Network Working Group H. Schulzrinne
Request for Comments: 4123 Columbia University
Category: Informational C. Agboh
July 2005
Network Working Group H. Schulzrinne
Request for Comments: 4123 Columbia University
Category: Informational C. Agboh
July 2005
Session Initiation Protocol (SIP)-H.323 Interworking Requirements
会话启动协议（SIP）-H.323互通要求
Status of this Memo
本备忘录的状况
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）。
IESG Note
IESG注释
This RFC is not a candidate for any level of Internet Standard. The IETF disclaims any knowledge of the fitness of this RFC for any purpose, and in particular notes that the decision to publish is not based on IETF review for such things as security, congestion control, or inappropriate interaction with deployed protocols. The RFC Editor has chosen to publish this document at its discretion. Readers of this document should exercise caution in evaluating its value for implementation and deployment. See [RFC3932] for more information.
本RFC不适用于任何级别的互联网标准。IETF不承认本RFC适用于任何目的的任何知识，并特别指出，发布决定并非基于IETF对安全、拥塞控制或与已部署协议的不当交互等事项的审查。RFC编辑已自行决定发布本文件。本文档的读者在评估其实施和部署价值时应谨慎。有关更多信息，请参阅[RFC3932]。
Abstract
摘要
This document describes the requirements for the logical entity known as the Session Initiation Protocol (SIP)-H.323 Interworking Function (SIP-H.323 IWF) that will allow the interworking between SIP and H.323.
本文件描述了称为会话发起协议（SIP）的逻辑实体的要求，即允许SIP和H.323之间互通的H.323互通功能（SIP-H.323 IWF）。
Table of Contents
目录
1. Introduction ....................................................3
2. Definitions .....................................................3
3. Functionality within the SIP-H.323 IWF ..........................4
4. Pre-Call Requirements ...........................................4
4.1. Registration with H.323 Gatekeeper .........................5
4.2. Registration with SIP Server ...............................5
5. General Interworking Requirements ...............................5
5.1. Basic Call Requirements ....................................5
5.1.1. General Requirements ................................5
5.1.2. Address Resolution ..................................6
5.1.3. Call with H.323 Gatekeeper ..........................6
5.1.4. Call with SIP Registrar .............................6
5.1.5. Capability Negotiation ..............................6
5.1.6. Opening of Logical Channels .........................7
5.2. IWF H.323 Features .........................................7
5.3. Overlapped Sending .........................................7
5.3.1. DTMF Support ........................................7
6. Transport .......................................................8
7. Mapping between SIP and H.323 ...................................8
7.1. General Requirements .......................................8
7.2. H.225.0 and SIP Call Signaling .............................8
7.3. Call Sequence ..............................................9
7.4. State Machine Requirements .................................9
8. Security Considerations ........................................10
9. Examples and Scenarios .........................................10
9.1. Introduction ..............................................10
9.2. IWF Configurations ........................................11
9.3. Call Flows ................................................11
9.3.1. Call from H.323 Terminal to SIP UA .................11
9.3.2. Call from SIP UA to H.323 Terminal .................12
10. Acknowledgments ...............................................12
11. Contributors ..................................................13
12. References ....................................................14
12.1. Normative References ....................................14
12.2. Informative References ..................................15
1. Introduction ....................................................3
2. Definitions .....................................................3
3. Functionality within the SIP-H.323 IWF ..........................4
4. Pre-Call Requirements ...........................................4
4.1. Registration with H.323 Gatekeeper .........................5
4.2. Registration with SIP Server ...............................5
5. General Interworking Requirements ...............................5
5.1. Basic Call Requirements ....................................5
5.1.1. General Requirements ................................5
5.1.2. Address Resolution ..................................6
5.1.3. Call with H.323 Gatekeeper ..........................6
5.1.4. Call with SIP Registrar .............................6
5.1.5. Capability Negotiation ..............................6
5.1.6. Opening of Logical Channels .........................7
5.2. IWF H.323 Features .........................................7
5.3. Overlapped Sending .........................................7
5.3.1. DTMF Support ........................................7
6. Transport .......................................................8
7. Mapping between SIP and H.323 ...................................8
7.1. General Requirements .......................................8
7.2. H.225.0 and SIP Call Signaling .............................8
7.3. Call Sequence ..............................................9
7.4. State Machine Requirements .................................9
8. Security Considerations ........................................10
9. Examples and Scenarios .........................................10
9.1. Introduction ..............................................10
9.2. IWF Configurations ........................................11
9.3. Call Flows ................................................11
9.3.1. Call from H.323 Terminal to SIP UA .................11
9.3.2. Call from SIP UA to H.323 Terminal .................12
10. Acknowledgments ...............................................12
11. Contributors ..................................................13
12. References ....................................................14
12.1. Normative References ....................................14
12.2. Informative References ..................................15
The SIP-H.323 Interworking function (IWF) converts between SIP (Session Initiation Protocol) [RFC3261] and the ITU Recommendation H.323 protocol [H.323]. This document describes requirements for this protocol conversion.
