M40e Routing Engine Description

The Routing Engine runs the Junos OS. The 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 M40e Routing Engine Architecture.

One or two host modules (paired Routing Engine and MCS) can be installed into the midplane from the rear of the chassis, as shown in M40e Chassis Description. If two host modules are installed, the Routing Engines together determine which is the master and which is in standby mode (and so performs no functions). By default, the Routing Engine in the slot labeled RE0 is the master. The master Routing Engine also determines which of the two PCGs is the master.

Note: If two Routing Engines are installed, they must both be the same hardware model.

The Routing Engine is hot-pluggable, as described in M40e Field-Replaceable Units (FRUs). For information about the effect of removing a Routing Engine, see M40e Host Module Description. For replacement instructions, see Replacing a Routing Engine in an M40e Router.

Figure 1 shows the Routing Engine location on the M40e router.

Figure 1: M40e Router Routing Engine Location