Network Working Group                                      J. Kempf, Ed.
Request for Comments: 3724                               R. Austein, Ed.
Category: Informational                                              IAB
                                                              March 2004
Network Working Group                                      J. Kempf, Ed.
Request for Comments: 3724                               R. Austein, Ed.
Category: Informational                                              IAB
                                                              March 2004

The Rise of the Middle and the Future of End-to-End: Reflections on the Evolution of the Internet Architecture


Status of this Memo


This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.


Copyright Notice


Copyright (C) The Internet Society (2004). All Rights Reserved.




The end-to-end principle is the core architectural guideline of the Internet. In this document, we briefly examine the development of the end-to-end principle as it has been applied to the Internet architecture over the years. We discuss current trends in the evolution of the Internet architecture in relation to the end-to-end principle, and try to draw some conclusion about the evolution of the end-to-end principle, and thus for the Internet architecture which it supports, in light of these current trends.


Table of Contents


   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
   2.  A Brief History of the End-to-End Principle. . . . . . . . . .  2
   3.  Trends Opposed to the End-to-End Principle . . . . . . . . . .  5
   4.  Whither the End-to-End Principle?. . . . . . . . . . . . . . .  8
   5.  Internet Standards as an Arena for Conflict. . . . . . . . . . 10
   6.  Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . 11
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
   8.  Security Considerations. . . . . . . . . . . . . . . . . . . . 12
   9.  Informative References . . . . . . . . . . . . . . . . . . . . 12
   10. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 13
   11. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 14
   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
   2.  A Brief History of the End-to-End Principle. . . . . . . . . .  2
   3.  Trends Opposed to the End-to-End Principle . . . . . . . . . .  5
   4.  Whither the End-to-End Principle?. . . . . . . . . . . . . . .  8
   5.  Internet Standards as an Arena for Conflict. . . . . . . . . . 10
   6.  Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . 11
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11
   8.  Security Considerations. . . . . . . . . . . . . . . . . . . . 12
   9.  Informative References . . . . . . . . . . . . . . . . . . . . 12
   10. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 13
   11. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 14
1. Introduction
1. 介绍

One of the key architectural guidelines of the Internet is the end-to-end principle in the papers by Saltzer, Reed, and Clark [1][2]. The end-to-end principle was originally articulated as a question of where best not to put functions in a communication system. Yet, in the ensuing years, it has evolved to address concerns of maintaining openness, increasing reliability and robustness, and preserving the properties of user choice and ease of new service development as discussed by Blumenthal and Clark in [3]; concerns that were not part of the original articulation of the end-to-end principle.


In this document, we examine how the interpretation of the end-to-end principle has evolved over the years, and where it stands currently. We examine trends in the development of the Internet that have led to pressure to define services in the network, a topic that has already received some amount of attention from the IAB in RFC 3238 [5]. We describe some considerations about how the end-to-end principle might evolve in light of these trends.

在本文件中,我们将研究多年来对端到端原则的解释是如何演变的,以及它目前所处的位置。我们研究了互联网发展的趋势,这些趋势导致了在网络中定义服务的压力,这一主题在RFC 3238[5]中已经受到了IAB的一些关注。我们描述了一些关于端到端原则如何根据这些趋势发展的考虑。

2. A Brief History of the End-to-End Principle
2. 端到端原则的简史

2.1. In the Beginning...

2.1. 一开始

The end-to-end principle was originally articulated as a question of where best to put functions in a communication system:


The function in question can completely and correctly be implemented only with the knowledge and help of the application standing at the end points of the communication system. Therefore, providing that questioned function as a feature of the communication system itself is not possible. (Sometimes an incomplete version of the function provided by the communication system may be useful as a performance enhancement.) [1].


