Data Network is a capability that allows users to combine separate data bases, telecommunication systems, and specialized computer operations into a single integrated system, so that data communication can be handled easily as voice messages. IP (Internet protocol) is the main pillar of the Internet and is designed primarily for internetworking as a simple protocol that can carry almost the network. The business world seems increasingly range of data communications and Internet and all modern data networks are based around either the Internet or at least about IP (Internet Protocol) based network. This volume is intended not only for network designers and practitioners, who for too long been confused by the jargon of complex data networks, but also for newcomers - are eager to put most of the "protocols" into context.