A design and implementation of nickname-based sockets for applications inside NATed network

The central IPv4 address pool managed by Internet Assigned Numbers Authority (IANA) was depleted in January 2011. Nevertheless, almost all nodes on the Internet still continue communicating with each other by using Internet protocol version 4 (IPv4). Since IPv4 addresses have been employed for a long time, it is difficult to immediately shift network layer protocol from IPv4 to IPv6. Therefore, the connectivity using IPv4 address is still required. There is a technology called Large Scale NAT (LSN) which keeps IPv4 address network being connected even though IPv4 addresses are depleted. In the case of home networks and small business networks by LSN, there is usually only a single private IPv4 address on the outside of network interface. Although NAT mechanism has many advantages, it has the negative effect which makes behavior of server side applications unavailable to the Internet. As a result, LSN also has the similar issue.

To overcome this issue, we propose a nickname-based network socket software library for future server-side applications. We developed a software which is P2P network based distributed directory service system called "CAGE" having NAT traversal mechanism. Further, using the functions of CAGE software, we also developed a software library of nickname-based sockets called "PRISON". Our proposed software library is available on operating systems such as Linux and MacOS X. In this paper, we discuss the design and implementation of CAGE software and PRISON software library.