IPNL: A NAT-extended Internet architecture

This paper presents and analyzes IPNL (for IP Next Layer), a NAT-extended I nternet protocol architecture designed to scalably solve the address deplet ion problem of IPv4. A NAT-extended architecture is one where only hosts an d NAT boxes are modified. IPv4 routers and support protocols remain untouch ed. IPNL attempts to maintain all of the original characteristics of IPv4, most notably address prefix location independence. IPNL provides true site isolation (no renumbering), and allows sites to be multi-homed without poll uting the default-free routing zone with per-site prefixes. We discuss IPNL 's architectural benefits and drawbacks, and show that it comes acceptably close to achieving its goals.