ESnet is a "backbone" network, that is, a network to interconnect other networks, in particular, the local area networks (LANS) of the directly connected sites. However, connectivity to numerous other scientific and educational locations is provided through extensive interconnections with other networks, making ESnet a member of the global Internet.
Connectivity requirements come in many forms: connections of new sites, general requirements to gain access to a university and other collaborator sites, requirements to connect with regional networks, requirements to share access with other agencies, and requirements to provide international access to selected sites or countries. This interconnectivity is provided in a variety of means that include indirect connections through other R&D networks as well as the direct connection of sites to the ESnet backbone.