RFC2893 日本語訳
2893 Transition Mechanisms for IPv6 Hosts and Routers. R. Gilligan, E.Nordmark. August 2000. (Format: TXT=62731 bytes) (Obsoletes RFC1933) (Obsoleted by RFC4213) (Status: PROPOSED STANDARD)
プログラムでの自動翻訳です。
英語原文
Network Working Group R. Gilligan
Request for Comments: 2893 FreeGate Corp.
Obsoletes: 1933 E. Nordmark
Category: Standards Track Sun Microsystems, Inc.
August 2000
コメントを求めるワーキンググループR.ギリガンの要求をネットワークでつないでください: 2893 FreeGate社は以下を時代遅れにします。 1933年のE.Nordmarkカテゴリ: 標準化過程サン・マイクロシステムズ・インク2000年8月
Transition Mechanisms for IPv6 Hosts and Routers
IPv6ホストとルータのための変遷メカニズム
Status of this Memo
このMemoの状態
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
このドキュメントは、インターネットコミュニティにインターネット標準化過程プロトコルを指定して、改良のために議論と提案を要求します。 このプロトコルの標準化状態と状態への「インターネット公式プロトコル標準」(STD1)の現行版を参照してください。 このメモの分配は無制限です。
Copyright Notice
版権情報
Copyright (C) The Internet Society (2000). All Rights Reserved.
Copyright(C)インターネット協会(2000)。 All rights reserved。
Abstract
要約
This document specifies IPv4 compatibility mechanisms that can be implemented by IPv6 hosts and routers. These mechanisms include providing complete implementations of both versions of the Internet Protocol (IPv4 and IPv6), and tunneling IPv6 packets over IPv4 routing infrastructures. They are designed to allow IPv6 nodes to maintain complete compatibility with IPv4, which should greatly simplify the deployment of IPv6 in the Internet, and facilitate the eventual transition of the entire Internet to IPv6. This document obsoletes RFC 1933.
このドキュメントはIPv6ホストとルータで実装することができるIPv4互換性メカニズムを指定します。 これらのメカニズムは、インターネットプロトコル(IPv4とIPv6)のバージョンとトンネリングIPv6パケットの両方の完全な実装をIPv4ルーティングインフラストラクチャの上に提供するのを含んでいます。 それらは、IPv6ノードがインターネットでのIPv6の展開を大いに簡素化するはずであるIPv4との完全な両立性を維持して、全体のインターネットのIPv6への最後の変遷を容易にするのを許容するように設計されています。 このドキュメントはRFC1933を時代遅れにします。
Gilligan & Nordmark Standards Track [Page 1] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[1ページ]。
Table of Contents
目次
1. Introduction............................................. 2
1.1. Terminology......................................... 3
1.2. Structure of this Document.......................... 5
2. Dual IP Layer Operation.................................. 6
2.1. Address Configuration............................... 7
2.2. DNS................................................. 7
2.3. Advertising Addresses in the DNS.................... 8
3. Common Tunneling Mechanisms.............................. 9
3.1. Encapsulation....................................... 11
3.2. Tunnel MTU and Fragmentation........................ 11
3.3. Hop Limit........................................... 13
3.4. Handling IPv4 ICMP errors........................... 13
3.5. IPv4 Header Construction............................ 15
3.6. Decapsulation....................................... 16
3.7. Link-Local Addresses................................ 17
3.8. Neighbor Discovery over Tunnels..................... 18
4. Configured Tunneling..................................... 18
4.1. Default Configured Tunnel........................... 19
4.2. Default Configured Tunnel using IPv4 "Anycast Address" 19
4.3. Ingress Filtering................................... 20
5. Automatic Tunneling...................................... 20
5.1. IPv4-Compatible Address Format...................... 20
5.2. IPv4-Compatible Address Configuration............... 21
5.3. Automatic Tunneling Operation....................... 22
5.4. Use With Default Configured Tunnels................. 22
5.5. Source Address Selection............................ 23
5.6. Ingress Filtering................................... 23
6. Acknowledgments.......................................... 24
7. Security Considerations.................................. 24
8. Authors' Addresses....................................... 24
9. References............................................... 25
10. Changes from RFC 1933................................... 26
11. Full Copyright Statement................................ 29
1. 序論… 2 1.1. 用語… 3 1.2. このDocumentの構造… 5 2. 二元的なIP層の操作… 6 2.1. 構成を扱ってください… 7 2.2. DNS… 7 2.3. DNSの広告アドレス… 8 3. 一般的なトンネリングメカニズム… 9 3.1. カプセル化… 11 3.2. MTUと断片化にトンネルを堀ってください… 11 3.3. 限界を飛び越してください… 13 3.4. 取り扱いIPv4 ICMP誤り… 13 3.5. IPv4ヘッダー工事… 15 3.6. 被膜剥離術… 16 3.7. リンクローカルのアドレス… 17 3.8. Tunnelsの上の隣人発見… 18 4. トンネリングを構成します… 18 4.1. デフォルトはトンネルを構成しました… 19 4.2. デフォルトは、4.3にIPv4「Anycastアドレス」19を使用することでトンネルを構成しました。 イングレスフィルタリング… 20 5. 自動トンネリング… 20 5.1. IPv4コンパチブルアドレス形式… 20 5.2. IPv4コンパチブルアドレス構成… 21 5.3. 自動トンネリング操作… 22 5.4. 構成されるデフォルトで、Tunnelsを使用してください… 22 5.5. ソースアドレス選択… 23 5.6. イングレスフィルタリング… 23 6. 承認… 24 7. セキュリティ問題… 24 8. 作者のアドレス… 24 9. 参照… 25 10. RFC1933からの変化… 26 11. 完全な著作権宣言文… 29
1. Introduction
1. 序論
The key to a successful IPv6 transition is compatibility with the large installed base of IPv4 hosts and routers. Maintaining compatibility with IPv4 while deploying IPv6 will streamline the task of transitioning the Internet to IPv6. This specification defines a set of mechanisms that IPv6 hosts and routers may implement in order to be compatible with IPv4 hosts and routers.
うまくいっているIPv6変遷のキーはIPv4ホストとルータの大きいインストールされたベースとの互換性です。 IPv6を配布している間、IPv4との互換性を維持すると、移行に関するタスクは能率化されるでしょう。IPv6へのインターネット。 この仕様はIPv6ホストとルータがIPv4ホストとルータと互換性があるように実装するかもしれない1セットのメカニズムを定義します。
The mechanisms in this document are designed to be employed by IPv6 hosts and routers that need to interoperate with IPv4 hosts and utilize IPv4 routing infrastructures. We expect that most nodes in
メカニズムは、IPv4ホストと共に共同利用して、IPv4ルーティングインフラストラクチャを利用する必要があるIPv6ホストとルータによって使われるように本書では設計されています。 私たちがそれを最も予想する、中のノード
Gilligan & Nordmark Standards Track [Page 2] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[2ページ]。
the Internet will need such compatibility for a long time to come, and perhaps even indefinitely.
インターネットはそのような互換性を今後ずっと、そして、恐らく無期限にさえ必要とするでしょう。
However, IPv6 may be used in some environments where interoperability with IPv4 is not required. IPv6 nodes that are designed to be used in such environments need not use or even implement these mechanisms.
しかしながら、IPv6はIPv4がある相互運用性が必要でないいくつかの環境で使用されるかもしれません。 環境が必要とするそのようなもので使用されるように設計されているIPv6ノードは、これらのメカニズムを使用もしませんし、実装してさえいません。
The mechanisms specified here include:
ここで指定されたメカニズムは:
- Dual IP layer (also known as Dual Stack): A technique for
providing complete support for both Internet protocols -- IPv4 and
IPv6 -- in hosts and routers.
- 二元的なIP層(また、Dual Stackとして、知られています): ホストのインターネットプロトコル(IPv4とIPv6)とルータの両方の完全なサポートを提供するためのテクニック。
- Configured tunneling of IPv6 over IPv4: Point-to-point tunnels
made by encapsulating IPv6 packets within IPv4 headers to carry
them over IPv4 routing infrastructures.
- IPv4の上のIPv6の構成されたトンネリング: IPv4ルーティングインフラストラクチャの上まで彼らを運ぶためにIPv4ヘッダーの中にパケットをIPv6にカプセルに入れることによって作られた二地点間トンネル。
- IPv4-compatible IPv6 addresses: An IPv6 address format that
employs embedded IPv4 addresses.
- IPv4コンパチブルIPv6アドレス: それが使うIPv6アドレス形式はIPv4アドレスを埋め込みました。
- Automatic tunneling of IPv6 over IPv4: A mechanism for using
IPv4-compatible addresses to automatically tunnel IPv6 packets
over IPv4 networks.
- IPv4の上のIPv6の自動トンネリング: 使用のためのIPv4コンパチブルメカニズムはIPv4ネットワークの上で自動的にトンネルIPv6にパケットを扱います。
The mechanisms defined here are intended to be part of a "transition toolbox" -- a growing collection of techniques which implementations and users may employ to ease the transition. The tools may be used as needed. Implementations and sites decide which techniques are appropriate to their specific needs. This document defines the initial core set of transition mechanisms, but these are not expected to be the only tools available. Additional transition and compatibility mechanisms are expected to be developed in the future, with new documents being written to specify them.
ここで定義されたメカニズムは「変遷道具箱」の一部であることを意図します--実装とユーザが変遷を緩和するのに使うかもしれないテクニックの増加している収集。 ツールは必要に応じて使用されるかもしれません。 実装とサイトは、どのテクニックが彼らの特定の必要性に適切であるかを決めます。 このドキュメントは初期の巻き癖の変遷メカニズムを定義しますが、これらは利用可能な唯一のツールでないと予想されます。 将来追加変遷と互換性メカニズムが開発されると予想されます、新しいドキュメントがそれらを指定するために書かれている状態で。
1.1. Terminology
1.1. 用語
The following terms are used in this document:
次の用語は本書では使用されます:
Types of Nodes
ノードのタイプ
IPv4-only node:
IPv4だけノード:
A host or router that implements only IPv4. An IPv4-only node
does not understand IPv6. The installed base of IPv4 hosts and
routers existing before the transition begins are IPv4-only
nodes.
IPv4だけを実装するホストかルータ。 IPv4だけノードはIPv6を理解していません。 変遷が始まる前にIPv4ホストとルータがいるインストールされたベースはIPv4だけノードです。
Gilligan & Nordmark Standards Track [Page 3] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[3ページ]。
IPv6/IPv4 node:
IPv6/IPv4ノード:
A host or router that implements both IPv4 and IPv6.
IPv4とIPv6の両方を実装するホストかルータ。
IPv6-only node:
IPv6だけノード:
A host or router that implements IPv6, and does not implement
IPv4. The operation of IPv6-only nodes is not addressed here.
IPv6を実装して、IPv4は実装しないホストかルータ。 IPv6だけノードの操作はここで扱われません。
IPv6 node:
IPv6ノード:
Any host or router that implements IPv6. IPv6/IPv4 and IPv6-
only nodes are both IPv6 nodes.
IPv6を実装するどんなホストやルータ。 IPv6/IPv4とIPv6唯一のノードは両方のIPv6ノードです。
IPv4 node:
IPv4ノード:
Any host or router that implements IPv4. IPv6/IPv4 and IPv4-
only nodes are both IPv4 nodes.
IPv4を実装するどんなホストやルータ。 IPv6/IPv4とIPv4唯一のノードは両方のIPv4ノードです。
Types of IPv6 Addresses
IPv6アドレスのタイプ
IPv4-compatible IPv6 address:
IPv4コンパチブルIPv6アドレス:
An IPv6 address bearing the high-order 96-bit prefix
0:0:0:0:0:0, and an IPv4 address in the low-order 32-bits.
IPv4-compatible addresses are used by IPv6/IPv4 nodes which
perform automatic tunneling,
高位の96ビットの接頭語を示すIPv6アドレス、0:0:0、:、0:0:0、そして、下位の32ビットのIPv4アドレス。 IPv4コンパチブルアドレスは自動トンネリングを実行するIPv6/IPv4ノードによって使用されます。
IPv6-native address:
ネイティブのIPv6アドレス:
The remainder of the IPv6 address space. An IPv6 address that
bears a prefix other than 0:0:0:0:0:0.
IPv6アドレス空間の残り。 0:0:0以外の接頭語を示すIPv6アドレス: 0:0:0。
Techniques Used in the Transition
変遷に使用されるテクニック
IPv6-over-IPv4 tunneling:
IPv6過剰IPv4トンネリング:
The technique of encapsulating IPv6 packets within IPv4 so that
they can be carried across IPv4 routing infrastructures.
IPv4ルーティングインフラストラクチャの向こう側にそれらを運ぶことができるようにIPv4の中でパケットをIPv6にカプセルに入れるテクニック。
Configured tunneling:
構成されたトンネリング:
IPv6-over-IPv4 tunneling where the IPv4 tunnel endpoint address
is determined by configuration information on the encapsulating
node. The tunnels can be either unidirectional or
bidirectional. Bidirectional configured tunnels behave as
virtual point-to-point links.
IPv4が終点アドレスにトンネルを堀るところでトンネルを堀るIPv6過剰IPv4が要約ノードに関する設定情報で決定します。 トンネルは、単方向か双方向である場合があります。 仮想のポイントツーポイントがリンクされるとき、双方向の構成されたトンネルは振る舞います。
Gilligan & Nordmark Standards Track [Page 4] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[4ページ]。
Automatic tunneling:
自動トンネリング:
IPv6-over-IPv4 tunneling where the IPv4 tunnel endpoint address
is determined from the IPv4 address embedded in the IPv4-
compatible destination address of the IPv6 packet being
tunneled.
IPv4が終点アドレスにトンネルを堀るところでトンネルを堀るIPv6過剰IPv4はトンネルを堀られるIPv6パケットのIPv4コンパチブル送付先アドレスに埋め込まれたIPv4アドレスから断固としています。
IPv4 multicast tunneling:
IPv4マルチキャストトンネリング:
IPv6-over-IPv4 tunneling where the IPv4 tunnel endpoint address
is determined using Neighbor Discovery [7]. Unlike configured
tunneling this does not require any address configuration and
unlike automatic tunneling it does not require the use of
IPv4-compatible addresses. However, the mechanism assumes that
the IPv4 infrastructure supports IPv4 multicast. Specified in
[3] and not further discussed in this document.
IPv4が終点アドレスにトンネルを堀るところでトンネルを堀るIPv6過剰IPv4は、Neighborディスカバリー[7]を使用することで断固としています。 構成されたトンネリングと異なって、これはどんなアドレス構成も必要としません、そして、自動トンネリングと異なって、それはIPv4コンパチブルアドレスの使用を必要としません。 しかしながら、メカニズムは、IPv4インフラストラクチャが、IPv4がマルチキャストであるとサポートすると仮定します。 [3]で指定されて、さらに本書では議論していません。
Other transition mechanisms, including other tunneling mechanisms, are outside the scope of this document.
このドキュメントの範囲の外に他のトンネリングメカニズムを含む他の変遷メカニズムがあります。
Modes of operation of IPv6/IPv4 nodes
IPv6/IPv4ノードの運転モード
IPv6-only operation:
IPv6だけ操作:
An IPv6/IPv4 node with its IPv6 stack enabled and its IPv4
stack disabled.
IPv6スタックが可能にされているIPv6/IPv4ノードとそのIPv4は身体障害者を積み重ねます。
IPv4-only operation:
IPv4だけ操作:
An IPv6/IPv4 node with its IPv4 stack enabled and its IPv6
stack disabled.
IPv4スタックが可能にされているIPv6/IPv4ノードとそのIPv6は身体障害者を積み重ねます。
IPv6/IPv4 operation:
IPv6/IPv4操作:
An IPv6/IPv4 node with both stacks enabled.
両方のスタックが可能にされているIPv6/IPv4ノード。
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this document, are to be interpreted as described in [16].
キーワードが解釈しなければならない、本書では現れるとき、[16]で説明されるようにNOT、REQUIRED、SHALL、SHALL NOT、SHOULD、SHOULD NOT、RECOMMENDED、5月、およびOPTIONALを解釈することになっていなければなりませんか?
1.2. Structure of this Document
1.2. このDocumentの構造
The remainder of this document is organized as follows:
このドキュメントの残りは以下の通り組織化されます:
- Section 2 discusses the operation of nodes with a dual IP layer,
IPv6/IPv4 nodes.
- セクション2は二元的なIP層、IPv6/IPv4ノードによるノードの操作について論じます。
Gilligan & Nordmark Standards Track [Page 5] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[5ページ]。
- Section 3 discusses the common mechanisms used in both of the
IPv6-over-IPv4 tunneling techniques.
- セクション3はIPv6過剰IPv4トンネリングのテクニックの両方で使用される一般的なメカニズムについて論じます。
- Section 4 discusses configured tunneling.
- セクション4は構成されたトンネリングについて論じます。
- Section 5 discusses automatic tunneling and the IPv4-compatible
IPv6 address format.
- セクション5は自動トンネリングとIPv4コンパチブルIPv6アドレス形式について論じます。
2. Dual IP Layer Operation
2. 二元的なIP層の操作
The most straightforward way for IPv6 nodes to remain compatible with IPv4-only nodes is by providing a complete IPv4 implementation. IPv6 nodes that provide a complete IPv4 and IPv6 implementations are called "IPv6/IPv4 nodes." IPv6/IPv4 nodes have the ability to send and receive both IPv4 and IPv6 packets. They can directly interoperate with IPv4 nodes using IPv4 packets, and also directly interoperate with IPv6 nodes using IPv6 packets.
IPv6ノードがIPv4だけノードと互換性があったままで残る最も簡単な方法は完全なIPv4実装を提供することです。 完全なIPv4とIPv6に実装を供給するIPv6ノードは「IPv6/IPv4ノード」と呼ばれます。 IPv6/IPv4ノードには、IPv4とIPv6パケットの両方を送って、受ける能力があります。 彼らは、IPv4ノードでIPv4パケットを使用することで直接共同利用して、また、IPv6ノードでIPv6パケットを使用することで直接共同利用できます。
Even though a node may be equipped to support both protocols, one or the other stack may be disabled for operational reasons. Thus IPv6/IPv4 nodes may be operated in one of three modes:
両方のプロトコルをサポートするためにノードを備えるかもしれませんが、1かもう片方のスタックが操作上の理由で無効にされるかもしれません。 したがって、IPv6/IPv4ノードは3つのモードの1つで操作されるかもしれません:
- With their IPv4 stack enabled and their IPv6 stack disabled.
- それらのIPv4スタックが可能にされて、それらのIPv6スタックが無効にされている状態で。
- With their IPv6 stack enabled and their IPv4 stack disabled.
- それらのIPv6スタックが可能にされて、それらのIPv4スタックが無効にされている状態で。
- With both stacks enabled.
- 両方のスタックが可能にされている状態で。
IPv6/IPv4 nodes with their IPv6 stack disabled will operate like IPv4-only nodes. Similarly, IPv6/IPv4 nodes with their IPv4 stacks disabled will operate like IPv6-only nodes. IPv6/IPv4 nodes MAY provide a configuration switch to disable either their IPv4 or IPv6 stack.
彼らのIPv6スタック身体障害者とのIPv6/IPv4ノードはIPv4だけノードのように作動するでしょう。 同様に、スタックが無効にしたそれらのIPv4とのIPv6/IPv4ノードはIPv6だけノードのように作動するでしょう。 IPv6/IPv4ノードは、それらのIPv4かIPv6スタックを無効にするために設定スイッチを備えるかもしれません。
The dual IP layer technique may or may not be used in conjunction with the IPv6-over-IPv4 tunneling techniques, which are described in sections 3, 4 and 5. An IPv6/IPv4 node that supports tunneling MAY support only configured tunneling, or both configured and automatic tunneling. Thus three modes of tunneling support are possible:
二元的なIP層のテクニックはIPv6過剰IPv4トンネリングのテクニックに関連して使用されるかもしれません。それは、セクション3、4、および5で説明されます。 トンネリングを支えるIPv6/IPv4ノードは、構成されたトンネリング、または唯一の両方が構成されて自動であるトンネリングであることを支えるかもしれません。 したがって、トンネリングサポートの3つの方法が可能です:
- IPv6/IPv4 node that does not perform tunneling.
- トンネリングを実行しないIPv6/IPv4ノード。
- IPv6/IPv4 node that performs configured tunneling only.
- 働くIPv6/IPv4ノードがトンネリングだけを構成しました。
- IPv6/IPv4 node that performs configured tunneling and automatic
tunneling.
- 働くIPv6/IPv4ノードがトンネリングと自動トンネリングを構成しました。
Gilligan & Nordmark Standards Track [Page 6] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[6ページ]。
2.1. Address Configuration
2.1. アドレス構成
Because they support both protocols, IPv6/IPv4 nodes may be configured with both IPv4 and IPv6 addresses. IPv6/IPv4 nodes use IPv4 mechanisms (e.g. DHCP) to acquire their IPv4 addresses, and IPv6 protocol mechanisms (e.g. stateless address autoconfiguration) to acquire their IPv6-native addresses. Section 5.2 describes a mechanism by which IPv6/IPv4 nodes that support automatic tunneling MAY use IPv4 protocol mechanisms to acquire their IPv4-compatible IPv6 address.
彼らが両方のプロトコルをサポートするので、IPv6/IPv4ノードはIPv4とIPv6アドレスの両方によって構成されるかもしれません。 IPv6/IPv4ノードはそれらのIPv4アドレスを習得するのに、IPv4メカニズム(例えば、DHCP)を使用します、そして、IPv6はそれらのネイティブのIPv6アドレスを習得するために、メカニズム(例えば、状態がないアドレス自動構成)について議定書の中で述べます。 セクション5.2は自動トンネリングを支えるIPv6/IPv4ノードがそれらのIPv4コンパチブルIPv6アドレスを習得するのにIPv4プロトコルメカニズムを使用するかもしれないメカニズムについて説明します。
2.2. DNS
2.2. DNS
The Domain Naming System (DNS) is used in both IPv4 and IPv6 to map between hostnames and IP addresses. A new resource record type named "A6" has been defined for IPv6 addresses [6] with support for an earlier record named "AAAA". Since IPv6/IPv4 nodes must be able to interoperate directly with both IPv4 and IPv6 nodes, they must provide resolver libraries capable of dealing with IPv4 "A" records as well as IPv6 "A6" and "AAAA" records.
Domain Naming System(DNS)はホスト名とIPアドレスの間で写像するIPv4とIPv6の両方で使用されます。 「A6"はIPv6アドレス[6]のために"AAAA"という以前の記録のサポートで定義された」という新しいリソースレコード種類。 IPv6/IPv4ノードが直接IPv4とIPv6ノードの両方で共同利用できなければならないので、それらはIPv6「A6"と"AAAA"記録」と同様にIPv4に伴う記録を取扱うことができるレゾルバライブラリを提供しなければなりません。
DNS resolver libraries on IPv6/IPv4 nodes MUST be capable of handling both A6/AAAA and A records. However, when a query locates an A6/AAAA record holding an IPv6 address, and an A record holding an IPv4 address, the resolver library MAY filter or order the results returned to the application in order to influence the version of IP packets used to communicate with that node. In terms of filtering, the resolver library has three alternatives:
IPv6/IPv4ノードの上のDNSレゾルバライブラリはA6/AAAAとA記録の両方を扱うことができなければなりません。 しかしながら、質問がIPv6アドレスを保持するA6/AAAA記録、およびIPv4アドレスを保持するA記録の場所を見つけるとき、レゾルバライブラリは、そのノードとコミュニケートするのに使用されるIPパケットのバージョンに影響を及ぼすために結果をアプリケーションに返すようフィルターにかけるか、または命令するかもしれません。 フィルタリングに関して、レゾルバライブラリには、3つの選択肢があります:
- Return only the IPv6 address to the application.
- IPv6アドレスだけをアプリケーションに返してください。
- Return only the IPv4 address to the application.
- IPv4アドレスだけをアプリケーションに返してください。
- Return both addresses to the application.
- 両方のアドレスをアプリケーションに返してください。
If it returns only the IPv6 address, the application will communicate with the node using IPv6. If it returns only the IPv4 address, the application will communicate with the node using IPv4. If it returns both addresses, the application will have the choice which address to use, and thus which IP protocol to employ.
IPv6アドレスだけを返すと、アプリケーションは、IPv6を使用することでノードとコミュニケートするでしょう。 IPv4アドレスだけを返すと、アプリケーションは、IPv4を使用することでノードとコミュニケートするでしょう。 両方のアドレスを返すと、アプリケーションには、選択があるでしょう(使用、およびその結果、どのIPに使うプロトコルを扱うか)。
If it returns both, the resolver MAY elect to order the addresses -- IPv6 first, or IPv4 first. Since most applications try the addresses in the order they are returned by the resolver, this can affect the IP version "preference" of applications.
両方を返すなら、レゾルバは、アドレスを注文するのを選ぶかもしれません--IPv6 1番目、またはIPv4 1番目。 ほとんどのアプリケーションがそれらがレゾルバによって返されるオーダーにおけるアドレスを試みるので、これは「好み」というアプリケーションのIPバージョンに影響できます。
Gilligan & Nordmark Standards Track [Page 7] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[7ページ]。
The decision to filter or order DNS results is implementation specific. IPv6/IPv4 nodes MAY provide policy configuration to control filtering or ordering of addresses returned by the resolver, or leave the decision entirely up to the application.
フィルタかオーダーDNS結果との決定は実装特有です。 IPv6/IPv4ノードは、レゾルバによって返されたアドレスがフィルターにかけるか、または注文されながら制御するために方針構成を備えるか、または完全にアプリケーションに決定を任せるかもしれません。
An implementation MUST allow the application to control whether or not such filtering takes place.
実装で、アプリケーションは、そのようなフィルタリングが行われるかどうかを制御できなければなりません。
2.3. Advertising Addresses in the DNS
2.3. DNSの広告アドレス
There are some constraint placed on the use of the DNS during transition. Most of these are obvious but are stated here for completeness.
変遷の間にDNSの使用に置かれた何らかの規制があります。 これらの大部分は、明白ですが、完全性のためにここに述べられています。
The recommendation is that A6/AAAA records for a node should not be added to the DNS until all of these are true:
推薦はこれらのすべてが本当になるまでノードのためのA6/AAAA記録をDNSに加えるべきでないということです:
1) The address is assigned to the interface on the node.
1) アドレスはノードの上のインタフェースに割り当てられます。
2) The address is configured on the interface.
2) アドレスはインタフェースで構成されます。
3) The interface is on a link which is connected to the IPv6
infrastructure.
3) IPv6インフラストラクチャに接続されるリンクの上にインタフェースがあります。
If an IPv6 node is isolated from an IPv6 perspective (e.g. it is not connected to the 6bone to take a concrete example) constraint #3 would mean that it should not have an address in the DNS.
IPv6ノードがIPv6見解から隔離されるなら(例えばそれは具体的な実例を取るために6boneに接続されません)、規制#3は、DNSにアドレスを持つべきでないことを意味するでしょう。
This works great when other dual stack nodes tries to contact the isolated dual stack node. There is no IPv6 address in the DNS thus the peer doesn't even try communicating using IPv6 but goes directly to IPv4 (we are assuming both nodes have A records in the DNS.)
孤立しているデュアルスタックノードに連絡する他のデュアルスタックノードトライであるときに、これはすばらしい状態で働いています。 IPv6アドレスが全くDNSになくて、その結果、同輩は、IPv6を使用することで交信してみないさえが、直接IPv4に行きます。(私たちは、両方のノードはDNSで前科があると思っています。)
However, this does not work well when the isolated node is trying to establish communication. Even though it does not have an IPv6 address in the DNS it will find A6/AAAA records in the DNS for the peer. Since the isolated node has IPv6 addresses assigned to at least one interface it will try to communicate using IPv6. If it has no IPv6 route to the 6bone (e.g. because the local router was upgraded to advertise IPv6 addresses using Neighbor Discovery but that router doesn't have any IPv6 routes) this communication will fail. Typically this means a few minutes of delay as TCP times out. The TCP specification says that ICMP unreachable messages could be due to routing transients thus they should not immediately terminate the TCP connection. This means that the normal TCP timeout of a few minutes apply. Once TCP times out the application will hopefully try the IPv4 addresses based on the A records in the DNS, but this will be painfully slow.
しかしながら、孤立しているノードがコミュニケーションを確立しようとしているとき、これはうまくいきません。 DNSにIPv6アドレスを持っていませんが、それは同輩のためにDNSでA6/AAAAに記録を見つけるでしょう。 孤立しているノードで少なくとも1つのインタフェースにIPv6アドレスを割り当てるので、それはIPv6を使用することで交信しようとするでしょう。 IPv6ルートを全く6boneに持っていないと(例えば、ローカルルータがNeighborを使用することでIPv6アドレスの広告を出すためにアップグレードしたので、ディスカバリーにもかかわらず、そのルータには、どんなIPv6ルートもありません)、このコミュニケーションは失敗するでしょう。 通常、これはTCP回として外で数分の遅れを意味します。 TCP仕様は、ICMPの手の届かないメッセージがルーティング過渡現象のためであるかもしれないと言います、その結果、それらはすぐに、TCP接続を終えるべきではありません。 これは、いくつかのタイムアウトが書き留める正常なTCPが適用することを意味します。 アプリケーションからの一度TCP回は希望をいだいてDNSでのA記録に基づくIPv4アドレスを試みるでしょうが、これは痛々しいほど遅くなるでしょう。
Gilligan & Nordmark Standards Track [Page 8] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[8ページ]。
A possible implication of the recommendations above is that, if one enables IPv6 on a node on a link without IPv6 infrastructure, and choose to add A6/AAAA records to the DNS for that node, then external IPv6 nodes that might see these A6/AAAA records will possibly try to reach that node using IPv6 and suffer delays or communication failure due to unreachability. (A delay is incurred if the application correctly falls back to using IPv4 if it can not establish communication using IPv6 addresses. If this fallback is not done the application would fail to communicate in this case.) Thus it is suggested that either the recommendations be followed, or care be taken to only do so with nodes that will not be impacted by external accessing delays and/or communication failure.
上の推薦の関与の可能性はそれです、1つがリンクの上のIPv6インフラストラクチャのないノードでIPv6を有効にして、これらのA6/AAAA記録を見るかもしれない外部のIPv6ノードがそのノードのためにA6/AAAA記録をDNSに加えるのを選んでください、IPv6を使用することでそのノードに達して、次に、「非-可到達性」のためことによると遅れか通信障害を受けようとするなら。 (アプリケーションが正しくIPv6アドレスを使用することでコミュニケーションを確立できないならIPv4を使用することへ後ろへ下がるなら、遅れは被られます。 この後退が完了していないなら、アプリケーションはこの場合交信しないでしょう。) その結果、推薦が続かれていることが提案されるか、または気にかけてください。遅れ、そして/または、通信障害にアクセスしながら取って、したがって、外部によって影響を与えられないノードを処理するだけであってください。
In the future when a site or node removes the support for IPv4 the above recommendations apply to when the A records for the node(s) should be removed from the DNS.
サイトかノードがIPv4のサポートを取り除く未来に、上の推薦はノードのためのA記録がDNSから取り除かれるべきである時に適用されます。
3. Common Tunneling Mechanisms
3. 一般的なトンネリングメカニズム
In most deployment scenarios, the IPv6 routing infrastructure will be built up over time. While the IPv6 infrastructure is being deployed, the existing IPv4 routing infrastructure can remain functional, and can be used to carry IPv6 traffic. Tunneling provides a way to utilize an existing IPv4 routing infrastructure to carry IPv6 traffic.
ほとんどの展開シナリオでは、IPv6ルーティングインフラストラクチャは時間がたつにつれて、確立されるでしょう。 IPv6インフラストラクチャが配布されている間、既存のIPv4ルーティングインフラストラクチャは、機能的に残ることができて、IPv6トラフィックを運ぶのに使用できます。 トンネリングはIPv6トラフィックを運ぶのに既存のIPv4ルーティングインフラストラクチャを利用する方法を提供します。
IPv6/IPv4 hosts and routers can tunnel IPv6 datagrams over regions of IPv4 routing topology by encapsulating them within IPv4 packets. Tunneling can be used in a variety of ways:
IPv4パケットの中でそれらをカプセル化することによって、IPv6/IPv4ホストとルータはIPv4ルーティングトポロジーの領域の上でIPv6データグラムにトンネルを堀ることができます。 さまざまな方法でトンネリングを使用できます:
- Router-to-Router. IPv6/IPv4 routers interconnected by an IPv4
infrastructure can tunnel IPv6 packets between themselves. In
this case, the tunnel spans one segment of the end-to-end path
that the IPv6 packet takes.
- ルータからルータ。 IPv4インフラストラクチャによってインタコネクトされたIPv6/IPv4ルータは自分たちの間のIPv6パケットにトンネルを堀ることができます。 この場合、トンネルは終わりから端へのIPv6パケットが取る経路の1つのセグメントにかかります。
- Host-to-Router. IPv6/IPv4 hosts can tunnel IPv6 packets to an
intermediary IPv6/IPv4 router that is reachable via an IPv4
infrastructure. This type of tunnel spans the first segment of
the packet's end-to-end path.
- ホストからルータ。 IPv6/IPv4ホストはIPv4インフラストラクチャで届いている仲介者IPv6/IPv4ルータにIPv6パケットにトンネルを堀ることができます。 このタイプのトンネルは終わりから端へのパケットの経路の最初のセグメントにかかっています。
- Host-to-Host. IPv6/IPv4 hosts that are interconnected by an IPv4
infrastructure can tunnel IPv6 packets between themselves. In
this case, the tunnel spans the entire end-to-end path that the
packet takes.
- ホストからホスト。 IPv4インフラストラクチャによってインタコネクトされるIPv6/IPv4ホストは自分たちの間のトンネルIPv6パケットをそうすることができます。 この場合、トンネルは終わりから端へのパケットが取る全体の経路にかかります。
- Router-to-Host. IPv6/IPv4 routers can tunnel IPv6 packets to
their final destination IPv6/IPv4 host. This tunnel spans only
the last segment of the end-to-end path.
- ルータからホスト。 IPv6/IPv4ルータは彼らの最終的な目的地IPv6/IPv4ホストにIPv6パケットにトンネルを堀ることができます。 このトンネルは終わりから端への経路の最後のセグメントだけにかかっています。
Gilligan & Nordmark Standards Track [Page 9] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[9ページ]。
Tunneling techniques are usually classified according to the mechanism by which the encapsulating node determines the address of the node at the end of the tunnel. In the first two tunneling methods listed above -- router-to-router and host-to-router -- the IPv6 packet is being tunneled to a router. The endpoint of this type of tunnel is an intermediary router which must decapsulate the IPv6 packet and forward it on to its final destination. When tunneling to a router, the endpoint of the tunnel is different from the destination of the packet being tunneled. So the addresses in the IPv6 packet being tunneled can not provide the IPv4 address of the tunnel endpoint. Instead, the tunnel endpoint address must be determined from configuration information on the node performing the tunneling. We use the term "configured tunneling" to describe the type of tunneling where the endpoint is explicitly configured.
要約ノードがトンネルの端でノードのアドレスを決定するメカニズムによると、通常、トンネリングのテクニックは分類されます。 上に記載された最初の2つのトンネリングメソッド(ルータからルータとホストからルータ)で、IPv6パケットはルータにトンネルを堀られています。 このタイプのトンネルの終点はIPv6パケットをdecapsulateして、最終的な目的地にそれを送らなければならない仲介者ルータです。 ルータにトンネルを堀るとき、トンネルの終点はトンネルを堀られるパケットの目的地と異なっています。 それで、トンネルを堀られるIPv6パケットのアドレスはトンネル終点のIPv4アドレスを提供できません。 代わりに、トンネル終点アドレスは、トンネリングを実行しながら、ノードで設定情報から決定していなければなりません。 私たちは終点が明らかに構成されるところでトンネルを堀るタイプについて説明するために「トンネリングを構成する」という用語を使用します。
In the last two tunneling methods -- host-to-host and router-to-host -- the IPv6 packet is tunneled all the way to its final destination. In this case, the destination address of both the IPv6 packet and the encapsulating IPv4 header identify the same node! This fact can be exploited by encoding information in the IPv6 destination address that will allow the encapsulating node to determine tunnel endpoint IPv4 address automatically. Automatic tunneling employs this technique, using an special IPv6 address format with an embedded IPv4 address to allow tunneling nodes to automatically derive the tunnel endpoint IPv4 address. This eliminates the need to explicitly configure the tunnel endpoint address, greatly simplifying configuration.
最後の2つのトンネリングメソッド(ホストからホストとルータからホスト)で、IPv6パケットは最終的な目的地までのいっぱいにトンネルを堀られます。 この場合、IPv6パケットと要約のIPv4ヘッダーの両方の送付先アドレスは同じノードを特定します! 要約ノードが自動的にトンネル終点IPv4アドレスを決定できるIPv6送付先アドレスの符号化情報はこの事実を利用できます。 自動トンネリングはこのテクニックを使います、トンネリングノードが自動的にトンネル終点IPv4アドレスを引き出すのを許容するのに埋め込まれたIPv4アドレスがある特別なIPv6アドレス形式を使用して。 構成を大いに簡素化して、これは明らかにトンネル終点アドレスを構成する必要性を排除します。
The two tunneling techniques -- automatic and configured -- differ primarily in how they determine the tunnel endpoint address. Most of the underlying mechanisms are the same:
彼らが主としてどうトンネル終点アドレスを決定するかに2つのトンネリングのテクニック(自動で構成されている)が異なります。 発症機序の大部分は同じです:
- The entry node of the tunnel (the encapsulating node) creates an
encapsulating IPv4 header and transmits the encapsulated packet.
- トンネル(要約ノード)のエントリーノードは、要約のIPv4ヘッダーを創造して、カプセル化されたパケットを伝えます。
- The exit node of the tunnel (the decapsulating node) receives the
encapsulated packet, reassembles the packet if needed, removes the
IPv4 header, updates the IPv6 header, and processes the received
IPv6 packet.
- トンネル(decapsulatingノード)の出口ノードは、カプセル化されたパケットを受けて、必要であるならパケットを組み立て直して、IPv4ヘッダーを取り除いて、IPv6ヘッダーをアップデートして、容認されたIPv6パケットを処理します。
- The encapsulating node MAY need to maintain soft state information
for each tunnel recording such parameters as the MTU of the tunnel
in order to process IPv6 packets forwarded into the tunnel. Since
the number of tunnels that any one host or router may be using may
grow to be quite large, this state information can be cached and
discarded when not in use.
- 要約ノードは、各トンネルのためのトンネルに送られたIPv6パケットを処理するためにトンネルのMTUのようなパラメタを記録する軟性国家情報を保守する必要があるかもしれません。 どんなホストかルータも使用しているかもしれないトンネルの数が成長して、かなり大きくなるかもしれないので、使用中でないときに、この州の情報をキャッシュして、捨てることができます。
Gilligan & Nordmark Standards Track [Page 10] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[10ページ]。
The remainder of this section discusses the common mechanisms that apply to both types of tunneling. Subsequent sections discuss how the tunnel endpoint address is determined for automatic and configured tunneling.
このセクションの残りは両方のタイプのトンネリングに適用される一般的なメカニズムについて議論します。 その後のセクションはトンネル終点アドレスが自動で構成されたトンネリングのためにどう決定するかを論じます。
3.1. Encapsulation
3.1. カプセル化
The encapsulation of an IPv6 datagram in IPv4 is shown below:
IPv4のIPv6データグラムのカプセル化は以下に示されます:
+-------------+
| IPv4 |
| Header |
+-------------+ +-------------+
| IPv6 | | IPv6 |
| Header | | Header |
+-------------+ +-------------+
| Transport | | Transport |
| Layer | ===> | Layer |
| Header | | Header |
+-------------+ +-------------+
| | | |
~ Data ~ ~ Data ~
| | | |
+-------------+ +-------------+
+-------------+ | IPv4| | ヘッダー| +-------------+ +-------------+ | IPv6| | IPv6| | ヘッダー| | ヘッダー| +-------------+ +-------------+ | 輸送| | 輸送| | 層| ===>| 層にしてください。| | ヘッダー| | ヘッダー| +-------------+ +-------------+ | | | | ~ データ~~データ~| | | | +-------------+ +-------------+
Encapsulating IPv6 in IPv4
IPv4でIPv6をカプセル化します。
In addition to adding an IPv4 header, the encapsulating node also has to handle some more complex issues:
IPv4ヘッダーを加えることに加えて、要約ノードもそれ以上の複雑な問題を扱わなければなりません:
- Determine when to fragment and when to report an ICMP "packet too
big" error back to the source.
- いつ断片化するか、そして、いつICMPを報告するか決定してください、「パケット、大き過ぎる、」 ソースへの誤り。
- How to reflect IPv4 ICMP errors from routers along the tunnel path
back to the source as IPv6 ICMP errors.
- IPv6 ICMP誤りとしてトンネル経路に沿ったルータからソースまでのIPv4 ICMP誤りを反映する方法。
Those issues are discussed in the following sections.
以下のセクションでそれらの問題について議論します。
3.2. Tunnel MTU and Fragmentation
3.2. トンネルMTUと断片化
The encapsulating node could view encapsulation as IPv6 using IPv4 as a link layer with a very large MTU (65535-20 bytes to be exact; 20 bytes "extra" are needed for the encapsulating IPv4 header). The encapsulating node would need only to report IPv6 ICMP "packet too big" errors back to the source for packets that exceed this MTU. However, such a scheme would be inefficient for two reasons:
The encapsulating node could view encapsulation as IPv6 using IPv4 as a link layer with a very large MTU (65535-20 bytes to be exact; 20 bytes "extra" are needed for the encapsulating IPv4 header). The encapsulating node would need only to report IPv6 ICMP "packet too big" errors back to the source for packets that exceed this MTU. However, such a scheme would be inefficient for two reasons:
Gilligan & Nordmark Standards Track [Page 11] RFC 2893 IPv6 Transition Mechanisms August 2000
Gilligan & Nordmark Standards Track [Page 11] RFC 2893 IPv6 Transition Mechanisms August 2000
1) It would result in more fragmentation than needed. IPv4 layer
fragmentation SHOULD be avoided due to the performance problems
caused by the loss unit being smaller than the retransmission unit
[11].
1) It would result in more fragmentation than needed. IPv4 layer fragmentation SHOULD be avoided due to the performance problems caused by the loss unit being smaller than the retransmission unit [11].
2) Any IPv4 fragmentation occurring inside the tunnel would have to
be reassembled at the tunnel endpoint. For tunnels that terminate
at a router, this would require additional memory to reassemble
the IPv4 fragments into a complete IPv6 packet before that packet
could be forwarded onward.
2) Any IPv4 fragmentation occurring inside the tunnel would have to be reassembled at the tunnel endpoint. For tunnels that terminate at a router, this would require additional memory to reassemble the IPv4 fragments into a complete IPv6 packet before that packet could be forwarded onward.
The fragmentation inside the tunnel can be reduced to a minimum by having the encapsulating node track the IPv4 Path MTU across the tunnel, using the IPv4 Path MTU Discovery Protocol [8] and recording the resulting path MTU. The IPv6 layer in the encapsulating node can then view a tunnel as a link layer with an MTU equal to the IPv4 path MTU, minus the size of the encapsulating IPv4 header.
The fragmentation inside the tunnel can be reduced to a minimum by having the encapsulating node track the IPv4 Path MTU across the tunnel, using the IPv4 Path MTU Discovery Protocol [8] and recording the resulting path MTU. The IPv6 layer in the encapsulating node can then view a tunnel as a link layer with an MTU equal to the IPv4 path MTU, minus the size of the encapsulating IPv4 header.
Note that this does not completely eliminate IPv4 fragmentation in the case when the IPv4 path MTU would result in an IPv6 MTU less than 1280 bytes. (Any link layer used by IPv6 has to have an MTU of at least 1280 bytes [4].) In this case the IPv6 layer has to "see" a link layer with an MTU of 1280 bytes and the encapsulating node has to use IPv4 fragmentation in order to forward the 1280 byte IPv6 packets.
Note that this does not completely eliminate IPv4 fragmentation in the case when the IPv4 path MTU would result in an IPv6 MTU less than 1280 bytes. (Any link layer used by IPv6 has to have an MTU of at least 1280 bytes [4].) In this case the IPv6 layer has to "see" a link layer with an MTU of 1280 bytes and the encapsulating node has to use IPv4 fragmentation in order to forward the 1280 byte IPv6 packets.
The encapsulating node can employ the following algorithm to determine when to forward an IPv6 packet that is larger than the tunnel's path MTU using IPv4 fragmentation, and when to return an IPv6 ICMP "packet too big" message:
The encapsulating node can employ the following algorithm to determine when to forward an IPv6 packet that is larger than the tunnel's path MTU using IPv4 fragmentation, and when to return an IPv6 ICMP "packet too big" message:
if (IPv4 path MTU - 20) is less than or equal to 1280
if packet is larger than 1280 bytes
Send IPv6 ICMP "packet too big" with MTU = 1280.
Drop packet.
else
Encapsulate but do not set the Don't Fragment
flag in the IPv4 header. The resulting IPv4
packet might be fragmented by the IPv4 layer on
the encapsulating node or by some router along
the IPv4 path.
endif
else
if packet is larger than (IPv4 path MTU - 20)
Send IPv6 ICMP "packet too big" with
MTU = (IPv4 path MTU - 20).
Drop packet.
else
if (IPv4 path MTU - 20) is less than or equal to 1280 if packet is larger than 1280 bytes Send IPv6 ICMP "packet too big" with MTU = 1280. Drop packet. else Encapsulate but do not set the Don't Fragment flag in the IPv4 header. The resulting IPv4 packet might be fragmented by the IPv4 layer on the encapsulating node or by some router along the IPv4 path. endif else if packet is larger than (IPv4 path MTU - 20) Send IPv6 ICMP "packet too big" with MTU = (IPv4 path MTU - 20). Drop packet. else
Gilligan & Nordmark Standards Track [Page 12] RFC 2893 IPv6 Transition Mechanisms August 2000
Gilligan & Nordmark Standards Track [Page 12] RFC 2893 IPv6 Transition Mechanisms August 2000
Encapsulate and set the Don't Fragment flag
in the IPv4 header.
endif
endif
Encapsulate and set the Don't Fragment flag in the IPv4 header. endif endif
Encapsulating nodes that have a large number of tunnels might not be able to store the IPv4 Path MTU for all tunnels. Such nodes can, at the expense of additional fragmentation in the network, avoid using the IPv4 Path MTU algorithm across the tunnel and instead use the MTU of the link layer (under IPv4) in the above algorithm instead of the IPv4 path MTU.
Encapsulating nodes that have a large number of tunnels might not be able to store the IPv4 Path MTU for all tunnels. Such nodes can, at the expense of additional fragmentation in the network, avoid using the IPv4 Path MTU algorithm across the tunnel and instead use the MTU of the link layer (under IPv4) in the above algorithm instead of the IPv4 path MTU.
In this case the Don't Fragment bit MUST NOT be set in the encapsulating IPv4 header.
In this case the Don't Fragment bit MUST NOT be set in the encapsulating IPv4 header.
3.3. Hop Limit
3.3. Hop Limit
IPv6-over-IPv4 tunnels are modeled as "single-hop". That is, the IPv6 hop limit is decremented by 1 when an IPv6 packet traverses the tunnel. The single-hop model serves to hide the existence of a tunnel. The tunnel is opaque to users of the network, and is not detectable by network diagnostic tools such as traceroute.
IPv6-over-IPv4 tunnels are modeled as "single-hop". That is, the IPv6 hop limit is decremented by 1 when an IPv6 packet traverses the tunnel. The single-hop model serves to hide the existence of a tunnel. The tunnel is opaque to users of the network, and is not detectable by network diagnostic tools such as traceroute.
The single-hop model is implemented by having the encapsulating and decapsulating nodes process the IPv6 hop limit field as they would if they were forwarding a packet on to any other datalink. That is, they decrement the hop limit by 1 when forwarding an IPv6 packet. (The originating node and final destination do not decrement the hop limit.)
The single-hop model is implemented by having the encapsulating and decapsulating nodes process the IPv6 hop limit field as they would if they were forwarding a packet on to any other datalink. That is, they decrement the hop limit by 1 when forwarding an IPv6 packet. (The originating node and final destination do not decrement the hop limit.)
The TTL of the encapsulating IPv4 header is selected in an implementation dependent manner. The current suggested value is published in the "Assigned Numbers RFC. Implementations MAY provide a mechanism to allow the administrator to configure the IPv4 TTL such as the one specified in the IP Tunnel MIB [17].
The TTL of the encapsulating IPv4 header is selected in an implementation dependent manner. The current suggested value is published in the "Assigned Numbers RFC. Implementations MAY provide a mechanism to allow the administrator to configure the IPv4 TTL such as the one specified in the IP Tunnel MIB [17].
3.4. Handling IPv4 ICMP errors
3.4. Handling IPv4 ICMP errors
In response to encapsulated packets it has sent into the tunnel, the encapsulating node might receive IPv4 ICMP error messages from IPv4 routers inside the tunnel. These packets are addressed to the encapsulating node because it is the IPv4 source of the encapsulated packet.
In response to encapsulated packets it has sent into the tunnel, the encapsulating node might receive IPv4 ICMP error messages from IPv4 routers inside the tunnel. These packets are addressed to the encapsulating node because it is the IPv4 source of the encapsulated packet.
Gilligan & Nordmark Standards Track [Page 13] RFC 2893 IPv6 Transition Mechanisms August 2000
Gilligan & Nordmark Standards Track [Page 13] RFC 2893 IPv6 Transition Mechanisms August 2000
The ICMP "packet too big" error messages are handled according to IPv4 Path MTU Discovery [8] and the resulting path MTU is recorded in the IPv4 layer. The recorded path MTU is used by IPv6 to determine if an IPv6 ICMP "packet too big" error has to be generated as described in section 3.2.
The ICMP "packet too big" error messages are handled according to IPv4 Path MTU Discovery [8] and the resulting path MTU is recorded in the IPv4 layer. The recorded path MTU is used by IPv6 to determine if an IPv6 ICMP "packet too big" error has to be generated as described in section 3.2.
The handling of other types of ICMP error messages depends on how much information is included in the "packet in error" field, which holds the encapsulated packet that caused the error.
The handling of other types of ICMP error messages depends on how much information is included in the "packet in error" field, which holds the encapsulated packet that caused the error.
Many older IPv4 routers return only 8 bytes of data beyond the IPv4 header of the packet in error, which is not enough to include the address fields of the IPv6 header. More modern IPv4 routers are likely to return enough data beyond the IPv4 header to include the entire IPv6 header and possibly even the data beyond that.
Many older IPv4 routers return only 8 bytes of data beyond the IPv4 header of the packet in error, which is not enough to include the address fields of the IPv6 header. More modern IPv4 routers are likely to return enough data beyond the IPv4 header to include the entire IPv6 header and possibly even the data beyond that.
If the offending packet includes enough data, the encapsulating node MAY extract the encapsulated IPv6 packet and use it to generate an IPv6 ICMP message directed back to the originating IPv6 node, as shown below:
If the offending packet includes enough data, the encapsulating node MAY extract the encapsulated IPv6 packet and use it to generate an IPv6 ICMP message directed back to the originating IPv6 node, as shown below:
+--------------+
| IPv4 Header |
| dst = encaps |
| node |
+--------------+
| ICMP |
| Header |
- - +--------------+
| IPv4 Header |
| src = encaps |
IPv4 | node |
+--------------+ - -
Packet | IPv6 |
| Header | Original IPv6
in +--------------+ Packet -
| Transport | Can be used to
Error | Header | generate an
+--------------+ IPv6 ICMP
| | error message
~ Data ~ back to the source.
| |
- - +--------------+ - -
+--------------+ | IPv4 Header | | dst = encaps | | node | +--------------+ | ICMP | | Header | - - +--------------+ | IPv4 Header | | src = encaps | IPv4 | node | +--------------+ - - Packet | IPv6 | | Header | Original IPv6 in +--------------+ Packet - | Transport | Can be used to Error | Header | generate an +--------------+ IPv6 ICMP | | error message ~ Data ~ back to the source. | | - - +--------------+ - -
IPv4 ICMP Error Message Returned to Encapsulating Node
IPv4 ICMP Error Message Returned to Encapsulating Node
Gilligan & Nordmark Standards Track [Page 14] RFC 2893 IPv6 Transition Mechanisms August 2000
Gilligan & Nordmark Standards Track [Page 14] RFC 2893 IPv6 Transition Mechanisms August 2000
3.5. IPv4 Header Construction
3.5. IPv4 Header Construction
When encapsulating an IPv6 packet in an IPv4 datagram, the IPv4 header fields are set as follows:
When encapsulating an IPv6 packet in an IPv4 datagram, the IPv4 header fields are set as follows:
Version:
Version:
4
4
IP Header Length in 32-bit words:
IP Header Length in 32-bit words:
5 (There are no IPv4 options in the encapsulating header.)
5 (There are no IPv4 options in the encapsulating header.)
Type of Service:
Type of Service:
0. [Note that work underway in the IETF is redefining the Type
of Service byte and as a result future RFCs might define a
different behavior for the ToS byte when tunneling.]
0. [Note that work underway in the IETF is redefining the Type of Service byte and as a result future RFCs might define a different behavior for the ToS byte when tunneling.]
Total Length:
Total Length:
Payload length from IPv6 header plus length of IPv6 and IPv4
headers (i.e. a constant 60 bytes).
Payload length from IPv6 header plus length of IPv6 and IPv4 headers (i.e. a constant 60 bytes).
Identification:
Identification:
Generated uniquely as for any IPv4 packet transmitted by the
system.
Generated uniquely as for any IPv4 packet transmitted by the system.
Flags:
Flags:
Set the Don't Fragment (DF) flag as specified in section 3.2.
Set the More Fragments (MF) bit as necessary if fragmenting.
Set the Don't Fragment (DF) flag as specified in section 3.2. Set the More Fragments (MF) bit as necessary if fragmenting.
Fragment offset:
Fragment offset:
Set as necessary if fragmenting.
Set as necessary if fragmenting.
Time to Live:
Time to Live:
Set in implementation-specific manner.
Set in implementation-specific manner.
Protocol:
Protocol:
41 (Assigned payload type number for IPv6)
41 (Assigned payload type number for IPv6)
Gilligan & Nordmark Standards Track [Page 15] RFC 2893 IPv6 Transition Mechanisms August 2000
Gilligan & Nordmark Standards Track [Page 15] RFC 2893 IPv6 Transition Mechanisms August 2000
Header Checksum:
Header Checksum:
Calculate the checksum of the IPv4 header.
Calculate the checksum of the IPv4 header.
Source Address:
Source Address:
IPv4 address of outgoing interface of the encapsulating node.
IPv4 address of outgoing interface of the encapsulating node.
Destination Address:
Destination Address:
IPv4 address of tunnel endpoint.
IPv4 address of tunnel endpoint.
Any IPv6 options are preserved in the packet (after the IPv6 header).
Any IPv6 options are preserved in the packet (after the IPv6 header).
3.6. Decapsulation
3.6. Decapsulation
When an IPv6/IPv4 host or a router receives an IPv4 datagram that is addressed to one of its own IPv4 address, and the value of the protocol field is 41, it reassembles if the packet if it is fragmented at the IPv4 level, then it removes the IPv4 header and submits the IPv6 datagram to its IPv6 layer code.
When an IPv6/IPv4 host or a router receives an IPv4 datagram that is addressed to one of its own IPv4 address, and the value of the protocol field is 41, it reassembles if the packet if it is fragmented at the IPv4 level, then it removes the IPv4 header and submits the IPv6 datagram to its IPv6 layer code.
The decapsulating node MUST be capable of reassembling an IPv4 packet that is 1300 bytes (1280 bytes plus IPv4 header).
The decapsulating node MUST be capable of reassembling an IPv4 packet that is 1300 bytes (1280 bytes plus IPv4 header).
The decapsulation is shown below:
The decapsulation is shown below:
+-------------+
| IPv4 |
| Header |
+-------------+ +-------------+
| IPv6 | | IPv6 |
| Header | | Header |
+-------------+ +-------------+
| Transport | | Transport |
| Layer | ===> | Layer |
| Header | | Header |
+-------------+ +-------------+
| | | |
~ Data ~ ~ Data ~
| | | |
+-------------+ +-------------+
+-------------+ | IPv4 | | Header | +-------------+ +-------------+ | IPv6 | | IPv6 | | Header | | Header | +-------------+ +-------------+ | Transport | | Transport | | Layer | ===> | Layer | | Header | | Header | +-------------+ +-------------+ | | | | ~ Data ~ ~ Data ~ | | | | +-------------+ +-------------+
Decapsulating IPv6 from IPv4
Decapsulating IPv6 from IPv4
Gilligan & Nordmark Standards Track [Page 16] RFC 2893 IPv6 Transition Mechanisms August 2000
Gilligan & Nordmark Standards Track [Page 16] RFC 2893 IPv6 Transition Mechanisms August 2000
When decapsulating the packet, the IPv6 header is not modified. [Note that work underway in the IETF is redefining the Type of Service byte and as a result future RFCs might define a different behavior for the ToS byte when decapsulating a tunneled packet.] If the packet is subsequently forwarded, its hop limit is decremented by one.
When decapsulating the packet, the IPv6 header is not modified. [Note that work underway in the IETF is redefining the Type of Service byte and as a result future RFCs might define a different behavior for the ToS byte when decapsulating a tunneled packet.] If the packet is subsequently forwarded, its hop limit is decremented by one.
As part of the decapsulation the node SHOULD silently discard a packet with an invalid IPv4 source address such as a multicast address, a broadcast address, 0.0.0.0, and 127.0.0.1. In general it SHOULD apply the rules for martian filtering in [18] and ingress filtering [13] on the IPv4 source address.
As part of the decapsulation the node SHOULD silently discard a packet with an invalid IPv4 source address such as a multicast address, a broadcast address, 0.0.0.0, and 127.0.0.1. In general it SHOULD apply the rules for martian filtering in [18] and ingress filtering [13] on the IPv4 source address.
The encapsulating IPv4 header is discarded.
The encapsulating IPv4 header is discarded.
After the decapsulation the node SHOULD silently discard a packet with an invalid IPv6 source address. This includes IPv6 multicast addresses, the unspecified address, and the loopback address but also IPv4-compatible IPv6 source addresses where the IPv4 part of the address is an (IPv4) multicast address, broadcast address, 0.0.0.0, or 127.0.0.1. In general it SHOULD apply the rules for martian filtering in [18] and ingress filtering [13] on the IPv4-compatible source address.
After the decapsulation the node SHOULD silently discard a packet with an invalid IPv6 source address. This includes IPv6 multicast addresses, the unspecified address, and the loopback address but also IPv4-compatible IPv6 source addresses where the IPv4 part of the address is an (IPv4) multicast address, broadcast address, 0.0.0.0, or 127.0.0.1. In general it SHOULD apply the rules for martian filtering in [18] and ingress filtering [13] on the IPv4-compatible source address.
The decapsulating node performs IPv4 reassembly before decapsulating the IPv6 packet. All IPv6 options are preserved even if the encapsulating IPv4 packet is fragmented.
The decapsulating node performs IPv4 reassembly before decapsulating the IPv6 packet. All IPv6 options are preserved even if the encapsulating IPv4 packet is fragmented.
After the IPv6 packet is decapsulated, it is processed almost the same as any received IPv6 packet. The only difference being that a decapsulated packet MUST NOT be forwarded unless the node has been explicitly configured to forward such packets for the given IPv4 source address. This configuration can be implicit in e.g., having a configured tunnel which matches the IPv4 source address. This restriction is needed to prevent tunneling to be used as a tool to circumvent ingress filtering [13].
After the IPv6 packet is decapsulated, it is processed almost the same as any received IPv6 packet. The only difference being that a decapsulated packet MUST NOT be forwarded unless the node has been explicitly configured to forward such packets for the given IPv4 source address. This configuration can be implicit in e.g., having a configured tunnel which matches the IPv4 source address. This restriction is needed to prevent tunneling to be used as a tool to circumvent ingress filtering [13].
3.7. Link-Local Addresses
3.7. Link-Local Addresses
Both the configured and automatic tunnels are IPv6 interfaces (over the IPv4 "link layer") thus MUST have link-local addresses. The link-local addresses are used by routing protocols operating over the tunnels.
Both the configured and automatic tunnels are IPv6 interfaces (over the IPv4 "link layer") thus MUST have link-local addresses. The link-local addresses are used by routing protocols operating over the tunnels.
The Interface Identifier [14] for such an Interface SHOULD be the 32-bit IPv4 address of that interface, with the bytes in the same order in which they would appear in the header of an IPv4 packet, padded at the left with zeros to a total of 64 bits. Note that the
The Interface Identifier [14] for such an Interface SHOULD be the 32-bit IPv4 address of that interface, with the bytes in the same order in which they would appear in the header of an IPv4 packet, padded at the left with zeros to a total of 64 bits. Note that the
Gilligan & Nordmark Standards Track [Page 17] RFC 2893 IPv6 Transition Mechanisms August 2000
Gilligan & Nordmark Standards Track [Page 17] RFC 2893 IPv6 Transition Mechanisms August 2000
"Universal/Local" bit is zero, indicating that the Interface Identifier is not globally unique. When the host has more than one IPv4 address in use on the physical interface concerned, an administrative choice of one of these IPv4 addresses is made.
"Universal/Local" bit is zero, indicating that the Interface Identifier is not globally unique. When the host has more than one IPv4 address in use on the physical interface concerned, an administrative choice of one of these IPv4 addresses is made.
The IPv6 Link-local address [14] for an IPv4 virtual interface is formed by appending the Interface Identifier, as defined above, to the prefix FE80::/64.
The IPv6 Link-local address [14] for an IPv4 virtual interface is formed by appending the Interface Identifier, as defined above, to the prefix FE80::/64.
+-------+-------+-------+-------+-------+-------+------+------+ | FE 80 00 00 00 00 00 00 | +-------+-------+-------+-------+-------+-------+------+------+ | 00 00 | 00 | 00 | IPv4 Address | +-------+-------+-------+-------+-------+-------+------+------+
+-------+-------+-------+-------+-------+-------+------+------+ | FE 80 00 00 00 00 00 00 | +-------+-------+-------+-------+-------+-------+------+------+ | 00 00 | 00 | 00 | IPv4 Address | +-------+-------+-------+-------+-------+-------+------+------+
3.8. Neighbor Discovery over Tunnels
3.8. Neighbor Discovery over Tunnels
Automatic tunnels and unidirectional configured tunnels are considered to be unidirectional. Thus the only aspects of Neighbor Discovery [7] and Stateless Address Autoconfiguration [5] that apply to these tunnels is the formation of the link-local address.
Automatic tunnels and unidirectional configured tunnels are considered to be unidirectional. Thus the only aspects of Neighbor Discovery [7] and Stateless Address Autoconfiguration [5] that apply to these tunnels is the formation of the link-local address.
If an implementation provides bidirectional configured tunnels it MUST at least accept and respond to the probe packets used by Neighbor Unreachability Detection [7]. Such implementations SHOULD also send NUD probe packets to detect when the configured tunnel fails at which point the implementation can use an alternate path to reach the destination. Note that Neighbor Discovery allows that the sending of NUD probes be omitted for router to router links if the routing protocol tracks bidirectional reachability.
If an implementation provides bidirectional configured tunnels it MUST at least accept and respond to the probe packets used by Neighbor Unreachability Detection [7]. Such implementations SHOULD also send NUD probe packets to detect when the configured tunnel fails at which point the implementation can use an alternate path to reach the destination. Note that Neighbor Discovery allows that the sending of NUD probes be omitted for router to router links if the routing protocol tracks bidirectional reachability.
For the purposes of Neighbor Discovery the automatic and configured tunnels specified in this document as assumed to NOT have a link- layer address, even though the link-layer (IPv4) does have address. This means that a sender of Neighbor Discovery packets
For the purposes of Neighbor Discovery the automatic and configured tunnels specified in this document as assumed to NOT have a link- layer address, even though the link-layer (IPv4) does have address. This means that a sender of Neighbor Discovery packets
- SHOULD NOT include Source Link Layer Address options or Target
Link Layer Address options on the tunnel link.
