BGP And Load Balancing With Two Routers

Discussion in 'Cisco' started by Matt, Oct 17, 2005.

  1. Matt

    Matt Guest

    Hi,
    Our network is setup as such:

    SPRINT (45Meg) -----> ROUTER A

    QWEST (10Meg) ------> ROUTER B

    Router A and B, then interconnect with a patch cable.

    We are currently running BGP between the routers, as well as with our
    peers (SPRINT/QWEST). As Qwest is only a 10Meg pipe I would like to
    reduce the amount of traffic that is going out. I have tried
    weighting, localpref, (for outbound traffic) and as-prepend (for inbound
    traffic) but have not been able to get anything to work. I have issued
    "clear ip bgp *" after each command, but still no go. Below are the
    commands I've issued.. any thoughts?

    ROUTER A:
    neighbor 160.81.248.77 remote-as 1239
    neighbor 160.81.248.77 description ebgp link to sprint
    neighbor 160.81.248.77 version 4
    neighbor 160.81.248.77 weight 150
    neighbor 160.81.248.77 soft-reconfiguration inbound
    neighbor 160.81.248.77 filter-list 2 out

    ROUTER B:
    bgp default local-preference 75
    neighbor 65.123.21.137 remote-as 209
    neighbor 65.123.21.137 description ebgp link to qwest
    neighbor 65.123.21.137 version 4
    neighbor 65.123.21.137 soft-reconfiguration inbound
    neighbor 65.123.21.137 route-map filter out


    route-map filter permit 10
    set as-path prepend 26383 26383 26383


    on ROUTER A, a sh ip bgp shows that localpref and weight are going in:
    *> 8.2.64.0/23 160.81.248.77 29 150 1239 7132
    16803 16803 16803 i
    *> 8.3.41.0/24 160.81.248.77 29 150 1239 7911
    7911 7911 30033 30033 i
    *> 8.3.43.0/24 160.81.248.77 29 150 1239 7911
    7911 7911 30033 30033 i
    *> 8.6.240.0/24 160.81.248.77 29 150 1239 7911
    7911 7911 31846 31846 31846 31846 31846 i
    *> 8.7.83.0/24 160.81.248.77 29 150 1239 5650
    5650 12284 ?
    *> 8.8.9.0/24 160.81.248.77 610 150 1239 27646 ?
    *>i8.10.50.0/24 65.123.21.137 8937 75 0 209 32760 i
    *> 8.10.119.0/24 160.81.248.77 190 150 1239 4323
    25642 ?
    *> 8.10.128.0/24 160.81.248.77 190 150 1239 4323
    25642 i
    *> 8.10.241.0/24 160.81.248.77 29 150 1239 6395
    22324 22324 22324 22324 i
    *> 8.15.2.0/24 160.81.248.77 29 150 1239 6395
    26049 26049 26049 26049 i
    *> 8.15.5.0/24 160.81.248.77 29 150 1239 6395
    26049 26049 26049 26049 i
    *> 8.15.6.0/24 160.81.248.77 29 150 1239 6395
    26049 26049 26049 26049 i
    *> 12.0.18.0/24 160.81.248.77 50 150 1239 27585 i
    *>i12.0.48.0/20 65.123.21.137 8710 75 0 209 1742 i

    But a traceroute from me to a site hosted on the qwest network goes out
    my qwest router, rather then going out my Sprint router.
    1 faste-2-0-medusa (63.174.244.17) 0.482 ms 32.847 ms 9.912 ms
    2 faste-2-0-hydra (65.165.94.77) 2.403 ms 12.238 ms 9.897 ms
    3 pa1-edge-03.inet.qwest.net (65.123.21.137) 9.949 ms 11.850 ms
    8.757 ms
    4 aggr-01.ewr.qwest.net (205.171.17.169) 10.402 ms 10.607 ms 11.627 ms
    5 jfk-core-02.inet.qwest.net (205.171.8.246) 10.982 ms 10.742 ms
    11.421 ms
    6 jfk-edge-01.inet.qwest.net (205.171.30.86) 10.839 ms 11.201 ms
    10.759 ms
    7 65.116.172.98 (65.116.172.98) 42.611 ms 42.381 ms 42.830 ms
    8 suscomweb.synacor.com (208.197.227.23) 41.574 ms 41.672 ms 41.730 ms

    I would like any traffic originating from ROUTER A to go out SPRINT
    (unless Sprint is down), and any traffic originating from ROUTER B to go
    out QWEST (unless Qwest is down).

    That doesn't seem to be happening...

    Any thoughts?
     
    Matt, Oct 17, 2005
    #1
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  2. Matt,

    Make sure that you see the route coming from Sprint as well for the
    destination in the traceroute. Do a 'sh ip bgp <prefix>' to confirm.
    If the network isn't advertised by Sprint, then traffic will have to go
    through the Qwest router (this is assuming your doing iBGP between the
    two).

    -Oliver
     
    oliver.ramirez, Oct 17, 2005
    #2
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