At each member AS, either IGRP or OSPF. They do not interact. By design... two of the AS's are across the Pacific from the other two :-) -Andy -- Andy McConnell アンディ マッコネル Network Architect, NTT Multimedia Communications Laboratories Slogan of 105.9, the classic rock radio station in Chicago: "Of all the radio stations in Chicago ... we're one of them." On Fri, 6 Mar 1998, Blake Willis wrote: blakew> Andy, blakew> blakew> What IGP are you running on this network? blakew> blakew> -Blake Willis blakew> CAIS Engineering blakew> blakew> --------------------------------------------------------------------------- blakew> Blake Willis 703-448-4470x483 blakew> Network Engineer, New Customers blakew@cais.net blakew> CAIS Internet, a CGX Communications Company blakew> --------------------------------------------------------------------------- blakew> blakew> On Fri, 6 Mar 1998, Andy McConnell wrote: blakew> blakew> > I have a problem I cannot solve. If anyone is running confederations like blakew> > mine, I would appreciate some help :-) blakew> > blakew> > We have a 4-memberAS confederation, each with two IBGP peers. The blakew> > arrangement looks sort of like an octagon. the "r" is AS3 is an internal blakew> > hop, not a BGP peer. blakew> > blakew> > _______ ______ blakew> > | R-----R---r | blakew> > | / | | | | blakew> > |AS2 R | |AS3 R | blakew> > ----|-- ----|- blakew> > | | blakew> > ____|__ ____|_ blakew> > |AS4 R | |AS1 R | blakew> > | \ | | / | blakew> > | R-------R | blakew> > ------- ------ blakew> > blakew> > The problem is this: How do you get BGP to choose the shortest "AS PATH", blakew> > since internal AS paths are ignored in selecting BGP routes? Right now, blakew> > to top router in AS4 will always choose a route through (2 3 1) instead of blakew> > (1), because it prefers "external" routes (even external confederation blakew> > routes) over internal routes. blakew> > blakew> > So, when given a choice, the router on the distant side of the AS will blakew> > ALWAYS prefer the three-AS-hop path, because it is external. Is there a blakew> > way around this?!? blakew> > blakew> > Avi Freedman suggested using a +1 metric when leaving each member-AS. blakew> > (Thanks Avi!) But it doesn't seem to help - perhaps I didn't do it right. blakew> > In fact, it doesn't look like the metrics are adjusted more than 1. for blakew> > example, from AS2, the lower router sees every route outside of AS2 as blakew> > having only metric 1! The top router in AS3 does not add 1 to the metrics blakew> > it readvertises to AS2. blakew> > blakew> > I've been stewing over this problem for some time... I believe there is blakew> > some clue that I've missed. Any help would be greatly appreciated! blakew> > blakew> > -Andy blakew> > blakew> > blakew> > -- blakew> > Andy McConnell アンディ マッコネル blakew> > Network Architect, NTT Multimedia Communications Laboratories blakew> > blakew> > Writing about music is like dancing about architecture. blakew> > blakew>