SIP-H.323互通功能（IWF）在SIP（会话发起协议）[RFC3261]和ITU推荐的H.323协议[H.323]之间进行转换。本文件描述了此协议转换的要求。
H.323 gatekeeper (GK): An H.323 gatekeeper is an optional component in an H.323 network. If it is present, it performs address translation, bandwidth control, admission control, and zone management.
H.323网守（GK）：H.323网守是H.323网络中的可选组件。如果存在，它将执行地址转换、带宽控制、许可控制和区域管理。
H.323 network: In this document, we refer to the collection of all H.323-speaking components as the H.323 network.
323网络：在本文档中，我们将所有讲H.323的组件的集合称为H.323网络。
SIP network: In this document, we refer to the collection of all SIP servers and user agents as the SIP network.
SIP网络：在本文档中，我们将所有SIP服务器和用户代理的集合称为SIP网络。
Interworking Function (IWF): This function performs interworking between H.323 and SIP. It belongs to both the H.323 and SIP networks.
互通功能（IWF）：该功能执行H.323和SIP之间的互通。它同时属于H.323和SIP网络。
SIP server: A SIP server can be a SIP proxy, redirect server, or registrar server.
SIP服务器：SIP服务器可以是SIP代理、重定向服务器或注册服务器。
Endpoint: An endpoint can call and be called. An endpoint is an entity from which the media such as voice, video, or fax originates or terminates. An endpoint can be H.323 terminal, H.323 Gateway, H.323 MCU [H.323], or SIP user agent (UA) [RFC3261].
端点：端点可以调用，也可以被调用。端点是一个实体，语音、视频或传真等媒体从该实体发起或终止。端点可以是H.323终端、H.323网关、H.323 MCU[H.323]或SIP用户代理（UA）[RFC3261]。
Media-Switching Fabric (MSF): This is an optional logical entity within the IWF. The MSF switches media such as voice, video, or fax from one network association to another.
媒体交换结构（MSF）：这是IWF中的可选逻辑实体。MSF将语音、视频或传真等媒体从一个网络协会切换到另一个网络协会。
This section summarizes the functional requirements of the SIP-H.323 interworking function (IWF).
本节总结了SIP-H.323互通功能（IWF）的功能需求。
A SIP-H.323 IWF may be integrated into an H.323 gatekeeper or SIP server. Interworking should not require any optional components in either the SIP or H.323 network, such as H.323 gatekeepers. IWF redundancy in the network is beyond the scope of this document.
SIP-H.323 IWF可以集成到H.323网守或SIP服务器中。互通不应要求SIP或H.323网络中的任何可选组件，如H.323网关守卫。网络中的IWF冗余超出了本文档的范围。
An IWF contains functions from the following list, inter alia:
除其他外，IWF包含以下列表中的函数：
o Mapping of the call setup and teardown sequences;
o 呼叫设置和拆卸序列的映射；
o Registering H.323 and SIP endpoints with SIP registrars and H.323 gatekeepers;
o 向SIP注册器和H.323网关管理员注册H.323和SIP端点；
o Resolving H.323 and SIP addresses;
o 解析H.323和SIP地址；
o Maintaining the H.323 and SIP state machines;
o 维护H.323和SIP状态机；
o Negotiating terminal capabilities;
o 谈判终端能力；
o Opening and closing media channels;
o 开放和关闭媒体渠道；
o Mapping media-coding algorithms for H.323 and SIP networks;
o 为H.323和SIP网络映射媒体编码算法；
o Reserving and releasing call-related resources;
o 预留和释放呼叫相关资源；
o Processing of mid-call signaling messages;
o 中间呼叫信令消息的处理；
o Handling of services and features.
o 服务和功能的处理。
The IWF should not process media. We assume that the same media transport protocols, such as RTP, are used in both the SIP and H.323 networks. Thus, media packets are exchanged directly between the endpoints. If a particular service requires the IWF to handle media, we assume that the IWF simply forwards media packets without modification from one network to the other, using a media-switching fabric (MSF). The conversion of media from one encoding or format to another is out of scope for SIP-H.323 protocol translation.
