The soccer server  system used successfully at RoboCup'97  during IJCAI'97 models a communication environment appropriate in a time-pressured, crowded environment. All 22 agents (11 on each team) use a single, unreliable communication channel. When one agent speaks, agents on both teams can hear the message immediately along with the (relative) direction from which it came. The speaker is not inherently known. Agents have a limited communication range, hearing only messages spoken from within a certain distance. They also have a limited communication capacity, hearing a maximum of 1 message every 200ms (actions are possible every 100ms, so if all other agents are speaking as fast as they can, only 1 of every 42 messages will be heard). Thus communication is extremely unreliable. Furthermore, on every 100ms action cycle, agents can either communicate or move in the world. Since the real-time nature of the domain requires quick and timely reactions, and since opponents hear all messages, communicating involves a significant cost.
Table 2: Characteristics of the Soccer Server communication model.