CHAPTER
5-1
ATM Switch Router Software Configuration Guide
OL-7396-01
5
Configuring Redundancy
The Catalyst 8540MSR supports redundant CPU operation with dual route processors. In addition,
Enhanced High System Availability (EHSA) is provided in the switching fabric when three switch
processors are installed in the chassis. These features and their configuration are descr ibed in the
following sections:
•Route Processor Redundant Operation (Catalyst 8540 MSR), page 5-1
•Synchronizing the Configurations (Catalyst 8540 MSR), page 5-5
•Synchronizing the Dynamic Information (Catalyst 8540 MSR), page 5-7
•Displaying the Route Processor Redundancy Configuration (Catalyst 8540 MSR), page 5-9
•Preparing a Route Processor for Removal (Catalyst 8540 MSR), page 5-10
•Configuring Switch Fabric Enhanced High System Availability Operation (Catalyst8540 MSR),
page 5-11
•Displaying the Switch Processor EHSA Configuration (Catalyst 8540 MSR), page 5-13
•Storing the Configuration, page 5-14

Route Processor Redundant Operation (Catalyst 8540 MSR)

The Catalyst 8540 MSR supports fault tolerance by allowing a secondary route processor to take over if
the primary fails. This secondary, or redundant, route processor runs in standby mode. In standby mod e,
the secondary route processor is partially booted with the Cisco IOS software; however, no configuration
is loaded.
At the time of a switchover, the secondary route processor takes over as primary and loads the
configuration as follows:
•If the running configuration between the primary and secondary route processors match, the new
primary uses the running configuration file.
•If the running configuration between the primary and secondar y route processors do not match, the
new primary uses the last saved configuration file in its nonvolatile random-access memory
(NVRAM), not the NVRAM of the former primary.
The former primary then becomes the secondary route processor.
Note If the secondary route processor is unavailable, a major alarm is re ported. Use the show facility-alarm
status command to display the redundancy alarm status.