A communications subsystem (20) comprises a plurality of interfaces (20.1, 20.2, 20.3), a routing data repository (29) for storing path information associating addresses to the interfaces, a packet forwarding module (25) adapted to detect a destination address of a received data packet and to switch the data packet between the interfaces as a function of the stored path information, and a routing update module (25) adapted to detect a source address (10.1) in a data packet received through a first interface (20.2) of the communications subsystem, retrieve path information relating to the source address from the routing data repository, determine that the retrieved path information associates first source address to a second interface (20.1) of the communications subsystem, and store path information in the routing data repository, wherein the path information associates the source address with the first interface instead of or in addition to the second interface.