A specific example of such a function is delivery guarantees [1]. The original ARPANET returned a message "Request for Next Message" whenever it delivered a packet. Although this message was found to be useful within the network as a form of congestion control, since the ARPANET refused to accept another message to the same destination until the previous acknowledgment was returned, it was never particularly useful as an indication of guaranteed delivery. The problem was that the host stack on the sending host typically doesn't want to know just that the network delivered a packet, but rather the stack layer on the sending host wants to know that the stack layer on the receiving host properly processed the packet. In terms of modern IP stack structure, a reliable transport layer requires an indication that transport processing has successfully completed, such as given


by TCP's ACK message [4], and not simply an indication from the IP layer that the packet arrived. Similarly, an application layer protocol may require an application-specific acknowledgement that contains, among other things, a status code indicating the disposition of the request.


The specific examples given in [1] and other references at the time [2] primarily involve transmission of data packets: data integrity, delivery guarantees, duplicate message suppression, per packet encryption, and transaction management. From the viewpoint of today's Internet architecture, we would view most of these as transport layer functions (data integrity, delivery guarantees, duplicate message suppression, and perhaps transaction management), others as network layer functions with support at other layers where necessary (for example, packet encryption), and not application layer functions.


2.2. ...In the Middle...

2.2. 在中间

As the Internet developed, the end-to-end principle gradually widened to concerns about where best to put the state associated with applications in the Internet: in the network or at end nodes. The best example is the description in RFC 1958 [6]:

随着互联网的发展,端到端原则逐渐扩大到关注与互联网中的应用程序相关联的状态的最佳位置:在网络中还是在终端节点。最好的例子是RFC 1958[6]中的描述:

This principle has important consequences if we require applications to survive partial network failures. An end-to-end protocol design should not rely on the maintenance of state (i.e., information about the state of the end-to-end communication) inside the network. Such state should be maintained only in the endpoints, in such a way that the state can only be destroyed when the endpoint itself breaks (known as fate-sharing). An immediate consequence of this is that datagrams are better than classical virtual circuits. The network's job is to transmit datagrams as efficiently and flexibly as possible. Everything else should be done at the fringes.


The original articulation of the end-to-end principle - that knowledge and assistance of the end point is essential and that omitting such knowledge and implementing a function in the network without such knowledge and assistance is not possible - took a while to percolate through the engineering community, and had evolved by this point to a broad architectural statement about what belongs in the network and what doesn't. RFC 1958 uses the term "application" to mean the entire network stack on the end node, including network, transport, and application layers, in contrast to the earlier articulation of the end-to-end principle as being about the communication system itself. "Fate-sharing" describes this quite clearly: the fate of a conversation between two applications is only

端到端原则的最初表述——端点的知识和协助是必不可少的,在没有此类知识和协助的情况下,省略此类知识和在网络中实现功能是不可能的——花了一段时间才渗透到工程界,到目前为止,它已经发展成为一个关于什么属于网络和什么不属于网络的广泛的体系结构声明。RFC 1958使用术语“应用程序”来表示终端节点上的整个网络堆栈,包括网络、传输和应用层,这与先前关于通信系统本身的端到端原则的表述不同。“命运共享”非常清楚地描述了这一点:两个应用程序之间的对话的命运只是

shared between the two applications; the fate does not depend on anything in the network, except for the network's ability to get packets from one application to the other.


The end-to-end principle in this formulation is specifically about what kind of state is maintained where:


To perform its services, the network maintains some state information: routes, QoS guarantees that it makes, session information where that is used in header compression, compression histories for data compression, and the like. This state must be self-healing; adaptive procedures or protocols must exist to derive and maintain that state, and change it when the topology or activity of the network changes. The volume of this state must be minimized, and the loss of the state must not result in more than a temporary denial of service given that connectivity exists. Manually configured state must be kept to an absolute minimum.[6]


In this formulation of the end-to-end principle, state involved in getting packets from one end of the network to the other is maintained in the network. The state is "soft state," in the sense that it can be quickly dropped and reconstructed (or even required to be periodically renewed) as the network topology changes due to routers and switches going on and off line. "Hard state", state upon which the proper functioning of the application depends, is only maintained in the end nodes. This formulation of the principle is a definite change from the original formulation of the principle, about end node participation being required for proper implementation of most functions.


