Something *completely* different to look at... Some older NMC revs would lose IP connectivity if you sent an SNMP request that was too large. If the response packet was bigger than 1500 bytes, the IP stack on the card would crash, and you'd have to reboot the card to get it to wake up again. Apparently it didn't deal with IP fragmentation very well... I think they finally did fix that bug somewhere in the 6.x.x NMC code. If you want to check, start a continuous ping up, then do a snmpget for several large string variables at once. Or maybe just the same integer variable repeated a bunch of times... but have it try to snmpget about 50 or 60 variables at once. If the card stops responding to pings, you need newer NMC code. If pings keep working, but the SNMP query just times out, then you're OK. I found this when writing a bulk chassis config tool (which I'm in the middle of rewriting from scratch today)... it essentially snmpwalks the whole box and compares the values to a list in a config file. I had to cut back the number of simultaneous snmpget requests it did at a time to about 10 to keep it from killing the boxes as I was programming them... :) Mike Andrews (MA12) * mandrews@dcr.net * http://www.bit0.com/ VP, sysadmin, & network guy, Digital Crescent Inc, Frankfort KY Internet services for Frankfort, Lawrenceburg, Owenton, Shelbyville "Don't sweat the petty things, and don't pet the sweaty things." On Wed, 9 Feb 2000 mmm3@cornell.edu wrote:
I'm having a problem with my 486 NMCs that seems to be getting progressively worse. They will be humming along in TCM just fine, then suddenly decide to stop doing SNMP. The ping returns tend to fluctuate all over the place, too, but I thought this was more or less "normal" for these guys:
ping -c50 -C dwan5 PING DWAN5.DIALUP.CORNELL.EDU (132.236.102.11): 64 data bytes !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ----DWAN5.DIALUP.CORNELL.EDU (132.236.102.11) PING Statistics---- 50 transmitted, 50 received, 0.00% packet loss. round-trip (ms) min/avg/max = 2.298/83.612/113.953 var/sdev/skew/kurt = 1244.830/35.282/-1.685/3.983
I have to telnet into my console switch to reset the cards in order to get them back on-line. They behave for a while, then drop off again. I'm hoping we can dig up the bucks for HiPerNMCs to replace all these bastards at some point. Anyone got a quick fix meanwhile? ********************************************************* Michelle M. Mogil Network and Computing Systems 721 Rhodes Hall, Cornell University, Ithaca, NY 14853 vox: (607) 255-0516, fax: (607) 255-8420 email: mmm3@cornell.edu **********************************************
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