Same as ifIndex:
|-------------+----------|------------|---------|---------|
|InterfaceType| rack No. |  Shelf No. | Slot No.| Port No.|
|  1 (4bits)  | (4bits)  |  (8bits)   | (8bits) | (8bits) |
+-------------+----------+------------+---------+---------+       

The multi-variables binding rule should be complied with 
when a manager configures rogue ONU control. 
According to this rule, all the related mib variables must be 
included in one SNMP set operation. 

There are two types of variables: mandatory and optional.
All of the mandatory variables must be included in one SNMP
set operation. Optional variables may be included in one 
SNMP set operation with the mandatory variables, but must 
not be used alone. 

To configure rogue ONU control, the mandatory and optional 
variables are as follows:
mandatoty: zxAnPonRogueOnuOltIndex,
           zxAnPonRogueOnuIndex