Java Message Service, 2nd Edition

To Multicast or Not to Multicast

An increasing number of vendors are releasing products based on IP multicasting. To understand the tradeoffs involved in these products, you need a basic understanding of how the TCP/IP protocol family works, and how multicasting fits into the bigger picture.^[15] We won’t discuss any particular JMS implementations or suggest that one vendor might be better than another; our goal is to give you the tools that you need to ask intelligent questions, evaluate different products, and map out a deployment strategy.

TCP/IP

TCP/IP is the name for a family of protocols that includes TCP (Transmission Control Protocol), UDP (User Datagram Protocol), and IP (Internet Protocol). The protocols are layered: IP provides low-level services; both TCP and UDP sit “on top of” IP.

TCP is a reliable, connection-oriented protocol. A process wishing to establish communication with one or more processes across a network creates a connection to each of the other processes and sends and receives data using those connections. The network software, rather than the application, is responsible for making sure that all the data arrives, and that it arrives in the correct order. It takes care of acknowledging that data has been received, automatically discards duplicate data, and performs many other services for the application. If something happens with the connection, the process on either side of the connection will know almost immediately that the connection has been permanently ...