由於ATM網路通訊技術包含動態頻寬配置、低傳輸延遲、頻寬獨享以及服務品質的保證等優點，並且能提供光纖、雙絞線、同軸電纜等不同的傳輸媒介，使它可以應用在區域網路、都會型網路及廣域網路上。因此ATM被認定為未來網路領域中最重要的技術之一，幾乎可能要扮演廣域網路的骨幹網路的角色，且寬頻整合數位網路也將逐漸建構ATM網路。
然而目前網際網路上最重要的通訊協定是IP，它與ATM是完全不同的型態。 IP是屬於非連結導向式的傳輸，而ATM則是連結導向的網路型態。因此如何在ATM網路上傳送IP封包是極為重要的課題。雖然ATM有眾多優點，但由於網路架構的演進亦需考慮既有的網路設備，所以當以ATM為主的骨幹網路要將廣域網路與傳統的區域網路連結起來時，設計出一套邊界路由器的硬體架構與軟體系統是必要的。
邊界路由器的主要目的既然在於連結不同型態的IP與ATM網路，當然最主要的功能就是IP與ATM資料格式間的轉換。區域網路將IP封包切割成ATM細胞送至骨幹網路中傳送，進入另一區域網路前再將ATM細胞重組回IP封包；另外還有IP封包以及ATM細胞的直接交換，都是本篇論文的重點所在。

Because ATM network communication technology includes the advantage of dynamic bandwidth location, low transmission delay, bandwidth and quality of service guarantee, and it can provide different transmission medium such as optical fiber, twisted pair and coaxial cable, so it can be applied to LAN(Local Area Networks), MAN (Metropolitan Area Network) and WAN(Wide Area Network). By reason of above description, ATM is regarded as one of the most important technology in the future network, and it is almost possible to play the role of the backbone of Wide Area Network. And Broadband—Integrated Service Digital Networks will also build ATM network.
However, at present the most important communication protocol in the internet is IP, it is entirely different from the type of ATM. IP is connectionless; but ATM is connection—oriented. Hence it is a very important subject about how to transmit IP packet in ATM network. Although ATM has many advantages, the network structure advance also must consider existed network device, therefore, when we want to use ATM backbone connecting WAN and traditional LAN, it is necessary to design the edge router hardware architecture and software system.
Since the major purpose of the edge router is to connect IP and ATM—two different types of network, its major function is the data format transformation between IP and ATM. LAN segments IP packets into ATM cells and transmitting them to the backbone. Before approach another LAN, the edge router reassembles ATM cells and let IP packets recover from ATM cells. Besides, its function also includes direct IP packet routing and ATM cell switching. The several related functions are the focus of this paper.

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