N-1-3-012.82, "Europe - HEPnet", by Brian Carpenter, , and Francois Fluckiger, HEPnet is the collection of lines, equipment and services partially or totally funded and operated by the European High Energy Physics (HEP) community for its 5,000 physicists and their support staff. It provides a range of services supported in collaboration by operational staff from major HEP institutes. HEPnet in Europe may be compared to the US Department of Energy's ESnet, although limited to particle physics. HEPnet was set up in response to very specific requirements of the community, such as the need for direct lines of fixed and guaranteed high bandwidth between major laboratories and data processing centres, or very short network latencies to support advanced distributed processing applications. It is thus complementary to HEP use of general-purpose research network infrastructure. The basic infrastructure relies on a set of point to point international leased lines between HEP institutes. In several cases, these leased lines result from sharing with other European initiatives, such as EASInet, the networking component of the IBM European Academic Supercomputing Initiative, EARN, EUnet or NORDUnet. HEPnet is fully connected via high speed lines to EBONE, the European IP backbone. The international topology is mainly a star around CERN, the European Particle Physics Laboratory located on the French-Swiss border near Geneva. With lines ranging from 9.6Kbps to 2Mbps it directly connects France, Hungary, Germany, Greece (on order), India, Israel, Italy, Netherlands, Poland, Russia, Spain (planned), Switzerland, the UK, and the USA. The aggregate bandwidth exceeds 12 Mbps, including shared lines. Nordic countries are also indirectly connected via NORDUnet. National traffic distribution occurs either through the national general purpose networks, or through a dedicated HEP network (such as in France and Italy). The leased lines either run native IP, or are multiplexed. TCP/IP, DECnet, RSCS and SNA (plus a residual X.25 service) are provided as "bearer" services, supporting application services such as distributed file and tape management and the World Wide Web (WWW) information access system. Monthly HEP traffic is estimated to be 150 Gbytes. The network is technically managed by the HEPnet Technical Committee (HTC) comprising the national HEPnet managers, complemented by a user driven group, the HEPnet Requirements Committee (HRC). Hopes for future evolution include a move to speeds in the range of 34 Mbps to meet the requirements of new European particle accelerators such as the planned Large Hadron Collider (LHC), or the introduction of multi-media applications for remote collaborative work. In addition, the community has launched a project for shipping physics files at 8Mbps over the Olympus satellite of the European Space Agency.