IWF不应处理介质。我们假设在SIP和H.323网络中使用相同的媒体传输协议，如RTP。因此，在端点之间直接交换媒体分组。如果特定服务需要IWF处理媒体，我们假设IWF使用媒体交换结构（MSF）简单地将媒体包从一个网络转发到另一个网络，而不进行修改。将媒体从一种编码或格式转换为另一种编码或格式超出了SIP-H.323协议转换的范围。
The IWF function may use a translation table to resolve the H.323 and SIP addresses to IP addresses. This translation table can be updated by using an H.323 gatekeeper, a SIP proxy server, or a locally-maintained database.
IWF功能可以使用转换表将H.323和SIP地址解析为IP地址。此转换表可以通过使用H.323网守、SIP代理服务器或本地维护的数据库进行更新。
An IWF may provide and update the H.323 gatekeeper with the addresses of SIP UAs. A SIP user agent can make itself known to the H.323 network by registering with an IWF serving as a registrar. The IWF creates an H.323 alias address and registers this alias, together with its own network address, with the appropriate GK.
IWF可以向H.323网守提供和更新SIP UAs的地址。SIP用户代理可以通过向充当注册器的IWF注册而使H.323网络知道自己。IWF创建一个H.323别名地址，并将该别名及其自己的网络地址注册到相应的GK。
The gatekeeper can then use this information to route calls to SIP UAs via the IWF, without being aware that the endpoint is not a "native" H.323 endpoint.
然后，网守可以使用此信息通过IWF将呼叫路由到SIP UAs，而不知道端点不是“本机”H.323端点。
The IWF can register SIP UAs with one or more H.323 gatekeepers.
IWF可以向一个或多个H.323网守注册SIP UAs。
The IWF can provide information about H.323 endpoints to a SIP registrar. This allows the SIP proxy using this SIP registrar to direct calls to the H.323 endpoints via the IWF.
IWF可以向SIP注册器提供关于H.323端点的信息。这允许使用此SIP注册器的SIP代理通过IWF将呼叫定向到H.323端点。
The IWF can easily obtain information about H.323 endpoints if it also serves as a gatekeeper. Other architectures require further study.
如果IWF还充当网守的话，它可以很容易地获得关于H.323端点的信息。其他架构需要进一步研究。
If the H.323 endpoints are known through E.164 (telephone number) addresses, the IWF can use IGREP [TGREP] or SLP [GWLOC] to inform the SIP proxy server of these endpoints.
如果通过E.164（电话号码）地址知道H.323端点，IWF可以使用IGREP[TGREP]或SLP[GWLOC]通知SIP代理服务器这些端点。
The IWF only needs to register with multiple SIP registrars if the H.323 terminal is to appear under multiple, different addresses-of-record.
如果H.323终端出现在多个不同的记录地址下，IWF只需要向多个SIP注册器注册。
The IWF should use H.323 Version 2 or later and SIP according to RFC 3261 [RFC3261]. The protocol translation function must not require modifications or additions to either H.323 or SIP. However, it may not be possible to support certain features of each protocol across the IWF.
IWF应根据RFC 3261[RFC3261]使用H.323版本2或更高版本和SIP。协议转换功能不得要求对H.323或SIP进行修改或添加。但是，可能不可能跨IWF支持每个协议的某些功能。
The IWF should provide default settings for translation parameters. The IWF specification must identify these defaults.
IWF应提供翻译参数的默认设置。IWF规范必须识别这些默认值。
The IWF must release any call-related resource at the end of a call. SIP session timers [RFC4028] may be used on the SIP side.
IWF必须在呼叫结束时释放任何与呼叫相关的资源。SIP会话计时器[RFC4028]可在SIP端使用。
The IWF should support all the addressing schemes in H.323, including the H.323 URI [RFC3508], and the "sip", "sips", and "tel" URI schemes in SIP. It should support the DNS-based SIP server location mechanisms described in [RFC3263] and H.323 Annex O, which details how H.323 uses DNS and, in particular, DNS SRV records.
IWF应该支持H.323中的所有寻址方案，包括H.323URI[RFC3508]，以及sip中的“sip”、“sips”和“tel”URI方案。它应该支持[RFC3263]和H.323附录O中描述的基于DNS的SIP服务器定位机制，其中详细说明了H.323如何使用DNS，尤其是DNS SRV记录。
The IWF should register with the H.323 Gatekeeper and the SIP registrar when available.
