[c-nsp] trouble with link aggregation on WS-X6716-10GE

Sebastian Beutel sebastian.beutel at rus.uni-stuttgart.de
Wed Mar 9 09:05:52 EST 2016

Hi List,

    i recently encountered a strange problem with a lacp port-channel on a
WS-X6716-10GE line card with a DFC3C. Both members reside on the same line
card, one of them is shut for a long time. The other end is an alcatel
customer switch.
    When i did a "no shut" on the second port, it refused to join the port
channel (Po17) and instead a second portchannel (Po17A) appeared, waiting to
be aggregated:

17     Po17(SU)        LACP      Te1/4(P)
17     Po17A(SN)       LACP      Te1/10(w) 

I have seen similar happenings when hardware on different linecards was too
different to aggregate links. But this time it's not only the same hardware,
it's the selfsame linecard and all four port-groups have oversubscription 
mode enabled. I also moved the second link to another linecard (also
WS-X6716-10GE with DFC3C) but with no success. Does anyone have an idea what
i did wrong?


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