At 10:22 AM 7/23/96 -0700, Dave Siegel wrote:

It's difficult to quantify wrt to how ATM plays a role in end-to-end performance on the Internet. There is very little research to support how ATM affects the overall performance. Even Ameritech and PacBell restricted the majority of their performance evaluation on performance in the switch, and only extended their scope if they leased an ADSU to a customer. Even with the improved buffering, if you fill your pipe into the ATM switch, your ATM switch still becomes a packet shredder, compared to the more graceful packet drops seen on a clear channel line.

It depends on what you mean when you say 'performance'. I think there is more and more interest being vested in ATM inefficiency, and alternate technologies to better efficiency in the long-haul. Recall Jerry Scharf's numbers; they're indicative of the issue. [snip] Date: Tue, 18 Jun 1996 23:24:12 -0700 (PDT) From: scharf@vix.com (Jerry Scharf) X-btw: vix.com is also gw.home.vix.com and vixie.sf.ca.us To: nanog@merit.edu Subject: tilting at windmills discussion 2 Sender: owner-nanog@merit.edu In an attempt to reduce the signal to noise ratio of NANOG, I felt like ATM should get equal time with registry policy for unending discussion of week award. In Bob Melcalfe's concept that all we care about is working code, I have included a PERL program for your benefit. The programs reads a histogram file like the ones kc generates from mae-west (http://www.nlanr.net/NA/Learn/packetsizes.html) and computes the overhead for various framing methods. Hopefully taking empirical data from the internet and giving people code will reduce the discussions of what the "cell tax" for real traffic is. Don't like my traffic, collect your own. Fighting over conclusions will be left to others. Jerry Here's the output from the 15 minute collection run on Feb 10th, '96: % packettax.pl < packetsizes.data total packets seen = 11708789, total payload bytes seen = 3010380871 HDLC framing bytes = 3080633605 HDLC efficiency = 97.72 ATM framing bytes = 3644304857 ATM efficiency = 82.61 ATM w/snap framing bytes = 3862101043 ATM w/snap efficiency = 77.95 [snip] - paul