In summary, the general awareness both of the principle itself and of its implications for how unavoidable state should be handled grew over time to become a (if not the) foundation principle of the Internet architecture.


2.3. ...And Now.

2.3. …现在。

An interesting example of how the end-to-end principle continues to influence the technical debate in the Internet community is IP mobility. The existing Internet routing architecture severely constrains how closely IP mobility can match the end-to-end principle without making fundamental changes. Mobile IPv6, described in the Mobile IPv6 specification by Johnson, Perkins, and Arkko [7], requires a routing proxy in the mobile node's home network (the Home Agent) for maintaining the mapping between the mobile node's routing locator, the care of address, and the mobile node's node identifier, the home address. But the local subnet routing proxy (the Foreign Agent), which was a feature of the older Mobile IPv4 design [8] that


compromised end-to-end routing, has been eliminated. The end node now handles its own care of address. In addition, Mobile IPv6 includes secure mechanisms for optimizing routing to allow end-to-end routing between the mobile end node and the correspondent node, removing the need to route through the global routing proxy at the home agent. These features are all based on end to end considerations. However, the need for the global routing proxy in the Home Agent in Mobile IPv6 is determined by the aliasing of the global node identifier with the routing identifier in the Internet routing architecture, a topic that was discussed in an IAB workshop and reported in RFC 2956 [9], and that hasn't changed in IPv6.

已消除受损的端到端路由。结束节点现在处理自己的转交地址。此外,移动IPv6包括用于优化路由的安全机制,以允许在移动端节点和对应节点之间进行端到端路由,从而消除了在归属代理处通过全局路由代理进行路由的需要。这些特性都基于端到端的考虑。然而,移动IPv6中归属代理中对全局路由代理的需求是由全局节点标识符与Internet路由体系结构中的路由标识符的别名决定的,这一主题在IAB研讨会上讨论过,并在RFC 2956[9]中报告过,在IPv6中没有改变。

Despite this constraint, the vision emerging out of the IETF working groups developing standards for mobile networking is of a largely autonomous mobile node with multiple wireless link options, among which the mobile node picks and chooses. The end node is therefore responsible for maintaining the integrity of the communication, as the end-to-end principle implies. This kind of innovative application of the end-to-end principle derives from the same basic considerations of reliability and robustness (wireless link integrity, changes in connectivity and service availability with movement, etc.) that motivated the original development of the end-to-end principle. While the basic reliability of wired links, routing, and switching equipment has improved considerably since the end-to-end principle was formalized 15 years ago, the reliability or unreliability of wireless links is governed more strongly by the basic physics of the medium and the instantaneous radio propagation conditions.


3. Trends Opposed to the End-to-End Principle
3. 与端到端原则相反的趋势

While the end-to-end principle continues to provide a solid foundation for much IETF design work, the specific application of the end-to-end principle described in RFC 1958 has increasingly come into question from various directions. The IAB has been concerned about trends opposing the end-to-end principle for some time, for example RFC 2956 [9] and RFC 2775 [12]. The primary focus of concern in these documents is the reduction in transparency due to the introduction of NATs and other address translation mechanisms in the Internet, and the consequences to the end-to-end principle of various scenarios involving full, partial, or no deployment of IPv6. More recently, the topic of concern has shifted to the consequences of service deployment in the network. The IAB opinion on Open Pluggable Edge Services (OPES) in RFC 3238 [5] is intended to assess the architectural desirability of defining services in the network and to raise questions about how such services might result in compromises

虽然端到端的原理继续为IETF的许多设计工作提供坚实的基础,但是在RFC 1958中描述的端到端原理的具体应用越来越受到各个方向的质疑。一段时间以来,IAB一直关注反对端到端原则的趋势,例如RFC 2956[9]和RFC 2775[12]。这些文件中主要关注的焦点是由于在互联网中引入NAT和其他地址转换机制而导致的透明度降低,以及涉及完全、部分或不部署IPv6的各种场景对端到端原则的影响。最近,关注的话题已经转移到网络中服务部署的后果上。RFC 3238[5]中IAB关于开放式可插拔边缘服务(OPE)的意见旨在评估在网络中定义服务的体系结构可取性,并提出有关此类服务如何导致妥协的问题

of privacy, security, and end-to-end data integrity. Clark, et al. in [10] and Carpenter in RFC 3234 [11] also take up the topic of service definition in the network.

