Abstract: A method of operating a node of a telecommunications system, the node comprising a plurality of entities each arranged to send and receive IP packets to peer entities, via a Network Address Translation function, using a layer 4 control protocol which facilitates multi-homing by allowing an entity to include more than one IP address in a layer 4 packet chunk. The method comprises maintaining at each of said plurality of entities a table mapping one or more private addresses of the entity to one or more public addresses of the Network Address Translation function, and, for each association initiation message generated by an entity, including in said layer 4 packet chunk of the message the public IP address(es) of the Network Address Translation function obtained from said table for the corresponding private IP address(es).