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

  • From: Patrick W.Gilmore
  • Date: Mon Mar 15 02:19:57 2004 
On Mar 13, 2004, at 4:57 PM, Stephen J. Wilcox wrote:


He'll be okie.  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.
I used to do this ages ago, I did it by setting MEDs on the incoming BGP
prefixes, in my route-maps I arbitrarily gave some nets (/8s or smaller) lower
med on one feed and higher on the others to influence path selection.

I shy away from anything but the gentlest of tweaks so I personally wouldnt mess
with as-path, localpref, weight etc
Yeah, probably a good idea not to use Weights, but not sure about AS_PATH. Nothing wrong with a prepend here or there, IMHO. :)

But also nothing wrong with setting the MEDs if you like. Just be fore to have "always compare MED" on, or MEDs between multiple providers are not useful (which you obviously had set or this wouldn't work).

I kinda like setting the origin code. No one pays attention to it, but it is in the selection criteria. that way you can use MEDs from the same provider and still influence routes between providers.

--
TTFN,
patrick