Re: [isp-bgp] TE practices when peered to two big upstreams?

[Jon Lewis <jlewis@...>]

On Fri, 7 Jan 2005, Colo Host wrote:

> Level 3 and GBLX are peered with so many people that 130,000
> or so routes tend to prefer the peer (of those two) that has
> been up longer or come up first if it's a reload while the other
> only handles the remaining 20k routes or so.  So I end up with
> 95% of my traffic favoring one link due to BGP's selection process.
>
> I think I'll go forward with Erik's suggestion and take it the
> manual method, trying to determine which large prefixes have
> better connectivity through each of my two providers so I

What I've done in cases where manual intervention has been necessary is
first of all revert to the older tie breaker:
 bgp bestpath compare-routerid

At least that way, your preference doesn't change every time a peer flaps.

Then, if you still find all your traffic prefers just one provider, you
can start picking ASNs you want to shift over to another provider and mess
with local preference or as-path prepending to make paths more or less
attractive.

----------------------------------------------------------------------
 Jon Lewis                   |  I route
 Senior Network Engineer     |  therefore you are
 Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________





To unsubscribe via postal mail, please contact us at:
Jupitermedia Corp.
Attn: Discussion List Management
475 Park Avenue South
New York, NY 10016

Please include the email address which you have been contacted with.

Copyright 2005 Jupitermedia Corporation All Rights Reserved.