cmEthernetTrafficPortIndex is a read-only integer (1-65535) that, together with the NE, shelf, and slot indices, uniquely identifies a specific Ethernet traffic port on a card, distinct from the BITS, IEEE-1588, and GPS timing ports covered elsewhere in this MIB. This is the base key management software uses to address every other per-port object in this large Ethernet traffic port table, from administrative state through OAM and shaping settings. For example, a card with 24 client-facing Ethernet ports would expose 24 rows in this table, each keyed by a distinct value of this index.