Network Working Group P. Marques
Request for Comments: 2545 cisco Systems, Inc.
Category: Standards Track F. Dupont
Inria
March 1999
Network Working Group P. Marques
Request for Comments: 2545 cisco Systems, Inc.
Category: Standards Track F. Dupont
Inria
March 1999
Use of BGP-4 Multiprotocol Extensions for IPv6 Inter-Domain Routing
使用BGP-4多协议扩展进行IPv6域间路由
Status of this Memo
本备忘录的状况
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.
本文件规定了互联网社区的互联网标准跟踪协议，并要求进行讨论和提出改进建议。有关本协议的标准化状态和状态，请参考当前版本的“互联网官方协议标准”（STD 1）。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (1999). All Rights Reserved.
版权所有（C）互联网协会（1999年）。版权所有。
Abstract
摘要
BGP-4 Multiprotocol Extensions [BGP-MP] defines the format of two BGP attributes (MP_REACH_NLRI and MP_UNREACH_NLRI) that can be used to announce and withdraw the announcement of reachability information. This document defines how compliant systems should make use of those attributes for the purpose of conveying IPv6 routing information.
BGP-4多协议扩展[BGP-MP]定义了两个BGP属性（MP_REACH_NLRI和MP_UNREACH_NLRI）的格式，可用于宣布和撤销可达性信息的宣布。本文档定义了兼容系统应如何利用这些属性来传输IPv6路由信息。
The BGP-4 protocol [BGP-4] in particular, and path vector routing protocols in general, are mostly independent of the particular Address Family for which the protocol is being used.
尤其是BGP-4协议[BGP-4]，以及一般的路径向量路由协议，大多独立于使用该协议的特定地址族。
IPv6 falls under the generic category of protocols for which BGP-4 is suitable and, unless stated otherwise in this document, the BGP-4 procedures to apply when using BGP-4 to carry IPv6 reachability information are those defined in [BGP-4] and in subsequent documents that extend or update the BGP-4 specification.
IPv6属于BGP-4适用的协议的一般类别，除非本文件另有规定，否则使用BGP-4携带IPv6可达性信息时适用的BGP-4程序是[BGP-4]和扩展或更新BGP-4规范的后续文件中定义的程序。
In terms of routing information, the most significant difference between IPv6 and IPv4 (for which BGP was originally designed) is the fact that IPv6 introduces scoped unicast addresses and defines particular situations when a particular address scope must be used. This document concerns itself essentially with the necessary rules to accommodate IPv6 address scope requirements.
就路由信息而言，IPv6和IPv4（BGP最初是为其设计的）之间最显著的区别在于IPv6引入了作用域单播地址，并定义了必须使用特定地址作用域的特定情况。本文档主要涉及满足IPv6地址范围要求的必要规则。
IPv6 defines 3 unicast address scopes [ADDR-ARCH]: global, site-local and link-local. Site-local addresses are non-link-local address which are valid within the scope of a "site" and cannot be exported beyond it. As this document makes no assumption on the characteristics of a particular routing realm where BGP-4 is used, it makes no distinction between global and site-local addresses and refers to both as "global" or "non-link-local". Network administrators must however respect address scope restrictions and should be aware that the concepts of a BGP-4 routing domain and "site" are orthogonal notions and that they may or may not coincide in a given situation.
IPv6定义了3个单播地址范围[ADDR-ARCH]：全局、站点本地和链路本地。站点本地地址是在“站点”范围内有效的非链接本地地址，不能导出到“站点”之外。由于本文件未对使用BGP-4的特定路由领域的特征进行假设，因此不区分全局地址和站点本地地址，并将其称为“全局”或“非链路本地”。然而，网络管理员必须尊重地址范围限制，并应意识到BGP-4路由域和“站点”的概念是正交的概念，在给定情况下它们可能一致，也可能不一致。
Companion IPv6 specifications further define that only link-local address can be used when generating ICMP Redirect Messages [ND] and as next hop addresses in some routing protocols (eg. RIPng [RIP]).
伴随的IPv6规范进一步定义，在某些路由协议（如RIPng[RIP]）中，在生成ICMP重定向消息[ND]和作为下一跳地址时，只能使用链路本地地址。
This restrictions does imply that an IPv6 router must have a link-local next hop address for all directly connected routes (routes for which the given router and the next hop router share a common subnet prefix).
此限制确实意味着IPv6路由器必须为所有直接连接的路由（给定路由器和下一跳路由器共享公共子网前缀的路由）提供链路本地下一跳地址。
Link-local addresses are not, however, well suited to be used as next hop attributes in BGP-4 given the rules defined for this attribute in the protocol specification [BGP-4].
然而，鉴于协议规范[BGP-4]中为该属性定义的规则，链路本地地址并不适合用作BGP-4中的下一跳属性。
For the above reasons, when BGP-4 is used to convey IPv6 reachability information it is sometimes necessary to announce a next hop attribute that consists of a global address and a link-local address. The following section describes the rules that should be followed when constructing the Network Address of Next Hop field of an MP_REACH_NLRI attribute.
出于上述原因，当使用BGP-4传输IPv6可达性信息时，有时需要宣布下一跳属性，该属性由全局地址和链路本地地址组成。以下部分描述了在构造MP_REACH_NLRI属性的下一跳网络地址字段时应遵循的规则。
A BGP speaker shall advertise to its peer in the Network Address of Next Hop field the global IPv6 address of the next hop, potentially followed by the link-local IPv6 address of the next hop.
BGP演讲者应在下一跃点的网络地址字段中向其对等方公布下一跃点的全局IPv6地址，随后可能是下一跃点的链路本地IPv6地址。
The value of the Length of Next Hop Network Address field on a MP_REACH_NLRI attribute shall be set to 16, when only a global address is present, or 32 if a link-local address is also included in the Next Hop field.
当仅存在全局地址时，MP_REACH_NLRI属性上的下一跳网络地址长度字段的值应设置为16，如果下一跳字段中还包括链路本地地址，则应设置为32。
The link-local address shall be included in the Next Hop field if and only if the BGP speaker shares a common subnet with the entity identified by the global IPv6 address carried in the Network Address of Next Hop field and the peer the route is being advertised to.
当且仅当BGP扬声器与下一跳网络地址字段中携带的全局IPv6地址所标识的实体共享一个公共子网时，链路本地地址应包含在下一跳字段中，并且该路由将被通告给对等方。
In all other cases a BGP speaker shall advertise to its peer in the Network Address field only the global IPv6 address of the next hop (the value of the Length of Network Address of Next Hop field shall be set to 16).
在所有其他情况下，BGP扬声器应在网络地址字段中仅向其对等方公布下一跳的全局IPv6地址（下一跳的网络地址长度字段的值应设置为16）。
As a consequence, a BGP speaker that advertises a route to an internal peer may modify the Network Address of Next Hop field by removing the link-local IPv6 address of the next hop.
因此，播发到内部对等方的路由的BGP扬声器可以通过删除下一跳的链路本地IPv6地址来修改下一跳的网络地址字段。
TCP connections, on top of which BGP-4 messages are exchanged, can be established either over IPv4 or IPv6. While BGP-4 itself is independent of the particular transport used it derives implicit configuration information from the address used to establish the peering session. This information (the network address of a peer) is taken in account in the route dissemination procedure. Thus, when using TCP over IPv4 as a transport for IPv6 reachability information, additional explicit configuration of the peer's network address is required.
TCP连接可以通过IPv4或IPv6建立，在此基础上交换BGP-4消息。虽然BGP-4本身独立于所使用的特定传输，但它从用于建立对等会话的地址派生隐式配置信息。该信息（对等方的网络地址）将在路由传播过程中考虑在内。因此，当使用IPv4上的TCP作为IPv6可达性信息的传输时，需要对对等方的网络地址进行额外的显式配置。
Note that the information referred above is distinct from the BGP Identifier used in the BGP-4 tie breaking procedure. The BGP Identifier is a 32 bit unsigned integer exchanged between two peers at session establishment time, within an OPEN message. This is a system wide value determined at startup which must be unique in the network and should be derived from an IPv4 address regardless of the network protocol(s) a particular BGP-4 instance is configured to convey at a given moment.
