SUMMARY: DE500 PCI Fast Ether Card produces many errors

From: Richard L Jackson Jr <rjackson_at_osf1.gmu.edu>
Date: Fri, 8 Sep 1995 19:10:35 -0400 (EDT)

Hello,

Thank you to the following individuals for their feedback...

Rajul Shah USG <rajul_at_zk3.dec.com>
treahy_at_ix.netcom.com (Barry Treahy)
Harald Lundberg <hl_at_tekla.fi>

-- 
Regards,
Richard Jackson                                George Mason University
Computer Systems Engineer                      UCIS / ISO
                                               Computer Systems Engineering
========================== QUESTION ================================
BACKGROUND:
We currently have two AlphaServer 2100s running Digital UNIX 3.2c and
Console Firmware 4.2.  The two systems are interconnected 
(point-to-point) via a pair of DE500-XA Fast EtherWORKS PCI 10/100
using a UTP Category 5 cable with RJ-45 connectors.  The mode, ew*0_mode,
is set to FastFD (Fast Ethernet (100baseT:100Mb/sec) Full Duplex).
It will be used to handle the NFS/NIS traffic for these multi-purpose
systems with over 18,000 accounts.  Sounds great, except...
PROBLEM:
Unfortunately, we receive dozens of framing errors every
few seconds from both cards during testing (ftp genvmunix) period.
Many times the ftp transfers at 100Mb/s produces poorer results than at
10Mb/s -- as bad as 16Kb/s.  I have noticed if I set the cards to 10Mb/sec,
then no errors occur and the transfer rates are consistent.  DEC field
service has already replaced cards with the same results.  I have also
tried three different UTP Cat 5 cables.
Anyone else have this configuration?  Anyone else have a clue why 100Mb/s
mode is producing so many errors?
O'Reilly & Associates "TCP/IP Network Administration", page 272, claims
more than 100 input or output errors are not normal.  I am getting
thousands of input and output (framing) errors.
If this can't be solved, then we will have to give another network
card, perhaps the PCI FDDI card (DEFPA-UA), a try.  Anyone using the PCI FDDI
cards in a point-to-point network?
============================ ANSWER =================================
The problem is caused by a "tuning" problem with the transmit threshold
in the device driver for the DE500.  An official patch should be made available
shortly.  Thank you to the capable Rajul of DEC in helping to identify and
solve this problem.  LONG LIVE DIGITAL!  :-)

Received on Sat Sep 09 1995 - 01:28:29 NZST