At 9:33 PM 7/23/96, Curtis Villamizar wrote:

In message <199607232130.QAA20147@uh.msc.edu>, Tim Salo writes:

...

"Good" ATM switches are doing Early Packet Discard and Partial Packet Discard. You can ask your favorite switch vendor for details, or look at the following for a nice summary:

http://www.fore.com/html/atm-edu/whitep/FTBMWP.html

Also in the "dead horse dept" (I hope) unless you are dealing with boneheaded switch vendors. Some don't believe in EPD/PPD preferring ABR. Are any of them still entirely clueless in this regard and not doing either EPD/PPD or ABR?

I think a better question is which switch vendors are supporting _any_ kind of xPD besides Fore? At my last recollection, though I am no switch expert, only Fore. Certainly other switch vendors were starting to throw large buffers at the problem. And still others said "ABR will solve this problem. Wait for ABR." (And I'll add that this was said even when it was clear ABR was a couple of years away.) As for ABR, ATM vendors have been forecasting '96 and '97 deliverables since at least '94. As such, I would expect most of them to be doing or at least working on bringing ABR to fruition. But in order for ABR to be useful in a router environment, routers need to understand ABR. Anyone know what routers do? There are also issues wrt telcos' sunk investment in switches -- switches built when switch vendors were nearly unanimously boneheaded. Given telcos' tendencies to depreciate equipment over long cycles, one can expect those switches to be in telcos' networks for some time. ISPs looking to deploy their own ATM switches needn't be concerned with this but those looking to buy ATM service from telcos most certainly do. All hoping aside, I'm not so sure these issues are in the "dead horse dept"... eric P.S. I took a stab at answering my own question and found that out of the two vendors I checked, at least Cascade now implements EPD. ---- R. Eric Bennett <reb@ieng.com> | Internet Engineering Group 313-669-8800 (v) 313-669-8661 (f) | 122 S. Main, Suite 280 http://www.ieng.com/ | Ann Arbor, MI 48104