[comp.protocols.tcp-ip] SCO <-> Sun == molasses

jsparkes@bwdls49.bnr.ca (Jeff Sparkes) (02/05/91)

	I've set up a PC running SCO Unix 3.2.1.  It mostly runs fine, but
FTP and NFS traffic between it and a SparcStation 1+ running SunOS 4.1.1 is
um, pathetic.  FTP transfers of 0.5 K/s.  NFS reads that (almost) never
complete.
	I suspect the window size negotiation breaks down, since telnet
works fine.  Anybody know any workarounds/bugfixes?
--
Jeff Sparkes jsparkes@bnr.ca	Bell-Northern Research, Ottawa (613)765-2503
Another feature is that the seats float, so that the airline can recover
them if the plane crashes into the ocean. -- Dave Barry

jel@tuura.UUCP (Jerry Lahti) (02/08/91)

jsparkes@bwdls49.bnr.ca (Jeff Sparkes) writes:

>	I've set up a PC running SCO Unix 3.2.1.  It mostly runs fine, but
>FTP and NFS traffic between it and a SparcStation 1+ running SunOS 4.1.1 is
>um, pathetic.  FTP transfers of 0.5 K/s.  NFS reads that (almost) never
>complete.
>	I suspect the window size negotiation breaks down, since telnet
>works fine.  Anybody know any workarounds/bugfixes?
>--
I have had similar problems and there is a workaround. In my case the
problem was that the default SCO TCP window and NFS request size are
4 KB.  Unfortunately when the SparcStation behaves accordingly and
pumps out three or four Ethernet frames in rapid succession the poor
PC Ethernet adapter can not keep up and drops all but the first frame.

The workaround with TCP is to give the  -onepacket flag to ifconfig 
(see manual for details). With NFS you have to give mount options
which make the read and write sizes small enough so that the request
will fit into a single Ethernet frame.

An alternative is buying a better Ethernet adapter. I saw the problem
with Etherlink II but the Western Digital cards do quite a bit better.
At least our 486 machine with WD8013EBT seems to keep up quite well 
with our SPARCserver 330 without any parameter tweaking.

Jerry Lahti
Nokia Data Systems Oy
Domains: jel@xerver.data.nokia.fi