【正文】 t play back audio at more than realtime speed without noticing. (You can speed it up slightly, but not much.) You can pensate for jitter by 邵陽。t everything to a voice call, however. If the latency is more than around 200 ms, you39。re paying not just for the bandwidth for an IM, but also for using the work39。t use it to municate with people who don39。re paying 10162。s work. If you walk in while making a call, you would want to switch automatically to using the coffee shop39。re sitting in a coffee shop with free WiFi, you may want to use the coffee shop39。ll suddenly switch IP addresses, which will break your connection. This is where Mobile IPv6 es in. IPv4 also had a mobile variant, which relied on triangular routing— in simple terms, the old work acted as a relay for packets, which added latency every time you moved. With IPv6, IPSec allows the routing tables to be updated securely. Currently, the switching time is around a second, which isn39。s uplink. Unfortunately, each access point has a different routable sub address, so if you switch to the new access point39。s packets are being relayed via a dozen access points to the far end, which isn39。s routed through the first house39。t notice。ve ever sat roughly an equal distance between two access points, you may have noticed that your connections periodically pause briefly as your working stack decides to switch between the access points. The standard improves this pause time, dropping the switching time down to well under a second. This change makes feasible for mobile telephone use. In an area with a load of .11rsupporting access points, you can walk around while talking on the telephone, and not notice when your call jumps between those points— just as you don39。t remember my friends39。 phone numbers. For me, it39。 memories are getting worse because they can39。re also making use of the peer agreements they have with other phone works, while enjoying the use of their routing system. Mapping from telephone numbers is much less important than it used to be. I used to make telephone calls by a plicated process. First, I would look up a number in a paper directory or a local cache— either a personal address book or my brain— and then enter this number on a dial (later, on a keypad). By contrast, now I just select the person39。t a very large number in parison to the number of devices connected to the mobile phone work, which is why mobile operators are likely to be among the first major deployments of IPv6. With v6, a pany (or even an individual) can easily 邵陽學院畢 業(yè)設計（論文） 35 get a /64, meaning that the first 64 bits identify the work and the last 64 bits identify the device. To put this into perspective, the pany has enough address space for every valid IPv4 address to be a work the size of the Inter, or for every person to have three billion devices on his or her work. More to the point, it allows every device to have its own IP address, and the routing tables to be sufficiently sparse that routing is cheap. One other advantage that IPv6 adds, of particular relevance in this arena, is Mobile IPv6, in which a device can change its location in the work and still be routable, without dropping existing connections. Moving between towers is generally handled lower down the protocol stack, but this new arrangement allows a phone to move between currentlyseparate works while still maintaining connections, as long as both endpoints have IPv6 connectivity. An allIP work emphasizes the distinction between selling access and selling services— a distinction that mobile phone panies currently try to blur. When you make a telephone call, you39。ve made in the past few years have cost me absolutely nothing beyond the fixed work connection rate I pay for a broadband connection. But their endpoints have been other devices connected to the Inter, rather than the old telephone work. In practice, most of the cable between the two endpoints will be the same, irrespective of which logical work places the call. AllIP Network The wired infrastructure in the UK (operated by BT) and the nextgeneration wireless telephone works all have one thing in mon: They use IP internally and run telephone calls as Voice over IP (VoIP). My current phone supports UMTS, and is assigned a 10/8 IP address whenever I use it. This means that it39。t exactly unlike Sir Arthur39。 邵陽學院畢 業(yè)設計（論文） 34 附錄 A：英文原文 The Future of Wireless Networking Wireless working is being increasingly ubiquitous, on both the large and small scales. David Chisnall attempts to better Arthur C. Clarke at predicting where these technologies are heading. January 1, 2022— a historic day. Tele panies around the world would simultaneously abolish longdistance calling charges, making every call a local call. At least, according to Arthur C. Clarke, writing around a decade earlier. In the real world, this didn39。 最后，我必須感謝我的朋友，正是因為他們在電腦技術上的無私指引，我才能得以順利完成該論文。焉得諼草，言樹之背，養(yǎng)育之恩，無以回報。我只有在今后的學習、工作中，以鍥而不舍的精神，努力做出點成績，以博恩師一笑。本文的寫作更是直接得益于他的悉心指點，從論文的選題到體系的安排，從觀點推敲到字句斟酌，無不凝聚著他的心血。感謝母校為 我們提供的良好學習環(huán)境，使我們能夠在此專心學習，陶冶情操。 邵陽學院畢 業(yè)設計（論文） 32 參考 文獻 : [1] Jeff Doyle/Jennifer [M]. California：人民郵電出版社 ,2022. [2] 謝希仁 .計算機網絡（第五版） [M].北京：電子工業(yè)出版社， 2022. [3] 張健忠，徐敬東 .計算機網絡實驗指導書 [M]. 鄭州：清華大學出版社， 2022. [4] 沈鑫利 .計算機網絡安全 [M]. 北京：人民郵電出版， 2022. [5] 中國密碼學會 .無線網絡安全 [M].北京：電子工業(yè)出版社， 2022. [6] 段永福，等 .無線局域網設計與實現 [M].杭州：浙江大學出版社， 2022. [7]吳華光，鄧晉素 .基于 論證的校園網安全機制的研究 . [8]黃家林 ,李福芳 ,黃煙波 .校園網認證系統(tǒng)的設計與實現 . [9]柏剛 .基于以太網端口的用戶訪問控制技術 [J].寬帶城域網 ,2022,(39). [10]張南雨 ,區(qū)雪蓮 .RADIUS 協(xié)議認證和授權方法及包結構 .重慶郵電學院 ,2022. [11]陳玲 ,黃杰 ,可向明 ,龔正虎 PPPOE 的實現與安全技術的研究 .國防科技大學 . [12]聶武超 ,張彥興 . 認證技術分析 .華為技術報 .第 133 期 ()類別 . [13]A Method for transmitting ppp over Ether. [14]岑賢道 ,常安青 .網絡管理協(xié)議及應用開發(fā) [M].清華大學出版社 ,. [15]以太網安全技術白皮書 .華為公司 . 邵陽學院畢 業(yè)設計（論文） 33 致 謝