隐私、安全和端到端数据完整性。Clark等人在[10]和Carpenter在RFC 3234[11]中也讨论了网络中的服务定义。

Perhaps the best review of the forces militating against the end-to-end principle is by Blumenthal and Clark in [3]. The authors make the point that the Internet originally developed among a community of like-minded technical professionals who trusted each other, and was administered by academic and government institutions who enforced a policy of no commercial use. The major stakeholders in the Internet are quite different today. As a consequence, new requirements have evolved over the last decade. Examples of these requirements are discussed in the following subsections. Other discussions about pressures on the end-to-end principle in today's Internet can be found in the discussion by Reed [13] and Moors' paper in the 2002 IEEE International Communications Conference [14].


3.1. Need for Authentication
3.1. 认证的需要

Perhaps the single most important change from the Internet of 15 years ago is the lack of trust between users. Because the end users in the Internet of 15 years ago were few, and were largely dedicated to using the Internet as a tool for academic research and communicating research results (explicit commercial use of the Internet was forbidden when it was run by the US government), trust between end users (and thus authentication of end nodes that they use) and between network operators and their users was simply not an issue in general. Today, the motivations of some individuals using the Internet are not always entirely ethical, and, even if they are, the assumption that end nodes will always co-operate to achieve some mutually beneficial action, as implied by the end-to-end principle, is not always accurate. In addition, the growth in users who are either not technologically sophisticated enough or simply uninterested in maintaining their own security has required network operators to become more proactive in deploying measures to prevent naive or uninterested users from inadvertently or intentionally generating security problems.


While the end-to-end principle does not require that users implicitly trust each other, the lack of trust in the Internet today requires that application and system designers make a choice about how to handle authentication, whereas that choice was rarely apparent 15 years ago. One of the most common examples of network elements interposing between end hosts are those dedicated to security: firewalls, VPN tunnel endpoints, certificate servers, etc. These intermediaries are designed to protect the network from unimpeded attack or to allow two end nodes whose users may have no inherent reason to trust each other to achieve some level of authentication.


At the same time, these measures act as impediments for end-to-end communications. Third party trust intermediaries are not a requirement for security, as end-to-end security mechanisms, such as S/MIME [15], can be used instead, and where third party measures such as PKI infrastructure or keys in DNS are utilized to exchange keying material, they don't necessarily impinge on end-to-end traffic after authentication has been achieved. Even if third parties are involved, ultimately it is up to the endpoints and their users in particular, to determine which third parties they trust.


3.2. New Service Models
3.2. 新服务模式

New service models inspired by new applications require achieving the proper performance level as a fundamental part of the delivered service. These service models are a significant change from the original best effort service model. Email, file transfer, and even Web access aren't perceived as failing if performance degrades, though the user may become frustrated at the time required to complete the transaction. However, for streaming audio and video, to say nothing of real time bidirectional voice and video, achieving the proper performance level, whatever that might mean for an acceptable user experience of the service, is part of delivering the service, and a customer contracting for the service has a right to expect the level of performance for which they have contracted. For example, content distributors sometimes release content via content distribution servers that are spread around the Internet at various locations to avoid delays in delivery if the server is topologically far away from the client. Retail broadband and multimedia services are a new service model for many service providers.


3.3. Rise of the Third Party
3.3. 第三方崛起

Academic and government institutions ran the Internet of 15 years ago. These institutions did not expect to make a profit from their investment in networking technology. In contrast, the network operator with which most Internet users deal today is the commercial ISP. Commercial ISPs run their networks as a business, and their investors rightly expect the business to turn a profit. This change in business model has led to a certain amount of pressure on ISPs to increase business prospects by deploying new services.


