Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!sdd.hp.com!news.cs.indiana.edu!ariel.unm.edu!wayback.unm.edu!honeywel From: honeywel@wayback.unm.edu (Honeywell Field Service) Newsgroups: comp.sys.apollo Subject: Re: Network layout Message-ID: <1990Dec13.232348.9645@ariel.unm.edu> Date: 13 Dec 90 23:23:48 GMT References: <1990Dec13.034921.25599@bnr.ca> Sender: news@ariel.unm.edu (USENET News System) Distribution: comp Organization: University of New Mexico, Albuquerque Lines: 41 Regarding a slow network: If you suspect hardware there are a couple of tools that might point you in the right direction. Take a look at some of the statistics "netstat" provides, if you're seeing a lot of "tokens inserted" you've got serious problems and this is probably why you're running slow. Invoke "netstat -l -a -save (some filename)" this will build a history of your nodes to date. Then after a day or two (or in some cases an hour or two) invoke "netstat -l -a -since (previously named file)" and this will compare the current history to the one you saved and list the results. Keep a sharp eye for "tokens inserted", if you're seeing anything more than 2 or 3 on a particular node this may be the indication of a problem. Sometimes nodes will cause tokens to be inserted when they've been powered off and on. If a node has added a lot of tokens, its time to check the BNC connectors and cabling. Another tool for troubleshooting network problems is "probenet". Just invoking "probenet" doesn't pound on the ring hard enough to shake out problems. Use the "-s" option to specify a large number of packets to be transmitted. I usually start with "-s 100" just to test the ring. To really pound the ring set "-s" to 1000 and also tell probenet to repeat every few minutes with the "-r" option. To physically check out your cabling and connectors save a netstat snapshot of your network statistics and then kick off probenet with the -s option set to a minimum of 100, repeating every 2-3 minutes. Then walk around your ring wiggling the connectors and cables at each node, checking the results of probenet occasionally. If your vibration testing of the cables and connectors causes probenet or netstat to complain, you've found the problem or a potential problem. Most of the sys-admins on the large sites have learned the hard way about the importance of the cabling and the BNC connectors. You *must* use the proper and approved cables. The connectors, whether they are crimp or nut type must be installed *perfectly*. The quick-disconnects must be installed *perfectly*. Find someone on your site that is obsessive about doing things right and let them do all of your cabling/connectors. When I was with Apollo and later while with Mentorgraphics, we found many "slow" rings or other network problems that were traced back to poorly assembled BNC connectors or improper cables. Regards, Mike Thomas, Honeywell Third Party Services.