Patch-ID# 100768-02
Keywords: collisions repeaters PC le.o 
Synopsis: SunOS 4.1.1,4.1.2,4.1.3: fixes to ethernet driver (le.o)
Date: Oct/18/93
 
Solaris Release: 1.0 1.0.1 1.1

SunOS Release: 4.1.1 4.1.2 4.1.3 4.1.3C 
 
Unbundled Product: 
 
Unbundled Release: 
 
Topic: Extremely high collision rate when using SS2 servers and repeaters,
       4.1.3C does not support X453A ethernet option in Classic
 
BugId's fixed with this patch: 1075049 1141618 

Changes incorporated in this version: 1141618

Relevant Architectures: sparc
    NOTE: sun4c sun4m

Patches accumulated and obsoleted by this patch: 101251-01 

Patches which conflict with this patch: 100300 

Patches required with this patch: 

Obsoleted by: 
	NOTE:4.1.3_U1 

Files included with this patch: 

 if_le.o 

Problem Description: 

 Bugid 1141618

 Solaris 1.1C(SunOS 4.1.3c)  will not support 2nd ethernet option 453A in an 
 LX/Classic .Support for the X453A is indicated in 
	"Systems Option Document for Solaris 1.1C."
 The Kernel does identify the device, but ifconfig fails with the following 
 message:

 "le1:  not used - unsupported SBus card for this machine!"

 (From 100768-01)

 Bugid 1075049

 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.


Patch Installation Instructions:
--------------------------------
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.{1,2,3,3c}/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 utilization 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.


Special Install Instructions: 
-----------------------------
None.
