As of January 2006, there were only
39,934 networks having an AS (Autonomous System) number assigned by the
regional Internet registries, such as ARIN or RIPE. Only networks that hold
such a number form the backbone of the Internet, and only routers between these
core networks run the BGP protocol. This protocol is used to exchange routing
information between the border routers. The routing information passed with
this protocol allows IP packets to find their path through the
Internet.
See Also:
Internet; Internet Protocol (IP); Packet; Routers.