Dears,
We have 4 switch 4948 (ring topology)
2 of them geographically on one site, 2 switch are in other one, we upgraded first two switches on one site from 15.x SG1 to 15.x SG6 version of ios, they worked fine, then we upgraded the 3 switch in the ring with the same version of ios SG6, after upgrade the whole traffic stopped on this switch, we couldnt ping any end device connected to this 3 switch, even a neighbor switch at this site, also on two upgraded switch on other site CPU level was at 50% (Cat4k Mgmt LoPr Cat4k Mmgmt HIpr), we returned back the old SG1 version and everything began work fine.
If it is ios bug any ideas?
Thank you