Topic
2 replies Latest Post - ‏2013-11-21T17:58:07Z by HendersonD
HendersonD
HendersonD
47 Posts
ACCEPTED ANSWER

Pinned topic LACP with 4 links, only two are used, why?

‏2013-09-25T00:41:52Z |

IBM Bladecenter H chasssis

Two IBM 10GB ethernet switch modules in the back of the Bladecenter, one in Bay7 and one in Bay9

Two physical connections from each switch to a stack of two Juniper EX4500 switches. The connections are crossed over for redundancy:

  • Connection1 - from IBM switch1 (Bay7) to Juniper switch1
  • Connection2 - from IBM switch1 (Bay7) to Juniper switch2
  • Connection3 - from IBM switch2 (Bay9) to Juniper switch1
  • Connection4 - from IBM switch2 (Bay9) to Juniper switch2

The 4 connections are setup in a single LACP bundle which is set active on both ends. We are running version 7.7.1.0 code on the IBM switches.

I see traffic on Connections 1 & 2 and nothing on Connections 3 & 4. In other words, the switch in Bay7 is passing traffic while switch in Bay9 has no traffic. I know LACP is used for redundancy but I thought it could also load balance. Why are half of my links not transmitted/receiving traffic?

Updated on 2013-09-25T01:14:20Z at 2013-09-25T01:14:20Z by HendersonD
  • an_ibm_user
    an_ibm_user
    21 Posts
    ACCEPTED ANSWER

    Re: LACP with 4 links, only two are used, why?

    ‏2013-11-21T17:33:12Z  in response to HendersonD

    Are the hosts in the Bladecenter using their link to bay 9? Or are they just using bay 7?

    • HendersonD
      HendersonD
      47 Posts
      ACCEPTED ANSWER

      Re: LACP with 4 links, only two are used, why?

      ‏2013-11-21T17:58:07Z  in response to an_ibm_user

      Just bay 7, the two links to the switch in bay 9 I cannot make part of the LACP bundle. I have been working with IBM support on this for 3 weeks and so far they are unsure why. I will be swapping the slots for these two switches to see if it is a slot problem or switch issue