This read-only Integer32 (1..64) indexes a priority-mapping table row, with the valid range depending on the port's priority-map mode: 1 to 8 for TOS and 802.1p modes, or 1 to 64 for DSCP mode. Admins need to understand this variable range when walking the priority map table, since assuming a fixed 1..8 range would silently miss most of a DSCP-mode port's 64 distinct mapping entries. For example, when auditing priority mappings on a port using DSCP-based classification, an admin should expect to see cmPrioMapIndex values up to 64 rather than the narrower 1..8 range used by 802.1p mode.