Chapter 37: Monitoring Redundant Routing Engines
Figure 198 shows the T640 routing node redundant Routing Engines that are components of the host subsystem.
Figure 198: T640 Routing Node Routing Engines
T640 router rear
Routing
Engines
The host subsystem consists of a Routing Engine and a Control Board. You can install two host subsystems in the T320 router and T640 routing node. For more information about monitoring redundant Control Boards, see “Monitoring
Redundant Control Boards” on page 559.
Both the Routing Engine and the Control Board must be installed for the host subsystem to function. When two host subsystems are installed in the router, both are powered on, but only one is the master; the second host subsystem is the backup and performs no functions. By default, the master host subsystem has components installed in slots RE0 and CB0 ; the backup host module has components installed in slots RE1 and CB1 . If one Routing Engine physically fails, the other one assumes the routing functions. If a software failure occurs, the other backup Routing Engine assumes routing functions if some preliminary configuration has been done. For more information, see“Host Redundancy
Overview” on page 463.
The T320 router and T640 routing node craft interface LEDs indicate the Routing
Engine operating status and mastership. (See “Check the T320 Router Routing
Engine LEDs” on page 144 and “Check the T640 Routing Node Routing Engine
LEDs” on page 145.)
Understanding Redundant Routing Engines !
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