Problems with specific routing policies for each exchange point

Robert Bowman rob at
Fri Oct 31 16:27:34 UTC 1997

Flexibility.  The "Other guy" can add/rm ASes without having to involve
your policy.
> > From: "Jake Khuon" <khuon at Merit.Net>
> > Date: Thu, 30 Oct 1997 23:45:25 -0500
> > Sender: owner-nanog at
> > 
> > ### On Thu, 30 Oct 1997 18:02:02 -0800, mark at (Mark Tripod) wrote
> > ### to <nanog at Merit.Net> concerning "Problems with specific routing policies
> > ### for each exchange point":
> > 
> > MT> I ran in to a little problem yesterday with my peering sessions wih the
> > MT> various route servers around the country. The problem was that I was not
> > MT> receiving routes from particular ASNs anymore. With a little help from Jake
> > MT> at Merit we were able to pinpoint the problem in my rs-in configuration. It
> > MT> seems that I was importing two different AS macros that each referenced the
> > MT> other (AS-GENUITY and AS-NAPNET). This created a loop in the macro parser
> > MT> on the route server which in turn nullified my routing policy.
> > 
> > I would reccommend anyone referencing any of those two macros in their rs-in
> > or rs-out to discontinue doing so at least until which time I can throw in a
> > bugfix to handle looping expansions.  Currently the expansion routine in the
> > preprocessor will reach a depth limit and then spit out an error which gets
> > interpretted by the main routine as a bogus expansion.  This will nullify
> > that import.
> I must admit that I do not see the reason for using AS macros in rs-in
> and rs-out statements. As far as I know these statements merely
> control which AS peers will receive your routes from the route server
> and vice-versa. Since these are direct peers with the route server, I
> can't see the need to put anything other than specific AS numbers into
> the rs-in and rs-out lines.
> Am I missing something obvious?
> -- 
> R. Kevin Oberman, Network Engineer
> Energy Sciences Network (ESnet)
> Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
> E-mail: oberman at			Phone: +1 510 486-8634

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