This object indicates the index of an AP's wired interface.
Numbering rule: port-index = port-type * 100 + port-number. For example, the indexes of a wall plate AP's GE0, eth0,
and eth1 are 200 (2 * 100 + 0 = 200), 100 (1 * 100 + 0 = 100), and 101 (1 * 100 + 1 = 101) respectively.