Topic
  • 2 replies
  • Latest Post - ‏2013-11-21T17:58:07Z by HendersonD
HendersonD
HendersonD
49 Posts

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

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

    ‏2013-11-21T17:33:12Z  

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

  • HendersonD
    HendersonD
    49 Posts

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

    ‏2013-11-21T17:58:07Z  

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

    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