In particular, the standard retail dialup bit pipe account with email and shell access has become a commodity service, resulting in low profit margins. While many ISPs are happy with this business model and are able to survive on it, others would like to deploy different service models that have a higher profit potential and provide the customer with more or different services. An example is retail broadband bit pipe access via cable or DSL coupled with streaming


multimedia. Some ISPs that offer broadband access also deploy content distribution networks to increase the performance of streaming media. These services are typically deployed so that they are only accessible within the ISP's network, and as a result, they do not contribute to open, end-to-end service. From an ISP's standpoint, however, offering such service is an incentive for customers to buy the ISP's service.


ISPs are not the only third party intermediary that has appeared within the last 10 years. Unlike the previous involvement of corporations and governments in running the Internet, corporate network administrators and governmental officials have become increasingly demanding of opportunities to interpose between two parties in an end-to-end conversation. A benign motivation for this involvement is to mitigate the lack of trust, so the third party acts as a trust anchor or enforcer of good behavior between the two ends. A less benign motivation is for the third parties to insert policy for their own reasons, perhaps taxation or even censorship. The requirements of third parties often have little or nothing to do with technical concerns, but rather derive from particular social and legal considerations.


4. Whither the End-to-End Principle?
4. 端到端原则在哪里?

Given the pressures on the end-to-end principle discussed in the previous section, a question arises about the future of the end-to-end principle. Does the end-to-end principle have a future in the Internet architecture or not? If it does have a future, how should it be applied? Clearly, an unproductive approach to answering this question is to insist upon the end-to-end principle as a fundamentalist principle that allows no compromise. The pressures described above are real and powerful, and if the current Internet technical community chooses to ignore these pressures, the likely result is that a market opportunity will be created for a new technical community that does not ignore these pressures but which may not understand the implications of their design choices. A more productive approach is to return to first principles and re-examine what the end-to-end principle is trying to accomplish, and then update our definition and exposition of the end-to-end principle given the complexities of the Internet today.


4.1. Consequences of the End-to-End Principle
4.1. 端到端原则的后果

In this section, we consider the two primary desirable consequences of the end-to-end principle: protection of innovation and provision of reliability and robustness.


4.1.1. Protection of Innovation
4.1.1. 保护创新

One desirable consequence of the end-to-end principle is protection of innovation. Requiring modification in the network in order to deploy new services is still typically more difficult than modifying end nodes. The counterargument - that many end nodes are now essentially closed boxes which are not updatable and that most users don't want to update them anyway - does not apply to all nodes and all users. Many end nodes are still user configurable and a sizable percentage of users are "early adopters," who are willing to put up with a certain amount of technological grief in order to try out a new idea. And, even for the closed boxes and uninvolved users, downloadable code that abides by the end-to-end principle can provide fast service innovation. Requiring someone with a new idea for a service to convince a bunch of ISPs or corporate network administrators to modify their networks is much more difficult than simply putting up a Web page with some downloadable software implementing the service.


4.1.2. Reliability and Trust
4.1.2. 可靠性和信任

Of increasing concern today, however, is the decrease in reliability and robustness that results from deliberate, active attacks on the network infrastructure and end nodes. While the original developers of the Internet were concerned by large-scale system failures, attacks of the subtlety and variety that the Internet experiences today were not a problem during the original development of the Internet. By and large, the end-to-end principle was not addressed to the decrease in reliability resulting from attacks deliberately engineered to take advantage of subtle flaws in software. These attacks are part of the larger issue of the trust breakdown discussed in Section 3.1. Thus, the issue of the trust breakdown can be considered another forcing function on the Internet architecture.


The immediate reaction to this trust breakdown has been to try to back fit security into existing protocols. While this effort is necessary, it is not sufficient. The issue of trust must become as firm an architectural principle in protocol design for the future as the end-to-end principle is today. Trust isn't simply a matter of adding some cryptographic protection to a protocol after it is designed. Rather, prior to designing the protocol, the trust relationships between the network elements involved in the protocol must be defined, and boundaries must be drawn between those network elements that share a trust relationship. The trust boundaries should be used to determine what type of communication occurs between the network elements involved in the protocol and which network elements signal each other. When communication occurs across a trust boundary, cryptographic or other security protection of some sort may


be necessary. Additional measures may be necessary to secure the protocol when communicating network elements do not share a trust relationship. For example, a protocol might need to minimize state in the recipient prior to establishing the validity of the credentials from the sender in order to avoid a memory depletion DoS attack.


