Establishing communication tunnels

A method for establishing a secure communications tunnel between a first node and a second node in a communication system includes a plurality of networks each having a respective tunnel control entity for controlling establishment of secure communications tunnels in the respective network. The first node operates in a first one of the networks and the second node operates in a second one of the networks. The method includes determining a route for the communications tunnel from the first network to the second network by way of one or more of the other networks. A request message digitally signed by the first node is formed and the identities of the tunnel control entity of the first network and the tunnel control entities of the other networks are included. The request message from the first node to the tunnel control entity of the second network is transmitted. In response to that message, the secure communication tunnel is established between the first node and the second node by way of the tunnel control entities identified in that message.