Partially meshed base tunnels plus hierarchical mp2p tunnel sequence LSPs
In order to provide any-CE-to-any-CE connectivity it is proposed to deploy an O(n)-sized set of base tunnels which form a reasonable partial mesh (e.g. chessboard topology), and to use them and re-use them many times as elements of concatenated hierarchical multipoint- to-point tunnel sequence LSPs. The number of saved tunnels is of order n-square. Multiple,differently routed tunnel sequence LSPs but rooted at the same node may cater for features like traffic balancing, path protection, QoS-routing, etc., without needing any extra tunnel. It is outlined how to establish such an optimal VPN inter-site tunneling.