Network Working Group J. Peterson
Request for Comments: 4079 NeuStar
Category: Informational July 2005
Network Working Group J. Peterson
Request for Comments: 4079 NeuStar
Category: Informational July 2005
A Presence Architecture for the Distribution of GEOPRIV Location Objects
GEOPRIV定位对象分布的存在体系结构
Status of This Memo
关于下段备忘
This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
本备忘录为互联网社区提供信息。它没有规定任何类型的互联网标准。本备忘录的分发不受限制。
Copyright Notice
版权公告
Copyright (C) The Internet Society (2005).
版权所有（C）互联网协会（2005年）。
Abstract
摘要
GEOPRIV defines the concept of a 'using protocol' -- a protocol that carries GEOPRIV location objects. GEOPRIV also defines various scenarios for the distribution of location objects that require the concepts of subscriptions and asynchronous notifications. This document examines some existing IETF work on the concept of presence, shows how presence architectures map onto GEOPRIV architectures, and moreover demonstrates that tools already developed for presence could be reused to simplify the standardization and implementation of GEOPRIV.
GEOPRIV定义了“使用协议”的概念，即承载GEOPRIV位置对象的协议。GEOPRIV还定义了需要订阅和异步通知概念的位置对象分布的各种场景。本文件审查了IETF在存在概念方面的一些现有工作，展示了存在体系结构如何映射到GEOPRIV体系结构，并证明了为存在而开发的工具可以重用，以简化GEOPRIV的标准化和实施。
Table of Contents
目录
1. Introduction ....................................................2
2. Framework Analysis ..............................................2
3. Presence Architecture for GEOPRIV ...............................3
4. GEOPRIV Extensions to PIDF ......................................5
5. Security Considerations .........................................5
6. Acknowledgements ................................................5
7. Informative References ..........................................6
1. Introduction ....................................................2
2. Framework Analysis ..............................................2
3. Presence Architecture for GEOPRIV ...............................3
4. GEOPRIV Extensions to PIDF ......................................5
5. Security Considerations .........................................5
6. Acknowledgements ................................................5
7. Informative References ..........................................6
GEOPRIV is a standard for the transmission of location information and privacy policies over the Internet. Location information is a description of a particular spatial location, which may be represented as coordinates (via longitude, latitude, and so on), as civil addresses (such as postal addresses), or in other ways. GEOPRIV focuses on the privacy and security issues, from both a technology perspective and a policy perspective, of sharing location information over the Internet; it essentially defines a secure container class capable of carrying both location information and policy data governing the distribution of this information. GEOPRIV also defines the concept of a 'using protocol' -- a protocol that carries the GEOPRIV location object.
GEOPRIV是通过互联网传输位置信息和隐私政策的标准。位置信息是特定空间位置的描述，可以表示为坐标（通过经度、纬度等）、民用地址（例如邮政地址）或其他方式。GEOPRIV从技术角度和政策角度关注通过互联网共享位置信息的隐私和安全问题；它本质上定义了一个安全容器类，能够承载位置信息和控制此信息分布的策略数据。GEOPRIV还定义了“使用协议”的概念，即承载GEOPRIV位置对象的协议。
Presence is a service defined in RFC2778 [2] that allows users of a communications service to monitor one another's availability and disposition in order to make decisions about communicating. Presence information is highly dynamic, and it generally characterizes whether a user is online or offline, busy or idle, away from communications devices or nearby, and the like.
存在是RFC2778[2]中定义的一种服务，它允许通信服务的用户监控彼此的可用性和配置，以便做出有关通信的决策。存在信息是高度动态的，并且它通常表征用户是在线还是离线、忙碌还是空闲、远离通信设备还是附近等等。
This document shows the applicability of presence to GEOPRIV and shows that a presence protocol could be a suitable using protocol for GEOPRIV. This document is not intended to demonstrate that presence is the only method by which GEOPRIV location objects might be distributed. However, there are numerous applications of GEOPRIV that depend on the fundamental subscription/notification architecture that also underlies presence.
