基于H.323电话网闸的设计与开发
摘要
随着计算机和宽带网络技术日新月异的发展,以多媒体通信为主体的信息网络已成为世界关注的热点,尤其是因特网的巨大成功已使IP成为未来信息网络的支柱技术。IP网络电话的出现预示了以IP为基础的新一代信息网络的出现。IP网络电话泛指在以IP为网络层协议的计算机网络中进行话音通信的系统。
IP电话作为"下一代电话"而倍受瞩目的原因,是与通信业务经营者所传输的语音量和IP信息量比率有关。以因特网为代表的IP通信的信息量,现在以指数函数的方式增加。由于在全部信息传输量中,IP信息量占极高的比例,因此整个网络应适应于IP信息量,少量的语言信息量也应搭载在IP网上,这比起分别建立IP网和语音网要经济得多。正因为如此,IP电话技术将成为未来的电话技术。
IP电话是一种数字电话,是技术创新的一种通信服务业务。它把语音、压缩编码、打包分组、分配路由、存储交换、解包解压等交换处理在IP网或互联网上实现语音通信。它促进了网络资源利用,降低语音业务成本。因此在全球范围内得到了迅速的发展,可以说是当仿世界上发展最快、普及最快的一门应用服务技术之一,也是计算机网络界关注的热点之一。
IP电话网闸是对IP电话系统中的节点(如:IP电话网关)进行管理,并为它们提供地址转换和呼叫控制服务。本文阐述了网闸的功能、特性及相关信令的描述与软件实现方案,并最终进行了系统测试;阐述了信令编/解码的基本原理、基本规则及系统信令编/解码的设计思想及方法。
With the development of computer networks and voice processing technology, real-time voice can be transmitted over the Internet, thus gives rise to the appearance of the IP telephony. Thanks to the voice compressing technology, the amount of data transferred over the Internet has been largely reduced. By using packet switch technology, the cost of IP telephone is remarkably lowered because of the full use of the network resources. Recently IP telephony technology has matured comparatively, and attracted a large number of customers.
The development of IP Telephony technology is very fast. Thought here has been integrity resolution, many problems should be paid more attention, such as QoS(quality of service) and network operating system. At present, most of IP Telephony system based on ITU-TH .323 standard, while some based on IETF SIP.
This dissertation introduces the programming idea of the gatekeeper system simply and discusses the key point of programming. Then, the frame and realization of the gateway program are discussed in details. In order to realize the real time transmission of voice and the credible transmission of signaling online and complete the control of flux of gateway communication, we often improve the structure of the gatekeeper program to adapt it. Finally, the debugging procedure is introduced.
IP电话作为"下一代电话"而倍受瞩目的原因,是与通信业务经营者所传输的语音量和IP信息量比率有关。以因特网为代表的IP通信的信息量,现在以指数函数的方式增加。由于在全部信息传输量中,IP信息量占极高的比例,因此整个网络应适应于IP信息量,少量的语言信息量也应搭载在IP网上,这比起分别建立IP网和语音网要经济得多。正因为如此,IP电话技术将成为未来的电话技术。
IP电话是一种数字电话,是技术创新的一种通信服务业务。它把语音、压缩编码、打包分组、分配路由、存储交换、解包解压等交换处理在IP网或互联网上实现语音通信。它促进了网络资源利用,降低语音业务成本。因此在全球范围内得到了迅速的发展,可以说是当仿世界上发展最快、普及最快的一门应用服务技术之一,也是计算机网络界关注的热点之一。
IP电话网闸是对IP电话系统中的节点(如:IP电话网关)进行管理,并为它们提供地址转换和呼叫控制服务。本文阐述了网闸的功能、特性及相关信令的描述与软件实现方案,并最终进行了系统测试;阐述了信令编/解码的基本原理、基本规则及系统信令编/解码的设计思想及方法。
With the development of computer networks and voice processing technology, real-time voice can be transmitted over the Internet, thus gives rise to the appearance of the IP telephony. Thanks to the voice compressing technology, the amount of data transferred over the Internet has been largely reduced. By using packet switch technology, the cost of IP telephone is remarkably lowered because of the full use of the network resources. Recently IP telephony technology has matured comparatively, and attracted a large number of customers.
The development of IP Telephony technology is very fast. Thought here has been integrity resolution, many problems should be paid more attention, such as QoS(quality of service) and network operating system. At present, most of IP Telephony system based on ITU-TH .323 standard, while some based on IETF SIP.
This dissertation introduces the programming idea of the gatekeeper system simply and discusses the key point of programming. Then, the frame and realization of the gateway program are discussed in details. In order to realize the real time transmission of voice and the credible transmission of signaling online and complete the control of flux of gateway communication, we often improve the structure of the gatekeeper program to adapt it. Finally, the debugging procedure is introduced.
