Date: Thu, 27 Jul 2000 12:17:11 -0600 (MDT) From: Nick Rogness <nick@rapidnet.com> To: Dan Debertin <airboss@bitstream.net> Cc: Paul Herman <pherman@frenchfries.net>, Albert Chin-A-Young <china@thewrittenword.com>, freebsd-net@FreeBSD.ORG Subject: Re: Routing help Message-ID: <Pine.BSF.4.21.0007271154280.84874-100000@rapidnet.com> In-Reply-To: <Pine.SGI.4.21.0007270703390.1929-100000@copper.air-boss.net>
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On Thu, 27 Jul 2000, Dan Debertin wrote: > On Thu, 27 Jul 2000, Nick Rogness wrote: > > > > NO, it is not too different. It is hard to work with the upstream > > provider to announce anything smaller than a /24. However, some > > of them do run other Routing protocols that you could > > accomplish the same thing (In some cases) and they are > > usually easier to work with on that level. Or maybe he's > > multi-homed within the same provider... > > > > Either way, it's a pain in the butt to work with these people. > > Hey now. Keep in mind the responsibilities of your upstreams. They have > around 80K BGP routes to manage; the feasibility of announcing and > propagating something smaller than a /24 is laughable, when the majority > of your routes are /19 and the like. Even if they did agree to run BGP out > to you for your /28 (or whatever), somehow getting other providers to > accept the announcement (most of whom will neither accept nor announce > anything smaller than a /24) would be impossible, and undesirable, even if > it were possible. I know I work for one ;-) And I was talking more of a multi-homed situation within the same upstream and running some sort of IRP. You are correct though, announcements of anything smaller than a /24 just is not doable in todays Backbones. > > The best way to do what he wants is to have a large-ish (larger than /24, > anyway) netblock that is portable, i.e. obtained from ARIN or other > registry, not leased from one of the upstreams, and run BGP to both, > advertising a lower MED to the preferred (primary) ISP, and a higher one > to the backup. Such a setup would also require an AS number. > ARIN will not give anything smaller than a /19... > With a smaller netblock, he could run another routing protocol such as > OSPF. You might run into problems if your address space isn't portable, > though. It would make it technically more difficult, as well as > administratively, as I doubt that ISP A will really want you advertising > its prefixes to ISP B. I am making a leap in logic here, though, so > correct me if this is inaccurate. > You are correct. This is practically undoable. Unless ISP-A and ISP-B are the same ISP... I think we have beat this dog to death... Nick Rogness - Drive defensively. Buy a tank. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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