Dual hubbed tree architecture for a communication network

Capacity demands are routed in an network including at least one ring having a pair of hub nodes and a number of additional nodes. A pair of routing trees is generated for the ring, with each of the routing trees specifying paths between nodes of the ring, and having as its root a corresponding one of the hub nodes of the ring. The routing trees are utilized to route capacity demands from nodes of the ring to other portions of the network, such as other rings. The routing trees for a given ring of the network are configured such that the two hub nodes of the ring are adjacent in each of the routing trees of that ring. In addition, the routing trees for the given ring are directed edge disjoint, such that if a link corresponding to one edge of a tree fails, an affected demand is routed to the other hub node of the ring using the other routing tree of the ring. The network may further include of pairs of "super" hub nodes, with pairs of the hub nodes of rings in the network each being assigned to pairs of the super hub nodes. A pair of routing trees generated for a given pair of the super hub nodes is then utilized to route demands for capacity from one of the hub nodes to one of the super hub nodes.