nanog mailing list archives
RE: how is cold-potato done?
From: "Gustavus, Wayne" <wgustavus () gnilink net>
Date: Wed, 26 Jun 2002 14:17:43 -0400
Ultimately there won't be any ties, since BGP will eventually have to select a best path. If necessary, the decision will come down to RID. If the metrics really are the same then theoretically it doesn't matter which path it takes. If it does matter, you will have to modify your policy to make a decision based on some other criteria that you are also influencing via policy. ___________________________________________________________ Wayne Gustavus, CCIE #7426 Operations Engineering Verizon Internet Services ___________________________________________________________ -----Original Message----- From: Ralph Doncaster [mailto:ralph () istop com] Sent: Wednesday, June 26, 2002 2:08 PM To: Jared Mauch Cc: nanog () merit edu Subject: Re: how is cold-potato done?
If I peer with network X in cities A and B, and receive the same route
in
both cities with an AS-path of X, how do I know which city to use for an exit? I can understand how if X uses communities to tag the geographic origin of the traffic, but I'm not aware of many networks that do this. Lots of networks claim to use cold-potato routing though, so how
do
they do it?they use the MED sent on the route (aka metric) from the other provider to determine which exit where they both interconnect is the "shortest". this can at times provide undesired results because of aggregation.
Besides aggregation, wouldn't this lead to a lot of ties? Let's say the cities are LA & Manhattan, and the route from X originates in Chicago. I would think that it would be a common occurrance for the route to have the same metric in LA & Manhattan. -Ralph
Current thread:
- Re: how is cold-potato done?, (continued)
- Re: how is cold-potato done? Jared Mauch (Jun 26)
- Re: how is cold-potato done? Ralph Doncaster (Jun 26)
- Re: how is cold-potato done? Leo Bicknell (Jun 26)
- Re: how is cold-potato done? dre (Jun 26)
- Re: how is cold-potato done? Ralph Doncaster (Jun 26)
- Re: how is cold-potato done? Stephen J. Wilcox (Jun 26)
- RE: how is cold-potato done? Daniel Golding (Jun 27)
- Re: how is cold-potato done? Mathew Richardson (Jun 26)
- Re: how is cold-potato done? dre (Jun 26)
- Re: how is cold-potato done? E.B. Dreger (Jun 26)
- Re: how is cold-potato done? Clayton Fiske (Jun 26)
- RE: how is cold-potato done? Gustavus, Wayne (Jun 26)
- Re: how is cold-potato done? Jared Mauch (Jun 26)