【正文】 ring is an increasingly frequent event. Both DHCP [RFC1541] and PPP [RFC 1661] promote the use of dynamic address allocation. To summarize, since the development and deployment of DHCP and PPP, and since it is expected that renumbering is likely to bee a mon event, IP address significance has indeed been changed. Spatial uniqueness should be the same, so addresses are still effective locators. Temporal uniqueness is no longer assured. It may be quite short, possibly shorter than a TCP connection time. In such cases an IP address is no longer a good identifier. This has some impact on endtoend security, and breaks TCP in its current form. . Multicast and Anycast Since we deployed multicast [RFC1112], we must separate the debate over meaning of IP addresses into meaning of source and destination addresses. A destination multicast address (. a locator for a topologically spread group of hosts) can traverse a NAT, and is not necessarily restricted to an intra (or to the public Inter). Its lifetime can be short too. The concept of an anycast address is of an address that semantically locates any of a group of systems performing equivalent functions. There is no way such an address can be anything but a locator。 。 interconnecting routing realms could be acplished via either ALGs or NATs. In principle such interconnection will have less functionality than if those Intras were directly connected. In practice the difference in functionality may or may not matter, depending on individual circumstances. 5. IPv6 Considerations As far as temporal uniqueness (identifierlike behaviour) is concerned, the IPv6 model [RFC1884] is very similar to the current state of the IPv4 model, only more so. IPv6 will provide mechanisms to autoconfigure IPv6 addresses on IPv6 hosts. Prefix changes, requiring the global IPv6 addresses of all hosts under a given prefix to change, are to be expected. Thus, IPv6 will amplify the existing problem of finding stable identifiers to be used for endtoend security and for session bindings such as TCP state. The IAB feels that this is unfortunate, and that the transition to IPv6 would be an ideal occasion to provide upper layer endtoend protocols with temporally unique identifiers. The exact nature of these identifiers requires further study. As far as spatial uniqueness (locatorlike behaviour) is concerned, the IPv6 address space is so big that a shortage of addresses, requiring an RFC1918like approach and address translation, is hardly conceivable. Although there is no shortage of IPv6 addresses, there is also a welldefined mechanism for obtaining linklocal and sitelocal addresses in IPv6 [RFC1884, section ]. These properties of IPv6 do not prevent separate routing realms for IPv6, if so desired (resulting in multiple security domains as well). While at the 共 6 頁 第 12 頁 present moment we cannot identify a case in which multiple IPv6 routing realms would be required, it is also hard to give a definitive answer to whether there will be only one, or more than one IPv6 routing realms. If one hypothesises that there will be more than one IPv6 routing realm, then such realms could be interconnected together via ALGs and NATs. Considerations for such ALGs and NATs appear to be identical to those for IPv4. 共 6 頁 第 13 頁 指 導(dǎo) 教 師 評 語 外文翻譯成績： 指導(dǎo)教師簽字： 2020 年 12 月 10 日 注： 1. 指導(dǎo)教師對譯文進(jìn)行評閱時(shí)應(yīng)注意以下幾個(gè)方面：①翻譯的外文文獻(xiàn)與畢業(yè)設(shè)計(jì)（論文）的主題是否高度相關(guān)，并作為外文參考文獻(xiàn)列入畢業(yè)設(shè)計(jì)（論文）的參考文獻(xiàn)；②翻譯的外文文獻(xiàn)字?jǐn)?shù)是否達(dá)到規(guī)定數(shù)量（ 3 000 字以上）；③譯文語言是否準(zhǔn)確、通順、具有參考價(jià)值。s position in the work39。 共 6 頁 第 5 頁 IPv4 Address Behaviour Today The main purpose of this note is to clarify the currentinterpretation of the 32bit IP version 4 address space, whosesignificance has changed substantially since it was originally defined in 1981 [RFC791]. This clarification is intended to assist protocol designers, productimplementors, Inter service providers, and user sites. It aims toavoid misunderstandings about IP addresses that can result from the substantial changes that have taken place in the last few years, as a result of the Inter39。 IPv6 的這些屬性不能阻止從 IPv6 中分離路由區(qū)域，如果這樣描述（在多安全域的結(jié)果）。 IAB 感覺這是不幸運(yùn)的，而且到 IPv6 的轉(zhuǎn)換將是提供端到端的暫時(shí)的唯一標(biāo)示的高層協(xié)議一個(gè)理想的原因。 5. IPv6討論 正如暫時(shí)的的唯一性的討論（好象標(biāo)示的行為）， IPv6 的模型與 IPv4 的模型很相似，只不過多了些。 . 小結(jié) 網(wǎng)絡(luò)的經(jīng)常的重組 取決于動(dòng)態(tài)地址的分配和不斷的增長， IPv4 地址的暫時(shí)的唯一性將不再是全局授權(quán)，而只是將他們的使用作為標(biāo)示放在服務(wù)請求中。它永遠(yuǎn)不可能作為一個(gè)在本文定義的標(biāo)示來服務(wù)，所以它不是唯一的標(biāo)示主機(jī)。 . 多播和廣播 . 既然我們討論多播 [RFC1112]， 我們必須把對 IP 地址意義的爭論轉(zhuǎn)化為對源和目標(biāo)地址的意義的思考?？臻g 的唯一性也將一樣，只要地址一直是有效的定位。 改變提供者只是被重新編號的一個(gè)可能。尤其是在 Inter 中。事實(shí)上這個(gè)已經(jīng)發(fā)生了。更詳細(xì)的討論看 [kre]。換句話說，在用于認(rèn)證和信任時(shí)， ALG 和 NAT 在兩個(gè)不同的 IP 安全域中 都被強(qiáng)制分界，除非設(shè)計(jì)了用于此目的特殊的增強(qiáng)的 IP 安全策略。然而，這樣一個(gè)設(shè)備將不能完全處理一個(gè)傳輸 IP 地址的應(yīng)用，當(dāng)設(shè)備不支持經(jīng)過ALG 功能的應(yīng)用時(shí)，寧愿