Internet Engineering Task Force (IETF) D. Malas, Ed.
Request for Comments: 6406 CableLabs
Category: Informational J. Livingood, Ed.
ISSN: 2070-1721 Comcast
November 2011
Internet Engineering Task Force (IETF) D. Malas, Ed.
Request for Comments: 6406 CableLabs
Category: Informational J. Livingood, Ed.
ISSN: 2070-1721 Comcast
November 2011
Session PEERing for Multimedia INTerconnect (SPEERMINT) Architecture
多媒体互连（SPEERMINT）体系结构的会话对等
Abstract
摘要
This document defines a peering architecture for the Session Initiation Protocol (SIP) and its functional components and interfaces. It also describes the components and the steps necessary to establish a session between two SIP Service Provider (SSP) peering domains.
本文档定义了会话启动协议（SIP）及其功能组件和接口的对等体系结构。它还描述了在两个SIP服务提供商（SSP）对等域之间建立会话所需的组件和步骤。
Status of This Memo
关于下段备忘
This document is not an Internet Standards Track specification; it is published for informational purposes.
本文件不是互联网标准跟踪规范；它是为了提供信息而发布的。
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741.
本文件是互联网工程任务组（IETF）的产品。它代表了IETF社区的共识。它已经接受了公众审查，并已被互联网工程指导小组（IESG）批准出版。并非IESG批准的所有文件都适用于任何级别的互联网标准；见RFC 5741第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6406.
有关本文件当前状态、任何勘误表以及如何提供反馈的信息，请访问http://www.rfc-editor.org/info/rfc6406.
Copyright Notice
版权公告
Copyright (c) 2011 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2011 IETF信托基金和确定为文件作者的人员。版权所有。
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(http://trustee.ietf.org/license-info)自本文件出版之日起生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本，并提供简化BSD许可证中所述的无担保。
This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English.
本文件可能包含2008年11月10日之前发布或公开的IETF文件或IETF贡献中的材料。控制某些材料版权的人员可能未授予IETF信托允许在IETF标准流程之外修改此类材料的权利。在未从控制此类材料版权的人员处获得充分许可的情况下，不得在IETF标准流程之外修改本文件，也不得在IETF标准流程之外创建其衍生作品，除了将其格式化以RFC形式发布或将其翻译成英语以外的其他语言。
Table of Contents
目录
1. Introduction ....................................................3
2. New Terminology .................................................3
2.1. Session Border Controller (SBC) ............................3
2.2. Carrier-of-Record ..........................................4
3. Reference Architecture ..........................................4
4. Procedures of Inter-Domain SSP Session Establishment ............6
5. Relationships between Functions/Elements ........................7
6. Recommended SSP Procedures ......................................7
6.1. Originating or Indirect SSP Procedures .....................7
6.1.1. The Lookup Function (LUF) ...........................8
6.1.1.1. Target Address Analysis ....................8
6.1.1.2. ENUM Lookup ................................8
6.1.2. Location Routing Function (LRF) .....................9
6.1.2.1. DNS Resolution .............................9
6.1.2.2. Routing Table ..............................9
6.1.2.3. LRF to LRF Routing ........................10
6.1.3. The Signaling Path Border Element (SBE) ............10
6.1.3.1. Establishing a Trusted Relationship .......10
6.1.3.2. IPsec .....................................10
6.1.3.3. Co-Location ...............................11
6.1.3.4. Sending the SIP Request ...................11
6.2. Target SSP Procedures .....................................11
6.2.1. TLS ................................................11
6.2.2. Receive SIP Requests ...............................11
6.3. Data Path Border Element (DBE) ............................12
7. Address Space Considerations ...................................12
8. Acknowledgments ................................................12
9. Security Considerations ........................................12
10. Contributors ..................................................13
11. References ....................................................14
11.1. Normative References .....................................14
11.2. Informative References ...................................15
1. Introduction ....................................................3
2. New Terminology .................................................3
2.1. Session Border Controller (SBC) ............................3
2.2. Carrier-of-Record ..........................................4
3. Reference Architecture ..........................................4
4. Procedures of Inter-Domain SSP Session Establishment ............6
5. Relationships between Functions/Elements ........................7
6. Recommended SSP Procedures ......................................7
6.1. Originating or Indirect SSP Procedures .....................7
6.1.1. The Lookup Function (LUF) ...........................8
6.1.1.1. Target Address Analysis ....................8
6.1.1.2. ENUM Lookup ................................8
6.1.2. Location Routing Function (LRF) .....................9
6.1.2.1. DNS Resolution .............................9
6.1.2.2. Routing Table ..............................9
6.1.2.3. LRF to LRF Routing ........................10
6.1.3. The Signaling Path Border Element (SBE) ............10
6.1.3.1. Establishing a Trusted Relationship .......10
6.1.3.2. IPsec .....................................10
6.1.3.3. Co-Location ...............................11
6.1.3.4. Sending the SIP Request ...................11
6.2. Target SSP Procedures .....................................11
6.2.1. TLS ................................................11
6.2.2. Receive SIP Requests ...............................11
6.3. Data Path Border Element (DBE) ............................12
7. Address Space Considerations ...................................12
8. Acknowledgments ................................................12
9. Security Considerations ........................................12
10. Contributors ..................................................13
11. References ....................................................14
11.1. Normative References .....................................14
11.2. Informative References ...................................15
This document defines a reference peering architecture for the Session Initiation Protocol (SIP) [RFC3261], it's functional components and interfaces in the context of session peering for multimedia interconnects. In this process, we define the peering reference architecture and its functional components, and peering interface functions from the perspective of a SIP Service Provider's (SSP's) [RFC5486] network. Thus, it also describes the components and the steps necessary to establish a session between two SSP peering domains.
