1. A method of operating a multicasting communications network comprising the steps of a) providing a multicasting communications network formed of a plurality of nodes and links connecting said nodes to facilitate communication among said nodes; b) calculating a first multicast routing scheme, said multicast routing scheme defining, for each of said nodes, a plurality of paths for facilitating communication with each of said other nodes in said network, said paths each being formed by one or more of said links; c) calculating one or more alternate multicast routing schemes to be employed if said first multicast routing scheme fails due to failure of one or more of said links or nodes; b) implementing multicasting communications between said nodes in said network by interconnecting said nodes in accordance with said first multicast routing scheme; and d) interconnecting said nodes in accordance with one of said alternate multicast routing schemes if said first multicast routing scheme fails.