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BGP and load balancing two routers

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

Any thoughts?

Reply to
Matt
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With a four to one bandwidth ratio, load balancing with BGP is going to be an exercise in futility unless your traffic is very predictable. My general rule of thumb is that if you need to balance BGP links to closer than +/- 50%, you either need a load balancing appliance or re-examination of your load balancing requirements. In your case, I would suggest reconsidering whether the complexity added by trying to move 20% of your Sprint traffic to Qwest would compensate for the miniscule (and possibly negative) performance improvement at any traffic loads under 35 Mbps total.

If your traffic loads routinely exceed 35 Mbps, you need to consider the performance hit when your Sprint link fails and all your traffic goes over the Qwest link. Bottom line: my thoughts are that you should either bump up the Qwest link to 45 Mbps or configure your BGP so Sprint is primary and the Qwest link is only used for backup (and maybe local Qwest destinations).

Good luck and have fun!

Reply to
Vincent C Jones

Matt,

Make sure that you see the route coming from Sprint as well for the destination in the traceroute. Do a 'sh ip bgp ' 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

Matt wrote:

Reply to
oliver.ramirez

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