虛擬網際網路協定閘之設計與實做

Abstract

由於網際網路蓬勃發展，網路用戶大量增加，對於網際網路位址的需求也 相對大增;然而網際網路協定以32 bits 表示網路位址空間，也就是網際 網路位址數目最多只有2^23個，因此導致網際網路位址不足的問題。對於 網際網路位址不足的問題，目前已經有一些解決方法被提出來，本篇論文 將對CIDR (Classless Inter-Domain Routing)，NAT (network address translation) 和IPv6 (internet protocol version 6)三個較具代表的 方法做一研究，然後接著提出我們所設計的解決方法，也就是所謂的虛擬 網際網路協定閘 (VIP Gate)。虛擬網際網路協定閘乃是用重複使用某一 區塊網際網路位址以及網際網路位址分享的方式來擴充網際網路，亦即擴 充在同一時間，連上網際網路的使用者的最大數目。其中網際網路位址分 享指的是虛擬網際網路內的所有主機，在對外的連結接時，皆使用同一個 網際網路位址。在我們的設計中，虛擬網際網路協定閘是採用較具彈性的 動態路由機制，並協同配合領域名稱系統，始可達成一網際網路主機和一 虛擬網際網路主機之間的雙向連接，也就是網際網路上的顧客主機也能擷 取到位於虛擬網際網路上伺服主機的資源。 The dramatically increasing number of users on the Internet has leadingto a heavy demand on IP addresses because the TCP/IP protocol suite is the most popular networking standard today and at least one IP address is required for each host to access IP networks. However, the address field of IP header of IPv4 is 32-bit wide so that the IP address spaceis limited to the number 232 inherently. The increasing demand for moreIP addresses and the inherent address space limitation of IPv4 are leading to a serious problem that the remaining IP addresses are runningout quickly. In order to provide enough IP addresses physically or logically for future use, some enhancement scheme should be development.In this thesis, we first study three solutions for solving the address depletion problem of IPv4 including CIDR (Classless Inter-Domain Routing),NAT (network address translation) and IPv6 (internet protocol version 6).We then propose our own approach, called VIP Gate. VIP Gate resolves the address depletion problem of IPv4 by IP address sharing and reusing. Domain name system (DNS) is cooperated to designate a destination insidethe stub network so that servers can be located inside the stub domain and visible from Internet. Dynamic route is used by VIP Gate in inter-domain routing. After that, the implementation of VIP Gate is described.