本文件说明了存在对GEOPRIV的适用性，并说明存在协议可能是GEOPRIV的合适使用协议。本文件并非旨在证明存在是分发GEOPRIV定位对象的唯一方法。然而，GEOPRIV的许多应用都依赖于基础订阅/通知体系结构，而基础订阅/通知体系结构也是存在的基础。
The GEOPRIV framework [1] defines four primary network entities: a Location Generator, a Location Server, a Location Recipient, and a Rule Holder. Three interfaces between these entities are defined, including a publication interface and a notification interface.
GEOPRIV框架[1]定义了四个主要网络实体：位置生成器、位置服务器、位置接收者和规则持有者。这些实体之间定义了三个接口，包括发布接口和通知接口。
GEOPRIV specifies that a 'using protocol' is employed to transport location objects from one place to another. If the publication interface and notification interface are network connections, then a using protocol would be responsible for the transmission of the location object. Location Recipients may request that a Location Server provide them with GEOPRIV location information concerning a particular Target. The Location Generator publishes Location Information to a Location Server, which, in coordination with policies set by the Rule Maker, distributes the location information to Location Recipients as necessary.
GEOPRIV指定使用“使用协议”将位置对象从一个地方传输到另一个地方。如果发布接口和通知接口是网络连接，则使用协议将负责位置对象的传输。位置接收者可以请求位置服务器向其提供有关特定目标的GEOPRIV位置信息。位置生成器将位置信息发布到位置服务器，该服务器与规则制定者设置的策略协调，根据需要将位置信息分发给位置收件人。
The GEOPRIV requirements document shows three scenarios for the use of the GEOPRIV protocol. In some of these scenarios (such as the third), a Location Recipient sends some kind of message to the Location Server to request the periodic transmission of location information. The location of a GEOPRIV Target is likely to vary over time (if the Target is a person, or something similarly mobile), and consequently the concept of a persistent subscription to the location of a Target resulting in periodic notification is valuable to GEOPRIV. In other scenarios, a Location Recipient may request a one-time notification of the geographical location of the Target.
GEOPRIV要求文件显示了使用GEOPRIV协议的三种方案。在其中一些场景中（例如第三种场景），位置接收者向位置服务器发送某种消息，请求定期传输位置信息。GEOPRIV目标的位置可能随时间而变化（如果目标是个人或类似的移动对象），因此，持续订阅目标位置的概念对GEOPRIV很有价值。在其他场景中，位置接收者可以请求一次性通知目标的地理位置。
GEOPRIV places few requirements on using protocols. However, it is clear from the description above that there must be some mechanism allowing Location Recipients to establish a persistent subscription in order to receive regular notification of the geographical location of a Target as their location changes over time. There must also be a way for Location Generators to publish location information to a Location Server that applies further policies for distribution.
GEOPRIV对使用协议的要求很少。但是，从上面的描述中可以清楚地看到，必须有某种机制允许位置接收者建立持久订阅，以便在其位置随时间变化时定期接收目标地理位置的通知。位置生成器还必须有一种方法将位置信息发布到位置服务器，该服务器应用进一步的策略进行分发。
This document adopts a model in which the using protocol is responsible for requesting subscriptions, handling publications, and sending notifications. There are other models for GEOPRIV in which these operations might be built into location objects themselves. However, there is a significant amount of pre-existing work in the IETF related to managing publications, subscriptions, and notifications for data sets that vary over time. In fact, these concepts all correspond exactly to architectures for presence that have been developed in support of real-time communications applications such as instant messaging, voice and video sessions.
