Catalyst 3850 stack non-disruptive upgrade

[Albert]

Hi,

I would like to upgrade a 3850 stack from version 3.2.3.SE to 3.3.5.SE using ISSU.  I can't seem to find any documentation showing the upgrade path for ISSU.  According to Cisco Feature Navigator, NSF/SSO (Nonstop Forwarding with Stateful Switchover) is available in both XE versions.  Can someone point me in the right direction?

[Leo Laohoo]

ISSU is only for 4500/6500 chassis.  

There is no such thing as "non-disruptive" IOS upgrade because you need to reboot each appliances for the new IOS to load.

[Albert]

thanks for the response. It just seems that with NSF/SSO as a feature that ISSU would be supported. According to the below link, support for ISSU was supposed to be available last year:

http://www.cisco.com/web/BG/events/ciscoday/pdf/unified_access_-_new_catalyst_3850.pdf#sthash.mOg2FqBb.dpuf

...But the below link for 3850 upgrade doco doesn't mention ISSU so it appears you're correct.

http://www.cisco.com/c/en/us/support/docs/switches/catalyst-3850-series-switches/117552-technote-cat3850-00.html#sthash.mWi1ZMNm.dpuf

thanks

[Leo Laohoo]

ISSU/SSU is supported on 4500/6500 chassis especially when you have dual supervisor.  The active supervisor can handover control to the standby supervisor with only a few ping drops. 

Switch stacks are totally different because each appliance not only serves as the "brain" but also a line card.  So it can't be non-disruptive, per se.  The only way for this to work "non-disruptive" is when each of the wired client is dual-homed to two (or more) switches in a stack and the upgrade performed is using RSU or rolling-switch-upgrade.