Cross Stack Etherchannel for 3750 12S

Unanswered Question
Feb 16th, 2010
User Badges:


I am looking at an issue with a cross stack etherchannel running LACP. Member port g1/0/1 of the bundle is changing state frequently without any known cause.

The two stacks are made of 1x Cisco 3750 12S and 1x Cisco 3750 E 24.

G1/0/1 on the 12S connects to G1/0/1 on the other 12S SFP.

G2/0/1 on the E connects to G 2/0/1 on the other E using copper.

Interface G1/0/1 is flapping. Bundle is active and passing traffic.

Anyone seen this combination?

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Leo Laohoo Wed, 10/06/2010 - 14:54
User Badges:
  • Super Gold, 25000 points or more
  • Hall of Fame,

    The Hall of Fame designation is a lifetime achievement award based on significant overall achievements in the community. 

  • Cisco Designated VIP,

    2017 LAN, Wireless

Have you changed the Gi1/0/1 fibre optic cable and/or SFP that connects the two 3750G-12S?

Reza Sharifi Wed, 10/06/2010 - 15:06
User Badges:
  • Super Bronze, 10000 points or more
  • Cisco Designated VIP,

    2017 LAN

I agree with Leo,

You may have a bad fiber patch cable or a bad SFP.


kimtoovey Wed, 10/06/2010 - 17:06
User Badges:

Thanks for the advice.

I had changed the SFP and the Fibre cabling. I eneded up having to move the link to an alternate slot on the 12S.

Might need to get a TAC raised.

Thanks again.


This Discussion