本文档采用的模型中，使用协议负责请求订阅、处理发布和发送通知。GEOPRIV还有其他一些模型，在这些模型中，这些操作可以内置到定位对象本身中。然而，IETF中已有大量与管理随时间变化的数据集的发布、订阅和通知相关的工作。事实上，这些概念完全对应于支持实时通信应用（如即时消息、语音和视频会话）而开发的存在架构。
Note that in some GEOPRIV scenarios, the Location Recipient does not actively request the location of a Target; rather, it receives an unsolicited notification of Target's location. This document focuses on the use of presence only for scenarios in which the Location Recipient actively solicits location information. However, it is possible that many of these base operations of the subscription/notification framework of presence could be reused for cases in which the Location Recipient is passive.
注意，在某些GEOPRIV场景中，位置接收者不会主动请求目标位置；相反，它会收到关于目标位置的未经请求的通知。本文档重点介绍仅在位置接收者主动请求位置信息的情况下使用状态。然而，在位置接收者是被动的情况下，存在的订阅/通知框架的这些基本操作中的许多都可能被重用。
The Common Profile for Presence [4] (CPP) defines a set of operations for delivery of presence information. These primarily consist of subscription operations and notification operations. A subscription creates a persistent connection between a 'watcher' (which corresponds to the Location Recipient of GEOPRIV) and a 'presentity' (which corresponds roughly to the GEOPRIV target). When a watcher subscribes to a presentity, a persistent connection is created;
状态的公共配置文件[4]（CPP）定义了一组用于传递状态信息的操作。这些操作主要包括订阅操作和通知操作。订阅在“观察者”（对应于GEOPRIV的位置接收者）和“存在实体”（大致对应于GEOPRIV目标）之间创建持久连接。当一个观察者订阅一个存在实体时，就会创建一个持久连接；
notifications of presence information will henceforth be sent to the watcher as the presence information changes. CPP also supports unsubscriptions (terminating the persistent subscription) and fetches (one-time requests for presence information that do not result in a persistent subscription).
此后，当存在信息发生变化时，存在信息的通知将发送给观察者。CPP还支持取消订阅（终止持久订阅）和获取（对状态信息的一次性请求，不会导致持久订阅）。
CPP provides a number of attributes of these operations that flesh out the presence system. There is a system for automatically expiring subscriptions if they are not refreshed at user-defined intervals (in order to eliminate stale subscriptions). There are transaction and subscription identifiers used to correlate messages, and a URI scheme ("pres:") is defined to identify watchers and presentities.
CPP提供了这些操作的许多属性，充实了状态系统。有一个系统可以在订阅未按用户定义的时间间隔刷新时自动终止订阅（以消除过期订阅）。有用于关联消息的事务和订阅标识符，并且定义了一个URI方案（“pres:”）来标识观察者和存在实体。
The IETF IMPP WG has also defined an XML data format for presence information, called the Presence Information Data Format [5] (PIDF). PIDF is a body that is carried by presence protocols and that contains presence information, including the current state of a presentity. PIDF is discussed in more detail in Section 4.
IETF IMPP WG还为状态信息定义了一种XML数据格式，称为状态信息数据格式[5]（PIDF）。PIDF是由存在协议承载的主体，包含存在信息，包括存在实体的当前状态。第4节将更详细地讨论PIDF。
At a high level, then, the presence architecture seems to have considerable applicability to the problem of delivering GEOPRIV information. However, the CPP framework is an abstract framework: it doesn't actually specify a protocol, instead it specifies a framework and a set of requirements to which presence protocols must conform. Also, CPP does not define any concept similar to a Location Server.
因此，在高层次上，存在体系结构似乎对交付GEOPRIV信息的问题具有相当大的适用性。然而，CPP框架是一个抽象框架：它实际上并没有指定协议，而是指定了一个框架和一组存在协议必须符合的需求。此外，CPP没有定义任何类似于位置服务器的概念。
However, the IETF has standardized protocols that instantiate this framework, such as SIMPLE [6] and XMPP [7]. XMPP and SIMPLE both have architectural elements comparable to a Location Server: points where presentities register their availability, and where policies for distributing presence can be managed. The presence community has also defined a policy protocol and schema set called XCAP [8] through which authorization policies can be provisioned in a presence server.
