*BSD News Article 35056


Return to BSD News archive

Xref: sserve comp.dcom.lans.ethernet:11247 comp.os.386bsd.misc:3418
Path: sserve!newshost.anu.edu.au!harbinger.cc.monash.edu.au!bunyip.cc.uq.oz.au!munnari.oz.au!ihnp4.ucsd.edu!network.ucsd.edu!equalizer!timbuk.cray.com!uunet!gumby!andrews-cc!gillham
From: gillham@andrews.edu (Andrew Gillham)
Newsgroups: comp.dcom.lans.ethernet,comp.os.386bsd.misc
Subject: Re: Unix PC as dedicated router?
Date: 25 Aug 1994 17:31:00 GMT
Organization: Andrews University
Lines: 47
Message-ID: <33ikgk$mgl@orion.cc.andrews.edu>
References: <33afek$8s8@rockall.cc.strath.ac.uk> <33b3r5$oml@orion.cc.andrews.edu> <33i467$2ve@fw.novatel.ca>
NNTP-Posting-Host: edmund.cs.andrews.edu

In article <33i467$2ve@fw.novatel.ca> hpeyerl@sidney.novatel.ca (Herb Peyerl) writes:
>
>You have to do other things like disable source routing inside the kernel
>too... Doesn't work so great until you at least do that...

I'm confused.. I thought 'source routing' was only with TR?  Or is
this a different use of the term?

>3c509's can saturate ethernet too. In fact; when I wrote the driver; I 
>didn't have a 3c579 and I was stomping on our corporate ethernet with
>2 3c509's and 2 486-66's... This isn't completely uncommon in todays world
>of ethernet adapters though... The problem appears to have risen to
>"which ethernet adapter can saturate an ethernet with the lowest amount
>of work on behalf of the computer the card is plugged into".

Yes, I meant '3c5x9s can saturate...'  I've both, but the 3c579 keeps
coming to mind.. :-)

>And yes; 3c5x9's have a drop-off problem but the way you allude to it
>is incorrect.  It's a flaw in the general design of the Etherlink-III
>adapter as opposed to a specific species of the Etherlink-III... The
>problem is when the 3c5x9 is used in conjunction with another device that
>has high-interrupt latencies.  ie: possibly in a machine with an IDE
>drive, etc...  In that scenario; it is possible that if several back-to-
>back MAX_MTU packets are received and a disk write happens, that one
>of those packets may overflow the teency buffer on the 3c5x9 and 
>consequently the packet will get dropped.  Also; we've seen weirdness
>with certain motherboards that also have a problem.  There doesn't seem
>to be any real pattern to it.  ie: I once switched one of my 486-66
>motherboards but left everything else intact, the new motherboard exhibited
>very *strange* problems with the 3c5x9 transfers... ie: I was getting
>transfer rates of 30KB/sec and frequent card hangs.  I then switched 
>motherboards again (remember; leaving everything else intact, like
>disk controller, keyboard, display, disk, etc) and everything was fine.

Hmm, I thought for sure that the FAQ or man page (something?) referred
to a problem where the 3c5x9 stopped communicating on the network?
If that is not correct, I apologize, I don't mean to slight the 3c5x9
driver at all. (but I *am* familiar with the problem you mentioned..)

-Andrew

-- 
#!/bin/sh - ==============================================
echo "Andrew Gillham                 gillham@andrews.edu"
echo "Winix Hacker"
#=========================================================