Engines are installed:
For replacement instructions, see

Routing Engine Components

The Routing Engine has the following major components (see
14
Routing Engine
on page 35.
. If two Routing Engines are installed, the High-Availability
Figure 1
RE0 is the master.
on page 3. Removal or failure of the standby Routing Engine does not affect
With the default router configuration, in case of failure you must correct the
problem manually. You can issue the appropriate
request chassis routing-engine master
Routing Engine, for example. For information about the command, see the JUNOS
System Basics and Services Command Reference.
On routers with two installed Routing Engines, you can configure graceful
switchover of Routing Engines or automatic Routing Engine mastership failover.
If the Routing Engines are configured for graceful switchover, the standby Routing
Engine immediately assumes Routing Engine functions and there is no
interruption to packet forwarding. Otherwise, packet forwarding halts while the
standby Routing Engine becomes the master and the Packet Forwarding Engine
components reset and connect to the new master Routing Engine. For information
about configuring graceful switchover or automatic mastership failover, see the
section about Routing Engine redundancy in the JUNOS System Basics
Configuration Guide.
We recommend you run JUNOS Release 7.0 or later on the M10i router to support
graceful switchover.
statement in the configuration, as described
"Field-Replaceable Units
command to switch mastership to the other
"Replacing the Routing Engine"
"Routing
on page 121.
):
Figure 5