LACP Cisco-Foundry

Discussion in 'Cisco' started by helmers, Jun 7, 2009.

  1. helmers

    helmers Guest

    Hi,
    we have a Problem with LACP between a Cisco Catalyst 6509 an a Foundry
    FastIron Super-X.

    The LACP is build of 2 Links.
    If wee unplug the first (primary) port of the LACP-Channel we will not
    see any traffic disruption. Also if we replug the port, no traffic
    disruption will happen. That's like expected.

    If we unplug the second port, the traffic will not be disrupted in the
    first moment. But after roundabout 90 seconds the traffic will stop an
    will come back again after other 35 seconds. If we replug the link, the
    traffic will stop again for 35 seconds.
    Any Idea?

    We can see that the LACP-Channel is build on both sides. So this is not
    a native Spanning Tree event, as it ca be expected by the 35 seconds
    downtime. Furthermore we are using Rapid Spanning Tree.


    !!!!!!!Config Cisco:
    !
    interface Port-channel57
    switchport
    switchport trunk encapsulation dot1q
    switchport mode trunk
    switchport nonegotiate
    !
    interface TenGigabitEthernet6/1
    switchport
    switchport trunk encapsulation dot1q
    switchport mode trunk
    switchport nonegotiate
    channel-group 57 mode active
    !
    interface TenGigabitEthernet6/1
    switchport
    switchport trunk encapsulation dot1q
    switchport mode trunk
    switchport nonegotiate
    channel-group 57 mode active



    !!!!!!!Config Foundry:
    !
    interface ethernet 6/1
    link-aggregate configure key 10057
    link-aggregate active
    !
    interface ethernet 6/2
    link-aggregate configure key 10057
    link-aggregate active
    !
     
    helmers, Jun 7, 2009
    #1
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  2. Interesting. 90 seconds is 3 times Slow Hello timer (30sec). It looks
    like switches don't react on port going down and rely on LACP hello to
    detect the failure. IIRC as minimum on Cisco side STP event is quite
    expected - when you have only one port left in aggregate it will revert
    to regular port and go through normal STP transition.

    debug lacp, debug spanning-tree and equivalents on Foundry side should
    help to figure out what is going on.

    Regards,
    Andrey.
     
    Andrey Tarasov, Jun 7, 2009
    #2
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  3. helmers

    cutetplt

    Joined:
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    Location:
    Bangkon, Thailand
    Hi mate!

    I got the problem like this but different model (ServerIron 4G-PREM). I did the LAB testing for fast convergent “fast uplink-span”. It’s totally different from Cisco STP. When the forwarding port is down, blocking port will be turned on in 4 seconds. But it’ll go down for 20 seconds again when the down port go up.

    In my opinion, Foundry has the problem with Spanning tree function. If you guys have any idea please let us know. Thanks.

    Cheer,
    Tony
     
    cutetplt, Jun 8, 2009
    #3
  4. helmers

    bod43 Guest

    This was mentioned here a while back. I don't believe it!

    If true would make the use of dual channel etherchannel for
    redundant link less than useful. I have used such links and
    never observed this behaviour. It would be astonishing to me
    if it had been present and in all of the cases I had worked on
    had never been observed. There seems no need for this
    behaviour and has obvious disadvantages, why would cisco
    put it in?

    Unfortunately I cannot do test at present. Maybe behaviour is
    platfrom dependent which would explain the differing observations.

    Ah!, maybe LACP is different from PAgP? I have not used
    LACP much.
     
    bod43, Jun 11, 2009
    #4
  5. You don't have to believe. It's quite possible to touch and see it.
    More important question is was PAgP or LACP used on those links? "mode
    on" doesn't use either one.

    Regards,
    Andrey.
     
    Andrey Tarasov, Jun 11, 2009
    #5
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