Multi-point to multi-point traffic engineering

The MPLS-TE technology, relying on the signaling protocol RSVP-TE, ensures traffic engineering (TE) features for point-to-point (P2P) and point-to-multipoint (P2MP) applications with strong bandwidth and availability needs. This paper defines the concept of multi-point to multi-point (MP2MP) TE-LSP that connects a group of nodes called leaves, acting as senders and/or receivers, with potentially distinct bandwidth needs. This helps in replacing the P2P or P2MP TE-LSPs that connect a group of nodes by one MP2MP TE-LSP which leads to reducing the number of TE-LSPs in MPLS-TE networks and hence improving its scalability. An MP2MP TE-LSP can be used also to support value added multi-point to multi-point applications such as visio-conferencing. The setup of an MP2MP TE-LSP relies upon minor extensions to RSVP-TE. An MP2MP TE-LSP is initiated by a root router and the signaling messages from the root to the leaves include the bandwidth requested by each leaf. The bandwidth reserved on a link in each direction is deduced from the bandwidth requested by upstream and downstream leaves. This mechanism inherits all good properties of MPLS-TE with only a few extensions and it permits to set up P2P and P2MP TE-LSPs since such TE-LSPs are special cases of MP2MP TE-LSPs.