MPLS Fundamentals

Multi-Virtual Circuit Tagged Bit Rate

With Multi-Virtual Circuit Tagged Bit Rate (Multi-VC TBR), multiple VCs are set up for the same destination to provide different class of service (CoS). Up to four parallel LVCs can go toward the same destination. The switches can then treat the cells differently based on which LVC they are on. The incoming IP packets are mapped with their IP precedence/DiffServ bits to the corresponding outgoing LVC. The labeled packets are mapped based on the EXP bits value of the top label onto the corresponding LVCs. On the ingress edge ATM LSRs are multiple outgoing VCs out of the LC-ATM interface. All of these VCs take the same path, which the least-cost route of the IGP determines.

Multiple VCs out of an interface ...