4.2. The End-to-End Principle in Applications Design
4.2. 应用程序设计中的端到端原则

The concern expressed by the end-to-end principle is applicable to applications design too. Two key points in designing application protocols are to ensure they don't have any dependencies that would break the end-to-end principle and to ensure that they can identify end points in a consistent fashion. An example of the former is layer violations - creating dependencies that would make it impossible for the transport layer, for example, to do its work appropriately. Another issue is the desire to insert more applications infrastructure into the network. Architectural considerations around this issue are discussed in RFC 3238 [5]. This desire need not result in a violation of the end-to-end principle if the partitioning of functioning is done so that services provided in the network operate with the explicit knowledge and involvement of endpoints, when such knowledge and involvement is necessary for the proper functioning of the service. The result becomes a distributed application, in which the end-to-end principle applies to each connection involved in implementing the application.

端到端原则所表达的担忧也适用于应用程序设计。设计应用程序协议的两个关键点是确保它们没有任何会破坏端到端原则的依赖关系,并确保它们能够以一致的方式识别端点。前者的一个例子是层冲突——例如,创建依赖项会使传输层无法适当地执行其工作。另一个问题是希望在网络中插入更多的应用程序基础设施。RFC 3238[5]中讨论了围绕此问题的体系结构考虑。如果功能划分是为了使网络中提供的服务在端点的明确知识和参与下运行,而这种知识和参与对于服务的正常运行是必要的,则这种愿望不必导致违反端到端原则。结果变成了一个分布式应用程序,其中端到端原则适用于实现应用程序所涉及的每个连接。

5. Internet Standards as an Arena for Conflict
5. 作为冲突舞台的互联网标准

Internet standards have increasingly become an arena for conflict [10]. ISPs have certain concerns, businesses and government have others, and vendors of networking hardware and software still others. Often, these concerns conflict, and sometimes they conflict with the concerns of the end users. For example, ISPs are reluctant to deploy interdomain QoS services because, among other reasons, every known instance creates a significant and easily exploited DoS/DDoS vulnerability. However, some end users would like to have end-to-end, Diffserv or Intserv-style QoS available to improve support for voice and video multimedia applications between end nodes in different domains, as discussed by Huston in RFC 2990 [16]. In this case, the security, robustness, and reliability concerns of the ISP conflict with the desire of users for a different type of service.

互联网标准日益成为冲突的舞台[10]。ISP有某些顾虑,企业和政府有其他顾虑,网络硬件和软件供应商还有其他顾虑。通常,这些关注点会发生冲突,有时还会与最终用户的关注点发生冲突。例如,ISP不愿意部署域间QoS服务,因为除其他原因外,每个已知实例都会产生一个重要且易于利用的DoS/DDoS漏洞。然而,正如Huston在RFC 2990[16]中所讨论的,一些终端用户希望提供端到端、区分服务或Intserv风格的QoS,以改善对不同域中终端节点之间语音和视频多媒体应用程序的支持。在这种情况下,ISP的安全性、健壮性和可靠性问题与用户对不同类型服务的需求相冲突。

These conflicts will inevitably be reflected in the Internet architecture going forward. Some of these conflicts are impossible to resolve on a technical level, and would not even be desirable, because they involve social and legal choices that the IETF is not empowered to make (for a counter argument in the area of privacy, see


Goldberg, et al. [17]). But for those conflicts that do involve technical choices, the important properties of user choice and empowerment, reliability and integrity of end-to-end service, supporting trust and "good network citizen behavior," and fostering innovation in services should be the basis upon which resolution is made. The conflict will then play out on the field of the resulting architecture.


