nanog mailing list archives

Re: value of co-location


From: hwb () upeksa sdsc edu (Hans-Werner Braun)
Date: Sat, 20 Jan 1996 10:57:12 -0800 (PST)

Religious arguments aside, we are getting superb performance across
the OC3 vBNS ATM network nationally for quite some time already,
though big buffers had been architected in there from the beginning.
Check on www.vbns.net and www.nlanr.net. Can't beat Jon's workstation
performance yet, unless we talk about bandwidth*miles.  ;) Then again,
that may change some time as well. Stay tuned.

At 04:57 PM 1/19/96 -0800, Paul A Vixie wrote:
... The telcos have really screwed the pooch
with ISDN, SMDS, and ATM.  I'm not sure why F-R has worked well without
years of delay, but it's a real anomoly.  I have little if any confidence
that I will be able to buy OC3 speed ATM and use it to contact 200
(or even 20) metro-area NAP partners any time this century.

ISP's who practice conservative engineering (i.e., safe sex) will continue
to buy the fastest telco pipes they can get _among_those_which_actually_work_
and this is probably going to be raw fibre before it starts to be 155Mb ATM.
I'm not in love with the idea of a barn full of routers all hooked up to
a GIGAswitch milking machine, but I have to prefer the config that works.

Religious arguments aside, the obstacle for TCP/IP performance over ATM has
been due to two factors, small buffers and no explicit flow control.

The new switches have large buffers. TCP works well with these switches.
Explicit flow control will allow more flexible bandwidth management. That
applies to TCP as well as ATM.

Check out the price of an ATM circuit (considering overhead, etc) and if you
perceive value for the BW then buy it. No apology needed, just purchase
orders.  :-)  If you find that you prefer raw bandwidth over optical fiber
and lots of cisco interfaces, fine, but if you like network level switching,
shared network bandwidth and the price for that, buy switched services. 

--Kent




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