too many routes

Alan Hannan hannan at
Sun Sep 14 17:12:01 UTC 1997

> AFAICT there is only one orderable, deployable and tested
> IP router which observably terminates multiple 622-Mbit/s bit
> pipes, notably that made by cisco.  

  Hmm, well, the lack of knowledge I suppose shouldn't be held
  against you.

  lists their support for such interfaces.

  ( nonsequiter comments deleted )

> >   These can be disaggregated into OC3 ATM pipes that can be fed into
> >   many routers with proven technology and reliability.  Granted, the
> >   disproportionality of the edge ckts to the backbone ckts provides
> >   for interesting flow aggregation dynamics, but it does work.
> Oh sure it works if you turn LS IGPs on their head and

  On their head?  I can assure you the IGP is still a manageable
  problem in larger ISPs with meshed backbones.  In fact, there is
  one solution available that is not yet even exercised.

> try to avoid thinking too hard about how to build spanning
> trees without building a physical VC topology for
> multicast and can put up with interesting buffering and
> switching effects 

  Okay, I'll bite: Which interesting buffering and switching effects?

> and, as you say, the dynamics of WHY it
> works vs. why it doesn't work when things break.

  Yes, indeed this is a tradeoff.

  But, the more I think about the KISS principle, I become convinced
  that only our own limitations, ignorance, and hesitancy prevent us
  from adding complexity to achieve increased control.

  Certainly, when solution A and solution B have net effect Z, we
  should choose the simpler.

  But to say that the benefit of B, even with increased complexity,
  isn't needed because we don't understand it, is just silly (unless
  you live in the real world, and have to work with people, as we
  do, but still, we should consider the question "Is the benefit
  + the increased knowledge worth the education and increased risk"
  not just "which is simpler".)

> I hate to say it but I think I have become old and this
> might explain why I like really simple and straightforward
> failure modes.

  See above comments.

> >   Your disdain for ATM does not stop its existence and use by the
> >   larger NSPs.
> Technical merit has only been offered up as a reason for
> using cells by your organization and ATMNET, AFAIK.

  Yes, we at '' are avid supporters of ATM in today's

  Why do you always insist on linking one's place of business with
  their technological idealogy?  Certainly I work at UUNET and my
  opinion is occasionally involved in certain decisions.  However, I
  am tempered by people more wise, experienced, and quite frankly,
  smarter, than me.  

  I don't speak for UUNET, I speak for me.  Golly.  Novel concept.

> Many of the people who did actual engineering work at
> cisco were also not very agnostic when it came to cells,
> and had an effect on the company, which is one of the
> reasons I have always liked cisco compared to its
> competitors, who were not quite agnostic either but in the
> opposite direction.

  Hmm, I tend to be atheistic about technology -- what can it do for
  me today, and what will it to do tomorrow with a reasonable chance
  of success.

> There may be choice in what you can put at the end of an
> OC12 though, but it's either something smart or something
> you'd find at Hobson's Tavern.

  How do you define smart?


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