This read-create enumerated value sets the Class of Service value for this path using named DiffServ-style classes such as expedited forwarding, various assured-forwarding classes, or best-effort. It gives an administrator a more descriptive way to assign QoS treatment to a tunnel than a raw numeric COS bit, directly tying the tunnel's forwarding behavior to standard traffic classes. An operator building a tunnel dedicated to VoIP traffic would set csMplsPathCosValue to ef(1) so it receives expedited-forwarding treatment across the network.