A communication system is disclosed in which a base station receives, from a communication device, NAS signalling for establishing a connection via the base station. The base station forwards the NAS signalling to a default MME for setting up the connection to the default MME. The default MME sends, responsive to the base station forwarding the NAS said signalling, a message identifying an MME group to which the NAS signalling should be rerouted. The base station selects an MME based on the message identifying the MME group, and forwards the NAS signalling to the selected MME, and includes information indicating that the NAS signalling shall not be rerouted.