IWF应在可用时向H.323网守和SIP注册器注册。
The IWF may use any means to translate between SIP and H.323 addresses. Examples include translation tables populated by the gatekeeper, SIP registrar or other database, LDAP, DNS or TRIP.
IWF可以使用任何方式在SIP和H.323地址之间进行转换。示例包括由网守、SIP注册器或其他数据库、LDAP、DNS或TRIP填充的转换表。
When an H.323 GK is present in the network, the IWF should resolve addresses with the help of the GK.
当网络中存在H.323 GK时，IWF应在GK的帮助下解析地址。
The IWF applies normal SIP call routing and does not need to be aware whether there is a proxy server.
IWF应用正常的SIP呼叫路由，不需要知道是否有代理服务器。
The IWF should not make any assumptions about the capabilities of either the SIP user agent or the H.323 terminal. However, it may indicate a guaranteed-to-be-supported list of codecs of the H.323 terminal or SIP user agent before exchanging capabilities with H.323 (using H.245) and SIP (using SDP [RFC2327]). H.323 defines mandatory capabilities, whereas SIP currently does not. For example, the G.711 audio codec is mandatory for higher bandwidth H.323 networks.
IWF不应对SIP用户代理或H.323终端的能力做出任何假设。然而，在与H.323（使用H.245）和SIP（使用SDP[RFC2327]）交换能力之前，它可以指示H.323终端或SIP用户代理的保证支持的编解码器列表。323定义了强制功能，而SIP目前没有。例如，G.711音频编解码器对于更高带宽的H.323网络是强制性的。
The IWF should attempt to map the capability descriptors of H.323 and SDP in the best possible fashion. The algorithm for finding the best mapping between H.245 capability descriptors and the corresponding SDP is left for further study.
IWF应尝试以最佳方式映射H.323和SDP的能力描述符。寻找H.245能力描述符与相应SDP之间最佳映射的算法留待进一步研究。
The IWF should be able to map the common audio, video, and application format names supported in H.323 to and from the equivalent RTP/AVP [RFC3550] names.
IWF应该能够将H.323中支持的通用音频、视频和应用程序格式名称映射到等效的RTP/AVP[RFC3550]名称，并从中映射。
The IWF may use the SIP OPTIONS message to derive SIP UA capabilities. It may support mid-call renegotiation of media capabilities.
IWF可以使用SIP选项消息来派生SIP UA能力。它可能支持媒体功能的通话中重新协商。
The IWF should support the seamless exchange of messages for opening, reopening, changing, and closing of media channels during a call. The procedures for opening, reopening, closing, and changing the existing media sessions during a call are for further study.
IWF应支持在通话期间打开、重新打开、更改和关闭媒体频道的无缝消息交换。通话期间打开、重新打开、关闭和更改现有媒体会话的程序有待进一步研究。
The IWF should open media channels between the endpoints whenever possible. If this is not possible, then the channel can be opened at the MSF of the IWF.
IWF应尽可能在端点之间打开媒体通道。如果不可能，则可以在IWF的MSF处打开通道。
The IWF should support unidirectional, symmetric bi-directional, and asymmetric bi-directional opening of channels.
IWF应支持单向、对称双向和非对称双向通道开放。
The IWF may respond to the mode request and to the request for reopening and changing an existing logical channel and may support the flow control mechanism in H.323.
IWF可以响应模式请求以及重新打开和改变现有逻辑信道的请求，并且可以支持H.323中的流控制机制。
The IWF should support Fast Connect; i.e., H.245 tunneling in H.323 Setup messages. If IWF and GK are the same device, pre-granted ARQ should be supported. If pre-granted ARQ is supported, the IWF may perform the address resolution from H.323 GK using the LRQ/LCF exchange.
IWF应支持快速连接；i、 例如，H.323设置消息中的H.245隧道。如果IWF和GK是同一设备，则应支持预先授予的ARQ。如果支持预授权ARQ，IWF可以使用LRQ/LCF交换从H.323 GK执行地址解析。
An IWF should follow the recommendations outlined in [RFC3578] when receiving overlapped digits from the H.323 side. If the IWF receives overlapped dialed digits from the SIP network, it may use the Q.931 Setup, Setup Ack, and Information Message in H.323.