- SHOULD NOT include Source Link Layer Address options or Target Link Layer Address options on the tunnel link.
- MUST silently ignore any received SLLA or TLLA options on the
tunnel link.
- MUST silently ignore any received SLLA or TLLA options on the tunnel link.
4. Configured Tunneling
4. Configured Tunneling
In configured tunneling, the tunnel endpoint address is determined from configuration information in the encapsulating node. For each tunnel, the encapsulating node must store the tunnel endpoint address. When an IPv6 packet is transmitted over a tunnel, the
In configured tunneling, the tunnel endpoint address is determined from configuration information in the encapsulating node. For each tunnel, the encapsulating node must store the tunnel endpoint address. When an IPv6 packet is transmitted over a tunnel, the
Gilligan & Nordmark Standards Track [Page 18] RFC 2893 IPv6 Transition Mechanisms August 2000
Gilligan & Nordmark Standards Track [Page 18] RFC 2893 IPv6 Transition Mechanisms August 2000
tunnel endpoint address configured for that tunnel is used as the destination address for the encapsulating IPv4 header.
tunnel endpoint address configured for that tunnel is used as the destination address for the encapsulating IPv4 header.
The determination of which packets to tunnel is usually made by routing information on the encapsulating node. This is usually done via a routing table, which directs packets based on their destination address using the prefix mask and match technique.
The determination of which packets to tunnel is usually made by routing information on the encapsulating node. This is usually done via a routing table, which directs packets based on their destination address using the prefix mask and match technique.
4.1. Default Configured Tunnel
4.1. Default Configured Tunnel
IPv6/IPv4 hosts that are connected to datalinks with no IPv6 routers MAY use a configured tunnel to reach an IPv6 router. This tunnel allows the host to communicate with the rest of the IPv6 Internet (i.e. nodes with IPv6-native addresses). If the IPv4 address of an IPv6/IPv4 router bordering the IPv6 backbone is known, this can be used as the tunnel endpoint address. This tunnel can be configured into the routing table as an IPv6 "default route". That is, all IPv6 destination addresses will match the route and could potentially traverse the tunnel. Since the "mask length" of such a default route is zero, it will be used only if there are no other routes with a longer mask that match the destination. The default configured tunnel can be used in conjunction with automatic tunneling, as described in section 5.4.
IPv6/IPv4 hosts that are connected to datalinks with no IPv6 routers MAY use a configured tunnel to reach an IPv6 router. This tunnel allows the host to communicate with the rest of the IPv6 Internet (i.e. nodes with IPv6-native addresses). If the IPv4 address of an IPv6/IPv4 router bordering the IPv6 backbone is known, this can be used as the tunnel endpoint address. This tunnel can be configured into the routing table as an IPv6 "default route". That is, all IPv6 destination addresses will match the route and could potentially traverse the tunnel. Since the "mask length" of such a default route is zero, it will be used only if there are no other routes with a longer mask that match the destination. The default configured tunnel can be used in conjunction with automatic tunneling, as described in section 5.4.
4.2. Default Configured Tunnel using IPv4 "Anycast Address"
4.2. Default Configured Tunnel using IPv4 "Anycast Address"
The tunnel endpoint address of such a default tunnel could be the IPv4 address of one IPv6/IPv4 router at the border of the IPv6 backbone. Alternatively, the tunnel endpoint could be an IPv4 "anycast address". With this approach, multiple IPv6/IPv4 routers at the border advertise IPv4 reachability to the same IPv4 address. All of these routers accept packets to this address as their own, and will decapsulate IPv6 packets tunneled to this address. When an IPv6/IPv4 node sends an encapsulated packet to this address, it will be delivered to only one of the border routers, but the sending node will not know which one. The IPv4 routing system will generally carry the traffic to the closest router.
The tunnel endpoint address of such a default tunnel could be the IPv4 address of one IPv6/IPv4 router at the border of the IPv6 backbone. Alternatively, the tunnel endpoint could be an IPv4 "anycast address". With this approach, multiple IPv6/IPv4 routers at the border advertise IPv4 reachability to the same IPv4 address. All of these routers accept packets to this address as their own, and will decapsulate IPv6 packets tunneled to this address. When an IPv6/IPv4 node sends an encapsulated packet to this address, it will be delivered to only one of the border routers, but the sending node will not know which one. The IPv4 routing system will generally carry the traffic to the closest router.
Using a default tunnel to an IPv4 "anycast address" provides a high degree of robustness since multiple border router can be provided, and, using the normal fallback mechanisms of IPv4 routing, traffic will automatically switch to another router when one goes down. However, care must be taking when using such a default tunnel to prevent different IPv4 fragments from arriving at different routers for reassembly. This can be prevented by either avoiding fragmentation of the encapsulated packets (by ensuring an IPv4 MTU of at least 1300 bytes) or by preventing frequent changes to IPv4 routing.
Using a default tunnel to an IPv4 "anycast address" provides a high degree of robustness since multiple border router can be provided, and, using the normal fallback mechanisms of IPv4 routing, traffic will automatically switch to another router when one goes down. However, care must be taking when using such a default tunnel to prevent different IPv4 fragments from arriving at different routers for reassembly. This can be prevented by either avoiding fragmentation of the encapsulated packets (by ensuring an IPv4 MTU of at least 1300 bytes) or by preventing frequent changes to IPv4 routing.
Gilligan & Nordmark Standards Track [Page 19] RFC 2893 IPv6 Transition Mechanisms August 2000
Gilligan & Nordmark Standards Track [Page 19] RFC 2893 IPv6 Transition Mechanisms August 2000
4.3. Ingress Filtering
4.3. Ingress Filtering
The decapsulating node MUST verify that the tunnel source address is acceptable before forwarding decapsulated packets to avoid circumventing ingress filtering [13]. Note that packets which are delivered to transport protocols on the decapsulating node SHOULD NOT be subject to these checks. For bidirectional configured tunnels this is done by verifying that the source address is the IPv4 address of the other end of the tunnel. For unidirectional configured tunnels the decapsulating node MUST be configured with a list of source IPv4 address prefixes that are acceptable. Such a list MUST default to not having any entries i.e. the node has to be explicitly configured to forward decapsulated packets received over unidirectional configured tunnels.
The decapsulating node MUST verify that the tunnel source address is acceptable before forwarding decapsulated packets to avoid circumventing ingress filtering [13]. Note that packets which are delivered to transport protocols on the decapsulating node SHOULD NOT be subject to these checks. For bidirectional configured tunnels this is done by verifying that the source address is the IPv4 address of the other end of the tunnel. For unidirectional configured tunnels the decapsulating node MUST be configured with a list of source IPv4 address prefixes that are acceptable. Such a list MUST default to not having any entries i.e. the node has to be explicitly configured to forward decapsulated packets received over unidirectional configured tunnels.
5. Automatic Tunneling
5. Automatic Tunneling
In automatic tunneling, the tunnel endpoint address is determined by the IPv4-compatible destination address of the IPv6 packet being tunneled. Automatic tunneling allows IPv6/IPv4 nodes to communicate over IPv4 routing infrastructures without pre-configuring tunnels.
In automatic tunneling, the tunnel endpoint address is determined by the IPv4-compatible destination address of the IPv6 packet being tunneled. Automatic tunneling allows IPv6/IPv4 nodes to communicate over IPv4 routing infrastructures without pre-configuring tunnels.
5.1. IPv4-Compatible Address Format
5.1. IPv4-Compatible Address Format
IPv6/IPv4 nodes that perform automatic tunneling are assigned IPv4- compatible address. An IPv4-compatible address is identified by an all-zeros 96-bit prefix, and holds an IPv4 address in the low-order 32-bits. IPv4-compatible addresses are structured as follows:
IPv6/IPv4 nodes that perform automatic tunneling are assigned IPv4- compatible address. An IPv4-compatible address is identified by an all-zeros 96-bit prefix, and holds an IPv4 address in the low-order 32-bits. IPv4-compatible addresses are structured as follows:
| 96-bits | 32-bits |
+--------------------------------------+--------------+
| 0:0:0:0:0:0 | IPv4 Address |
+--------------------------------------+--------------+
IPv4-Compatible IPv6 Address Format
| 96-bits | 32-bits | +--------------------------------------+--------------+ | 0:0:0:0:0:0 | IPv4 Address | +--------------------------------------+--------------+ IPv4-Compatible IPv6 Address Format
IPv4-compatible addresses are assigned exclusively to nodes that support automatic tunneling. A node SHOULD be configured with an IPv4-compatible address only if it is prepared to accept IPv6 packets destined to that address encapsulated in IPv4 packets destined to the embedded IPv4 address.
IPv4-compatible addresses are assigned exclusively to nodes that support automatic tunneling. A node SHOULD be configured with an IPv4-compatible address only if it is prepared to accept IPv6 packets destined to that address encapsulated in IPv4 packets destined to the embedded IPv4 address.
An IPv4-compatible address is globally unique as long as the IPv4 address is not from the private IPv4 address space [15]. An implementation SHOULD behave as if its IPv4-compatible address(es) are assigned to the node's automatic tunneling interface, even if the implementation does not implement automatic tunneling using a concept of interfaces. Thus the IPv4-compatible address SHOULD NOT be viewed as being attached to e.g. an Ethernet interface i.e. implications
An IPv4-compatible address is globally unique as long as the IPv4 address is not from the private IPv4 address space [15]. An implementation SHOULD behave as if its IPv4-compatible address(es) are assigned to the node's automatic tunneling interface, even if the implementation does not implement automatic tunneling using a concept of interfaces. Thus the IPv4-compatible address SHOULD NOT be viewed as being attached to e.g. an Ethernet interface i.e. implications
Gilligan & Nordmark Standards Track [Page 20] RFC 2893 IPv6 Transition Mechanisms August 2000
Gilligan & Nordmark Standards Track [Page 20] RFC 2893 IPv6 Transition Mechanisms August 2000
should not use the Neighbor Discovery mechanisms like NUD [7] at the Ethernet. Any such interactions should be done using the encapsulated packets i.e. over the automatic tunneling (conceptual) interface.
should not use the Neighbor Discovery mechanisms like NUD [7] at the Ethernet. Any such interactions should be done using the encapsulated packets i.e. over the automatic tunneling (conceptual) interface.
5.2. IPv4-Compatible Address Configuration
5.2. IPv4-Compatible Address Configuration
An IPv6/IPv4 node with an IPv4-compatible address uses that address as one of its IPv6 addresses, while the IPv4 address embedded in the low-order 32-bits serves as the IPv4 address for one of its interfaces.
An IPv6/IPv4 node with an IPv4-compatible address uses that address as one of its IPv6 addresses, while the IPv4 address embedded in the low-order 32-bits serves as the IPv4 address for one of its interfaces.
An IPv6/IPv4 node MAY acquire its IPv4-compatible IPv6 addresses via IPv4 address configuration protocols. It MAY use any IPv4 address configuration mechanism to acquire its IPv4 address, then "map" that address into an IPv4-compatible IPv6 address by pre-pending it with the 96-bit prefix 0:0:0:0:0:0. This mode of configuration allows IPv6/IPv4 nodes to "leverage" the installed base of IPv4 address configuration servers.
An IPv6/IPv4 node MAY acquire its IPv4-compatible IPv6 addresses via IPv4 address configuration protocols. It MAY use any IPv4 address configuration mechanism to acquire its IPv4 address, then "map" that address into an IPv4-compatible IPv6 address by pre-pending it with the 96-bit prefix 0:0:0:0:0:0. This mode of configuration allows IPv6/IPv4 nodes to "leverage" the installed base of IPv4 address configuration servers.
The specific algorithm for acquiring an IPv4-compatible address using IPv4-based address configuration protocols is as follows:
The specific algorithm for acquiring an IPv4-compatible address using IPv4-based address configuration protocols is as follows:
1) The IPv6/IPv4 node uses standard IPv4 mechanisms or protocols to
acquire the IPv4 address for one of its interfaces. These
include:
1) The IPv6/IPv4 node uses standard IPv4 mechanisms or protocols to acquire the IPv4 address for one of its interfaces. These include:
- The Dynamic Host Configuration Protocol (DHCP) [2]
- The Dynamic Host Configuration Protocol (DHCP) [2]
- The Bootstrap Protocol (BOOTP) [1]
- The Bootstrap Protocol (BOOTP) [1]
- The Reverse Address Resolution Protocol (RARP) [9]
- The Reverse Address Resolution Protocol (RARP) [9]
- Manual configuration
- Manual configuration
- Any other mechanism which accurately yields the node's own IPv4
address
- Any other mechanism which accurately yields the node's own IPv4 address
2) The node uses this address as the IPv4 address for this interface.
2) The node uses this address as the IPv4 address for this interface.
3) The node prepends the 96-bit prefix 0:0:0:0:0:0 to the 32-bit IPv4
address that it acquired in step (1). The result is an IPv4-
compatible IPv6 address with one of the node's IPv4-addresses
embedded in the low-order 32-bits. The node uses this address as
one of its IPv6 addresses.
