2960x Amber Interface LEDS after adding new trunk interface

[brian.bushmaker]

Site B (2960x) is currently connected to our network via fiber using spectrum as a provider. Because the location is directly across the street from Site A, we ran private fiber. In connecting the single mode fiber to Site A switch stack (2960x), as soon as the link was active and up (green LED), all of the interfaces on that switch stack immediately went to amber LED's. Site B was operational, but all devices connected to Site A switch were not operational (stayed amber even after a power cycle). Unfortunately, debug logs were not enabled at that time. Ultimately, I ended up resetting the switches to factory and rebuilt them. I ran a simulation via packet tracer and unable to duplicate the problem, but those were on 3560's, so I assume the issue has less to do with the trunking interfaces and more to do with additional configuration on the 2960x's that I have not encountered before.

Site A 

Uplink interface from Core (gi2/0/49)

switchport trunk native vlan 999
switchport mode trunk 

(VLAN's 480, 680)

Uplink to Site B

switchport trunk allowed vlan 360,600,610
switchport trunk native vlan 999
switchport mode trunk

Site B

Uplink to Site A

switchport trunk allowed vlan 360,600,610
switchport trunk native vlan 999
switchport mode trunk

Based on the description of the issue, what other information is needed to further troubleshoot?

Thanks in advance for your assistance.

[balaji.bandi]

Did you had any link before  you connecting Fibre patch from site  A to Site B (this is only link ?)

Looks for me Either STP, or VTP, what is the VTP status, if they running VTP Server, that where may have issue.

Make sure you run VTP transparent before connecting each other.  nice if you can post both the switch config.

[brian.bushmaker]

Thanks for your response. Prior to this connection, Site B was connected to our Core switch in the data center via spectrum fiber using the current configuration. Site A and Site B were never interconnected directly until we ran the private fiber. We are not running VTP server on either switch. I've attached the switch configs.

[brian.bushmaker]

I stand correct, I may be running the VTP server. See attached VTP Status.

[balaji.bandi · Accepted solution]

Looks you were running both VTP Server, is the VTP required here ? if not make it VTP Transparent each device save the config.

how is your network diagram now, you may have also loops, if they connected Traingle ? you may see STP Loops ? since you mentioned no collected Logs. you need to collect the Logs to undersdtand the issue ?

1. Disable VTP

2. Make sure there is no Layer 2 Loops

and re-connect you should be ok., before re-connecting, make sure you make a small network diagram and check spanning tree

[brian.bushmaker]

VTP is not required and see now how this impacted the Site A switch by removing that VLAN. Before I connect the two switches again, I'm going to do some testing with non-prod units just to confirm. I'm also going to enable my log collector prior to connecting the prod switches so I can better catch the issue as it occurs. Thanks for the feedback. My next update will be after I connect the prod switches on Thursday (9/16).

[balaji.bandi]

Sure feed us any information required.

[Leo Laohoo]

What does the logs say?