当从H.323侧接收重叠数字时，IWF应遵循[RFC3578]中概述的建议。如果IWF从SIP网络接收到重叠拨号数字，它可以使用H.323中的Q.931设置、设置确认和信息消息。
The IWF may support the transfer of digits during a call by using the appropriate SIP mechanism and UserInputIndication in H.245 (H.323).
IWF可以通过使用H.245（H.323）中的适当SIP机制和用户输入指示来支持呼叫期间的数字传输。
An IWF should support the mapping between DTMF and possibly other telephony tones carried in signaling messages.
IWF应支持DTMF和信令消息中可能携带的其他电话铃声之间的映射。
The H.323 and SIP systems do not have to be in close proximity. The IP networks hosting the H.323 and SIP systems do not need to assure quality of service (QoS). In particular, the IWF should not assume that signaling messages have priority over packets from other applications. H.323 signaling over UDP (H.323 Annex E) is optional.
H.323和SIP系统不必非常接近。承载H.323和SIP系统的IP网络不需要确保服务质量（QoS）。特别地，IWF不应假定信令消息比来自其他应用的分组具有优先级。UDP上的H.323信令（H.323附录E）是可选的。
o The call message sequence of both protocols must be maintained.
o 必须维护两个协议的呼叫消息序列。
o The IWF must not set up or tear down calls on its own.
o IWF不得自行设置或中断呼叫。
o Signaling messages that do not have a match for the destination protocol should be terminated on the IWF, with the IWF taking the appropriate action for them. For example, SIP allows a SIP UA to discard an ACK request silently for a non-existent call leg.
o 对于与目标协议不匹配的信令消息，应在IWF上终止，并由IWF对其采取适当的操作。例如，SIP允许SIP UA对不存在的呼叫段无提示地放弃ACK请求。
o If the IWF is required to generate a message on its own, IWF should use pre-configured default values for the message parameters.
o 如果需要IWF自行生成消息，IWF应使用消息参数的预配置默认值。
o The information elements and header fields of the respective messages are to be converted as follows:
o 各消息的信息元素和报头字段将转换如下：
* The contents of connection-specific information elements, such as Call Reference Value for H.323, are converted to similar information required by SIP or SDP, such as the SDP session ID and the SIP 'Call-ID'.
* 连接特定信息元素的内容，例如H.323的呼叫参考值，被转换为SIP或SDP所需的类似信息，例如SDP会话ID和SIP“呼叫ID”。
* The IWF generates protocol elements that are not available from the other side.
* IWF生成从另一端不可用的协议元素。
o The IWF must conform to the call signaling procedures recommended for the SIP side regardless of the behavior of the H.323 elements.
o 无论H.323元素的行为如何，IWF必须符合为SIP侧推荐的呼叫信令过程。
o The IWF must conform to the call signaling procedures recommended for the H.323 side regardless of the behavior of the SIP elements.
o 无论SIP元素的行为如何，IWF必须符合H.323侧建议的呼叫信令程序。
o The IWF serves as the endpoint for the Q.931 Call Signaling Channel to either an H.323 endpoint or H.323 Gatekeeper (in case of GK routed signaling). The IWF also acts as a SIP user agent client and server.
o IWF用作H.323端点或H.323网守（在GK路由信令的情况下）的Q.931呼叫信令信道的端点。IWF还充当SIP用户代理客户端和服务器。
o The IWF also establishes a Registration, Admission, Status (RAS) Channel to the H.323 GK, if available.
o IWF还建立了H.323 GK的注册、接纳、状态（RAS）通道（如果可用）。
o The IWF should process messages for H.323 supplementary services (FACILITY, NOTIFY, and the INFORMATION messages) only if the service itself is supported.
o 仅当支持H.323补充业务时，IWF才应处理该业务的消息（设施、通知和信息消息）。
The call sequence on both sides should be maintained in such a way that neither the H.323 terminal nor the SIP UA is aware of presence of the IWF.
