Network Communications

UDP is the mechanism that lets publishers and subscribers exchange packets of data, called datagrams.

A datagram is an independent, self-contained message sent over the network whose arrival, arrival time, and content are not guaranteed. Although UDP does not guarantee delivery, RAP ensures that all messages reach their intended target. Publishers temporarily cache all message packets and subscribers track all messages deliveries. If a message is lost, a subscriber requests a new copy, and the publisher resends the message from the pool of cached messages.

• UDP Multicasting
  UDP is one of the two main transport protocols (TCP being the second) utilized in IP networks, and is used by applications to transmit messages (also known as datagrams or packets) between networked hosts.
• Local Interfaces
  In UDP multicasting, every multicast group is bound to a network interface, using the IP address of the interface. RAP documentation calls this the local interface. RAP uses IPv4 multicasting, and requires IP addresses configured for the network interface to be 32-bit IPv4 addresses.