Date: Sat, 16 Aug 1997 13:56:32 -0400 (EDT) From: Bradley Dunn <bradley@dunn.org> To: freebsd-isp@FreeBSD.ORG Subject: Re: Multi-homed - Load Balancing - No Single Point of Failure Message-ID: <Pine.BSF.3.96.970816132148.25631A-100000@ns2.harborcom.net> In-Reply-To: <199708161251.WAA12886@junior.portal.net.au>
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On Sat, 16 Aug 1997, Matt Baker wrote: > >From what I've heard, the 2501 won't handle a full BGP load due to the lack > of memory. A couple of questions: It is more an issue of the 2501 lacking the CPU power to handle large changes in the routing table, but memory is also a consideration at 16MB. > 1. Is it possible to only exist with a limited set of BGP data in Australia? > Is this the iBGP you mention? Yes, there are a number of options you have to only take a subset of the global routing table. For example, you could have your upstreams only send you routes for their AS and customer ASes. Then you could use equal cost default routes over both of your upstreams and still ensure that traffic to upstream Y's customer doesn't go over your link to upstream X. http://www.netaxs.com/~freedman/multi.html and http://www.netaxs.com/~freedman/bgp/ have a discussion of this and other issues related to multihoming and BGP. iBGP is internal BGP, which is BGP spoken between routers in the same AS. For a good intro to BGP which will familiarize you with the terminology (with cisco specific stuff of course), see http://www.cisco.com/univercd/data/doc/cintrnet/ics/icsbgp4.htm > 2. Would it be possible to let the 2501 handle the serial traffic on the > link, with a default route to a FreeBSD box which then looks after the > full BGP dataset? The second link could either also hang off the 2501, > or the FreeBSD box. This may be possible if you use eBGP multihop. Your upstream would peer with the PC router instead of the 2501. eBGP multihop is more complicated that straight eBGP, though, and it has a few "gotchas" that you have to look out for. > I really don't have any problem with using FreeBSD boxes as main routers, > but we've got the 2501, so I might as well use it if possible. 2501s work fine for connecting customers. pbd -- Going to church does not make a person religious, nor does going to school make a person educated, any more than going to a garage makes a person a car.
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