Cisco Catalyst 4500 Series Configuration Manual page 257

Chapter 6 Configuring the Cisco IOS XE In Service Software Upgrade Process
After a switchover (NSF/SSO, not RPR), the standby supervisor engine takes over as the new active
supervisor engine (see
Figure 6-6
OL-25340-01
Figure 6-6).
Switch Over to Standby Supervisor Engine
Run new version
of Cisco IOS XE
the new active
Cisco IOS XE Cisco IOS XE Cisco IOS XE
3.x.y.SG 3.x.y.SG 3.x.y.SG
Old
Active NSF/SSO NSF/SSO
Supervisor
Supervisor Switchover Switchover
Engine
Line cards
Software Configuration Guide—Release IOS XE 3.3.0SG and IOS 15.1(1)SG
Cisco IOS XE Cisco IOS XE Cisco IOS XE
3.z.y.SG 3.z.y.SG 3.z.y.SG
New
Active
Engine
About Performing ISSU
6-9