本文档定义了会话初始化协议（SIP）[RFC3261]的参考对等体系结构，它的功能组件和接口在多媒体互连的会话对等环境中。在此过程中，我们从SIP服务提供商（SSP）的[RFC5486]网络的角度定义对等参考体系结构及其功能组件和对等接口功能。因此，它还描述了在两个SSP对等域之间建立会话所需的组件和步骤。
An SSP may also be referred to as an Internet Telephony Service Provider (ITSP). While the terms ITSP and SSP are frequently used interchangeably, this document and other subsequent SIP peering-related documents should use the term SSP. SSP more accurately depicts the use of SIP as the underlying Layer 5 signaling protocol.
SSP也可称为互联网电话服务提供商（ITSP）。虽然术语ITSP和SSP经常互换使用，但本文档和其他后续SIP对等相关文档应使用术语SSP。SSP更准确地描述了SIP作为底层第5层信令协议的使用。
This architecture enables the interconnection of two SSPs in Layer 5 peering, as defined in the SIP-based session peering requirements [RFC6271].
根据基于SIP的会话对等需求[RFC6271]中的定义，该体系结构支持第5层对等中两个SSP的互连。
Layer 3 peering is outside the scope of this document. Hence, the figures in this document do not show routers so that the focus is on Layer 5 protocol aspects.
第3层对等不在本文档的范围内。因此，本文档中的图没有显示路由器，因此重点放在第5层协议方面。
This document uses terminology defined in "Session Peering for Multimedia Interconnect (SPEERMINT) Terminology" [RFC5486]. In addition to normative references included herein, readers may also find [RFC6405] informative.
本文档使用“多媒体互连会话对等（SPEERMINT）术语”[RFC5486]中定义的术语。除了本文包含的规范性参考文献外，读者还可以找到[RFC6405]信息性参考文献。
[RFC5486] is a key reference for the majority of the SPEERMINT-related terminology used in this document. However, some additional new terms are used here as follows in this section.
[RFC5486]是本文件中使用的大多数与专家相关术语的关键参考。但是，本节中使用了一些新术语，如下所示。
A Session Border Controller (SBC) is referred to in Section 5. An SBC can contain a Signaling Function (SF), Signaling Path Border Element (SBE) and Data Path Border Element (DBE), and may perform the Lookup Function (LUF) and Location Routing Function (LRF), as described in Section 3. Whether the SBC performs one or more of these functions is, generally speaking, dependent upon how a SIP Service Provider (SSP) configures such a network element. In addition, requirements for an SBC can be found in [RFC5853].
会话边界控制器（SBC）见第5节。SBC可以包含信令功能（SF）、信令路径边界元素（SBE）和数据路径边界元素（DBE），并且可以执行查找功能（LUF）和位置路由功能（LRF），如第3节所述。一般来说，SBC是否执行这些功能中的一个或多个取决于SIP服务提供商（SSP）如何配置这样的网元。此外，SBC的要求见[RFC5853]。
A carrier-of-record, as used in Section 6.1.2.2, is defined in [RFC5067]. That document describes the term as referring to the entity having discretion over the domain and zone content and acting as the registrant for a telephone number, as represented in ENUM. This can be as follows:
[RFC5067]中定义了第6.1.2.2节中使用的记录载体。该文件将该术语描述为指对域和区域内容拥有自由裁量权并作为电话号码注册人的实体，如ENUM所示。这可以如下所示：
o the service provider to which the E.164 number was allocated for end user assignment, whether by the National Regulatory Authority (NRA) or the International Telecommunication Union (ITU), for instance, a code under "International Networks" (+882) or "Universal Personal Telecommunications (UPT)" (+878), or
o 国家管理局（NRA）或国际电信联盟（ITU）为最终用户分配了E.164号码的服务提供商，例如，“国际网络”（+882）或“通用个人电信（UPT）”（+878）下的代码，或
o if the number is ported, the service provider to which the number was ported, or
o 如果该号码已被移植，则该号码被移植到的服务提供商，或
o where numbers are assigned directly to end users, the service provider that the end user number assignee has chosen to provide a Public Switched Telephone Network / Public Land Mobile Network (PSTN/PLMN) point-of-interconnect for the number.
o 如果号码直接分配给最终用户，则指最终用户号码受让人选择为号码提供公共交换电话网络/公共陆地移动网络（PSTN/PLMN）互连点的服务提供商。
It is understood that the definition of "carrier-of-record" within a given jurisdiction is subject to modification by national authorities.
据了解，特定管辖区内“记录载体”的定义可由国家当局修改。
The following figure depicts the architecture and logical functions that form peering between two SSPs.
下图描述了在两个SSP之间形成对等的体系结构和逻辑功能。
For further details on the elements and functions described in this figure, please refer to [RFC5486]. The following terms, which appear in Figure 1 and are documented in [RFC5486], are reproduced here for simplicity.
有关本图中所述元件和功能的更多详细信息，请参阅[RFC5486]。以下术语出现在图1中，并记录在[RFC5486]中，为简单起见，在此复制。
o Data Path Border Element (DBE): A data path border element (DBE) is located on the administrative border of a domain through which the media associated with an inter-domain session flows. Typically, it provides media-related functions such as deep packet inspection and modification, media relay, and firewall-traversal support. The DBE may be controlled by the SBE.
o 数据路径边界元素（DBE）：数据路径边界元素（DBE）位于域的管理边界上，与域间会话关联的媒体通过该边界流动。通常，它提供与媒体相关的功能，如深度数据包检查和修改、媒体中继和防火墙穿越支持。DBE可由SBE控制。
o E.164 Number Mapping (ENUM): See [RFC6116].
o E.164数字映射（枚举）：参见[RFC6116]。
o Fully Qualified Domain Name (FQDN): See [RFC1035].
