Cisco Cisco IOS Software Release 12.2(33)SRE

© 2007 Cisco Systems, Inc. All rights reserved.

GLBP supports In Service Software Upgrade (ISSU). ISSU allows a high-availability (HA) system to 
run in Stateful Switchover (SSO) mode even when different versions of Cisco IOS software are running 
on the active and standby Route Processors (RPs) or line cards.

ISSU allows a high-availability (HA) system to run in Stateful Switchover (SSO) mode even when 
different versions of Cisco IOS software are running on the active and standby Route Processors (RPs). 
This feature allows the system to switch over to a secondary RP running upgraded (or downgraded) 
software and continue forwarding packets without session loss and with minimal or no packet loss.

This feature is enabled by default.

Configuration information is included in the Cisco IOS In Service Software Upgrade Process document at: 

For detailed information about ISSU on the 7600 series routers, see the ISSU and eFSU on Cisco 7600 
Series Routers document at the following URL:

Cisco IOS master commands lists provide an alphabetical list of all Cisco IOS commands in a Cisco IOS 
release.

Cisco IOS new, modified, removed, and replaced commands lists provide an alphabetized list of all new, 
modified, removed, and replaced commands in a Cisco IOS release.

Cisco IOS Master Commands List, Release 12.2SB, at the following URL: