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

[Patrick W.Gilmore <patrick () ianai net>]

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