This table may be used for MPLS PSNs if there is a need
to hold multiple VC, each with different COS, for the same
user service (port + PW VLAN). Such a need may arise if the
MPLS network is capable of L-LSP or E-LSP without multiple
COS capabilities. Each row is indexed by the cpwVcIndex
and indicate the PRI bits on the packet recieved from the
user port (or VPLS virtual port) that are
classified to this VC. Note that the EXP bit value of the VC
is configured in the CISCO-IETF-PW-MPLS-MIB.