两侧的呼叫序列应以这样的方式保持，即H.323终端或SIP UA都不知道IWF的存在。
The state machine for IWF will follow the following general guidelines:
IWF的状态机将遵循以下一般准则：
o Unexpected messages in a particular state shall be treated as "error" messages.
o 特殊状态下的意外消息应视为“错误”消息。
o All messages that do not change the state shall be treated as "non-triggering" or informational messages.
o 所有不改变状态的信息应视为“非触发”或信息性信息。
o All messages that expect a change in state shall be treated as "triggering" messages.
o 所有预期状态变化的信息应视为“触发”信息。
For each state, an IWF specification must classify all possible protocol messages into the above three categories. It must specify the actions taken on the content of the message and the resulting state. Below is an example of such a table:
对于每个状态，IWF规范必须将所有可能的协议消息分类为上述三类。它必须指定对消息内容采取的操作以及结果状态。以下是此类表格的示例：
State: Idle
状态：空闲
Possible Messages Message Category Action Next state
-------------------------------------------------------------------
All RAS msg. Triggering Add Reg.Info. WaitForSetup
All H.245 msg. Error Send 4xx Idle
SIP OPTIONS Non Triggering Return cap. Idle
SIP INVITE Triggering Send SETUP WaitForConnect
Possible Messages Message Category Action Next state
-------------------------------------------------------------------
All RAS msg. Triggering Add Reg.Info. WaitForSetup
All H.245 msg. Error Send 4xx Idle
SIP OPTIONS Non Triggering Return cap. Idle
SIP INVITE Triggering Send SETUP WaitForConnect
Because the IWF whose requirements have been described in this document combines both SIP and H.323 functionality, security considerations for both of these protocols apply.
由于本文档中描述了其要求的IWF结合了SIP和H.323功能，因此适用于这两种协议的安全注意事项。
The eventual security solution for interworking must rely on the standard mechanisms in RFC3261 [RFC3261] and H.323, without extending them for the interworking function. Signaling security for H.323 is described in H.235 [H.235].
互通的最终安全解决方案必须依赖于RFC3261[RFC3261]和H.323中的标准机制，而不扩展它们的互通功能。H.235[H.235]中描述了H.323的信令安全性。
Because all data elements in SIP or H.323 have to terminate at the IWF, the resulting security cannot be expected to be end-to-end. Thus, the IWF terminates not only the signalling protocols but also the security in each domain. Therefore, users at the SIP or H.323 endpoint have to trust the IWF, like they would any other gateway, to authenticate the other side correctly. Similarly, they have to trust the gateway to respect the integrity of data elements and to apply appropriate security mechanisms on the other side of the IWF.
由于SIP或H.323中的所有数据元素都必须在IWF处终止，因此不能期望得到端到端的安全性。因此，IWF不仅终止信令协议，而且终止每个域中的安全性。因此，SIP或H.323端点的用户必须信任IWF，就像他们信任任何其他网关一样，才能正确地对另一方进行身份验证。类似地，他们必须信任网关尊重数据元素的完整性，并在IWF的另一端应用适当的安全机制。
The IWF must not indicate the identity of a user on one side without first performing authentication. For example, if the SIP user was not authenticated, it would be inappropriate to use mechanisms on the H.323 side, such as H.323 Annex D, to indicate that the user identity had been authenticated.
在未首先执行身份验证之前，IWF不得在一侧指示用户的身份。例如，如果SIP用户未被认证，则在H.323侧使用诸如H.323附录D的机制来指示用户身份已被认证是不合适的。
An IWF must not accept 'sips' requests unless it can guarantee that the H.323 side uses equivalent H.235 [H.235] security mechanisms. Similarly, the IWF must not accept H.235 sessions unless it succeeds in using SIP-over-TLS (sips) on the SIP side of the IWF.
IWF不得接受“sips”请求，除非它能保证H.323端使用等效的H.235[H.235]安全机制。类似地，IWF必须不接受H.235会话，除非它成功地在IWF的SIP端使用SIPover TLS（sips）。
We present some examples of call scenarios that will show the signaling messages received and transmitted. The following situations can occur:
我们给出了一些呼叫场景的示例，这些示例将显示接收和传输的信令消息。可能出现以下情况：
o Some signaling messages can be translated one-to-one.
o 一些信令消息可以一对一地翻译。
o In some cases, parameters on one side do not match those on the other side.
o 在某些情况下，一侧的参数与另一侧的参数不匹配。
o Some signaling messages do not have an equivalent message on the other side. In some cases, the IWF can gather further information and the signal on the other side. In some cases, only an error indication can be provided.
