nanog mailing list archives

RE: Load Balancing Multiple DS3s (outgoing) on a 7500


From: "Michel Py" <michel () arneill-py sacramento ca us>
Date: Fri, 12 Mar 2004 20:46:39 -0800


Patrick W.Gilmore wrote:
It's just a little difficult for BGP to "load balance"
outbound bits when the bulk of the Internet these days
is 2 AS hops away from each of four upstreams.  Not
impossible, but it doesn't happen by default either.

Indeed.

If the following conditions are met:

a) all four upstreams are transit providers (and therefore even a
default to any would be fair game)

b) the goal is to distribute more evenly (in terms of bandwidth) the
egress traffic between the four upstreams (in other terms, the egress
traffic tends to peg one of the upstreams (which are being paid to carry
the traffic) for no clear reason)

IMHO there is nothing wrong with some WAEG route-map to police egress
traffic to a different upstream that the one the BGP process would have
chose at the 5th tie-breaker, all 4 including the AS-PATH being equal.

My $0.02 plus tax.

Michel.


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