[AG-TECH] Linux networking problems

[Stuart Levy]

I've had this kind of problem too, where I seemed to need to
force the 3c59x/3c90x drivers to a specific duplex setting
to avoid catastrophic packet loss.  It might have been the
switch's fault, but how can I tell?

You can compile the mii diag tools yourself under RH 6.2,
and it might well be rewarding.  I just tried fetching from:
   http://www.scyld.com/diag/

which has instructions, and links to the necessary pieces:
   ftp://ftp.scyld.com/pub/diag/mii-diag.c
   ftp://ftp.scyld.com/pub/diag/libmii.c

After fetching these, just say
   gcc -Wall -Wstrict-prototypes -O mii-diag.c -DLIBMII libmii.c -o mii-diag
(quoting from the last couple lines of mii-diag.c) and then

   mii-diag -v -w

will report the duplex, etc. status and -- better --
watch for link state changes.  I just saw a couple transitions
when trying a 10MB TCP transfer:
  11:26:43.869  MII BMSR now 1000:   no link, NWay busy, No Jabber (41e1).
  11:26:43.879  MII BMSR now 782d: Good link, NWay done, No Jabber (41e1).
Unfortunately, I can't seem to replicate any problems right now --
all the transfers I tried ran at about 11 MB/sec -- but maybe you can.

   Stuart Levy