Abstract: Data network signals, methods and devices that are suitable for multiplexing payload data in a packet switched data network are disclosed. Payload associated with multiple packets is multiplexed into a single multiplexed packet. Each payload portion is identified by a mini-header within the multiplexed packet. Mapping information may also be transferred as part of such multiplexed packets which include multiplexed payload data. Preferably, the mapping information is used to form mapping tables within routers at edges of access networks. The mapping tables may be used to establish a relationship between mini-headers and full headers. The mapping tables may be used to multiplex data from packets to form a multiplexed packet at an ingress router, and demultiplex the multiplexed packet at an egress router. Conveniently, neither gateways nor out of band signalling are required.