[转帖]基于H.323和SIP协议的视频会议网关的设计和实现

翔羽

<p class="MsoNormal" align="center" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: center;"><b><span style="FONT-SIZE: 16pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">基于</span></b><b><span lang="EN-US" style="FONT-SIZE: 16pt; mso-bidi-font-size: 12.0pt;"><font face="Times New Roman">H.323</font></span></b><b><span style="FONT-SIZE: 16pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">和</span></b><b><span lang="EN-US" style="FONT-SIZE: 16pt; mso-bidi-font-size: 12.0pt;"><font face="Times New Roman">SIP</font></span></b><b><span style="FONT-SIZE: 16pt; FONT-FAMILY: 宋体; mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">协议的视频会议网关的设计和实现</span></b><b><span lang="EN-US" style="FONT-SIZE: 16pt; mso-bidi-font-size: 12.0pt;"><p></p></span></b></p><p class="MsoNormal" align="center" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: center;"><b><span lang="EN-US" style="FONT-SIZE: 16pt; mso-bidi-font-size: 12.0pt;"><p><font face="Times New Roman">&nbsp;</font></p></span></b></p><p class="MsoNormal" align="center" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: center;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">何泽松</span><span lang="EN-US"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp; </font></span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">洪</span><font face="Times New Roman"> </font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">玫</span><span lang="EN-US"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp; </font></span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">孙子龙</span></p><p class="MsoNormal" align="center" style="MARGIN: 0cm 0cm 0pt; TEXT-ALIGN: center;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">（四川大学</span><font face="Times New Roman"> </font><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">计算机科学与技术学院</span><span lang="EN-US"><font face="Times New Roman"> 610065</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">）</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">摘要</span><span lang="EN-US"><span style="mso-spacerun: yes;"><font face="Times New Roman">&nbsp; </font></span></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">随着</span><span lang="EN-US"><font face="Times New Roman">VOIP</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">技术的不断发展和成熟，视频会议系统已成为计算机通信技术的重要方面。本文针对支持多协议的视频会议系统的设计和实现，分析了目前在可视通信领域的两大主流协议</span><span lang="EN-US"><font face="Times New Roman">H.323</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">和</span><span lang="EN-US"><font face="Times New Roman">SIP</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">的特点和差异，给出了解决</span><span lang="EN-US"><font face="Times New Roman">H.323</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">和</span><span lang="EN-US"><font face="Times New Roman">SIP</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">之间的协议转换的网关设计方案。</span><span lang="EN-US"><font face="Times New Roman"> </font></span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21pt; mso-char-indent-count: 2.0;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">关键词</span><span lang="EN-US"><font face="Times New Roman"> H.323</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">；</span><span lang="EN-US"><font face="Times New Roman">SIP</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">；</span><span lang="EN-US"><font face="Times New Roman">MC</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">；视频会议网关；协议转换</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"><b><span lang="EN-US" style="FONT-SIZE: 12pt;"><font face="Times New Roman">1<span style="mso-spacerun: yes;">&nbsp; </span></font></span></b><b><span style="FONT-SIZE: 12pt; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">引言</span></b><b><span lang="EN-US" style="FONT-SIZE: 12pt;"><p></p></span></b></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">随着宽带网络的不断发展和普及，人们对视频通讯的需求也越来越大。在视频通讯领域起主导地位的两大协议包括：由</span><span lang="EN-US"><font face="Times New Roman">ITU-U</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">（</span><font face="Times New Roman"><span lang="EN-US" style="COLOR: black; mso-bidi-font-size: 10.0pt;">International Telecommunications Union – Telecommunication Standardization Secto</span><span lang="EN-US" style="FONT-SIZE: 10pt; COLOR: black;">r</span></font><span style="FONT-SIZE: 10pt; COLOR: black; FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">，国际电信联盟电信标准部</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">）推荐的</span><span lang="EN-US"><font face="Times New Roman">H.323</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">协议和由</span><span lang="EN-US"><font face="Times New Roman">IETF</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">（</span><span lang="EN-US"><font face="Times New Roman">Internet Engineering Task Force,<span style="mso-spacerun: yes;">&nbsp; </span></font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">因特网工程任务组）推荐的</span><span lang="EN-US"><font face="Times New Roman">SIP</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">协议（</span><span lang="EN-US"><font face="Times New Roman">Session Initiation Protocol, </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">会话发起协议），由于这两个协议产生的时代背景</span><span style="FONT-FAMILY: 宋体;">、</span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">现有的发展状况和协议本身的特点等诸多不同的特性，决定了它们将会在视频通讯领域中长期的并存，形成相互竞争，相互补充的格局。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">因此，在可视通讯当中一项重要的工作就是要解决</span><span lang="EN-US"><font face="Times New Roman">H.323</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">和</span><span lang="EN-US"><font face="Times New Roman">SIP</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">之间的协议转换，即采用这两种协议的可视终端和设备的互连互通的问题。而视频会议系统是可视通讯中的重要应用，在设计视频会议系统时，采用网关设计实现不同网络之间的集成。</span><span lang="EN-US"><font face="Times New Roman">H.323</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">协议族中采用多点控制单元（</span><span lang="EN-US"><font face="Times New Roman">MCU</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">）来控制和管理会议系统，它由多点控制器（</span><span lang="EN-US"><font face="Times New Roman">MC</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">）和多点处理器（</span><span lang="EN-US"><font face="Times New Roman">MP</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">）组成，并运用集中、分散和混合三种不同的方法来实现会议的多点控制和管理。而在</span><span lang="EN-US"><font face="Times New Roman">SIP</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">协议中，则通过会话通告协议（</span><span lang="EN-US"><font face="Times New Roman">SAP</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">）和会话描述协议（</span><span lang="EN-US"><font face="Times New Roman">SDP</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';">）来建立多方会议。两者在机制上存在一定的差别，所以要实现互通就需要视频会议网关的支持。</span></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt;"></p><p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt;"><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman';"></span></p><p></p> 2DPDMEdV.doc (131 KB, 下载次数: 12)

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[转帖]基于H.323和SIP协议的视频会议网关的设计和实现

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