o 某些信令消息在另一侧没有等效消息。在某些情况下，IWF可以收集另一侧的进一步信息和信号。在某些情况下，只能提供错误指示。
Below are some common architectures involving an IWF:
以下是一些涉及IWF的常见架构：
Basic Configuration: H.323 EP -- IWF -- SIP UA
Basic Configuration: H.323 EP -- IWF -- SIP UA
Calls using H.323 GK: H.323 EP -- H.323 GK -- IWF -- SIP UA
Calls using H.323 GK: H.323 EP -- H.323 GK -- IWF -- SIP UA
Calls using SIP proxies: H.323 EP -- IWF -- SIP proxies -- SIP UA
Calls using SIP proxies: H.323 EP -- IWF -- SIP proxies -- SIP UA
Calls using both H.323 GK and SIP proxy: H.323 EP -- H.323 GK -- IWF
-- SIP proxies -- SIP UA
Calls using both H.323 GK and SIP proxy: H.323 EP -- H.323 GK -- IWF
-- SIP proxies -- SIP UA
SIP trunking between H.323 networks: H.323 EP -- IWF -- SIP network
-- IWF -- H.323 EP
SIP trunking between H.323 networks: H.323 EP -- IWF -- SIP network
-- IWF -- H.323 EP
H.323 trunking between SIP networks: SIP EP -- IWF -- H.323 network
-- IWF -- SIP UA
H.323 trunking between SIP networks: SIP EP -- IWF -- H.323 network
-- IWF -- SIP UA
Some call flow examples for two different configurations and call scenarios are given below.
下面给出了两种不同配置和调用场景的一些调用流示例。
H.323 SIP
EP Setup IWF UA
|------------>| INVITE |
| |------------>|
| | 180 RINGING |
| Alerting |<------------|
|<------------| 200 OK |
| Connect |<------------|
|<------------| |
| H.245 | |
|<----------->| ACK |
| |------------>|
| RTP |
|<.........................>|
H.323 SIP
EP Setup IWF UA
|------------>| INVITE |
| |------------>|
| | 180 RINGING |
| Alerting |<------------|
|<------------| 200 OK |
| Connect |<------------|
|<------------| |
| H.245 | |
|<----------->| ACK |
| |------------>|
| RTP |
|<.........................>|
SIP H.323
UA IWF EP
| | |
| INVITE | |
|------------>| Setup |
| |------------>|
| | Alerting |
| 180 RINGING |<------------|
|<------------| Connect |
| |<------------|
| | H.245 |
| 200 OK |<----------->|
|<------------| |
| ACK | |
|------------>| |
| RTP |
|<.........................>|
SIP H.323
UA IWF EP
| | |
| INVITE | |
|------------>| Setup |
| |------------>|
| | Alerting |
| 180 RINGING |<------------|
|<------------| Connect |
| |<------------|
| | H.245 |
| 200 OK |<----------->|
|<------------| |
| ACK | |
|------------>| |
| RTP |
|<.........................>|
The authors would like to acknowledge the many contributors who discussed the SIP-H.323 interworking architecture and requirements on the IETF, SIP, and SG16 mailing lists. In particular, we would like to thank Joon Maeng, Dave Walker, and Jean-Francois Mule. Contributions to this document have also been made by members of the H.323, aHIT!, TIPHON, and SG16 forums.
作者想感谢许多讨论SIP-H.323互通体系结构和IETF、SIP和SG16邮件列表要求的贡献者。特别是，我们要感谢Joon Maeng、Dave Walker和Jean-Francois Mule。H.323，aHIT！的成员也对本文件作出了贡献！，TIPHON和SG16论坛。
In addition to the editors, the following people provided substantial technical and written contributions to this document. They are listed alphabetically.
除编辑外，以下人员为本文件提供了大量技术和书面意见。它们按字母顺序排列。
Hemant Agrawal Telverse Communications 1010 Stewart Drive Sunnyale, CA 94085 USA
美国加利福尼亚州桑尼亚勒斯图尔特大道1010号赫曼特·阿格拉瓦尔Telverse Communications，邮编94085
EMail: hagrawal@telverse.com
EMail: hagrawal@telverse.com
Alan Johnston MCI WorldCom 100 South Fourth Street St. Louis, MO 63102 USA
美国密苏里州圣路易斯南第四街100号艾伦·约翰斯顿MCI世界通信公司，邮编63102
EMail: alan.johnston@wcom.com
EMail: alan.johnston@wcom.com
Vipin Palawat Cisco Systems Inc. 900 Chelmsford Street Lowell, MA 01851 USA
Vipin Palawat思科系统有限公司，地址：美国马萨诸塞州洛厄尔切姆斯福德街900号，邮编：01851
EMail: vpalawat@cisco.com
EMail: vpalawat@cisco.com
Radhika R. Roy AT&T Room C1-2B03 200 Laurel Avenue S. Middletown, NJ 07748 USA
美国新泽西州米德尔顿市劳雷尔大道200号拉迪卡R.罗伊电话电报室C1-2B03 07748
EMail: rrroy@att.com
EMail: rrroy@att.com
Kundan Singh Dept. of Computer Science Columbia University 1214 Amsterdam Avenue, MC 0401 New York, NY 10027 USA
昆丹·辛格美国纽约州纽约市阿姆斯特丹大道1214号哥伦比亚大学计算机科学系邮编：10027
EMail: kns10@cs.columbia.edu
EMail: kns10@cs.columbia.edu
David Wang Nuera Communications Inc. 10445 Pacific Center Court San Diego, CA 92121 USA
David Wang Nuera Communications Inc.美国加利福尼亚州圣地亚哥太平洋中心法院10445号，邮编92121
EMail: dwang@nuera.com
EMail: dwang@nuera.com
[H.235] International Telecommunication Union, "Security and encryption for H-Series (H.323 and other H.245-based) multimedia terminals", Recommendation H.235, February 1998.
