Node for use by a network, a system for interconnecting multiple networks and methods of operating the node and system

A method of operating an intermediate node for use in interconnecting multiple networks, a first network of the multiple networks applying an authentication process in order to allow subscribers of the first network access to a network, wherein authentication information used in the authentication process is derived using keys associated with subscriber identities of subscribers, the method comprising the steps of:

• storing, at the intermediate node, information regarding the locations at which keys associated with subscriber identities are stored, wherein for a subscriber identity that indicates that subscriber subscribes to the first network, the stored information regarding the location at which the key associated with the subscriber identity of the subscriber of the first network is stored comprises the identity of another one of the networks, in which the key for the subscriber of the first network is stored, the another one of the networks differing from the first network;
• receiving, at the intermediate node, a request for authentication information from the first network, the request indicating the subscriber identity to which the request for authentication information relates;
• retrieving, by the intermediate node, the identity of said another one of the networks in which the key is stored using the subscriber identity;
• and
• routing, by the intermediate node, the request for authentication information to said another one of the networks.

A node for use in a first network, the first network applying an authentication process in order to allow a subscriber of the first network access to a network, wherein authentication information used in the authentication process is derived using keys associated with subscriber identities of subscribers, the node comprising:

• a database configured to store information regarding the locations at which keys associated with subscriber identities are stored;
• a communications interface circuit configured to receive a request for authentication information, the request indicating a subscriber identity to which the request for authentication information relates, the subscriber identity indicating that the subscriber subscribes to the first network;
• and
• a processing circuit configured to use said subscriber identity to retrieve information regarding the location at which the key associated with said subscriber identity is stored from the database, said location being a location outside the first network, and to route the request via the communications interface circuit according to the retrieved information regarding the location at which the key is stored.

An intermediate node for use in interconnecting multiple networks, a first network of the multiple networks applying an authentication process in order to allow subscribers of the first network access to a network, wherein authentication information used in the authentication process is derived using keys associated with subscriber identities of subscribers, the intermediate node comprising:

• a database configured to store information regarding the locations at which keys associated with subscriber identities are stored, wherein for a subscriber identity that indicates that subscriber subscribes to the first network, the stored information regarding the location at which the key associated with the subscriber identity is stored comprises the identity of another one of the networks, in which the key for the subscriber of the first network is stored, the another one of the networks differing from the first network;
• a communications interface circuit configured to receive a request for authentication information from the first network, the request indicating the subscriber identity to which the request for authentication information relates;
• a processing circuit configured to use the subscriber identity to retrieve the identity of said another one of the networks in which the key is stored from the database, and to route the request via the communications interface to said another one of the networks.