o 完全限定域名（FQDN）：请参阅[RFC1035]。
o Location Routing Function (LRF): The Location Routing Function (LRF) determines, for the target domain of a given request, the location of the SF in that domain, and optionally develops other Session Establishment Data (SED) required to route the request to that domain. An example of the LRF may be applied to either example in Section 4.3.3 of [RFC5486]. Once the ENUM response or SIP 302 redirect is received with the destination's SIP URI, the LRF must derive the destination peer's SF from the FQDN in the domain portion of the URI. In some cases, some entity (usually a third party or federation) provides peering assistance to the Originating SSP by providing this function. The assisting entity may provide information relating to direct (Section 4.2.1 of [RFC5486]) or indirect (Section 4.2.2 of [RFC5486]) peering as necessary.
o 位置路由功能（LRF）：对于给定请求的目标域，位置路由功能（LRF）确定SF在该域中的位置，并可选地开发将请求路由到该域所需的其他会话建立数据（SED）。LRF示例可应用于[RFC5486]第4.3.3节中的任一示例。一旦接收到带有目标SIP URI的枚举响应或SIP 302重定向，LRF必须从URI的域部分中的FQDN派生目标对等方的SF。在某些情况下，某些实体（通常是第三方或联盟）通过提供此功能向发起SSP提供对等协助。协助实体可根据需要提供与直接（RFC5486第4.2.1节）或间接（RFC5486第4.2.2节）对等相关的信息。
o Lookup Function (LUF): The Lookup Function (LUF) determines, for a given request, the target domain to which the request should be routed. An example of an LUF is an ENUM [4] look-up or a SIP INVITE request to a SIP proxy providing redirect responses for peers. In some cases, some entity (usually a third party or federation) provides peering assistance to the Originating SSP by providing this function. The assisting entity may provide information relating to direct (Section 4.2.1 of [RFC5486]) or indirect (Section 4.2.2 of [RFC5486]) peering as necessary.
o 查找函数（LUF）：对于给定的请求，查找函数（LUF）确定请求应路由到的目标域。LUF的一个示例是对SIP代理的枚举[4]查找或SIP INVITE请求，该SIP代理为对等方提供重定向响应。在某些情况下，某些实体（通常是第三方或联盟）通过提供此功能向发起SSP提供对等协助。协助实体可根据需要提供与直接（RFC5486第4.2.1节）或间接（RFC5486第4.2.2节）对等相关的信息。
o Real-time Transport Protocol (RTP): See [RFC3550].
o 实时传输协议（RTP）：参见[RFC3550]。
o Session Initiation Protocol (SIP): See [RFC3261].
o 会话启动协议（SIP）：请参阅[RFC3261]。
o Signaling Path Border Element (SBE): A signaling path border element (SBE) is located on the administrative border of a domain through which inter-domain session-layer messages will flow. Typically, it provides Signaling Functions such as protocol inter-working (for example, H.323 to SIP), identity and topology hiding, and Session Admission Control for a domain.
o 信令路径边界元素（SBE）：信令路径边界元素（SBE）位于域的管理边界上，域间会话层消息将通过该边界流动。通常，它提供信令功能，例如协议互通（例如，H.323到SIP）、身份和拓扑隐藏以及域的会话许可控制。
o Signaling Function (SF): The Signaling Function (SF) performs routing of SIP requests for establishing and maintaining calls and in order to assist in the discovery or exchange of parameters to be used by the Media Function (MF). The SF is a capability of SIP processing elements such as SIP proxies, SBEs, and User Agents.
o 信令功能（SF）：信令功能（SF）执行SIP请求的路由，以建立和维护呼叫，并协助发现或交换媒体功能（MF）使用的参数。SF是SIP处理元素（如SIP代理、SBE和用户代理）的能力。
o SIP Service Provider (SSP): A SIP Service Provider (SSP) is an entity that provides session services utilizing SIP signaling to its customers. In the event that the SSP is also a function of the SP, it may also provide media streams to its customers. Such an SSP may additionally be peered with other SSPs. An SSP may also interconnect with the PSTN.
o SIP服务提供商（SSP）：SIP服务提供商（SSP）是利用SIP信令向其客户提供会话服务的实体。如果SSP也是SP的一项功能，它还可以向其客户提供媒体流。此类SSP还可与其他SSP进行对等。SSP还可以与PSTN互连。
+=============++ ++=============+
|| ||
+-----------+ +-----------+
| SBE | +-----+ | SBE |
| +-----+ | SIP |Proxy| | +-----+ |
| | LUF |<-|------>|ENUM | | | LUF | |
| +-----+ | ENUM |TN DB| | +-----+ |
SIP | | +-----+ | |
------>| +-----+ | DNS +-----+ | +-----+ |
| | LRF |<-|------>|FQDN | | | LRF | |
| +-----+ | |IP | | +-----+ |
| +-----+ | SIP +-----+ | +-----+ |
| | SF |<-|----------------|->| SF | |
| +-----+ | | +-----+ |
+-----------+ +-----------+
|| ||
+-----------+ +-----------+
RTP | DBE | RTP | DBE |
------>| |--------------->| |
+-----------+ +-----------+
|| ||
SSP1 Network || || SSP2 Network
+=============++ ++=============+
+=============++ ++=============+
|| ||
+-----------+ +-----------+
| SBE | +-----+ | SBE |
| +-----+ | SIP |Proxy| | +-----+ |
| | LUF |<-|------>|ENUM | | | LUF | |
| +-----+ | ENUM |TN DB| | +-----+ |
SIP | | +-----+ | |
------>| +-----+ | DNS +-----+ | +-----+ |
| | LRF |<-|------>|FQDN | | | LRF | |
| +-----+ | |IP | | +-----+ |
| +-----+ | SIP +-----+ | +-----+ |
| | SF |<-|----------------|->| SF | |
| +-----+ | | +-----+ |
+-----------+ +-----------+
|| ||
+-----------+ +-----------+
RTP | DBE | RTP | DBE |
------>| |--------------->| |
+-----------+ +-----------+
|| ||
SSP1 Network || || SSP2 Network
+=============++ ++=============+
Reference Architecture
参考体系结构
Figure 1
图1
This document assumes that in order for a session to be established from a User Agent (UA) in the Originating (or Indirect) SSP's network to a UA in the Target SSP's network the following steps are taken:
本文件假设，为了建立从发起（或间接）SSP网络中的用户代理（UA）到目标SSP网络中的UA的会话，采取以下步骤：
1. Determine the Target or Indirect SSP via the LUF. (Note: If the target address represents an intra-SSP resource, the behavior is out of scope with respect to this document.)