[H.235]国际电信联盟，“H系列（H.323和其他基于H.245的）多媒体终端的安全和加密”，建议H.235，1998年2月。
[H.323] International Telecommunication Union, "Packet based multimedia communication systems", Recommendation H.323, July 2003.
[H.323]国际电信联盟，“基于分组的多媒体通信系统”，建议H.323，2003年7月。
[RFC2327] Handley, M. and V. Jacobson, "SDP: Session Description Protocol", RFC 2327, April 1998.
[RFC2327]Handley，M.和V.Jacobson，“SDP：会话描述协议”，RFC 2327，1998年4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。
[RFC3508] Levin, O., "H.323 Uniform Resource Locator (URL) Scheme Registration", RFC 3508, April 2003.
[RFC3508]Levin，O.，“H.323统一资源定位器（URL）方案注册”，RFC3508，2003年4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。
[GWLOC] Zhao, W. and H. Schulzrinne, "Locating IP-to-Public Switched Telephone Network (PSTN) Telephony Gateways via SLP", work in progress, February 2004.
[GWLOC]Zhao，W.和H.Schulzrinne，“通过SLP将IP定位到公共交换电话网（PSTN）电话网关”，正在进行的工作，2004年2月。
[RFC3578] Camarillo, G., Roach, A., Peterson, J., and L. Ong, "Mapping of Integrated Services Digital Network (ISDN) User Part (ISUP) Overlap Signalling to the Session Initiation Protocol (SIP)", RFC 3578, August 2003.
[RFC3578]Camarillo，G.，Roach，A.，Peterson，J.，和L.Ong，“综合业务数字网（ISDN）用户部分（ISUP）重叠信令到会话发起协议（SIP）的映射”，RFC 3578，2003年8月。
[RFC3932] Alvestrand, H., "The IESG and RFC Editor Documents: Procedures", BCP 92, RFC 3932, October 2004.
[RFC3932]Alvestrand，H.，“IESG和RFC编辑文件：程序”，BCP 92，RFC 3932，2004年10月。
[RFC4028] Donovan, S. and J. Rosenberg, "Session Timers in the Session Initiation Protocol (SIP)", RFC 4028, April 2005.
[RFC4028]Donovan，S.和J.Rosenberg，“会话启动协议（SIP）中的会话计时器”，RFC4028，2005年4月。
[TGREP] Bangalore, M., "A Telephony Gateway REgistration Protocol (TGREP)", work in progress, March 2004.
[TGREP]班加罗尔，M.，“电话网关注册协议（TGREP）”，正在进行的工作，2004年3月。
Authors' Addresses
作者地址
Henning Schulzrinne Columbia University Department of Computer Science 450 Computer Science Building New York, NY 10027 US
美国纽约州纽约市哥伦比亚大学计算机科学系计算机科学大楼450号
Phone: +1 212 939 7042
EMail: hgs@cs.columbia.edu
URI: http://www.cs.columbia.edu
Phone: +1 212 939 7042
EMail: hgs@cs.columbia.edu
URI: http://www.cs.columbia.edu
Charles Agboh 61 Bos Straat 3540 Herk-de-Stad Belgium
Charles Agboh 61 Bos Straat 3540 Herk de Stad比利时
Phone: +32479736250
EMail: charles.agboh@packetizer.com
Phone: +32479736250
EMail: charles.agboh@packetizer.com
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确认
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