links on the blink (fwd)

Dennis Ferguson dennis at Ipsilon.COM
Thu Nov 9 04:52:27 UTC 1995


> router). Historically that was often a router problem, as they were too
> slow to deal with the onslaught of packets for a plain
> packet-per-second-rate (remember, in 1987 the NSF solicitation asked
> for a then whopping 1000 packets per second per router, which was just
> barely achievable then). Today you can buy technology off the shelf
> that does not have a pps problem for typical situations. So what is the
> problem, if it is not the rouuter interconnection or the router
> technology? The answer is bad network engineering, little consideration
> for architectural requirements, and lack of understanding for the
> Internet workload profile. Intra-NSP, perhaps even more among NSPs. Or,
> in other words, it is people that kill the network, not the routers or
> phone lines, particularly people who are trying to make money off it,
> probably using their unique optimization function focused on profit
> and limiting expenses as much as they can, not understanding the fate
> sharing yet.

I disagree with you about the adequacy of routers you can buy off the
shelf, and in fact would reach an exactly opposite conclusion.  I think
we are reaching the end of the ability to support the core of the U.S.
Internet (once the NSFnet, now the collection of high-end NSPs) with
routers you can obtain now in the fashion to which we've become
accustomed.  In fact I think we're fast approaching the state of
the 56kbps network just before the deployment of the factor-of-8
bandwidth increment in trunk bandwidth that the IBM RT network
provided, only at a bandwidth level 2.5 orders of magnitude higher,
and I think the sagging at the center of the Internet is taking the
edges with it due to the lack of push-me-pull-you incentive to keep
the edges growing.

I am old enough to be able to assemble the following timeline for upgrades
of the U.S. Internet core trunk bandwidth over the last 10 years, along with
the corresponding increase in local interconnect bandwidth.  Feel free
to correct the dates, but I don't think I'm too far off.

  1986  1987   1988   1989   1990   1991   1992   1993   1994   1995   1996
                   x8     x3.3             x14         x2               ^
 56kbps           1/3 T1 full T1          1/2 T3     full T3            ?
      Ethernet                            FDDI                          ?

Given that it is now almost 1996, and the growth rate of the Internet
has shown no signs of having slowed, what would you extrapolate we should
have been working on deploying about now?  My best guess would be that we'd
be due for another big increment, say a factor of 12 or so, both in backbone
and in interconnect technology, to take us another couple of years, had
we been following the historical rollout of new technology.  Yet not only
can you not buy OC-12 routers off the shelf, or anywhere else, you can't
even buy honest OC-3 routers at this point (I will avoid progressing into
a rant on how the bizillions invested in ATM development to produce very
little of practical use so far might have been better spent...).

And I would suggest that if you were, say, a big phone company, and you
actually understood, in your own inimicable big phone company way, that
percentage packet loss rates in your infrastructure with anything other
than zeros to the left of the decimal point were unacceptable, and you
were willing, at least for now, to do whatever you could to build, maintain
and grow a high quality Internet infrastructure even if you hadn't yet
figured out how to make a profit from it, you would still find that meeting
your traffic growth projections with even the most creative arrangements
of 5-slot T3 routers and whatever else you could buy to help them along
to be a bleak prospect.  There comes a point where you just run out of
router bandwidth, and nothing but more router bandwidth is going to fix
it, but the bigger bandwidth boxes are no where to be found.

So we've got routing problems front and center, here and there, with
bandwidth problems creeping up behind.  We've got some companies with
relatively deep pockets, or which are flush with IPO money, which would
very probably spend to fix it if they could, if only to avoid being
featured on the 10 o'clock news when disasters occur, except there doesn't
seem to be anything to spend the money on which is clearly going to fix
anything.  I don't think this is a happy state to be in, in fact it sucks,
but I don't think it is correct to attribute this state to counter-productive
profit motives.  I think we're victims of our having own success creep up
to and pass the technology when we weren't paying close enough attention,
and the only thing left to do seems to be to try to play catch-up from
a position of increasing disadvantage.

Dennis Ferguson

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