1. 通过LUF确定目标或间接SSP。（注意：如果目标地址表示内部SSP资源，则该行为超出本文档的范围。）
2. Determine the address of the SF of the Target SSP via the LRF.
2. 通过LRF确定目标SSP的SF地址。
3. Establish the session.
3. 建立会议。
4. Exchange the media, which could include voice, video, text, etc.
4. 交换媒体，包括语音、视频、文本等。
5. End the session (BYE)
5. 结束会话（再见）
The Originating or Indirect SSP would perform steps 1-4, the Target SSP would perform step 4, and either one can perform step 5.
发起或间接SSP将执行步骤1-4，目标SSP将执行步骤4，任何一个都可以执行步骤5。
In the case that the Target SSP changes, steps 1-4 would be repeated. This is reflected in Figure 1, which shows the Target SSP with its own peering functions.
如果目标SSP发生变化，将重复步骤1-4。这反映在图1中，图1显示了具有自己对等功能的目标SSP。
Please also refer to Figure 1.
也请参考图1。
o An SBE can contain a Signaling Function (SF).
o SBE可以包含信令功能（SF）。
o An SF can perform a Lookup Function (LUF) and Location Routing Function (LRF).
o SF可以执行查找功能（LUF）和位置路由功能（LRF）。
o As an additional consideration, a Session Border Controller, can contain an SF, SBE and DBE, and may act as both an LUF and LRF.
o 作为附加考虑，会话边界控制器可以包含SF、SBE和DBE，并且可以同时充当LUF和LRF。
o The following functions may communicate as follows in an example SSP network, depending upon various real-world implementations:
o 在示例SSP网络中，以下功能可以进行如下通信，具体取决于各种实际实现：
* SF may communicate with the LUF, LRF, SBE, and SF
* SF可与LUF、LRF、SBE和SF通信
* LUF may communicate with the SF and SBE
* LUF可与SF和SBE通信
* LRF may communicate with the SF and SBE
* LRF可与SF和SBE通信
This section describes the functions in more detail and provides some recommendations on the role they would play in a SIP call in a Layer 5 peering scenario.
本节将更详细地描述这些功能，并就它们在第5层对等场景中的SIP调用中所扮演的角色提供一些建议。
Some of the information in this section is taken from [RFC6271] and is included here for continuity purposes. It is also important to refer to Section 3.2 of [RFC6404], particularly with respect to the use of IPsec and TLS.
本节中的一些信息摘自[RFC6271]，并包含在此处以保持连续性。参考[RFC6404]第3.2节也很重要，特别是关于IPsec和TLS的使用。
This section describes the procedures of the Originating or indirect SSP.
本节描述了发起或间接SSP的程序。
The purpose of the LUF is to determine the SF of the target domain of a given request and optionally to develop Session Establishment Data. It is important to note that the LUF may utilize the public e164.arpa ENUM root, as well as one or more private roots. When private roots are used, specialized routing rules may be implemented; these rules may vary depending upon whether an Originating or Indirect SSP is querying the LUF.
LUF的目的是确定给定请求的目标域的SF，并可选地开发会话建立数据。需要注意的是，LUF可能使用公共e164.arpa枚举根以及一个或多个私有根。当使用私有根时，可以实现专门的路由规则；这些规则可能会有所不同，具体取决于发起SSP还是间接SSP正在查询LUF。
When the Originating (or Indirect) SSP receives a request to communicate, it analyzes the target URI to determine whether the call needs to be routed internally or externally to its network. The analysis method is internal to the SSP; thus, outside the scope of SPEERMINT.
当发起（或间接）SSP接收到通信请求时，它分析目标URI，以确定呼叫是否需要在内部或外部路由到其网络。分析方法是SSP内部的；因此，在SPEERMINT的范围之外。
If the target address does not represent a resource inside the Originating (or Indirect) SSP's administrative domain or federation of domains, then the Originating (or Indirect) SSP performs a Lookup Function (LUF) to determine a target address, and then it resolves the call routing data by using the Location Routing Function (LRF).
如果目标地址不代表发起（或间接）SSP的管理域或域联盟内的资源，则发起（或间接）SSP执行查找功能（LUF）以确定目标地址，然后使用位置路由功能（LRF）解析呼叫路由数据。
For example, if the request to communicate is for an im: or pres: URI type [RFC3861] [RFC3953], the Originating (or Indirect) SSP follows the procedures in [RFC3861]. If the highest priority supported URI scheme is sip: or sips:, the Originating (or Indirect) SSP skips to SIP DNS resolution in Section 5.1.3. Likewise, if the target address is already a sip: or sips: URI in an external domain, the Originating (or Indirect) SSP skips to SIP DNS resolution in Section 6.1.2.1. This may be the case, to use one example, with "sips:bob@biloxi.example.com".
例如，如果通信请求是针对im:或pres:URI类型[RFC3861][RFC3953]，则发起（或间接）SSP遵循[RFC3861]中的过程。如果支持的最高优先级URI方案是sip:或sips:，则发起（或间接）SSP将跳过第5.1.3节中的sip DNS解析。同样，如果目标地址已经是外部域中的sip:或sips:URI，则发起（或间接）SSP将跳过第6.1.2.1节中的sip DNS解析。例如，“sips:bob@biloxi.example.com".
