Reducing storage requirement for route information

A computer-readable medium containing instructions for controlling a node of a network to process messages using a Session Initiation Protocol, by a method comprising:

• receiving a first request of a dialog from a source node to a destination node, the first request having route information;
• generating a mapping of the source node to the route information;
• forwarding the first request with route information identifying the node and without the mapped route information;
• receiving a second request of the dialog sent to the source node;
• retrieving the route information for the dialog indicated in the second request from the mapping;
• adding the retrieved route information to the second request;
• and
• forwarding the second request to the node indicated by the retrieved route information.

A method in a destination node of a network for processing messages, the method comprising:

• receiving from a registration node a first request from a source node to the destination node, the source node having a user;
• and
• when the destination node and the registration node are within the same domain,
• retrieving from a mapping of users to registration nodes an indication of the registration node of the user;
• and
• forwarding a request to the source node to the registration node indicated by the mapping.