[eepro100] collisions

[Donald Becker]

On Fri, 19 Jan 2001, Pooya Woodcock wrote:

> eth0      Link encap:Ethernet  HWaddr 00:A0:C9:D7:CD:77
>           RX packets:523598 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:375423 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:614 txqueuelen:100
...
> Basic registers of MII PHY #1:  0000 780d 02a8 0150 01e1 0021 0000 ffff.
>  Speed fixed at 10 mbps, half-duplex.
...
> question: i must have a 10mbps half duplex connection (for now). is there
> a way to eliminate all of the collisions?

No.  Collisions are not a bad thing.  They are a normal part of Ethernet
operation.  Think of them as "contention events", not "packets crashing
into each other".

> full duplex 10baseT creates many frame errors.

Forcing full duplex is Bad!
Collisions that should be a contention events are instead treated as
corrupted packets.

If you want full duplex, but need to limit the speed to 10Mbps, only
advertise 10baseT and autonegotiation take place.
   mii-diag -A 10baseT
or
   mii-diag -A 0x0061


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