If the target address corresponds to a specific E.164 address, the SSP may need to perform some form of number plan mapping according to local policy. For example, in the United States, a dial string beginning "011 44" could be converted to "+44"; in the United Kingdom, "00 1" could be converted to "+1". Once the SSP has an E.164 address, it can use ENUM.
如果目标地址对应于特定的E.164地址，SSP可能需要根据当地政策执行某种形式的编号计划映射。例如，在美国，以“011 44”开头的拨号字符串可以转换为“+44”；在联合王国，“01”可以转换为“+1”。一旦SSP拥有E.164地址，它就可以使用ENUM。
If an external E.164 address is the target, the Originating (or Indirect) SSP consults the public "User ENUM" rooted at e164.arpa, according to the procedures described in [RFC6116]. The SSP must query for the "E2U+sip" enumservice as described in [RFC3764], but may check for other enumservices. The Originating (or Indirect) SSP
如果外部E.164地址是目标地址，则发起（或间接）SSP将根据[RFC6116]中所述的程序咨询根于e164.arpa的公共“用户枚举”。SSP必须查询[RFC3764]中所述的“E2U+sip”枚举服务，但可以检查其他枚举服务。发起（或间接）SSP
may consult a cache or alternate representation of the ENUM data rather than actual DNS queries. Also, the SSP may skip actual DNS queries if the Originating (or Indirect) SSP is sure that the target address country code is not represented in e164.arpa.
可以咨询枚举数据的缓存或替代表示，而不是实际的DNS查询。此外，如果发起（或间接）SSP确定e164.arpa中未表示目标地址国家代码，则SSP可能跳过实际DNS查询。
If an im: or pres: URI is chosen based on an "E2U+im" [RFC3861] or "E2U+pres" [RFC3953] enumserver, the SSP follows the procedures for resolving these URIs to URIs for specific protocols such as SIP or Extensible Messaging and Presence Protocol (XMPP) as described in the previous section.
如果基于“E2U+im”[RFC3861]或“E2U+pres”[RFC3953]枚举服务器选择im:或pres:URI，则SSP将按照上一节所述的步骤将这些URI解析为特定协议（如SIP或可扩展消息和状态协议（XMPP））的URI。
The Naming Authority Pointer (NAPTR) response to the ENUM lookup may be a SIP address of record (AOR) (such as "sips:bob@example.com") or SIP URI (such as "sips:bob@sbe1.biloxi.example.com"). In the case when a SIP URI is returned, the Originating (or Indirect) SSP has sufficient routing information to locate the Target SSP. In the case of when a SIP AoR is returned, the SF then uses the LRF to determine the URI for more explicitly locating the Target SSP.
对枚举查找的命名机构指针（NAPTR）响应可以是SIP记录地址（AOR）（例如“sips:bob@example.com）或SIP URI（如“sips:bob@sbe1.biloxi.example.com"). 在返回SIP URI的情况下，发起（或间接）SSP具有足够的路由信息来定位目标SSP。在返回SIP AoR的情况下，SF然后使用LRF确定URI以更明确地定位目标SSP。
The LRF of an Originating (or Indirect) SSP analyzes target address and target domain identified by the LUF, and discovers the next-hop Signaling Function (SF) in a peering relationship. The resource to determine the SF of the target domain might be provided by a third party as in the assisted-peering case. The following sections define mechanisms that may be used by the LRF. These are not in any particular order and, importantly, not all of them have to be used.
发起（或间接）SSP的LRF分析LUF识别的目标地址和目标域，并发现对等关系中的下一跳信令功能（SF）。用于确定目标域的SF的资源可能由第三方提供，如在辅助对等情况下。以下章节定义了LRF可能使用的机制。这些不是以任何特定的顺序排列的，重要的是，并非所有这些都必须使用。
The Originating (or Indirect) SSP uses the procedures in Section 4 of [RFC3263] to determine how to contact the receiving SSP. To summarize the [RFC3263] procedure: unless these are explicitly encoded in the target URI, a transport is chosen using NAPTR records, a port is chosen using SRV records, and an address is chosen using A or AAAA records.
发起（或间接）SSP使用[RFC3263]第4节中的程序确定如何联系接收SSP。总结[RFC3263]过程：除非在目标URI中显式编码，否则使用NAPTR记录选择传输，使用SRV记录选择端口，使用a或AAAA记录选择地址。
When communicating with another SSP, entities compliant to this document should select a TLS-protected transport for communication from the Originating (or Indirect) SSP to the receiving SSP if available, as described further in Section 6.2.1.
当与另一个SSP通信时，符合本文件要求的实体应选择TLS保护的传输，以便从发起（或间接）SSP到接收SSP（如有）进行通信，如第6.2.1节所述。
If there are no End User ENUM records and the Originating (or Indirect) SSP cannot discover the carrier-of-record or if the Originating (or Indirect) SSP cannot reach the carrier-of-record via
如果没有最终用户枚举记录，且发起（或间接）SSP无法发现记录载体，或者发起（或间接）SSP无法通过
SIP peering, the Originating (or Indirect) SSP may deliver the call to the PSTN or reject it. Note that the Originating (or Indirect) SSP may forward the call to another SSP for PSTN gateway termination by prior arrangement using the local SIP proxy routing table.
SIP对等，发起（或间接）SSP可以向PSTN发送呼叫或拒绝呼叫。注意，发起（或间接）SSP可通过使用本地SIP代理路由表的事先安排将呼叫转发到另一SSP以用于PSTN网关终止。
If so, the Originating (or Indirect) SSP rewrites the Request-URI to address the gateway resource in the Target SSP's domain and may forward the request on to that SSP using the procedures described in the remainder of these steps.
