A communication network comprising a Network Address Translator (NAT) arranged to translate between a public NAT address and a plurality of private NAT addresses. A network element has a plurality of network interfaces each of which corresponds to a private NAT address. A connection processor sets up a connection for data communication which is capable of supporting a plurality of network interfaces of the network element. An identifier processor initializes a network interface identifier for identifying individual network interfaces for the connection. The network interface identifier is distributed to the NAT and the network elements of the connection. Incoming data packets for the network elements are then adapted to include the network interface identifier and the NAT uses this to address the data packets in response to the first network interface identifier.