请注意，上述信息不同于BGP-4断连程序中使用的BGP标识符。BGP标识符是在会话建立时在开放消息中的两个对等方之间交换的32位无符号整数。这是在启动时确定的系统范围内的值，该值在网络中必须是唯一的，并且应该从IPv4地址派生，而不考虑特定BGP-4实例在给定时刻配置为传输的网络协议。
The use of TCP over IPv6 as transport protocol for IPv6 reachability information also has the advantage of providing explicit confirmation of IPv6 network reachability between two peers.
使用TCP over IPv6作为IPv6可达性信息的传输协议还具有提供两个对等方之间IPv6网络可达性的明确确认的优势。
The extensions defined in this document allow BGP to propagate reachability information about IPv6 routes. As such, no new security issues are raised beyond those that already exist in BGP-4 and its use with IPv4.
本文档中定义的扩展允许BGP传播有关IPv6路由的可达性信息。因此，除了BGP-4及其与IPv4的配合使用中已经存在的安全问题外，没有提出任何新的安全问题。
This document derives from the work on BGP-4 Multiprotocol Extensions by Tony Bates, Ravi Chandra, Dave Katz and Yakov Rekhter.
本文档来源于Tony Bates、Ravi Chandra、Dave Katz和Yakov Rekhter关于BGP-4多协议扩展的工作。
[ADDR-ARCH] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 2373, July 1998.
[ADDR-ARCH]Hinden，R.和S.Deering，“IP版本6寻址体系结构”，RFC 23731998年7月。
[BGP-4] Rekhter, Y. and T. Li, "A Border Gateway Protocol 4 (BGP-4)", RFC 1771, March 1995.
[BGP-4]Rekhter，Y.和T.Li，“边境网关协议4（BGP-4）”，RFC 17711995年3月。
[BGP-MP] Bates, T., Chandra, R., Katz, D. and Y. Rekhter, "Multiprotocol Extensions for BGP-4", RFC 2283, February 1998.
[BGP-MP]Bates，T.，Chandra，R.，Katz，D.和Y.Rekhter，“BGP-4的多协议扩展”，RFC 2283，1998年2月。
[IPv6] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", RFC 2460, December 1998.
[IPv6]Deering，S.和R.Hinden，“互联网协议，第6版（IPv6）规范”，RFC 2460，1998年12月。
[ND] Narten, T., Nordmark, E. and W. Simpson, "Neighbor Discovery for IP Version 6 (IPv6)", RFC 2461, December 1998.
[ND]Narten，T.，Nordmark，E.和W.Simpson，“IP版本6（IPv6）的邻居发现”，RFC24611998年12月。
[RIP] Malkin, G. and R. Minnear, "RIPng for IPv6", RFC 2080, January 1997.
[RIP]Malkin，G.和R.Minnear，“IPv6的RIPng”，RFC 20801997年1月。
Pedro R. Marques cisco Systems, Inc. 170 W. Tasman Dr. San Jose, CA 95134 USA
Pedro R.Marques cisco Systems，Inc.170 W.Tasman Dr.San Jose，CA 95134美国
Phone: +1 408 527-5202
Fax: +1 408 526-4952
EMail: roque@cisco.com
Phone: +1 408 527-5202
Fax: +1 408 526-4952
EMail: roque@cisco.com
Francis Dupont GIE DYADE INRIA Rocquencourt Domaine de Voluceau BP 105 78153 Le Chesnay CEDEX FRANCE
弗朗西斯·杜邦（Francis Dupont）在法国沃卢西奥庄园（BP 105 78153 Le Chesnay CEDEX FRANCE）
Phone: +33 1 39 63 52 13
Fax: +33 1 39 63 58 66
EMail: Francis.Dupont@inria.fr
Phone: +33 1 39 63 52 13
Fax: +33 1 39 63 58 66
EMail: Francis.Dupont@inria.fr
Copyright (C) The Internet Society (1999). All Rights Reserved.
版权所有（C）互联网协会（1999年）。版权所有。
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