Cisco Cisco IOS Software Release 12.2(33)SRE

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Gateway Load Balancing Protocol (GLBP) is now Stateful Switchover (SSO) aware. GLBP can detect 
when a router is failing over to the secondary Route Processor (RP) and continue in its current GLBP 
group state.

Prior to being SSO aware, GLBP was not able to detect that a second RP was installed and configured 
to take over in the event that the primary RP failed. When the primary failed, the GLBP device would 
stop participating in the GLBP group and, depending on its role, could trigger another router in the group 
to take over as the active router. With this enhancement, GLBP detects the failover to the secondary RP 
and no change occurs to the GLBP group. If the secondary RP fails and the primary is still not available, 
then the GLBP group detects this and re-elects a new active GLBP router. 

Configuration information is included in the “Configuring GLBP” module of the Cisco IOS IP 
Application Services Configuration Guide, Release 12.4T, at the following URL:

The following sections provide information about this feature:

GLBP SSO

Customizing GLBP

For a complete list of features included in the “Configuring GLBP” module, see the Feature Information 
Table located toward the end of the module.

Command reference information is included in the Cisco IOS IP Application Services Command 
Reference, Release 12.2SR, at the following URL:

The following commands are new or modified for this feature: