1. National Service Providers (NSPs). These entities would provide the backbone services formerly provided by the NSFNET backbone. Commercial firms would provide these services. Currently, the major players at this level are Sprint[9], MCI[10], BBN[11], UUNET[12], and ANS[7]. NSPs are also sometimes referred to as Level 2 in the new Internet architecture.
2. Network Access Points (NAPs)[3]. These facilities serve as primary interconnection points between NSPs and as entry points for Regional Networks and Internet Service Providers (ISPs) into the NSP backbone networks. Officially, there are 3 NSPs, located in Chicago, San Francisco, and Pennsauken, NJ (vic Philadelphia, PA -- the "New York" NAP); in actual practice, these are supplemented by three legacy interconnection points and five Metropolitan Area Ethernet (MAE) systems operated by MFS Communications. The legacy sites are the Commercial Internet Exchange, or CIX, from the NSFNET period, located in Santa Clara, CA, and two Federal Internet Exchange locations -- College Park, MD, and Moffet Field, CA. The five MAEs serving as de facto NAPs are MAE-East (Washington, DC); MAE-West (San Jose, CA); MAE-LA (Los Angeles, CA); MAE-Chicago (Chicago, IL); and MAE-Dallas (Dallas, TX). NSPs are often referred to as Level 1 of the new Internet architecture.
3. Regional Networks form the third component of the new Internet architecture. Regional networks are largely unchanged from the NSFNET period (other than speed increases due to advancing technology). These entities provide connectivity to the NSP backbones for ISPs throughought their region. CERFNet [13]is an example of a major reigional network. Regional Networks comprise Level 3 of the new architecture.
4. Internet Service Providers (ISPs) form the fourth level of the new Internet architecture. ISPs provide Internet connectivitity through points of presence and connectivity to Regional Networks or NSPs. ISPs may also operate relatively large backbone networks and be geographically large. The boundary between ISPs, Regional Networks, and NSPs is relatively unclear.
5. The Consumer and Business Market --the end users of Internet services -- comprise the fifth level of the new Internet architecture.
Though no longer operating the US Internet backbone, the National Science Foundation is not completely out of the network business. The Very High Speed Backbone Network Services -- vBNS[14] -- is currently under development.