[eepro100] eepro100 performance

Donald Becker becker@scyld.com
Tue, 13 Feb 2001 20:32:59 -0500 (EST)

On Mon, 12 Feb 2001, Jeffrey Hundstad wrote:

> With all due respect to Mr. Becker, I agree with his conclusion that your
> duplex is not matching.  But in my experience, if you are using CISCO
> equipment with the eepro cards you MUST force duplex on your card side and the
> switch side.  We get 100% mismatch between card and switch if we allow the
> duplex to autoset.

I'll be blunt about the Cisco situation:
  Old Cisco switches had broken autonegotiation
  Cisco recommended duplex be forced to hide this bug.
  New Cisco switches, with functional autonegotiation, tend to be set to
    forced duplex due to this recommendation.

The best institutional policy is to never force full duplex.
The minor performance gain is not worth the problems caused.

If you have an older switch with broken autonegotiation, just disable
autonegotiation and allow the link to default to half duplex.

Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Second Generation Beowulf Clusters
Annapolis MD 21403			410-990-9993