nanog mailing list archives
Re: sell shell accounts?
From: salo () msc edu (Tim Salo)
Date: Wed, 24 Jul 1996 00:10:30 -0500 (CDT)
Date: Tue, 23 Jul 1996 19:03:08 -0400 To: salo () msc edu (Tim Salo) From: Paul Ferguson <pferguso () cisco com> Subject: Re: sell shell accounts? Cc: freedman () netaxs com, nanog () merit edu At 05:06 PM 7/23/96 -0500, Tim Salo wrote:The desire for a full mesh of VCs between routers becomes more compelling if you have more than three routers. The diagram is left as an exercise to the reader; I rather dislike having to draw in ASCII. Note that the two paths between A and C, (directly versus via B), seem to take distinctly different paths. (Perhaps, I missed your point).Perhaps I missed your point. Tim, I could've sworn that you had been following the IETF ION WG mailing list, where this has been discussed on hundreds of occasions. I hesitate to even mention this on NANOG (I really don't want to re-hash this on this list), but I can't hold my tongue. The scalability of an ATM network where each end-point is fully meshed to all other end-points decreases in direct proportion to the number of end-points. This is not so much a layer 2 problem, per se, but rather the ability to maintain functional routing (convergence, et al.) in a fully meshed network topology. This does not scale.
I believe that given my [secret] assumptions, (some of which are revealed below), it scales well beyond the financial abilities of most any NSP. I assumed that the wide-area ATM service supported only PVCs and PVPs. (I keep hearing promises of SVCs "next year" but I don't think anyone [domestically] has delivered them.) I believe this address your concern about maintaining functional routing, but I make no claims to being a routing expert, so I might not fully comprehend the issue. I also assumed that the going price for a DS-3 xwide-area ATM connection is, to more or less pull a number out of the air, $250,000/year. This has two implications: o Any one NSP isn't going to be able to afford all that many connections. A full mesh of 100 routers, (i.e., $25 millino/year in ATM services) would require 4,950 PVCs. That is a lot to configure, but... o Given that each link is rather expensive, it behooves the NSP to try to avoid needlessly moving a packet back and forth across a DS-3 local loop just because my ATM provider can't provide me with any more PVCs. (Which was my major point, by the way.) On the other hand, you are correct that this doesn't sale to thousands of routers. But, I didn't think that was the problem we were trying to solve here, (just yet). -tjs - - - - - - - - - - - - - - - - -
Current thread:
- Re: sell shell accounts?, (continued)
- Re: sell shell accounts? Arun Welch (Jul 22)
- RE: sell shell accounts? David Whipple (Jul 19)
- Re: sell shell accounts? Perry E. Metzger (Jul 19)
- Re: sell shell accounts? Brett D. Watson (Jul 20)
- Re: sell shell accounts? Brett D. Watson (Jul 20)
- Re: sell shell accounts? Tim Salo (Jul 23)
- Re: sell shell accounts? Tim Salo (Jul 23)
- Re: sell shell accounts? Sean Doran (Jul 23)
- Re: sell shell accounts? Sean Doran (Jul 24)
- Re: sell shell accounts? Paul Ferguson (Jul 23)
- Re: sell shell accounts? Tim Salo (Jul 23)
- Re: sell shell accounts? Sean Doran (Jul 23)