A gateway device in a communications system, the gateway device comprising: a receiver configured to: receive information from a plurality of user terminals of a digital video broadcast communications system; and receive data to be transmitted to a first user terminal of the plurality of user terminals, the first user terminal associated with a first data link layer address; a processor, communicatively coupled with the receiver, and configured to identify an addressing format for the received data; and a transmitter, communicatively coupled with the processor, configured to transmit the received data according to the addressing format, characterised in that: the communications system comprises a satellite communications system, and the received information comprises log-in information from the plurality of user terminals, each associated with a different data link layer address and characterised by the processor being configured to: associate each of the data link layer addresses with an identifier for use in lieu of the associated data link layer addresses, the identifier of shorter length than the associated data link layer address; and determine, for the received data, whether the identifier associated with the first data link layer address is to be used in lieu of the first data link layer address for addressing, and further characterised in that: the addressing format for the received data is identified based at least in part on the determination. a receiver configured to: receive information from a plurality of user terminals of a digital video broadcast communications system; and receive data to be transmitted to a first user terminal of the plurality of user terminals, the first user terminal associated with a first data link layer address; receive information from a plurality of user terminals of a digital video broadcast communications system; and receive data to be transmitted to a first user terminal of the plurality of user terminals, the first user terminal associated with a first data link layer address; a processor, communicatively coupled with the receiver, and configured to identify an addressing format for the received data; and a transmitter, communicatively coupled with the processor, configured to transmit the received data according to the addressing format, characterised in that: the communications system comprises a satellite communications system, and the received information comprises log-in information from the plurality of user terminals, each associated with a different data link layer address and characterised by the processor being configured to: associate each of the data link layer addresses with an identifier for use in lieu of the associated data link layer addresses, the identifier of shorter length than the associated data link layer address; and determine, for the received data, whether the identifier associated with the first data link layer address is to be used in lieu of the first data link layer address for addressing, and further characterised in that: the addressing format for the received data is identified based at least in part on the determination. the communications system comprises a satellite communications system, and the received information comprises log-in information from the plurality of user terminals, each associated with a different data link layer address and characterised by the processor being configured to: associate each of the data link layer addresses with an identifier for use in lieu of the associated data link layer addresses, the identifier of shorter length than the associated data link layer address; and determine, for the received data, whether the identifier associated with the first data link layer address is to be used in lieu of the first data link layer address for addressing, and further characterised in that: the addressing format for the received data is identified based at least in part on the determination. associate each of the data link layer addresses with an identifier for use in lieu of the associated data link layer addresses, the identifier of shorter length than the associated data link layer address; and determine, for the received data, whether the identifier associated with the first data link layer address is to be used in lieu of the first data link layer address for addressing, and further characterised in that: the addressing format for the received data is identified based at least in part on the determination.