然而，IETF有标准化的协议来实例化这个框架，比如SIMPLE[6]和XMPP[7]。XMPP和SIMPLE都有类似于位置服务器的体系结构元素：存在实体注册其可用性的点，以及可以管理分布存在的策略的点。状态社区还定义了一个名为XCAP[8]的策略协议和模式集，通过它可以在状态服务器中提供授权策略。
In summary, like GEOPRIV, presence requires an architecture for publication, subscription, and notification for a mutable set of data associated with a principal. Presence has already tackled many of the harder issues associated with subscription management, including subscription expiration, development of identifiers for principals, and defining document formats for presence information. Rather than reinvent work that has been done elsewhere in the IETF, GEOPRIV has reused this existing work by specifying presence protocols as GEOPRIV using protocols. Moreover, the existing foundational presence tools developed in IMPP, such as PIDF, have immediate applicability to the efforts underway in GEOPRIV to develop objects for sharing location information.
总之，与GEOPRIV一样，presence需要一个体系结构来发布、订阅和通知与主体关联的可变数据集。Presence已经解决了许多与订阅管理相关的难题，包括订阅过期、主体标识符的开发以及为Presence信息定义文档格式。GEOPRIV没有重新发明IETF中其他地方已经完成的工作，而是通过使用协议将存在协议指定为GEOPRIV来重用现有的工作。此外，IMPP中开发的现有基础存在工具，如PIDF，可立即适用于GEOPRIV中正在进行的开发共享位置信息对象的工作。
As was mentioned above, the presence architecture developed in the IETF IMPP WG has defined a format for presence information called PIDF. PIDF is an XML format that provides presence information about a presentity. Primarily, this consists of status information, but it also optionally includes contact addresses (a way of reaching the presentity), timestamps, and textual notes with arbitrary content.
如上所述，IETF IMPP WG中开发的状态体系结构定义了一种称为PIDF的状态信息格式。PIDF是一种XML格式，提供有关实体的状态信息。这主要包括状态信息，但也可以选择包括联系人地址（一种到达实体的方式）、时间戳和带有任意内容的文本注释。
PIDF is an extensible format. It defines an XML element for representing the status of a presentity (the status element), and it gives some guidance as to how this element might be extended. Although the authors of PIDF viewed geographical location as a potential category of presence information, baseline PIDF defines no format for location information.
PIDF是一种可扩展格式。它定义了一个XML元素来表示存在实体的状态（status元素），并提供了一些关于如何扩展该元素的指导。尽管PIDF的作者将地理位置视为存在信息的潜在类别，但基线PIDF没有定义位置信息的格式。
PIDF meets the security requirements given in RFC2779 [3] (see especially sections 5.1, 5.2, and 5.3), which parallel those of the GEOPRIV location object given in the GEOPRIV requirements [1]. CPP and PIDF specify mechanisms for mutual authentication of participants in a presence exchange as well as for confidentiality and integrity properties for presence information.
PIDF符合RFC2779[3]中给出的安全要求（特别参见第5.1、5.2和5.3节），与GEOPRIV要求[1]中给出的GEOPRIV定位对象的安全要求平行。CPP和PIDF为状态交换中的参与者的相互认证以及状态信息的机密性和完整性属性指定了机制。
In short, many of the requirements of GEOPRIV objects map well onto the capabilities of PIDF.
简言之，GEOPRIV对象的许多需求很好地映射到PIDF的功能上。
GEOPRIV information, like presence information, has very sensitive security requirements. The requirements of RFC2779 [3], which are instantiated by CPP, PIDF, and XCAP, in addition to the various derivative concrete presence protocols, such as XMPP and SIMPLE, map well onto the security requirements of the GEOPRIV protocol, as defined in the GEOPRIV requirements document and the GEOPRIV threat analysis [9] document. Specifically, the presence security requirements call for authentication of watchers, integrity and confidentiality properties, and similar measures to prevent abuse of presence information.
