tmnxOamAtmPingCtlPortId

A portid is an unique 32 bit number encoded as shown below.
          
32 30 | 29 26 | 25 22 | 21 16 | 15  1 |
+-----+-------+-------+-------+-------+
|000  |  slot |  mda  | port  |  zero | Physical Port
+-----+-------+-------+-------+-------+
          
32 30 | 29 26 | 25 22 | 21 16 | 15  1 |
+-----+-------+-------+-------+-------+
|001  |  slot |  mda  | port  |channel| Channel
+-----+-------+-------+-------+-------+
          
Slots, mdas (if present), ports, and channels are numbered
starting with 1.
          
32     29 | 28             10 | 9   1 |
+---------+-------------------+-------+
| 0 1 0 0 |   zeros           |   ID  | Virtual Port
+---------+-------------------+-------+
          
32     29 | 28                9 | 8 1 |
+---------+---------------------+-----+
| 0 1 0 1 |   zeros             | ID  | LAG Port
+---------+---------------------+-----+
          
A card port number (cpn) has significance within the context
of the card on which it resides(ie., cpn 2 may exist in one or
more cards in the chassis).  Whereas, portid is an
unique/absolute port number (apn) within a given chassis.
          
An 'invalid portid' is a TmnxPortID with a value of 0x1e000000 as 
represented below.
          
32 30 | 29 26 | 25 22 | 21 16 | 15  1 |
+-----+-------+-------+-------+-------+
|zero | ones  | zero  |  zero |  zero | Invalid Port
+-----+-------+-------+-------+-------+