cmAccPortPcpDEPairIndex is a read-only integer (1-3) that uniquely identifies a row in the access port's PCP drop-eligible priority pair table, which holds up to three paired drop-eligible/drop-ineligible priority definitions. An administrator relies on this index to configure or reference a specific one of the (at most three) priority pairs used for PCP-based drop-eligibility marking on that access port. For example, a deployment needing three distinct drop-eligibility priority pairs for different service classes would populate rows indexed 1, 2, and 3 in this table.