An octet string that defines the physical port
to which this interface is assigned. It has
implementation-specific significance. Its value
shall be unique within the administered
system. It must contain only ASCII printable
characters. Should an implementation choose to
accept a write operation for this object, it
causes the logical port definition associated
with the table instance to be moved to a
different physical port. A write operation
shall not take effect until the port is cycled
inactive.