GEOPRIV信息与状态信息一样，具有非常敏感的安全要求。由CPP、PIDF和XCAP实例化的RFC2779[3]的要求，以及各种衍生的具体存在协议，如XMPP和SIMPLE，很好地映射到GEOPRIV协议的安全要求，如GEOPRIV要求文件和GEOPRIV威胁分析[9]文件中所定义。具体而言，存在安全要求要求对观察者进行身份验证、完整性和保密性属性，以及防止存在信息滥用的类似措施。
Thanks to Randall Gellens, John Morris, Hannes Tschofenig, and Behcet Sarikaya for their comments.
感谢Randall Gellens、John Morris、Hannes Tschofenig和Behcet Sarikaya的评论。
[1] Cuellar, J., Morris, J., Mulligan, D., Peterson, J., and J. Polk, "GEOPRIV requirements", RFC 3693, February 2004.
[1] Cuellar，J.，Morris，J.，Mulligan，D.，Peterson，J.，和J.Polk，“地质驱动要求”，RFC 3693，2004年2月。
[2] Day, M., Rosenberg, J., and H. Sugano, "A Model for Presence and Instant Messaging", RFC 2778, February 2000.
[2] Day，M.，Rosenberg，J.，和H.Sugano，“状态和即时信息模型”，RFC 27782000年2月。
[3] Day, M., Aggarwal, S., and J. Vincent, "Instant Messaging / Presence Protocol Requirements", RFC 2779, February 2000.
[3] Day，M.，Aggarwal，S.，和J.Vincent，“即时消息传递/存在协议要求”，RFC 27792000年2月。
[4] Peterson, J., "Common Profile for Presence (CPP)", RFC 3859, August 2004.
[4] 彼得森，J.，“在场的共同概况（CPP）”，RFC 3859，2004年8月。
[5] Sugano, H., Fujimoto, S., Klyne, G., Bateman, A., Carr, W., and J. Peterson, "Presence Information Data Format (PIDF)", RFC 3863, August 2004.
[5] Sugano，H.，Fujimoto，S.，Klyne，G.，Batman，A.，Carr，W.，和J.Peterson，“状态信息数据格式（PIDF）”，RFC 38632004年8月。
[6] Rosenberg, J., "A Presence Event Package for the Session Initiation Protocol (SIP)", RFC 3856, August 2004.
[6] Rosenberg，J.，“会话启动协议（SIP）的状态事件包”，RFC3856，2004年8月。
[7] Saint-Andre, P., "Extensible Messaging and Presence Protocol (XMPP): Instant Messaging and Presence", RFC 3921, October 2004.
[7] Saint Andre，P.，“可扩展消息和状态协议（XMPP）：即时消息和状态”，RFC 39212004年10月。
[8] Rosenberg, J., "The Extensible Markup Language (XML) Configuration Access Protocol (XCAP)", Work in Progress, February 2004.
[8] Rosenberg，J.，“可扩展标记语言（XML）配置访问协议（XCAP）”，正在进行的工作，2004年2月。
[9] Danley, M., Morris, J., Mulligan, D., and J. Peterson, "Threat Analysis of the GEOPRIV Protocol", RFC 3694, February 2004.
[9] Danley，M.，Morris，J.，Mulligan，D.，和J.Peterson，“GEOPRIV协议的威胁分析”，RFC 36942004年2月。
Author's Address
作者地址
Jon Peterson NeuStar, Inc. 1800 Sutter St., Suite 570 Concord, CA 94520 USA
美国加利福尼亚州康科德市萨特街1800号570室Jon Peterson NeuStar公司，邮编94520
Phone: +1 925/363-8720
EMail: jon.peterson@neustar.biz
URI: http://www.neustar.biz/
Phone: +1 925/363-8720
EMail: jon.peterson@neustar.biz
URI: http://www.neustar.biz/
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