pkline at cisco.com
Sun Sep 14 20:13:27 UTC 1997
At 12:52 PM 9/14/97 -0400, Alan Hannan wrote:
> pps. I'm really not all that in love with ATM. But it does work.
> If IP could do the things that ATM/FR can, then off we go. My
> experience and knowledge say that managing a really large,
> dynamic, and robust network requires more than flexibility than L1
> pipes and L3 routers. Something in the middle is needed to smooth
> out the corners.
It runs at right angles to my nature and my intellect, but in the
networking world I've become a huge fan of pragmatism (if it works right
now, do it). Building out a national network on a bizarrely short
timeline, with no idea of what traffic flows would look like, I found ATM a
great way to get things started. If my initial estimates were wrong (and
they were), just provision more bandwidth between the two distressed
endpoints. And frequently that bandwidth was available in days/weeks as
opposed to the months that it was taking to get DS3s to build out a ring.
So now I think in terms of the appropriate technology for the job; packet
over SONET is a terrific way to connect two L3 devices which currently
exchange ~40 Mbps and will probably want to exchange ~150 Mbps (or ~600
Mbps, or ...) within a few months or a year. But when you're trying to
bring up a new device in a bandwidth starved city (Seattle a year ago comes
to mind) and DS3 ATM is the only thing you can get, ATM does a bang up job,
even if it's only 1 PVC to somewhere else.
The network equipment market has made an outstanding leap from one choice
(some would argue no choice) of tools to do any given job, to multiple
tools to do the same job in any number of slightly different ways. Each
tool, and each approach, is appropriate to some real-life situation.
So given the pants-on-fire growth in this business, and the disjoint ways
demand for equipment and bandwidth move v. supply, I'm in love with
whatever works right now.
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