如果是这样，发起（或间接）SSP将重写请求URI以寻址目标SSP域中的网关资源，并可使用这些步骤剩余部分中描述的过程将请求转发到该SSP。
Communications between the LRF of two interconnecting SSPs may use DNS or statically provisioned IP addresses for reachability. Other inputs to determine the path may be code-based routing, method-based routing, time of day, least cost and/or source-based routing.
两个互连ssp的LRF之间的通信可以使用DNS或静态配置的IP地址来实现可达性。用于确定路径的其他输入可以是基于代码的路由、基于方法的路由、时间、最低成本和/或基于源的路由。
The purpose of the Signaling Function is to perform routing of SIP messages as well as optionally implement security and policies on SIP messages and to assist in discovery/exchange of parameters to be used by the Media Function (MF). The Signaling Function performs the routing of SIP messages. The SBE may be a back-to-back user agent (B2BUA) or it may act as a SIP proxy. Optionally, an SF may perform additional functions such as Session Admission Control, SIP Denial-of-Service protection, SIP Topology Hiding, SIP header normalization, SIP security, privacy, and encryption. The SF of an SBE can also process SDP payloads for media information such as media type, bandwidth, and type of codec; then, communicate this information to the media function.
信令功能的目的是执行SIP消息的路由以及可选地对SIP消息实施安全和策略，并协助媒体功能（MF）使用的参数的发现/交换。信令功能执行SIP消息的路由。SBE可以是背对背的用户代理（B2BUA），也可以充当SIP代理。可选地，SF可以执行附加功能，例如会话许可控制、SIP拒绝服务保护、SIP拓扑隐藏、SIP报头规范化、SIP安全、隐私和加密。SBE的SF还可以处理媒体信息的SDP有效载荷，例如媒体类型、带宽和编解码器的类型；然后，将此信息传达给媒体功能。
Depending on the security needs and trust relationships between SSPs, different security mechanisms can be used to establish SIP calls. These are discussed in the following subsections.
根据安全需求和SSP之间的信任关系，可以使用不同的安全机制来建立SIP调用。这些将在以下小节中讨论。
In certain deployments, the use of IPsec between the Signaling Functions of the originating and terminating domains can be used as a security mechanism instead of TLS. However, such IPsec use should be the subject of a future document as additional specification is necessary to use IPsec properly and effectively.
在某些部署中，在发起域和终止域的信令功能之间使用IPsec可以用作安全机制，而不是TLS。但是，这种IPsec的使用应该是未来文档的主题，因为正确有效地使用IPsec需要附加规范。
In this scenario, the SFs are co-located in a physically secure location and/or are members of a segregated network. In this case, messages between the Originating and Terminating SSPs could be sent as clear text (unencrypted). However, even in these semi-trusted co-location facilities, other security or access control mechanisms may be appropriate, such as IP access control lists or other mechanisms.
在这种情况下，SF共同位于物理安全位置和/或是隔离网络的成员。在这种情况下，发起和终止SSP之间的消息可以作为明文（未加密）发送。然而，即使在这些半可信的同一位置设施中，也可以使用其他安全或访问控制机制，例如IP访问控制列表或其他机制。
Once a trust relationship between the peers is established, the Originating (or Indirect) SSP sends the request.
一旦对等方之间建立了信任关系，发起（或间接）SSP将发送请求。
This section describes the Target SSP Procedures.
本节介绍目标SSP程序。
The section defines the usage of TLS between two SSPs [RFC5246] [RFC5746] [RFC5878]. When the receiving SSP receives a TLS client hello, it responds with its certificate. The Target SSP certificate should be valid and rooted in a well-known certificate authority. The procedures to authenticate the SSP's originating domain are specified in [RFC5922].
本节定义了两个SSP之间TLS的使用[RFC5246][RFC5746][RFC5878]。当接收SSP接收到TLS客户机hello时，它将使用其证书进行响应。目标SSP证书应是有效的，并在知名的证书颁发机构中扎根。[RFC5922]中规定了验证SSP原始域的程序。
The SF of the Target SSP verifies that the Identity header is valid, corresponds to the message, corresponds to the Identity-Info header, and that the domain in the From header corresponds to one of the domains in the TLS client certificate.
目标SSP的SF验证标识标头是否有效、是否对应于消息、是否对应于标识信息标头，以及From标头中的域是否对应于TLS客户端证书中的一个域。
As noted above in Section 6.1.3.2, some deployments may utilize IPsec rather than TLS.
如上文第6.1.3.2节所述，某些部署可能使用IPsec而不是TLS。
Once a trust relationship is established, the Target SSP is prepared to receive incoming SIP requests. For new requests (dialog forming or not), the receiving SSP verifies if the target (Request-URI) is a domain for which it is responsible. For these requests, there should be no remaining Route header field values. For in-dialog requests, the receiving SSP can verify that it corresponds to the top-most Route header field value.
一旦建立了信任关系，目标SSP就准备好接收传入的SIP请求。对于新请求（是否形成对话框），接收SSP验证目标（请求URI）是否为其负责的域。对于这些请求，应该没有剩余的路由头字段值。对于对话内请求，接收SSP可以验证它是否对应于最顶端的路由标头字段值。
The receiving SSP may reject incoming requests due to local policy. When a request is rejected because the Originating (or Indirect) SSP is not authorized to peer, the receiving SSP should respond with a 403 response with the reason phrase "Unsupported Peer".
由于本地策略，接收SSP可能会拒绝传入请求。当请求因发起（或间接）SSP未被授权对等而被拒绝时，接收SSP应以403响应响应，原因短语为“不支持的对等”。
The purpose of the DBE [RFC5486] is to perform media-related functions such as media transcoding and media security implementation between two SSPs.
DBE[RFC5486]的目的是在两个SSP之间执行媒体相关功能，如媒体转码和媒体安全实现。
An example of this is to transform a voice payload from one codec (e.g., G.711) to another (e.g., EvRC). Additionally, the MF may perform media relaying, media security [RFC3711], privacy, and encryption.
