cliff@violet.berkeley.edu (Cliff Frost) (06/02/90)
In article <11737@blia.BLI.COM> ted@blia.BLI.COM (Ted Marshall) writes: >In article <1990May30.181740.14203@agate.berkeley.edu>, cliff@violet.berkeley.edu (Cliff Frost) writes: >- In article <11702@blia.BLI.COM> ted@blia.BLI.COM (Ted Marshall) writes: >- >because the blip comes early within the required 9.6us inter-packet gap, >- >stations waiting to transmit shouldn't be affected either. >- >- But the 9.6us gap is per transmitter. You've got one station that has just > >Indeed. I hadn't thought that out fully. Sorry about that. Thanks, except that I'd just come to the conclusion that *I* was wrong and *you* were right. ;-) Yesterday I looked at the 802.3 spec and it seems to clearly state that the 9.6us gap is global. I don't know why I thought it wasn't. So it would seem that it should be safe to turn on SQE to a multiport as long as you don't have any repeaters hanging on it. The only problems should come from controllers that get upset if they see SQE when they aren't expecting it. It could be argued that such a controller is brain-dead. I first asked about this on 15 May. Since then I've gotten a ton of mail and it runs about 50/50. At first it was overwhelmingly opposed to ever using SQE with a multiport, but since then others have argued that it is not only OK but desirable. That's why I took the radical step of rereading the 802.3 spec (which I obviously should have done first, sigh). One kind person pointed me at the Tektronix TDR 1503B with Option 6. We will be testing one out at some point. I'll post again if I come upon any other nice test gear. Cliff Frost