This object indicates how the link status
of the port came up.
autoNegotiate(2) -- the port will try to
negotiate the link with the partner port.
If successful, the link will come up,
otherwise the link will remain down.
forceUp(3) -- the port will force the link
up irrespective of its partner port. This
will bring up the link in full duplex only.
Default is autoNegotiate(2).