In-service upgrades allow new routing engine software and microcode to be installed on the 7705 SAR while existing services continue to operate. Software upgrades can be performed only for specific maintenance releases (generally R4 loads and higher). Software upgrades also require NSR. If software or microcode on the CSM needs to be upgraded, CSM redundancy is required.
The in-service upgrade requires the adapter cards to be reset. This causes a short outage.
Follow the steps below to upgrade routing engine software on the 7705 SAR without affecting existing services:
Install new software on the standby CSM.
Reboot the standby CSM for the new software to take effect.
Perform a manual switchover on the active CSM by using the force-switchover command on the CLI. The standby CSM becomes the active CSM, placing the formerly active CSM into standby.
Repeat steps 1 and 2 to upgrade the standby CSM.