I am trying to upgrade two Sup V-10GE modules in SSO mode on a 4507R-E chassis. They are currently running 12.2(50)SG6. I would like to somehow get to the12.2(53)SG maintenance train. My biggest problem is that I cannot find a migration path that will allow for the ISSU upgrade to be performed in SSO mode. I've tried numerous firmware and when I enter the "issu loadversion" command, the backup Sup comesback in RPR mode and is listed as "Cold Standby" instead of "Standby Hot". I have the output of the "show module" command below. Does anybody know where I can find the documentation to plan a migration path that would retain SSO mode? Or has anyone been in this situation?
Although I'm running 12.2(50)SG6 and this doc is for the 12.2(53) maintenance train, the document specifies that if the "no ip routing" command is configured the redundant supervisor module will fallback to RPR mode during ISSU. After doing some testing, I'm finding that this is the case and the root cause of my issue. Doing some more research, I'm finding that ISSU will try to sync CEF information for the NSF feature for SSO. If IP routing is disabled, CEF is not running. (The command "show cef state" will show CEF not running on a box without IP routing.)
SOLUTION: When performing ISSU with dual supervisor modules on the 4500R series, make sure the "ip routing" command is applied so the upgrade can be completed with SSO mode. This will reduce downtime from 60 seconds to < 200 ms.