Research And Implementation Of NAT

The most compelling problem facing the IP Internet is IP address depletion. One of the effective solutions - address reuse is to place Network Address Translation (NAT) at the borders of private network and global network. Study and design of the NAT are very important to applications. The advantages and disadvantages of the NAT in wideband metropolitan area network (MAN) are discussed in this paper. A solution to the design, realization, and application of the NAT in wideband MAN is proposed. The main works are as follows:1. The software reference models, OSI and TCP/IP, in computer networks have been analyzed thoroughly. The embedded model of the NAT is proposed.2. The client-server model is studied. The conclusion that the client-server model is simpler than TCP/IP is deduced. A simple and efficient solution that can improve the system reliability is proposed.3. The NAT protocol is studied carefully. Three methods for the realization of the NAT are developed. The processes of connection establishment and data storage in this protocol are studied. The transformation and process of data in the NAT device in the previous methods are analyzed carefully.4. ALG, including the processing policy of TCP/UDP, ICMP, and FTP packets, is analyzed and designed.5. The NAT board management policy is analyzed in wideband WAN. The realization of NAT depends on both software and hardware. NAT has found practical applications.