NAP/ISP Saturation WAS: Re: Exchanges that matter...

> From: Jim Van Baalen <>
> I have a question that fits this topic. Why does everybody seem to be so
> sold on Gigaswitch based Xchange points?

A pretty good reason: it worked a lot better than everything else tried!

As a bit of history, the only NAP that worked was with ethernet, which
seemed a lot faster to most folks than the T1 links coming into the
NAPs. But, the implementation was terribly flaky as a MAN technology.

Then, ethernet got too congested, and folks moved to FDDI. Then, FDDI
got congested and GigaSwitches were put in. They were the only thing
available, and they made everything work better.

Makes sense.

My guess is that the next step will toss the LAN/MAN model for
exchange GigaRouters directly connected by OC-3c/STM-1 and OC-12c/STM-4
WAN links -- but that's only a guess. It seems to be working. We are
driven by things that actually work.

Which leads to my question, since the Gigaswitch NAPs are not scaling to
today's traffic shouldn't we be looking for something new that can? It may
not be an ATM solution, but that is one obvious alternative and I think that
there now exist tested ATM NAPs that, though they are not carrying as much
traffic today, should scale more gracefully.

> Based on membership and traffic it
> appears that there is still a stigma associated with Xchanges (PBnap and AADS
> for example) that have chosen different architectures. It was also my
> impression that people were much more critical of these "other" NAPS at the
> recent NANOG than SprintNAP and the MAEs.
That's because the ATM NAPs were started at the same time as MAE-East,
but didn't work! They all took more than an extra year to get working.

Oh, yeah, they cost a lot of money for some projects that really
couldn't afford it, and it all went down the drain.

I don't question that ATM was a much less mature technology than FDDI a couple
of years ago. On the other hand, ATM is much more scalable and has matured
considerably in the past few years.

Folks have a tendency to be critical of stuff with a history of failure.

> In addition,
> with new line cards due out early next year, the BPXs will support ABR and,
> relatively speaking, huge buffers at high density OC3 and 2 port OC12.
Well, since they don't exist, why would anyone bank on deploying them?
Let us know how well they work in a year or two.

Meanwhile, PPP/SONET has been deployed for over 6 months at these
speeds, and we are already getting experience with it. Yep, needs
bigger buffers on those Ciscos, and PMC-Sierra didn't follow the SONET
spec exactly, but ...

    experience is a much better teacher than promises.

Yes, and we have a lot more experience with OC3 and above devices running