Figures Figure 1 Rendezvous Operating Environment Figure 2 Point-to-Point Message Figure 3 Reliable Multicast Message Figure 4 Event-Driven Publish/Subscribe Interaction Figure 5 Demand-Driven Request/Reply Interaction Figure 6 Multicast Request/Reply Interaction Figure 7 Default Event Queue Figure 8 Prioritize Event Queues in a Group Figure 9 Remove Event Queues from a Group to Suspend Dispatch Figure 10 Listener Activation and Dispatch Figure 11 I/O Event Activation and Dispatch Figure 12 Timer Activation and Dispatch Figure 13 Direct Communication between Two Programs Figure 14 Relay Agents Figure 15 Relay Agents and Delays: Network Figure 16 Relay Agents and Delays: Timing Figure 17 Relay Agents: Reply Name Substitution Figure 18 One-of-N Delivery to a Distributed Queue Figure 19 Fault Tolerance Operating Environment Figure 20 Mutual Backup across a WAN