3) The node prepends the 96-bit prefix 0:0:0:0:0:0 to the 32-bit IPv4 address that it acquired in step (1). The result is an IPv4- compatible IPv6 address with one of the node's IPv4-addresses embedded in the low-order 32-bits. The node uses this address as one of its IPv6 addresses.
Gilligan & Nordmark Standards Track [Page 21] RFC 2893 IPv6 Transition Mechanisms August 2000
Gilligan & Nordmark Standards Track [Page 21] RFC 2893 IPv6 Transition Mechanisms August 2000
5.3. Automatic Tunneling Operation
5.3. Automatic Tunneling Operation
In automatic tunneling, the tunnel endpoint address is determined from the packet being tunneled. If the destination IPv6 address is IPv4-compatible, then the packet can be sent via automatic tunneling. If the destination is IPv6-native, the packet can not be sent via automatic tunneling.
In automatic tunneling, the tunnel endpoint address is determined from the packet being tunneled. If the destination IPv6 address is IPv4-compatible, then the packet can be sent via automatic tunneling. If the destination is IPv6-native, the packet can not be sent via automatic tunneling.
A routing table entry can be used to direct automatic tunneling. An implementation can have a special static routing table entry for the prefix 0:0:0:0:0:0/96. (That is, a route to the all-zeros prefix with a 96-bit mask.) Packets that match this prefix are sent to a pseudo-interface driver which performs automatic tunneling. Since all IPv4-compatible IPv6 addresses will match this prefix, all packets to those destinations will be auto-tunneled.
A routing table entry can be used to direct automatic tunneling. An implementation can have a special static routing table entry for the prefix 0:0:0:0:0:0/96. (That is, a route to the all-zeros prefix with a 96-bit mask.) Packets that match this prefix are sent to a pseudo-interface driver which performs automatic tunneling. Since all IPv4-compatible IPv6 addresses will match this prefix, all packets to those destinations will be auto-tunneled.
Once it is delivered to the automatic tunneling module, the IPv6 packet is encapsulated within an IPv4 header according to the rules described in section 3. The source and destination addresses of the encapsulating IPv4 header are assigned as follows:
Once it is delivered to the automatic tunneling module, the IPv6 packet is encapsulated within an IPv4 header according to the rules described in section 3. The source and destination addresses of the encapsulating IPv4 header are assigned as follows:
Destination IPv4 address:
Destination IPv4 address:
Low-order 32-bits of IPv6 destination address
Low-order 32-bits of IPv6 destination address
Source IPv4 address:
Source IPv4 address:
IPv4 address of interface the packet is sent via
IPv4 address of interface the packet is sent via
The automatic tunneling module always sends packets in this encapsulated form, even if the destination is on an attached datalink.
目的地が付属データリンクにあっても、自動トンネリングモジュールはこのカプセル化されたフォームでいつもパケットを送ります。
The automatic tunneling module MUST NOT send to IPv4 broadcast or multicast destinations. It MUST drop all IPv6 packets destined to IPv4-compatible destinations when the embedded IPv4 address is broadcast, multicast, the unspecified (0.0.0.0) address, or the loopback address (127.0.0.1). Note that the sender can only tell if an address is a network or subnet broadcast for broadcast addresses assigned to directly attached links.
自動トンネリングモジュールはIPv4放送かマルチキャストの目的地に発信してはいけません。 埋め込まれたIPv4アドレスが放送されるときIPv4コンパチブル目的地に運命づけられたすべてのIPv6パケットを下げなければなりません、マルチキャスト、不特定である、(0.0.0.0)アドレス、またはループバックアドレス、(127.0 .0 .1)。 送付者が、アドレスが直接付属しているリンクに割り当てられた放送演説のためのネットワークかそれともサブネット放送であるかを言うことができるだけであることに注意してください。
5.4. Use With Default Configured Tunnels
5.4. 構成されるデフォルトで、Tunnelsを使用してください。
Automatic tunneling is often used in conjunction with the default configured tunnel technique. "Isolated" IPv6/IPv4 hosts -- those with no on-link IPv6 routers -- are configured to use automatic tunneling and IPv4-compatible IPv6 addresses, and have at least one default configured tunnel to an IPv6 router. That IPv6 router is
自動トンネリングはしばしばデフォルトの構成されたトンネルのテクニックに関連して使用されます。 「孤立している」IPv6/IPv4ホスト(リンクの上のIPv6ルータのないそれら)は、自動トンネリングとIPv4コンパチブルIPv6アドレスを使用して、少なくともデフォルトが構成した1つをIPv6ルータにトンネルを堀らせるために構成されます。 そのIPv6ルータはそうです。
Gilligan & Nordmark Standards Track [Page 22] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[22ページ]。
configured to perform automatic tunneling as well. These isolated hosts send packets to IPv4-compatible destinations via automatic tunneling and packets for IPv6-native destinations via the default configured tunnel. IPv4-compatible destinations will match the 96- bit all-zeros prefix route discussed in the previous section, while IPv6-native destinations will match the default route via the configured tunnel. Reply packets from IPv6-native destinations are routed back to the an IPv6/IPv4 router which delivers them to the original host via automatic tunneling. Further examples of the combination of tunneling techniques are discussed in [12].
また、自動トンネリングを実行するのを構成しました。 これらの孤立しているホストは自動トンネリングでIPv4コンパチブル目的地にパケットを送ります、そして、デフォルトを通したネイティブのIPv6の目的地へのパケットはトンネルを構成しました。 IPv4コンパチブル目的地は前項で議論した96の噛み付いているオールゼロ接頭語ルートに合うでしょう、ネイティブのIPv6の目的地が構成されたトンネルを通ってデフォルトルートに合うでしょうが。 ネイティブのIPv6の目的地からの回答パケットが発送して戻される、自動トンネリングでそれらをオリジナルホストに提供するIPv6/IPv4ルータ。 [12]でトンネリングのテクニックの組み合わせに関するさらなる例について議論します。
5.5. Source Address Selection
5.5. ソースアドレス選択
When an IPv6/IPv4 node originates an IPv6 packet, it must select the source IPv6 address to use. IPv6/IPv4 nodes that are configured to perform automatic tunneling may be configured with global IPv6-native addresses as well as IPv4-compatible addresses. The selection of which source address to use will determine what form the return traffic is sent via. If the IPv4-compatible address is used, the return traffic will have to be delivered via automatic tunneling, but if the IPv6-native address is used, the return traffic will not be automatic-tunneled. In order to make traffic as symmetric as possible, the following source address selection preference is RECOMMENDED:
IPv6/IPv4ノードがIPv6パケットを溯源するとき、それはIPv6が使用に演説するソースを選ばなければなりません。 自動トンネリングを実行するために構成されるIPv6/IPv4ノードはIPv4コンパチブルアドレスと同様にグローバルなネイティブのIPv6アドレスによって構成されるかもしれません。 を通してどのソースアドレスを使用したらよいかに関する選択が、リターントラフィックがどんなフォームに送られるかを決定する。 IPv4コンパチブルアドレスが使用されていると、リターントラフィックは自動トンネリングで提供されなければならないでしょうが、ネイティブのIPv6アドレスが使用されていると、リターントラフィックは自動にトンネルにならないでしょう。 トラフィックをできるだけ左右対称にするように、以下のソースアドレス選択好みはRECOMMENDEDです:
Destination is IPv4-compatible:
目的地はIPv4互換性があります:
Use IPv4-compatible source address associated with IPv4 address
of outgoing interface
外向的なインタフェースのIPv4アドレスに関連しているIPv4コンパチブルソースアドレスを使用してください。
Destination is IPv6-native:
目的地はネイティブのIPv6です:
Use IPv6-native address of outgoing interface
外向的なインタフェースのネイティブのIPv6アドレスを使用してください。
If an IPv6/IPv4 node has no global IPv6-native address, but is originating a packet to an IPv6-native destination, it MAY use its IPv4-compatible address as its source address.
IPv6/IPv4ノードがどんなグローバルなネイティブのIPv6アドレスも持っていませんが、ネイティブのIPv6の目的地にパケットを溯源しているなら、それはソースアドレスとしてIPv4コンパチブルアドレスを使用するかもしれません。
5.6. Ingress Filtering
5.6. イングレスフィルタリング
The decapsulating node MUST verify that the encapsulated packets are acceptable before forwarding decapsulated packets to avoid circumventing ingress filtering [13]. Note that packets which are delivered to transport protocols on the decapsulating node SHOULD NOT be subject to these checks. Since automatic tunnels always encapsulate to the destination (i.e. the IPv4 destination will be the destination) any packet received over an automatic tunnel SHOULD NOT be forwarded.
decapsulatingノードは、推進が[13]をフィルターにかけるイングレスを回避するのを避けるためにパケットをdecapsulatedする前にカプセル化されたパケットが許容できることを確かめなければなりません。 decapsulatingノードSHOULD NOTでプロトコルを輸送するために提供されるパケットはこれらのチェックを受けることがあることに注意してください。 自動トンネルがいつもどんなパケットも自動トンネルSHOULD NOTの上で受けた目的地(すなわち、IPv4の目的地は目的地になる)に要約されるので、進めてください。
Gilligan & Nordmark Standards Track [Page 23] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[23ページ]。
6. Acknowledgments
6. 承認
We would like to thank the members of the IPng working group and the Next Generation Transition (ngtrans) working group for their many contributions and extensive review of this document. Special thanks are due to Jim Bound, Ross Callon, and Bob Hinden for many helpful suggestions and to John Moy for suggesting the IPv4 "anycast address" default tunnel technique.
このドキュメントの彼らの多くの貢献と大量のレビューについてIPngワーキンググループとNext Generation Transition(ngtrans)ワーキンググループのメンバーに感謝申し上げます。 多くの役立つ提案のためのジムBoundと、ロスCallonと、ボブHindenとIPv4「anycastアドレス」デフォルトトンネルのテクニックを示すためのジョンMoyに特別な感謝があります。
7. Security Considerations
7. セキュリティ問題
Tunneling is not known to introduce any security holes except for the possibility to circumvent ingress filtering [13]. This is prevented by requiring that decapsulating routers only forward packets if they have been configured to accept encapsulated packets from the IPv4 source address in the receive packet. Additionally, in the case of automatic tunneling, nodes are required by not forwarding the decapsulated packets since automatic tunneling ends the tunnel and the destination.
トンネリングが[13]をフィルターにかけるイングレスを回避する可能性以外のどんなセキュリティーホールも紹介するのが知られません。 前方だけにルータをdecapsulatingして、それらが受け入れるために構成されたならパケットがパケットをカプセルに入れったのを必要とすることによってこれが中のIPv4ソースアドレスから防がれる、パケットを受けてください。 さらに、自動トンネリングの場合では、ノードが、自動トンネリングがトンネルと目的地を終わらせるのでdecapsulatedパケットを進めないことによって、必要です。
8. Authors' Addresses
8. 作者のアドレス
Robert E. Gilligan FreeGate Corp 1208 E. Arques Ave Sunnyvale, CA 94086 USA
ロバートE.ギリガンFreeGate Corp1208E.Arques Aveカリフォルニア94086サニーベル(米国)
Phone: +1-408-617-1004 Fax: +1-408-617-1010 EMail: gilligan@freegate.com
以下に電話をしてください。 +1-408-617-1004 Fax: +1-408-617-1010 メールしてください: gilligan@freegate.com
Erik Nordmark Sun Microsystems, Inc. 901 San Antonio Rd. Palo Alto, CA 94303 USA
エリックNordmarkサン・マイクロシステムズ・インク901サンアントニオ通り パロアルト、カリフォルニア94303米国
Phone: +1-650-786-5166 Fax: +1-650-786-5896 EMail: nordmark@eng.sun.com
以下に電話をしてください。 +1-650-786-5166 Fax: +1-650-786-5896 メールしてください: nordmark@eng.sun.com
Gilligan & Nordmark Standards Track [Page 24] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[24ページ]。
9. References
9. 参照
[1] Croft, W. and J. Gilmore, "Bootstrap Protocol", RFC 951,
September 1985.
[1] 耕地とW.とJ.ギルモア、「プロトコルを独力で進んでください」、RFC951、1985年9月。
[2] Droms, R., "Dynamic Host Configuration Protocol", RFC 1541,
October 1993.
[2]Droms、R.、「ダイナミックなホスト構成プロトコル」、RFC1541、1993年10月。
[3] Carpenter, B. and C. Jung, "Transmission of IPv6 over IPv4
Domains without Explicit Tunnels", RFC 2529, March 1999.
[3] 大工とB.とC.ユング、「明白なTunnelsのいないIPv4ドメインの上のIPv6のトランスミッション」、RFC2529、1999年3月。
[4] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6)
Specification", RFC 2460, December 1998.
[4] デアリング、S.とR.Hinden、「インターネットプロトコル、バージョン6(IPv6)仕様」、RFC2460、12月1998日
[5] Thomson, S. and T. Narten, "IPv6 Stateless Address
Autoconfiguration," RFC 2462, December 1998.