引文
[1] ITU-T Recommendation H.323v2,Packet Based Multimedia Communication Systems,1998
[2] ITU-T Recommendation H.225.0v2,Media Stream Packetization and Synchronization for Visual Telephone Systems on Non-Guaranteed Quality of Service LANs,1998
[3] ITU-T Recommendation Q.931,Digital Subscriber Signalling System No.1(DSS 1)-ISDN User-Network Interface Layer 3 Specification for Basic Call Control,1993
[4] ITU-T Recommendation Q.932,Digital Subscriber Signalling System No.1(DSS 1)-Generic Procedures for the Control of ISDN Supplementary Services,1993
[5] ITU-T Recommendation Q.850,Usage of Cause and Location in the Digital Subscriber Signalling System No.1 and the Signalling System No.7 ISDN User Part,1998
[6] ITU-T Recommendation H.221,Frame structure for a 64 to 1920 kbit/s channel in audiovisual teleservices,1997
[7] ITU-T Recommendation E.164,The International Public Telecommunication Numbering Plan,1997
[8] ITU-T Recommendation X.680,Information Technology - Abstract Syntax Notation One(ASN.1):Specification of Basic Notation,1994
[9] ITU-T Recommendation X.680/Amd.1,Information Technology - Abstract Syntax Notation One(ASN.1):Specification of Basic Notation - Amendment 1:Rules of Extensibility ,1994
[10] ITU-T Recommendation X.682,Information Technology - Abstract Syntax Notation One(ASN.1):Constraint Specification,1994
[11] ITU-T Recommendation X.690,Information Technology - ASN.1 Encoding rules:Specification of Basic Encoding Rules(BER),Canonical Encoding Rules(CER)and Distinguished Encoding Rules(DER),1995
[12] ITU-T Recommendation X.691,Information Technology - ASN.1 Encoding rules - Specification of Packet Encoding Rules(PER),1995
[13]周明天,汪文勇:TCP/IP网络原理与技术,清华大学出版社,1993
[14]勾学荣,温致等:通信网的信令系统,人民邮电出版社,1996
[15] DOUALAS E.COMER,DAVID L.STEVENS。Internetworking With TCP/IP, Vol 3:Client– Server Programming and Application, Second Edition,,Prentice Hall Inc.,1991
[16]鲁士文:计算机网络原理与网络技术,机械工业出版社,1996
[17] H. Schulzrinne, "RTP Profile for Audio and Video Conferences with Minimal Control," RFC 1890, Internet Engineering Task Force,1996
[18] Kris Jamsa, Ken Cope: INTERNET编程,电子工业出版社1996.5
[19]蒋东兴,林鄂华:Windows Sockets网络程序设计指南,清华大学出版社,1995.12
[20]谭浩强:C程序设计,清华大学出版社,1991年7月
[21]张海藩:软件工程导论,清华大学出版社,1992年6月
[22]川木林森,高峰霞,奚红宇:Visual C++5.0使用与开发,清华大学出版社,199 7年11月
[23]黄东霖:多媒体视听业务,北京邮电大学出版社,1999年1月
[24]白刚,程时端: IP网上的话音通信技术,电信技术。1999年12月
[2] ITU-T Recommendation H.225.0v2,Media Stream Packetization and Synchronization for Visual Telephone Systems on Non-Guaranteed Quality of Service LANs,1998
[3] ITU-T Recommendation Q.931,Digital Subscriber Signalling System No.1(DSS 1)-ISDN User-Network Interface Layer 3 Specification for Basic Call Control,1993
[4] ITU-T Recommendation Q.932,Digital Subscriber Signalling System No.1(DSS 1)-Generic Procedures for the Control of ISDN Supplementary Services,1993
[5] ITU-T Recommendation Q.850,Usage of Cause and Location in the Digital Subscriber Signalling System No.1 and the Signalling System No.7 ISDN User Part,1998
[6] ITU-T Recommendation H.221,Frame structure for a 64 to 1920 kbit/s channel in audiovisual teleservices,1997
[7] ITU-T Recommendation E.164,The International Public Telecommunication Numbering Plan,1997
[8] ITU-T Recommendation X.680,Information Technology - Abstract Syntax Notation One(ASN.1):Specification of Basic Notation,1994
[9] ITU-T Recommendation X.680/Amd.1,Information Technology - Abstract Syntax Notation One(ASN.1):Specification of Basic Notation - Amendment 1:Rules of Extensibility ,1994
[10] ITU-T Recommendation X.682,Information Technology - Abstract Syntax Notation One(ASN.1):Constraint Specification,1994
[11] ITU-T Recommendation X.690,Information Technology - ASN.1 Encoding rules:Specification of Basic Encoding Rules(BER),Canonical Encoding Rules(CER)and Distinguished Encoding Rules(DER),1995
[12] ITU-T Recommendation X.691,Information Technology - ASN.1 Encoding rules - Specification of Packet Encoding Rules(PER),1995
[13]周明天,汪文勇:TCP/IP网络原理与技术,清华大学出版社,1993
[14]勾学荣,温致等:通信网的信令系统,人民邮电出版社,1996
[15] DOUALAS E.COMER,DAVID L.STEVENS。Internetworking With TCP/IP, Vol 3:Client– Server Programming and Application, Second Edition,,Prentice Hall Inc.,1991
[16]鲁士文:计算机网络原理与网络技术,机械工业出版社,1996
[17] H. Schulzrinne, "RTP Profile for Audio and Video Conferences with Minimal Control," RFC 1890, Internet Engineering Task Force,1996
[18] Kris Jamsa, Ken Cope: INTERNET编程,电子工业出版社1996.5
[19]蒋东兴,林鄂华:Windows Sockets网络程序设计指南,清华大学出版社,1995.12
[20]谭浩强:C程序设计,清华大学出版社,1991年7月
[21]张海藩:软件工程导论,清华大学出版社,1992年6月
[22]川木林森,高峰霞,奚红宇:Visual C++5.0使用与开发,清华大学出版社,199 7年11月
[23]黄东霖:多媒体视听业务,北京邮电大学出版社,1999年1月
[24]白刚,程时端: IP网上的话音通信技术,电信技术。1999年12月