6. Conclusions
6. 结论

The end-to-end principle continues to guide technical development of Internet standards, and remains as important today for the Internet architecture as in the past. In many cases, unbundling of the end-to-end principle into its consequences leads to a distributed approach in which the end-to-end principle applies to interactions between the individual pieces of the application, while the unbundled consequences, protection of innovation, reliability, and robustness, apply to the entire application. While the end-to-end principle originated as a focused argument about the need for the knowledge and assistance of end nodes to properly implement functions in a communication system, particular second order properties developed by the Internet as a result of the end-to-end principle have come to be recognized as being as important, if not more so, than the principle itself. End user choice and empowerment, integrity of service, support for trust, and "good network citizen behavior" are all properties that have developed as a consequence of the end-to-end principle. Recognizing these properties in a particular proposal for modifications to the Internet has become more important than before as the pressures to incorporate services into the network have increased. Any proposal to incorporate services in the network should be weighed against these properties before proceeding.


7. Acknowledgements
7. 致谢

Many of the ideas presented here originally appeared in the works of Dave Clark, John Wroclawski, Bob Braden, Karen Sollins, Marjory Blumenthal, and Dave Reed on forces currently influencing the evolution of the Internet. The authors would particularly like to single out the work of Dave Clark, who was the original articulator of the end-to-end principle and who continues to inspire and guide the evolution of the Internet architecture, and John Wroclawski, with whom conversations during the development of this paper helped to clarify issues involving tussle and the Internet.

这里提出的许多想法最初出现在戴夫·克拉克、约翰·沃克罗夫斯基、鲍勃·布拉登、卡伦·索林斯、马乔里·布卢门塔尔和戴夫·里德关于当前影响互联网发展的力量的著作中。作者特别想挑出Dave Clark和John Wroclawski的作品,Dave Clark是端到端原则的最初阐述者,他继续激励和指导互联网架构的发展,在这篇论文的撰写过程中,与谁的对话有助于澄清涉及争斗和互联网的问题。

8. Security Considerations
8. 安全考虑

This document does not propose any new protocols, and therefore does not involve any security considerations in that sense. However, throughout this document, there are discussions of the privacy and integrity issues and the architectural requirements created by those issues.


9. Informative References
9. 资料性引用

[1] Saltzer, J.H., Reed, D.P., and Clark, D.D., "End-to-End Arguments in System Design," ACM TOCS, Vol 2, Number 4, November 1984, pp 277-288.

[1] Saltzer,J.H.,Reed,D.P.,和Clark,D.D.,“系统设计中的端到端参数”,ACM TOCS,第2卷,第4期,1984年11月,第277-288页。

[2] Clark, D., "The Design Philosophy of the DARPA Internet Protocols," Proc SIGCOMM 88, ACM CCR Vol 18, Number 4, August 1988, pp. 106-114.

[2] Clark,D.,“DARPA互联网协议的设计理念”,Proc SIGCOMM 88,ACM CCR第18卷,第4期,1988年8月,第106-114页。

[3] Blumenthal, M., Clark, D.D., "Rethinking the design of the Internet: The end-to-end arguments vs. the brave new world", ACM Transactions on Internet Technology, Vol. 1, No. 1, August 2001, pp 70-109.

[3] Blumenthal,M.,Clark,D.D.,“重新思考互联网的设计:端到端的争论与勇敢的新世界”,ACM互联网技术交易,第一卷,第一期,2001年8月,第70-109页。

[4] Postel, J., "Transmission Control Protocol", STD 7, RFC 793, September 1981.

[4] 《传输控制协议》,标准7,RFC 793,1981年9月。

[5] Floyd, S. and L. Daigle, "IAB Architectural and Policy Considerations for Open Pluggable Edge Services", RFC 3238, January 2002.

[5] Floyd,S.和L.Daigle,“开放可插拔边缘服务的IAB架构和政策考虑”,RFC 3238,2002年1月。

[6] Carpenter, B., Ed., "Architectural Principles of the Internet", RFC 1958, June 1996.

