SUMMARY: Excessive collision patch

From: Charlie Mengel - LGI (crm@reston.eri.com)
Date: Tue Jul 27 1993 - 20:35:12 CDT


Hey Folks -

Thanks for the quick response! The patch I was looking for was # 100768.
Randy Ott of Logicon on beatiful Bellvue, WA sent the README, so I will
in my summary.

The specific patch was designed to work with SS2, but you will notice in
the README that sun4m is supported.

--- cut here ---

Patch-ID# 100768-01
Keywords: collisions, repeaters, PC
Synopsis: 4.1.1;4.1.2;4.1.3: Extremely high collision rate when using SS2 servers and repeaters
Date: 13-Oct-92
 
SunOS release: 4.1.1, 4.1.2, 4.1.3
 
Unbundled Product: Not Applicable
 
Unbundled Release: Not Applicable
 
Topic: Network performance with SS2's.
 
BugId's fixed with this patch: 1075049

Changes incorporated in this version:

Architectures for which this patch is available: sun4c,sun4m

Patches which may conflict with this patch: 100330

Obsoleted by:

Files included with this patch: if_le.o

Problem Description:

In a multi-vendor network (with PC's,etc),collision-rate was going
sky high when the first SparcSation-2's were installed as servers.
Collision rate was around 1-3% and goes to 30-50% when connecting
SS-2's on the net.

INSTALL:

1) mv /sys/sun{4c,4m}/OBJ/if_le.o /sys/sun{4c,4m}/OBJ/if_le.o.fcs
        cp sun{4c,4m}/4.1.{1,2,3}/if_le.o /sys/sun{4c,4m}/OBJ

2) In case of sun4m and 4.1.2 also:
        cp sun4m/4.1.2/atom.h /sys/os

     Please Refer to the System and Networking Administration Manual
             section on building and installing a custom kernel.
 

CAVEATS :

1) The patch should be installed on ALL Sparcstations on the
   network for obtaining lowered collision rate.

2) When the network utilisation is high for ex > 30%, this patch will
   NOT be effective - since the load is high and high collision rate is
   inevitable. This patch is NOT a cure-all and should be used as a
   last resort

3) There is a possible performance hit with this patch installed-
   though this was found to be nominal even at high CPU utilisation.

4) This patch is more effective in a Multi-vendor environment as against
   a Sun Workstation only network because the original problem was that
   the slower machines ,such as the PC's, could not get on the network
   and used to time out.

OTHER NOTES:

The patch for the "le" driver is designed such that "le" interface switches
from "back-to-back packet" mode to "packet-at-a-time" mode at a collision rate
of 10 % by default (lecollhi = 100 Decimal). When the collision rate drops
below 5% by default (lecolllo = 50 Decimal), the "le" interface switches
back to "back-to-back packet" mode.

--- END ---
Thanks to all those who responded:

 Randy Ott <randy@sisdbell.Logicon.COM
"Harold A. Miller" <Hal.Miller@mel.dit.csiro.au
shandelm@jpmorgan.com (Joel Shandelman



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