Quality of service and fairness in ATM based MPLS switches implementing packet based VC-merge

Multiprotocol Label Switching is a proposed enhancement to the IP routing paradigm that can improve routing performance and functionality for IP networks. When an ATM infrastructure is used to support MPLS, VC-merging provides scalability that is not achieved with point-to-point ATM MPLS implementations. VC-merging requires special handling in the ATM switch to avoid interleaving cells from multiple packet sources. An architecture for an ATM based MPLS switch is presented. This architecture efficiently provides VC-merging capability without requiring packet reassembly. Fairness and QoS issues for VC-merging are presented, and performance concerns for mixed packet sizes are shown. This architecture is analyzed for support of non-flow controlled traffic, such as IP UDP traffic, and for the TCP/IP congestion control traffic. A novel congestion control architecture is developed to handle fairness for UDP and TCP traffic across multiple packet sizes. This architecture is shown to provide performance improvements and handle mixed traffic with less tuning then conventional mechanisms.