MII-TOOL(8)							   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 interfaces 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 spec
	      ified media technologies.  Multiple technologies should be sepa
	      rated  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)