ExtremeSwitching (EXOS)

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Transmitting Received BGP routes with AS in tact

  • 1.  Transmitting Received BGP routes with AS in tact

    Posted 11-19-2018 15:43
    I am having an issue with what appears to be two networks that are advertised to me via BGP..one is pretty standard and the other one is maybe a little less typical. I receive the route from an EBGP peer for a /24 and it goes into our routing table. When I advertise these upstream, there is no record of the source ASN. To complicate things further, one of the peers is using a SWIP'd range which is fine but it is part of an aggregate network that we advertise. I have an advertisement policy that removes that from the summary but so far that doesn't seem to be working.

    To recap, networks that I receive via an EBGP customer are not being transmitted to other EBGP peers even when permitted and I am hoping to retain the ASN so that when it gets further upstream it has the full AS-path.

    Let me know what details I can share but so far I'm not finding any gtac guides or any similar requests on the community site. Thank you!


  • 2.  RE: Transmitting Received BGP routes with AS in tact

    Posted 11-26-2018 20:46
    Can you post the running configuration of bgp


  • 3.  RE: Transmitting Received BGP routes with AS in tact

    Posted 11-26-2018 20:55
    Padmashree, Thanks for your reply. I think I found a few things out which might help the community...some might not.

    The ultimate cure was to add:
    configure bgp add network SMALLERSUB/NET

    modify aggregate address to remove SMALLERSUB/NET from aggregation:
    configure bgp add aggregate-address LARGERSUB/NET summary-only advertise-policy RemoveSummary

    edit RemoveSummary.pol
    entry removefromsummary {
    if match any {
    nlri SMALLERSUB/NET exact;
    } then {
    deny;
    }
    }

    entry accept_others {
    if { } then {
    permit;
    }
    }

    Last but not least, one of my routers was routers was kicking out the route received from an ebgp peer..haven't had the time to look at release notes but I suspect it is a previously addressed bug.

    Hope this info helps somebody!