[6] Carpenter,B.,Ed.,“互联网的架构原则”,RFC 19581996年6月。

[7] Johnson, D., Perkins, C. and J. Arkko, "Mobility Support in IPv6", Work in Progress.

[7] Johnson,D.,Perkins,C.和J.Arkko,“IPv6中的移动支持”,正在进行中。

[8] Perkins, C., Ed., "IP Mobility Support for IPv4", RFC 3344, August 2002.

[8] Perkins,C.,编辑,“IPv4的IP移动支持”,RFC 3344,2002年8月。

[9] Kaat, M., "Overview of 1999 IAB Network Layer Workshop," RFC 2956, October 2000.

[9] Kaat,M.,“1999年IAB网络层研讨会概述”,RFC 2956,2000年10月。

[10] Clark, D.D., Wroclawski, J., Sollins, K., and Braden, B., "Tussle in Cyberspace: Defining Tomorrow's Internet", Proceedings of Sigcomm 2002.

[10] Clark,D.D.,Wroclawski,J.,Sollins,K.,和Braden,B.,“网络空间中的争斗:定义明天的互联网”,SIGCOM2002年会议记录。

[11] Carpenter, B. and S. Brim, "Middleboxes: Taxonomy and Issues", RFC 3234, February, 2002.

[11] Carpenter,B.和S.Brim,“中间盒:分类和问题”,RFC 32342002年2月。

[12] Carpenter, B., "Internet Transparency", RFC 2775, February 2000.

[12] Carpenter,B.,“互联网透明度”,RFC 27752000年2月。

[13] Reed, D., "The End of the End-to-End Argument?", dprframe.asp?section=paper&fn=endofendtoend.html, April 2000.

[13] 里德,D.,“端到端论证的结尾?”, dprframe.asp?section=paper&fn=endofendtoend.html,2000年4月。

[14] Moors, T., "A Critical Review of End-to-end Arguments in System Design," Proc. 2000 IEEE International Conference on Communications, pp. 1214-1219, April, 2002.

[14] Moors,T.,“系统设计中端到端参数的批判性评论”,Proc。2000年IEEE国际通信会议,第1214-1219页,2002年4月。

[15] Ramsdell, B., Ed., "S/MIME Version 3 Message Specification", RFC 2633, June 1999.

[15] Ramsdell,B.,编辑,“S/MIME版本3消息规范”,RFC 2633,1999年6月。

[16] Huston, G., "Next Steps for the IP QoS Architecture", RFC 2990, November 2000.

[16] Huston,G.“IP QoS架构的下一步”,RFC 29902000年11月。

[17] Goldberg, I., Wagner, D., and Brewer, E., "Privacy-enhancing technologies for the Internet," Proceedings of IEEE COMPCON 97, pp. 103-109, 1997.

[17] Goldberg,I.,Wagner,D.,和Brewer,E.,“互联网隐私增强技术”,IEEE COMPCON 97会议录,第103-109页,1997年。

10. Author Information
10. 作者信息

Internet Architecture Board EMail:


IAB Membership at time this document was completed:


Bernard Aboba Harald Alvestrand Rob Austein Leslie Daigle Patrik Faltstrom Sally Floyd Jun-ichiro Itojun Hagino Mark Handley Geoff Huston Charlie Kaufman James Kempf Eric Rescorla Mike St. Johns


11. Full Copyright Statement
11. 完整版权声明

Copyright (C) The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78 and except as set forth therein, the authors retain all their rights.

版权所有(C)互联网协会(2004年)。本文件受BCP 78中包含的权利、许可和限制的约束,除其中规定外,作者保留其所有权利。



Intellectual Property


The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79.

IETF对可能声称与本文件所述技术的实施或使用有关的任何知识产权或其他权利的有效性或范围,或此类权利下的任何许可可能或可能不可用的程度,不采取任何立场;它也不表示它已作出任何独立努力来确定任何此类权利。有关RFC文件中权利的程序信息,请参见BCP 78和BCP 79。

Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at


The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at




Funding for the RFC Editor function is currently provided by the Internet Society.