MII-TOOL(8)						      System Manager's Manual						       MII-TOOL(8)

NAME

       mii-tool - view, manipulate media-independent interface status

SYNOPSIS

       mii-tool  [-v,  --verbose]  [-V,  --version]  [-R,  --reset]  [-r,  --restart]  [-w, --watch] [-l, --log] [-A, --advertise=media,...]  [-F,
       --force=media] [interface ...]

DESCRIPTION

       This utility checks or sets the status of a network interface's Media Independent Interface (MII) unit.	Most fast ethernet adapters use an
       MII to autonegotiate link speed and duplex setting.

       Most  intelligent  network devices use an autonegotiation protocol to communicate what media technologies they support, and then select the
       fastest mutually supported media technology.  The -A or --advertise options can be used to tell the MII to only advertise a subset  of  its
       capabilities.  Some passive devices, such as single-speed hubs, are unable to autonegotiate.  To handle such devices, the MII protocol also
       allows for establishing a link by simply detecting either a 10baseT or 100baseT link beat.  The -F or --force options can be used to  force
       the MII to operate in one mode, instead of autonegotiating.  The -A and -F options are mutually exclusive.

       The default short output reports the negotiated link speed and link status for each interface.  If an interface or interfaces are not spec-
       ified on the command line, then mii-tool will check any available interfaces from eth0 through eth7.

OPTIONS

       -v, --verbose
	      Display more detailed MII status information.  If used twice, also display raw MII register contents.

       -V, --version
	      Display program version information.

       -R, --reset
	      Reset the MII to its default configuration.

       -r, --restart
	      Restart autonegotiation.

       -w, --watch
	      Watch interface(s) and report changes in link status.  The MII interfaces are polled at one second intervals.

       -l, --log
	      Used with -w, records link status changes in the system log instead of printing on standard output.

       -F media, --force=media
	      Disable autonegotiation, and force the MII to either 100baseTx-FD, 100baseTx-HD, 10baseT-FD, or 10baseT-HD operation.

       -A media,..., --advertise=media,...
	      Enable and restart autonegotiation, and advertise only the specified media technologies.	Multiple technologies should be  separated
	      by commas.  Valid media are 100baseT4, 100baseTx-FD, 100baseTx-HD, 10baseT-FD, and 10baseT-HD.

DIAGNOSTICS

       SIOCGMIIPHY on 'eth?' failed: Invalid argument
	      If the interface is not running (up), kernel will refuse to report its link state.

       SIOCGMIIPHY on 'eth?' failed: Operation not permitted
	      Most kernels restrict access to root.

       SIOCGMIIPHY on 'eth?' failed: No such device
	      This error is shown, if the kernel does not know about the named device.

       SIOCGMIIPHY on 'eth?' failed: Operation not supported
	      The interface in question does not support MII queries. Most likely, it does not have MII transceivers, at all.

AUTHORS

       David Hinds - dhinds@pcmcia.sourceforge.org
       Donald Becker - becker@scyld.com
       Bernd Eckenfels - ecki@debian.org

net-tools							2004/03/28 23:30:00						       MII-TOOL(8)