From: PD82@brx.th-damrstadt.de (A.G. Schindler)
Newsgroups: vmsnet.networks.tcp-ip.cmu-tek
Subject: Need HELP with crashing IPACP
Date: 23 Jul 92 22:02:09 GMT
Organization: Technical University Darmstadt, Germany, Computer Center
X-News-Reader: VMS NEWS 1.20


	Hello CMU/Tek Cracks,

	there's a general problem I have experienced (since V-6.6-2
	or so) with CMU/Tek. There is obviously a severe system
	parameter alignment mismatch or maybe a bug in CMU/Tek itself.

	The fault can be reproduced by triggering an external client
	(local always works fine !) to send large ammounts of data
	to our poor uVax. The disaster starts with IPACP generating
	mass of page faults (>10000 or so) in a few seconds, while
	the transmission stalls (sometimes MWAIT and PFW states can
	be monitored). Then later on, IPACP eventually decides to die with
	"SYSTEM-F-Insufficient virtual memory", despite the fact I've
	already raised the IPACP's paging quota by a factor of 5.
	Sometimes it survives, but with the consequence that all
	further operations are VERY slow.

	I'm able to generate the fault by FTP'ing or LPR'ing large
	files from a PC/AT running NCSA or from a PC-based
	Interactive-Unix system over unbriged local Ethernet.
	Slowing down the PC-Client by using Debug-Mode or MS-Windows -;)
	prevents IPACP's problems. BTW using NFS remote mounts go o.k.,
	but the first "real" access GENERALLY crashes the ACP as stated
	above. Not very long time ago, there was a similar sounding problem
	posted to this group. The Guru's answer was:

		Set Your Default Window to a smaller value.
		
	I've done this by introducing the variable DEFAULT_WINDOWSIZE=4096
	in INTERNET.CONFIG. After restart, IPACP comes up without an
	error, but the problem doesn't go away.

	After all, I suppose the whole thing might be caused by a lack
	of memory in our VAX, which actually has (only, nowadays!) 12 MB.
	Watching the memory states, there is always more than 20% free,
	the page file is big enough (about 40 MB, generally 30-50% free).
	The pool seems o.k. and all the SYSGEN changes required by CMU/Tek
	have been made.

	Now, where is the hook ? 
	We cannot use the IP System in a state like this, where IPACP
	has to be restarted many times a day. Please HELP.

	Your's Andreas
	
     +-------------------------------------+----------------------------+
     | Andreas G. Schindler                |        ^   ^      The best |
     | c/o IID Schindler & Schubert GbR    |       (O v O)     is yet   |
     | Lammertsgasse 12 , D-6140 Bensheim  |     /(       )\   to come  |
     | Tel: 0 (49) 6251 62081              | ======""===""======        |
     | Net: pd82@brx.hrz.th-darmstadt.de   |                            |
     +-------------------------------------+----------------------------+

     +-------------------------------------+----------------------------+
     | Andreas G. Schindler                |        ^   ^      The best |
     | c/o IID Schindler & Schubert GbR    |       (O v O)     is yet   |
     | Lammertsgasse 12 , D-6140 Bensheim  |     /(       )\   to come  |
     | Tel: 0 (49) 6251 62081              | ======""===""======        |
     | Net: pd82@brx.hrz.th-darmstadt.de   |                            |
     +-------------------------------------+----------------------------+