Network Address Translation
Network Address Translation
Design and Implementation
Abstract—This is the final report for a research project covering network address translation (NAT). Research topics include: the history and necessity for NAT, overall design, implementation, the different types, and examples of its use.
Keywords—NAT; networking; project; research
Necessity
IP addresses were originally designed to be globally unique. In an IP network, each computer is allocated a unique IP address. In the current version of IP protocol (IPv4) an IP address is 4 bytes, and because an address is 4 bytes, the total number of available addresses is 2 to the power of 32, which is 4,294,967,296. This represents the total theoretical number of computers that can be directly connected to the Internet. This property of the IP address is fundamental in supporting the end-to-end architecture of the Internet.
Until recently, almost all of the Internet protocol designs were based on the original IP address model. However, the explosive growth of the Internet during the 1990s made clear the danger of IP address space exhaustion. This also created an instant demand on IP addresses. Connecting large numbers of user networks and home computers demanded IP addresses instantly and in large quantities. The regular IP address allocation process could not possibly meet such a demand.
IP increasingly became the standard for networked digital communication; the wide-spread mobile phones have become viable internet hosts. The introduction of broadband Internet access increased IP penetration. These connections are always active and are rarely turned off compared to what was common in dial-up networks. Inefficiencies caused by subnetting made it difficult to use all addresses in a block. [RFC 3194] defines the host-density ratio; it is a metric for utilization of IP address blocks used in allocation policies. The advanced hardware infrastructure made it possible to host many instances of an
Design and Implementation
Abstract—This is the final report for a research project covering network address translation (NAT). Research topics include: the history and necessity for NAT, overall design, implementation, the different types, and examples of its use.
Keywords—NAT; networking; project; research
Necessity
IP addresses were originally designed to be globally unique. In an IP network, each computer is allocated a unique IP address. In the current version of IP protocol (IPv4) an IP address is 4 bytes, and because an address is 4 bytes, the total number of available addresses is 2 to the power of 32, which is 4,294,967,296. This represents the total theoretical number of computers that can be directly connected to the Internet. This property of the IP address is fundamental in supporting the end-to-end architecture of the Internet.
Until recently, almost all of the Internet protocol designs were based on the original IP address model. However, the explosive growth of the Internet during the 1990s made clear the danger of IP address space exhaustion. This also created an instant demand on IP addresses. Connecting large numbers of user networks and home computers demanded IP addresses instantly and in large quantities. The regular IP address allocation process could not possibly meet such a demand.
IP increasingly became the standard for networked digital communication; the wide-spread mobile phones have become viable internet hosts. The introduction of broadband Internet access increased IP penetration. These connections are always active and are rarely turned off compared to what was common in dial-up networks. Inefficiencies caused by subnetting made it difficult to use all addresses in a block. [RFC 3194] defines the host-density ratio; it is a metric for utilization of IP address blocks used in allocation policies. The advanced hardware infrastructure made it possible to host many instances of an
References: Egevang, K, and P Francis. The IP Network Address Translator (NAT). RFC 1631. Cray Communications, NTT, 1994. Web. 25 Mar. 2013. . Droms, R. Dynamic Host Configuration Protocol. RFC 2131. Bucknell University, 1997. Web. 25 Mar. 2013. . Dorton, Doug. Introduction to Network Address Translation. Webjunction, 2012. Web. 25 Mar. 2013. . Wikipedia contributors. "Network address translation."Wikipedia, The Free Encyclopedia. 17 Mar 2013. . Hasenstein, Michael. "IP NETWORK ADDRESS TRANSLATION." http://hasenstein.com. Nikos Drakos, 5 Dec 1997. Web. 25 Mar 2013. . Zhang, Lixia. A Retrospective View of Network Address Translation. Los Angeles: University of California, 2008. Web. 25 Mar. 2013. . Doyle, Jeff, and Jennifer Carroll. "NAT Issues."ciscopress.com. Cisco Press, 8 Feb 2002. Web. 25 Mar 2013.