Issue between C9300 and C2960X

[TR65]

Hello

I have recently upgraded my Cisco Cat 9300-48U to 17.12.3 and Im seeing something a bit weird. I cant confirm this was like this before as I did not run this command on the old version.

On the 2960x-24ts when I do a show cdp neigh it shows the remote interface as Gi1/0/10 but the port on the C9300 is Fiv1/0/10. Is this an issue? The site is reporting intermittent issues from the devices connected to the 2960X,

Port config on the 2960X:

!
interface GigabitEthernet0/24
description UPLINK
switchport mode trunk
switchport nonegotiate
storm-control broadcast level 1.00
spanning-tree link-type point-to-point

Config on the 9300 interface:

!
interface FiveGigabitEthernet1/0/10
switchport mode trunk
storm-control broadcast level 1.00
spanning-tree portfast
spanning-tree bpduguard enable
spanning-tree guard root

[M02@rt37]

Hello @TR65 

The site is reporting intermittent issues from the devices connected to the 2960X

-- Portfast is intended for edge/access ports...not Trunk. You could create a loop and you will almost trigger bpduguard !

As concerned CDP report... it is more like CDP/ifName reporting oddity...

[balaji.bandi]

What is the full model of Cat 9300 - some new models have multi-gig ports (1/2.5/5/10 options)

Learning from this lesson, always take a snapshot of the current running state before any network upgrade takes place in the future, so there are no surprises for you.