(NSFNET) A high speed hierarchical "network of networks" in the US, funded by the National Science Foundation. At the highest level, it is a backbone network comprising 16 nodes connected to a 45Mb/s facility which spans the continental United States. Attached to that are mid-level networks and attached to the mid-levels are campus and local networks. NSFNET also has connections out of the US to Canada, Mexico, Europe, and the Pacific Rim. The NSFNET is part of the Internet.