这方面的一个示例是将语音有效载荷从一个编解码器（例如，g.711）转换为另一个（例如，EvRC）。此外，MF可以执行媒体中继、媒体安全[RFC3711]、隐私和加密。
Peering must occur in a common IP address space, which is defined by the federation, which may be entirely on the public Internet, or some private address space [RFC1918]. The origination or termination networks may or may not entirely be in the same address space. If they are not, then a Network Address Translation (NAT) or similar may be needed before the signaling or media is presented correctly to the federation. The only requirement is that all associated entities across the peering interface are reachable.
对等必须发生在公共IP地址空间中，该地址空间由联合会定义，可能完全位于公共Internet上，或者某些专用地址空间[RFC1918]。发起或终止网络可能或可能不完全在同一地址空间中。如果不是，则在信令或媒体正确呈现给联邦之前，可能需要网络地址转换（NAT）或类似。唯一的要求是对等接口上的所有关联实体都是可访问的。
The working group would like to thank John Elwell, Otmar Lendl, Rohan Mahy, Alexander Mayrhofer, Jim McEachern, Jean-Francois Mule, Jonathan Rosenberg, and Dan Wing for their valuable contributions to various versions of this document.
工作组感谢John Elwell、Otmar Lendl、Rohan Mahy、Alexander Mayrhofer、Jim McEachern、Jean-Francois Mule、Jonathan Rosenberg和Dan Wing对本文件各版本的宝贵贡献。
The level (or types) of security mechanisms implemented between peering providers is, in practice, dependent upon on the underlying physical security of SSP connections. This means, as noted in Section 6.1.3.3, whether peering equipment is in a secure facility or not may bear on other types of security mechanisms that may be appropriate. Thus, if two SSPs peered across public Internet links, they are likely to use IPsec or TLS since the link between the two domains should be considered untrusted.
对等提供者之间实现的安全机制的级别（或类型）实际上取决于SSP连接的底层物理安全性。这意味着，如第6.1.3.3节所述，对等设备是否位于安全设施中可能会影响其他类型的安全机制。因此，如果两个SSP通过公共Internet链接进行窥视，则它们可能会使用IPsec或TLS，因为这两个域之间的链接应被视为不受信任。
Many detailed and highly relevant security requirements for SPEERMINT have been documented in Section 5 of [RFC6271]. As a result, that document should be considered required reading.
[RFC6271]第5节中记录了许多详细且高度相关的SPEERMINT安全要求。因此，该文件应被视为必读文件。
Additional and important security considerations have been documented separately in [RFC6404]. This document describes the many relevant security threats to SPEERMINT, as well the relevant countermeasures and security protections that are recommended to combat any potential threats or other risks. This includes a wide range of detailed threats in Section 2 of [RFC6404]. It also includes key requirements in Section 3.1 of [RFC6404], such as the requirement for the LUF and LRF to support mutual authentication for queries, among other requirements which are related to [RFC6271]. Section 3.2 of [RFC6404] explains how to meet these security requirements, and then Section 4 explores a wide range of suggested countermeasures.
[RFC6404]中单独记录了其他和重要的安全注意事项。本文件描述了SPEERMINT面临的许多相关安全威胁，以及为应对任何潜在威胁或其他风险而建议的相关对策和安全保护措施。这包括[RFC6404]第2节中的一系列详细威胁。它还包括[RFC6404]第3.1节中的关键要求，如LUF和LRF支持查询相互认证的要求，以及与[RFC6271]相关的其他要求。[RFC6404]的第3.2节解释了如何满足这些安全要求，然后第4节探讨了广泛的建议对策。
Mike Hammer Cisco Systems Herndon, VA US EMail: mhammer@cisco.com
Mike Hammer Cisco Systems Herndon，弗吉尼亚州美国电子邮件：mhammer@cisco.com
Hadriel Kaplan Acme Packet Burlington, MA US EMail: hkaplan@acmepacket.com
Hadriel Kaplan Acme数据包马萨诸塞州伯灵顿美国电子邮件：hkaplan@acmepacket.com
Sohel Khan, Ph.D. Comcast Cable Philadelphia, PA US EMail: sohel_khan@cable.comcast.com
苏赫尔·汗博士。康卡斯特有线电视美国宾夕法尼亚州费城电子邮件：sohel_khan@cable.comcast.com
Reinaldo Penno Juniper Networks Sunnyvale, CA US EMail: rpenno@juniper.net
加利福尼亚州桑尼维尔市雷纳尔多·佩诺·杜松网络公司美国电子邮件：rpenno@juniper.net
David Schwartz XConnect Global Networks Jerusalem Israel EMail: dschwartz@xconnnect.net
David Schwartz XConnect全球网络耶路撒冷以色列电子邮件：dschwartz@xconnnect.net
Rich Shockey Shockey Consulting US EMail: Richard@shockey.us
Rich Shockey Shockey Consulting US电子邮件：Richard@shockey.us
Adam Uzelac Global Crossing Rochester, NY US EMail: adam.uzelac@globalcrossing.com
Adam Uzelac环球穿越美国纽约州罗切斯特电子邮件：Adam。uzelac@globalcrossing.com
[RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987.
[RFC1035]Mockapetris，P.，“域名-实现和规范”，STD 13，RFC 1035，1987年11月。
[RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and E. Lear, "Address Allocation for Private Internets", BCP 5, RFC 1918, February 1996.
[RFC1918]Rekhter，Y.，Moskowitz，R.，Karrenberg，D.，Groot，G.，和E.Lear，“私人互联网地址分配”，BCP 5，RFC 1918，1996年2月。
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002.
