Label Assignment and Failure Recovery Approaches for IP Multicast Communication in MPLS Networks

Label Assignment and Failure Recovery Approaches for IP Multicast Communication in MPLS Networks Omar Qasem Banimelhem, Ph.D. Concordia University, 2005 Multiprotocol Label Switching (MPLS) is an Internet Engineering Task Force (IETF) framework that provides for the efficient designation, routing, forwarding, and switching of traffic flows through the network. MPLS is widely used for multicast traffic engineering. However, integrating MPLS with IP multicast communication is difficult. This thesis proposes solutions for two problems: label assignment and failure recovery. When a set of multicast flows (sessions) is deployed in an MPLS network, each multicast entry for the sessions consumes an MPLS label. However, MPLS labels are significant resources in MPLS networks, as the 20-bit field of the MPLS header limits the number of available labels. It is advantageous if different multicast sessions can share the same multicast tree in the network and re-use the MPLS label. In the first part of the thesis, we propose two algorithms to do this. The first one is called State Encoding (SE), in which a code is calculated for every tree built in an MPLS network. The second algorithm is called Tree Numbering (TN), where a number represents each tree. If the IP packets of different multicast sessions are delivered over the same tree, all those packets are then classified to the same Forwarding Equivalence Class (FEC) and only one label is used instead of using a number of labels equal to the number of those sessions. If the SE