PHYSICAL PORT

         Name of the port entity in the Physical layer returned when the port
 	is opened. If this is null, the port is not open.

     STATE

         State of the DDCMP link. The value of this attribute is determined by
 	the enable and disable commands.

         OFF - The entity is disabled.

         ON  - The entity is enabled.

 	In addition the link is disabled and its state set to off if the
 	Physical layer port that the link uses is deleted.