Application generates one message according to the entered parameters. The Message Identification Number uses the source Node Identification Number and message generation time. If a scenario requires more than one message, then the scenario must include multiple Application message generators.

Since future work may use packets instead of messages for data traffic, our protocol implementation is backwards compatible with raw packets. When a node generates a packet that does not have the Packet Header, the DTN router on that node creates a Packet Header for that data packet. `RouteInput` handles Packet Header generation for standard packets. The Message Identification Number uses the packet’s generation time in microseconds and the packet’s source Node Identification Number to generate the Message Identification Number. A node then treats each packet as an individual message, permiting ’s default packet generators to work with the protocols.

Node Discovery {#sec:NodeDiscovery}
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DTNs do not have constant connectivity, so nodes must discover other nodes to initiate a connection. Unlike , the simulator handles node discovery independently of any routing protocol. As a result, the DTN protocols must include a node discovery mechanism. In PacketEpidemic, nodes transmit `BEACON` control packets at a specific time interval for node discovery. The 