TITLE    : How to enquire/set the speed of the network interfaces
OS LEVEL : Linux (any version)
DATE     : 27/11/2003
VERSION  : 1.0
AUTHOR   : Hubertus A. Haniel (hubba@unixcook.com)
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This is very much dependant on the network card and if the driver supports
this. To enquire the speed a tool called mii-tool can be used on some systems
while on others it is best to check in /proc/net for driver specific status 
files. An example would be /proc/net/PRO_LAN_Adapters/eth0.info if eth0 is an
Intel PRO 10/100 adapter. A lot of info for specific interfaces can be found 
in the kernel-source (/usr/src/linux/Documentation/networking/). 
The same applies to setting the speed. Setting the speed is normally done at
module load time but also can be done with mii-tool if the card supports it.
A few examples of module load options are shown below:

The Broadcom Gigabit bcm5700 adapter (10/100/1000): 
alias eth0 bcm5700
alias eth1 bcm5700
options bcm5700 line_speed=100,100 auto_speed=0,0 full_duplex=1,1

The Intel PRO 10/100 adapter:
alias eth2 e100
alias eth3 e100
options e100 e100_speed_duplex=4,4

Intel PRO 1000 adapter:
alias eth2 e1000
alias eth3 e1000
options e1000 Duplex=2,2 Speed=100,100



Note: The option lines have the ability to configure multiple adapters.
For example the bcm5700 adapter has "line_speed=100,100" which means force
the first two adapters found to 100mb