Establishing a communication channel via a relay server with reduced setup time. Upon request by an initiating communication device a relay allocation server may allocate a single relay server for use in a communication session between the initiating communication device and one or more recipient communication devices. The relay server may be selected to perform favorably for the initiating communication device. Messaging for establishment of the communication session may be performed using persistent messaging connections, to avoid connection establishment cost. Messaging may also be performed using address tokens to avoid the cost of discovering global IP addresses. Following establishment of the communication session, the relay server may discover the IP address of one or more recipient communication devices, and may initiate reallocation of those devices to another relay server.