Guidelines for creation, selection, and registration of an Autonomous System (AS)

This memo discusses when it is appropriate to register and utilize an Autonomous System (AS), and lists criteria for such. ASes are the unit of routing policy in the modern world of exterior routing, and are specifically applicable to protocols like EGP (Exterior Gateway Protocol, now at historical status; see [EGP]), BGP (Border Gateway Protocol, the current de facto standard for inter-AS routing; see [BGP-4]), and IDRP (The OSI Inter-Domain Routing Protocol, which the Internet is expected to adopt when BGP becomes obsolete; see [IDRP]). It should be noted that the IDRP equivalent of an AS is the RDI, or Routing Domain Identifier.