C3850-24S SFP fiber Interface links fail

[bryantsteve]

In the process of upgrading several C3750X switches from 122-55.SE5 IOS to 150-2.SE10a. which are uplinked to C3850-24S SFP fiber  Interfaces.

The C3850 IOS-XE is 03.06.03.E.152-2.E3

In almost all of the upgrades, which are successful on the C3750 switch, it has been necessary to reset(shut/no shut) the 3850 interface in order to restore connectivity to the 3750 switch. Has anyone experienced this issue/have any suggestions to enable the connection with out manual intervention?

[Julio E. Moisa]

Hi

Nop, have you verified if the ports got any err-disable error?

[bryantsteve]

Hi Julio,

No the ports are not in err-disable state, they are in not connected state and reset brings the interface back up

[Leo Laohoo · Accepted solution]

Has anyone experienced this issue/have any suggestions to enable the connection with out manual intervention?

Check the Release Notes of the 3850, particularly the 3.6.5 or 3.6.6.  I've seen several identified bugs which involves 3750X fibre interfaces behaving like this after a reboot.