Networks for high energy physics

High-speed wide-area networks are an essential element of high energy physics research. The need for such networks today is critical. It is a direct result of the new generation of experiments at CERN, Fermilab, SLAC, KEK and DESY which are now, or will soon, start taking data. Larger and more diverse networks will have to be developed for the next generation of hadron colliders. This talk reviews the status of networking for HEP experiments, from the physicists' point of view. The networking requirements, in terms of functionality and bandwidth, are discussed. The equipment and protocol choices that face physics groups at the 'end nodes' of HEPNET are often complex. This is partly a result of the diversity of the needs related to HEP computing. An addition source of complexity is the existence of, or plans for, multiple national and international networks, where the network architectures and protocols may not be compatible from one large scale network to another.