[wellylug] Network cards running at 10mb/s instead of 100 - w hy?

[Ewen McNeill]

In message <1066630345.3088.37.camel at damon.asianreflection.com>, Damon Lynch writes:
>> Crossover connections are prone to failures in negotitation, leading to
>> one end thinking the connection is at one speed, and the other at the
>> other speed.
>
>I had no idea about this class of problem.  Speaking as a general
>principle, it does seem to be a pain to have to get a switch / hub just
>to connect one DMZ machine to a gateway.

It is a pain.  But it's the easiest solution if you want it to
"magically" work.  If you don't care about magic and are willing to do
some manual maintenance, then what is normally done is to force both
ends of the connection to the same settings.  mii-tool (etc) can be used
to do this under Linux.

>Do you mean force down to 10, or force up to 100?

Why short change yourself; if both ends are capable of 100, and the
network cable is reasonable (eg, Cat5/Cat5e, not too long) then you
might as well use 100.  The key point is that both ends should be set to
(a) the same speed, and (b) the same duplex settings.

Some combinations of cards, OS, etc, can handle autonegotiate on a cross
over connection, but others work "some of the time" or "not at all".
Hence the common wisdom about forcing both ends to the same speed/duplex.

Ewen