RFC 2008 (rfc2008) - Page 2 of 13

Implications of Various Address Allocation Policies for Internet Routing

RFC 2008                                                    October 1996


   fraction of the total destinations in the Internet, and could express
   such reachability through a single IP address prefix the document
   suggests to use the "address ownership" policy. However, applying the
   "address ownership" policy to every individual site or organization
   that connects to the Internet results in a non-scalable routing.

   Consequently, this document also recomments that the "address
   lending" policy should be formally added to the set of address
   allocation policies in the Public Internet. The document also
   recommends that organizations that do not provide a sufficient degree
   of routing information aggregation, but wish to obtain access to the
   Internet routing services should be strongly encouraged to use this
   policy to gain access to the services.

2 On the intrinsic value of IP addresses

   Syntactically, the set of IPv4 unicast addresses is the (finite) set
   of integers in the range 0x00000000 - 0xDFFFFFFF. IP addresses are
   used for Network Layer (IP) routing. An IP address is the sole piece
   of information about the node injected into the routing system.

   The notable semantics of an IP unicast address is its ability to
   interact with the Public Internet routing service and thereby
   exchange data with the remainder of the Internet. In other words, for
   the Public Internet, it is the reachability of an IP address that
   gives it an intrinsic value. Observe, however, that IP addresses are
   used outside of the Public Internet. This document does not cover the
   value of addresses in other than the Public Internet context.

   The above implies that in the Public Internet it is the service
   environment (the Internet) and its continued operation, including its
   routing system, which gives an IP address its intrinsic value, rather
   than the inverse. Consequently, if the Public Internet routing system
   ceases to be operational, the service disappears, and the addresses
   cease to have any functional value in the Internet. At this point,
   for the Public Internet, all address allocation and management
   policies, including existing policies, are rendered meaningless.

3 Hierarchical routing and its implication on address allocation

   Hierarchical routing [Kleinrock 77] is a mechanism that improves the
   scaling properties of a routing system. It is the only proven
   mechanism for scaling routing to the current size of the Internet.

   Hierarchical routing requires that addresses be assigned to reflect
   the actual network topology. Hierarchical routing works by taking the
   set of addresses covered by a portion of the topology, and generating
   a single routing advertisement (route) for the entire set. Further,



Rekhter & Li             Best Current Practice