how do i check the "speed" the network interface is connect to?

[Tomoki Taniguchi]

thanks for your reply.

when i ran mii-tool i got this reply
SIOCGMIIPHY on 'eth0' failed: Operation not supported
eth1: negotiated 100baseTx-FD, link ok
eth2: no link
eth3: no link

the system is feisty running as dom0 for a 32bit ubuntu-xen-server.
eth0 is the bridged network interface for xen
when i set eth1 to be bridged as well
mii-tool returns
SIOCGMIIPHY on 'eth0' failed: Operation not supported
SIOCGMIIPHY on 'eth1' failed: Operation not supported
eth2: no link
eth3: no link

so it seems the act of bridging the interface for xen
causes a problem with mii-tool