Xref: utzoo alt.sys.sun:4291 comp.dcom.lans:8432 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!unhd.unh.edu!kepler.unh.edu!wrt From: wrt@kepler.unh.edu (Walter R Trachim) Newsgroups: alt.sys.sun,comp.dcom.lans Subject: Re: Cabletron Repeater Problems Keywords: Cabletron MMAC Shiva FastPath Ethernet collision statistics bogus Message-ID: <1991Jun20.203445.12130@unhd.unh.edu> Date: 20 Jun 91 20:34:45 GMT References: <1991Jun7.200603.9378@ns.network.com> <1991Jun20.075328.6540@qualcomm.com> Sender: usenet@unhd.unh.edu (USENET News System) Organization: University of New Hampshire Lines: 70 Nntp-Posting-Host: kepler.unh.edu In article <1991Jun20.075328.6540@qualcomm.com> antonio@qualcom.qualcomm.com (Franklin Antonio) writes: > >isolate problems to a particular port? We've recently implemented >Remote-Lanview, so we can see all these statistics for all the repeaters >remotely. This SOUNDS great, but since all the collision statistics are >unreliable, all this provides is a very fancy Windows program to display >random numbers. I expect these statistics should be a TOOL i can use to >diagnose my network. Do i ask too much? No, you're not asking for too much. However, there is something you might not have done: If you have the most recent version of Remote LANview (2.00. 11 or 12, I don't remember) you should upgrade the firmware on your IRM boards. Apparently the re-write of the f/w is specifically to correct some timing- related issues between LANview and hardware on the IRM. This does seem, at least to some degree, to affect statistics. With the new firmware, we've had seemingly very accurate counts of all the vitals. I think the upgrade for us was free of charge, but I'm not certain. >We've had better luck when we use one repeater port for EACH Shiva >FastPath. That's the way we've been running for a long time. We still >get lots of collisions on these ports, sometimes 10% or 15%, but the >network still seems to work. Just a few days ago we made yet another >discovery. We can reduce the number of collisions by choosing WHICH >Cabletron ports we wire up to the Shiva FastPaths. We used to take the >first THN-MIM card in the MMAC, and dedicate it to the FastPaths. >Now we find that we get many fewer collisions if we spread out the >ports which connect to FastPaths, putting no more than one FastPath >on each THN-MIM card, then using the other 7 ports on each THN-MIM for >anything else. I'm not sure exactly what to conclude from this. >Sure looks like this has uncovered some kind of timing problem in the >MMAC design, but that's just one possibility. I can't speak for the problems with Shiva that you've had, but the collision trouble you're having with your THN-MIM cards sounds like something bizarre that happens to us here with an MT8-MIM and the PC we use to run LANview. We have certain MMACs that, if the PC is connected to a port on the MT8-MIM, will frequently (whenever the MMAC is polled) drop the connection. LANview then thr- ows out an alarm (gee, I can't understand why :-). We then moved the PC's drop to a 10BT-MIM on another MMAC we have in the same building. The problem ceased as soon as we did this. An interesting side to this is that when we had an older release of LANview (the non-Windows 3.0 release), we had the exact same problem. Makes me think the MT8-MIM itself is exhibiting a timing problem of some sort. It could be related to the collision problem you're describing... >Anybody else got Cabletron collision bogosity? >Anybody out there using Cabletron's collision statistics AND finding >them meaningful? At one time we did - it was before we made the upgrades (see above). Since then the worst trouble I've had to deal with has been getting the proper video drivers for Windows and LANview to work correctly together. Otherwise the issue with collisions and statistics has seemed to clear up. Unfortunately we don't have any Cabletron repeaters on campus anywhere (sorry I didn't reference), so I can't comment on the problem you're experiencing. BTW: I don't represent Cabletron in any way, shape, or form. I'm just a reasonably satisfied customer. >Thanks. >Franklin Antonio No problem. I hope my comments are worth at least 2 cents. Walt --------------------------------------------------------------- Walter R. Trachim - UNH Network Services, Durham, NH 03824 Phone: 603-862-4742/4773 Fax: 603-862-2030 E-Mail: walt@unhsst.unh.edu / "My home away from home." ---------------------------------------------------------------