IP network technology was originally developed for interconnecting computers to provide resource sharing. IP networking has becoming an integral part of many broadcast and program production infrastructures. It starts with a description of the structure of IP packets and the allocation of IP addresses. It explains why NAT (network address translation) is required and describe its limitations. Routing protocols for interconnecting IP routers are the cornerstone of any IP network. Many routing protocols have been developed by the IETF (Internet engineering task force) over the years and the basic principles of the primary routing protocols. The IP network QoS (quality of service) signalling mechanisms that link up the traffic management in individual routers to form a network wide path. The proliferation of multimedia applications on the Internet has raised interest in IP multicast. IP multicast is a resource efficient way of delivering high volume data to multiple destinations in a network and the principle of multicast routing. Our increasing dependency on networks has raised demands to provide secure network communications. (22 pages)