[RFC3261]Rosenberg，J.，Schulzrinne，H.，Camarillo，G.，Johnston，A.，Peterson，J.，Sparks，R.，Handley，M.，和E.Schooler，“SIP：会话启动协议”，RFC 3261，2002年6月。
[RFC3263] Rosenberg, J. and H. Schulzrinne, "Session Initiation Protocol (SIP): Locating SIP Servers", RFC 3263, June 2002.
[RFC3263]Rosenberg，J.和H.Schulzrinne，“会话启动协议（SIP）：定位SIP服务器”，RFC 3263，2002年6月。
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, July 2003.
[RFC3550]Schulzrinne，H.，Casner，S.，Frederick，R.，和V.Jacobson，“RTP：实时应用的传输协议”，STD 64，RFC 35502003年7月。
[RFC3764] Peterson, J., "enumservice registration for Session Initiation Protocol (SIP) Addresses-of-Record", RFC 3764, April 2004.
[RFC3764]Peterson，J.，“会话启动协议（SIP）记录地址的枚举服务注册”，RFC 3764，2004年4月。
[RFC3861] Peterson, J., "Address Resolution for Instant Messaging and Presence", RFC 3861, August 2004.
[RFC3861]Peterson，J.，“即时消息和状态的地址解析”，RFC 38612004年8月。
[RFC3953] Peterson, J., "Telephone Number Mapping (ENUM) Service Registration for Presence Services", RFC 3953, January 2005.
[RFC3953]Peterson，J.，“状态服务的电话号码映射（ENUM）服务注册”，RFC 3953，2005年1月。
[RFC5067] Lind, S. and P. Pfautz, "Infrastructure ENUM Requirements", RFC 5067, November 2007.
[RFC5067]Lind，S.和P.Pfautz，“基础设施枚举要求”，RFC 5067，2007年11月。
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC5246]Dierks，T.和E.Rescorla，“传输层安全（TLS）协议版本1.2”，RFC 5246，2008年8月。
[RFC5486] Malas, D. and D. Meyer, "Session Peering for Multimedia Interconnect (SPEERMINT) Terminology", RFC 5486, March 2009.
[RFC5486]Malas，D.和D.Meyer，“多媒体互连的会话对等（SPEERMINT）术语”，RFC 54862009年3月。
[RFC5746] Rescorla, E., Ray, M., Dispensa, S., and N. Oskov, "Transport Layer Security (TLS) Renegotiation Indication Extension", RFC 5746, February 2010.
[RFC5746]Rescorla，E.，Ray，M.，Dispensa，S.，和N.Oskov，“传输层安全（TLS）重新协商指示扩展”，RFC 57462010年2月。
[RFC5853] Hautakorpi, J., Camarillo, G., Penfield, R., Hawrylyshen, A., and M. Bhatia, "Requirements from Session Initiation Protocol (SIP) Session Border Control (SBC) Deployments", RFC 5853, April 2010.
[RFC5853]Hautakorpi，J.，Camarillo，G.，Penfield，R.，Hawrylyshen，A.，和M.Bhatia，“会话启动协议（SIP）会话边界控制（SBC）部署的要求”，RFC 58532010年4月。
[RFC5878] Brown, M. and R. Housley, "Transport Layer Security (TLS) Authorization Extensions", RFC 5878, May 2010.
[RFC5878]Brown，M.和R.Housley，“传输层安全（TLS）授权扩展”，RFC 5878，2010年5月。
[RFC5922] Gurbani, V., Lawrence, S., and A. Jeffrey, "Domain Certificates in the Session Initiation Protocol (SIP)", RFC 5922, June 2010.
[RFC5922]Gurbani，V.，Lawrence，S.，和A.Jeffrey，“会话启动协议（SIP）中的域证书”，RFC 59222010年6月。
[RFC6116] Bradner, S., Conroy, L., and K. Fujiwara, "The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application (ENUM)", RFC 6116, March 2011.
[RFC6116]Bradner，S.，Conroy，L.，和K.Fujiwara，“E.164到统一资源标识符（URI）动态委托发现系统（DDDS）应用程序（ENUM）”，RFC 6116，2011年3月。
[RFC6271] Mule, J-F., "Requirements for SIP-Based Session Peering", RFC 6271, June 2011.
[RFC6271]Mule，J-F，“基于SIP的会话对等的要求”，RFC6271，2011年6月。
[RFC6404] Seedorf, J., Niccolini, S., Chen, E., and H. Scholz, "Session PEERing for Multimedia INTerconnect (SPEERMINT) Security Threats and Suggested Countermeasures", RFC 6404, November 2011.
[RFC6404]Seedorf，J.，Niccolini，S.，Chen，E.，和H.Scholz，“多媒体互连的会话对等（SPEERMINT）安全威胁和建议对策”，RFC 6404，2011年11月。
[RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, "The Secure Real-time Transport Protocol (SRTP)", RFC 3711, March 2004.
[RFC3711]Baugher，M.，McGrew，D.，Naslund，M.，Carrara，E.，和K.Norrman，“安全实时传输协议（SRTP）”，RFC 37112004年3月。
[RFC6405] Uzelac, A., Ed. and Y. Lee, Ed., "Voice over IP (VoIP) SIP Peering Use Cases", RFC 6405, November 2011.
[RFC6405]Uzelac，A.，Ed.和Y.Lee，Ed.，“IP语音（VoIP）SIP对等用例”，RFC6405，2011年11月。
Authors' Addresses
作者地址
Daryl Malas (editor) CableLabs Louisville, CO US
Daryl Malas（编辑）美国路易斯维尔有线实验室
EMail: d.malas@cablelabs.com
EMail: d.malas@cablelabs.com
Jason Livingood (editor) Comcast Philadelphia, PA US
贾森·利文戈德（编辑）美国宾夕法尼亚州费城康卡斯特
EMail: Jason_Livingood@cable.comcast.com
EMail: Jason_Livingood@cable.comcast.com