【正文】 ming mobile node. When the mobile node is away from home link, it registers its careof address to its home agent. This is done through exchange of a Registration Request and Registration Reply messages (which are sent with UDP using well known port number 434). Depending on the method of attachment, the mobile node will register either directly with its home agent, or through a foreign agent, which forwards the registration to the home agent. The careof address can either be determined from a foreign agent’s advertisements (a foreign agent careof address), or by some external assignment mechanism such as DHCP (a colocated careof address). When the home agent receives the register message, it will maintain a register message WP=46table in the server, where the original registered care of address will be replaced by the new registered careof address. Then a reply message will be sent to the mobile node also by wellknown port 434. OK, all the register and reply process .the register, the packet can be routed in IP layer. Among all the routing process, our thesis emphasizes on the mobile node. The work of the mobile node mainly involves two parts, the one is that mobile node receives packets from other nodes, and the other is the mobile node actively municates with other nodes. If the mobile node receives packets from other nodes, there es two condition: one way is that its position is on the home route, then it will discover that the destination address of the packets is the home address, so it receives packets. The other way is that the mobile node is on the roaming foreign link, at this time, the packet’s destination address it receives will be the care of address transmitted by the home agent. In order to municate with other nodes only with its home address, the mobile node will dispose the packets like this: First, it will shuck off the IP head, so es out the home address which be added by home agent. Second, the mobile node can use home address to send packets to the munication opposite. Generally, the home agent substitutes the mobile node to receive packets in home link, then send all the packets through the channel to the careof address, so the roaming mobile node receives the packets on the foreign link on the other hand, the mobile node maybe actively municates with other nodes. Here also two conditions: the one is the mobile node discovers that it is on the home link through agent searching, then no. 【關(guān)鍵詞】 移動(dòng)節(jié)點(diǎn)； 數(shù)據(jù)包； 家鄉(xiāng)鏈路； 代理搜索； 外地鏈路； 轉(zhuǎn)交地址； 移動(dòng)通信； 設(shè)計(jì)與實(shí)現(xiàn)； 隧道技術(shù)； 目錄 1 引言 .......................................................................................................................... 1 2 移動(dòng)通訊中移動(dòng) IP 節(jié)點(diǎn)技術(shù)的實(shí)現(xiàn) ............................................................ 1 移動(dòng) IP 節(jié)點(diǎn)的關(guān)鍵技術(shù) ................................................................................ 1 移動(dòng) IP 技術(shù) 的工作過程 ................................................................................ 2 3 移動(dòng) IP 技術(shù)的具體方案 .......................................................................................... 5 技術(shù)優(yōu)化概述 ................................................................................................... 5 移動(dòng)節(jié)點(diǎn)的切換操作 ...................................