This is the numeric table index that links this pseudowire row to its full set of CoS parameters stored in the separate cienaCesMplsPwCosProfile table (which contains the policy, map, and fixed-TC details examined further below). This index is what an SNMP management application would use to programmatically join the pseudowire's basic attributes with its detailed CoS configuration held in a different table. Without this index, correlating a specific pseudowire to its exact CoS policy details would require matching on the profile name string instead, which is less reliable for automated tooling.