Book Image

Learning Network Programming with Java

Book Image

Learning Network Programming with Java

Overview of this book

Network-aware applications are becoming more prevalent and play an ever-increasing role in the world today. Connecting and using an Internet-based service is a frequent requirement for many applications. Java provides numerous classes that have evolved over the years to meet evolving network needs. These range from low-level socket and IP-based approaches to those encapsulated in software services. This book explores how Java supports networks, starting with the basics and then advancing to more complex topics. An overview of each relevant network technology is presented followed by detailed examples of how to use Java to support these technologies. We start with the basics of networking and then explore how Java supports the development of client/server and peer-to-peer applications. The NIO packages are examined as well as multitasking and how network applications can address practical issues such as security. A discussion on networking concepts will put many network issues into perspective and let you focus on the appropriate technology for the problem at hand. The examples used will provide a good starting point to develop similar capabilities for many of your network needs
Table of Contents (16 chapters)
Learning Network Programming with Java
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Chapter 6. UDP and Multicasting

User Datagram Protocol (UDP) sits on top of IP and provides an unreliable counterpart to TCP. UDP sends individual packets between two nodes in a network. UDP packets do not have knowledge of other packets, and there is no guarantee that a packet will actually arrive at its intended destination. When multiple packets are sent, there is no guarantee of the arrival order. UDP messages are simply sent and then forgotten as there are no acknowledgements sent from a recipient.

UDP is a connectionless protocol. There is no exchange of messages between two nodes to facilitate the packet transmission. No state information is maintained about the connection.

UDP is appropriate for services where delivery needs to be efficient, and no guarantee of delivery is needed. For example, it is used for Domain Name System (DNS) services, Network Time Protocol (NTP) services, Voice Over IP (VOIP), network communication coordination by P2P networks, and for video streaming. If...