[5] トムソンとS.とT.Narten、「IPv6の状態がないアドレス自動構成」、RFC2462、1998年12月。
[6] Crawford, M., Thomson, S., and C. Huitema. "DNS Extensions to
Support IPv6 Address Allocation and Renumbering", RFC 2874, July
2000.
[6] クロフォード、M.、トムソン、S.、およびC.Huitema。 「IPv6をサポートするDNS拡張子は配分と番号を付け替えることを扱う」、RFC2874、7月2000日
[7] Narten, T., Nordmark, E. and W. Simpson, "Neighbor Discovery for
IP Version 6 (IPv6)", RFC 2461, December 1998.
[7]NartenとT.とNordmarkとE.とW.シンプソン、「IPバージョン6(IPv6)のための隣人発見」、RFC2461、1998年12月。
[8] Mogul, J. and S. Deering, "Path MTU Discovery", RFC 1191,
November 1990.
[8] ムガール人とJ.とS.デアリング、「経路MTU発見」、RFC1191、1990年11月。
[9] Finlayson, R., Mann, T., Mogul, J. and M. Theimer, "Reverse
Address Resolution Protocol", STD 38, RFC 903, June 1984.
[9] フィンリースンとR.とマンとT.とムガール人とJ.とM.Theimer、「逆アドレス解決プロトコル」、STD38、RFC903、1984年6月。
[10] Braden, R., "Requirements for Internet Hosts - Communication
Layers", STD 3, RFC 1122, October 1989.
[10] ブレーデン、R.、「インターネットのためのホスト--コミュニケーションが層にされるという要件」、STD3、RFC1122、10月1989日
[11] Kent, C. and J. Mogul, "Fragmentation Considered Harmful". In
Proc. SIGCOMM '87 Workshop on Frontiers in Computer
Communications Technology. August 1987.
[11] ケントとC.とJ.ムガール人、「有害であると考えられた断片化。」 Procで。 コンピュータ通信技術によるフロンティアーズに関するSIGCOMM87年のワークショップ。 1987年8月。
[12] Callon, R. and D. Haskin, "Routing Aspects of IPv6 Transition",
RFC 2185, September 1997.
[12]Callon、R. and D.ハスキン、「IPv6変遷のルート設定局面」、RFC2185、1997年9月。
[13] Ferguson, P. and D. Senie, "Network Ingress Filtering: Defeating
Denial of Service Attacks which employ IP Source Address
Spoofing", RFC 2267, January 1998.
[13] ファーガソン、P.、およびD.Senieは「以下をフィルターにかけるイングレスをネットワークでつなぎます」。 「IP Source Address Spoofingを使うサービス妨害Attacksを破ります」、RFC2267、1998年1月。
[14] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 2373, July 1998.
[14]HindenとR.とS.デアリング、「IPバージョン6アドレッシング体系」、RFC2373、1998年7月。
Gilligan & Nordmark Standards Track [Page 25] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[25ページ]。
[15] Rechter, Y., Moskowitz, B., Karrenberg, D., de Groot, G.J. and
E. Lear, "Address Allocation for Private Internets", BCP 5, RFC
1918, February 1996.
[15] Rechter(Y.、マスコウィッツ、B.、Karrenberg、D.、deグルート、G.J.、およびE.リア)は「個人的なインターネットのための配分を扱います」、BCP5、RFC1918、1996年2月。
[16] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[16] ブラドナー、S.、「Indicate Requirement LevelsへのRFCsにおける使用のためのキーワード」、BCP14、RFC2119、1997年3月。
[17] Thaler, D., "IP Tunnel MIB", RFC 2667, August 1999.
D.、「IPトンネルMIB」、RFC2667 1999年8月の[17]ターレル。
[18] Baker, F., "Requirements for IP Version 4 Routers", RFC 1812,
June 1995.
[18] ベイカー、F.、「IPバージョン4ルータのための要件」、RFC1812、1995年6月。
10. Changes from RFC 1933
10. RFC1933からの変化
- Deleted section 3.1.1 (IPv4 loopback address) in order to prevent
it from being mis-construed as requiring routers to filter the
address ::127.0.0.1, which would put another test in the
forwarding path for IPv6 routers.
- アドレスをフィルターにかけるためにルータを必要とするのがそれに誤解されるのを防ぐために、セクション3.1.1(IPv4ループバックアドレス)を削除します:、:127.0.0.1 どれがIPv6ルータのために推進経路に別のテストを置くでしょうか?
- Deleted section 4.4 (Default Sending Algorithm). This section
allowed nodes to send packets in "raw form" to IPv4-compatible
destinations on the same datalink. Implementation experience has
shown that this adds complexity which is not justified by the
minimal savings in header overhead.
- 削除されたセクション4.4 (デフォルトSending Algorithm。) このセクションで、ノードは同じデータリンクで「生のフォーム」でIPv4コンパチブル目的地にパケットを送ることができました。 実装経験は、これがヘッダーオーバーヘッドにおける最小量の貯蓄によって正当化されない複雑さを加えるのを示しました。
- Added definitions for operating modes for IPv6/IPv4 nodes.
- IPv6/IPv4ノードのためにオペレーティング・モードのための定義を加えました。
- Revised DNS section to clarify resolver filtering and ordering
options.
- オプションをフィルターにかけて、注文しているレゾルバをはっきりさせるためにDNS部を改訂しました。
- Re-wrote the discussion of IPv4-compatible addresses to clarify
that they are used exclusively in conjunction with the automatic
tunneling mechanism. Re-organized document to place definition of
IPv4-compatible address format with description of automatic
tunneling.
- それらははっきりさせるIPv4コンパチブルアドレスの議論ですが、排他的に自動トンネリングメカニズムに関連して使用されて、書き直しました。 自動トンネリングの記述によるIPv4コンパチブルアドレス形式の定義を置くためにドキュメントを再編成しました。
- Changed the term "IPv6-only address" to "IPv6-native address" per
current usage.
- 「IPv6だけアドレス」という用語を現在の用法あたりの「ネイティブのIPv6アドレス」に変えました。
- Updated to algorithm for determining tunnel MTU to reflect the
change in the IPv6 minimum MTU from 576 to 1280 bytes [4].
- トンネルMTUが576〜1280バイト[4]からIPv6の最小のMTUにおける変化を反映することを決定するためのアルゴリズムに、アップデートします。
- Deleted the definition for the term "IPv6-in-IPv4 encapsulation."
It has not been widely used.
- 「IPv4のIPv6カプセル化」という用語のための定義を削除しました。 それは広く使用されていません。
- Revised IPv4-compatible address configuration section (5.2) to
recognize multiple interfaces.
- 倍数を認識する改訂されたIPv4コンパチブルアドレス構成節(5.2)は連結します。
Gilligan & Nordmark Standards Track [Page 26] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[26ページ]。
- Added discussion of source address selection when using IPv4-
compatible addresses.
- IPv4コンパチブルアドレスを使用するとき、ソースアドレス選択の議論を加えました。
- Added section on the combination of the default configured
tunneling technique with hosts using automatic tunneling.
- デフォルトの組み合わせの加えられたセクションは、ホストで自動トンネリングを使用することでトンネリングのテクニックを構成しました。
- Added prohibition against automatic tunneling to IPv4 broadcast or
multicast destinations.
- IPv4放送かマルチキャストの目的地への自動トンネリングに対して禁止を加えました。
- Clarified that configured tunnels can be unidirectional or
bidirectional.
- はっきりさせられて、それは、トンネルが単方向か双方向である場合があることを構成しました。
- Added description of bidirectional virtual links as another type
of tunnels. Nodes MUST respond to NUD probes on such links and
SHOULD send NUD probes.
- 別のタイプのトンネルとして双方向の仮想のリンクの記述を加えました。 ノードはそのようなリンクの上にNUD徹底的調査に応じなければなりません、そして、SHOULDは探測装置をNUDに送ります。
- Added reference to [16] specification as an alternative for
tunneling over a multicast capable IPv4 cloud.
- マルチキャストのできるIPv4雲の上でトンネルを堀るための代替手段として[16] 仕様の参照を加えました。
- Clarified that IPv4-compatible addresses are assigned exclusively
to nodes that support automatic tunnels i.e. nodes that can
receive such packets.
- IPv4そんなに互換性があった状態ではっきりさせられて、アドレスは排他的にすなわち、自動トンネルがそのようなパケットを受けることができるノードであることを支えるノードに割り当てられます。
- Added text about formation of link-local addresses and use of
Neighbor Discovery on tunnels.
- リンクローカルのアドレスの構成とトンネルにおけるNeighborディスカバリーの使用に関するテキストを加えました。
- Added restriction that decapsulated packets not be forwarded
unless the source address is acceptable to the decapsulating
router.
- ソースアドレスがdecapsulatingルータに許容できない場合decapsulatedパケットが進められないという制限を加えました。
- Clarified that decapsulating nodes MUST be capable of reassembling
an IPv4 packet that is 1300 bytes (1280 bytes plus IPv4 header).
- はっきりさせられて、そんなにdecapsulatingしているノードは1300バイト(1280バイトとIPv4ヘッダー)であるIPv4パケットを組み立て直すことができなければなりません。
- Clarified that when using a default tunnel to an IPv4 "anycast
address" the network must either have an IPv4 MTU of least 1300
bytes (to avoid fragmentation of minimum size IPv6 packets) or be
configured to avoid frequent changes to IPv4 routing to the
"anycast address" (to avoid different IPv4 fragments arriving at
different tunnel endpoints).
- IPv4「anycastアドレス」にデフォルトトンネルを使用して、ネットワークを最少の1300バイト(最小規模IPv6パケットの断片化を避ける)のIPv4 MTUを持たなければならないか、または「anycastアドレス」としてIPv4ルーティングへの頻繁な変化を避けるために構成しなければならないとき(異なったトンネル終点に到着する異なったIPv4断片を避ける)、それをはっきりさせました。
- Using A6/AAAA instead of AAAA to reference IPv6 address records in
the DNS.
- 参照IPv6アドレスへのAAAAの代わりにA6/AAAAを使用するのはDNSに記録します。
- Specified when to put IPv6 addresses in the DNS.
- いつIPv6アドレスをDNSに入れるかを指定しました。
- Added reference to the tunnel mib for TTL specification for the
tunnels.
- トンネルmibのトンネルのためのTTL仕様の参照を加えました。
Gilligan & Nordmark Standards Track [Page 27] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[27ページ]。
- Added a table of contents.
- 目次を加えました。
- Added recommendations for use of source and target link layer
address options for the tunnel links.
- ソースの使用のための加えられた推薦と目標リンクレイヤはトンネルのリンクのためのオプションを扱います。
- Added checks in the decapsulation checking both an IPv4-compatible
IPv6 source address and the outer IPv4 source addresses for
multicast, broadcast, all-zeros etc.
- IPv4コンパチブルIPv6ソースアドレスと外側のIPv4ソースの両方がマルチキャスト、オールゼロ放送などのために扱う被膜剥離術の照合における加えられたチェック
Gilligan & Nordmark Standards Track [Page 28] RFC 2893 IPv6 Transition Mechanisms August 2000
ギリガンとNordmark規格はIPv6変遷メカニズム2000年8月にRFC2893を追跡します[28ページ]。
11. Full Copyright Statement
11. 完全な著作権宣言文
Copyright (C) The Internet Society (2000). All Rights Reserved.
Copyright(C)インターネット協会(2000)。 All rights reserved。
This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English.
それに関するこのドキュメントと翻訳は、コピーして、それが批評するか、またはそうでなければわかる他のもの、および派生している作品に提供するか、または準備されているかもしれなくて、コピーされて、発行されて、全体か一部分配された実装を助けるかもしれません、どんな種類の制限なしでも、上の版権情報とこのパラグラフがそのようなすべてのコピーと派生している作品の上に含まれていれば。 しかしながら、このドキュメント自体は何らかの方法で変更されないかもしれません、インターネット協会か他のインターネット組織の版権情報か参照を取り除くのなどように、それを英語以外の言語に翻訳するのが著作権のための手順がインターネットStandardsプロセスで定義したどのケースに従わなければならないか、必要に応じてさもなければ、インターネット標準を開発する目的に必要であるのを除いて。
The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns.
上に承諾された限られた許容は、永久であり、インターネット協会、後継者または案配によって取り消されないでしょう。
This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
このドキュメントとそして、「そのままで」という基礎とインターネットの振興発展を目的とする組織に、インターネット・エンジニアリング・タスク・フォースが速達の、または、暗示しているすべての保証を放棄するかどうかというここにことであり、他を含んでいて、含まれて、情報の使用がここに侵害しないどんな保証も少しもまっすぐになるという情報か市場性か特定目的への適合性のどんな黙示的な保証。
Acknowledgement
承認
Funding for the RFC Editor function is currently provided by the Internet Society.
RFC Editor機能のための基金は現在、インターネット協会によって提供されます。
Gilligan & Nordmark Standards Track [Page 29]
ギリガンとNordmark標準化過程[29ページ]
一覧
スポンサーリンク
