The brief description and comparison are given to the following two signaling protocol standards that are currently used in Internet: ITU T Recommendation H .323 and IETF Session Initiation Protocol ( SIP...The brief description and comparison are given to the following two signaling protocol standards that are currently used in Internet: ITU T Recommendation H .323 and IETF Session Initiation Protocol ( SIP ). After the introduction to the latest Distributed Gateway ( DG ) architecture and its internal protocol Media Gateway Control Protocol ( MGCP ), we describe a framework for DG interworking with H.323/SIP . Other topics, such as address translation, relocation of signaling transport protocol architecture and adding components to DG for interworking with H.323/SIP , are also addressed.展开更多
Session Initiation Protocol (SIP) is a key technology in the Internettelephony or Voice-over- IP (VoIP), also it is an important signaling technology in the nextgeneration multimedia communications. Based on the compa...Session Initiation Protocol (SIP) is a key technology in the Internettelephony or Voice-over- IP (VoIP), also it is an important signaling technology in the nextgeneration multimedia communications. Based on the comparison between SIP and H. 323 technology,this paper concludes the advantages of SIP. Then grounded on the major components and theirinteraction, it analyzes the mechanism and features of the Internet telephony based on SIP. Finally,it discusses the disadvantages of SIP and provides the emphasis of future work.展开更多
The demand for the telecommunication services,such as IP telephony,has increased dramatically during the COVID-19 pandemic lockdown.IP tele-phony should be enhanced to provide the expected quality.One of the issues th...The demand for the telecommunication services,such as IP telephony,has increased dramatically during the COVID-19 pandemic lockdown.IP tele-phony should be enhanced to provide the expected quality.One of the issues that should be investigated in IP telephony is bandwidth utilization.IP telephony pro-duces very small speech samples attached to a large packet header.The header of the IP telephony consumes a considerable share of the bandwidth allotted to the IP telephony.This wastes the network's bandwidth and influences the IP telephony quality.This paper proposes a mechanism(called Smallerize)that reduces the bandwidth consumed by both the speech sample and the header.This is achieved by assembling numerous IP telephony packets in one header and use the header'sfields to carry the speech sample.Several metrics have been used to measure the achievement Smallerize mechanism.The number of calls has been increased by 245.1%compared to the typical mechanism.The bandwidth saving has also reached 68%with the G.28 codec.Therefore,Smallerize is a possible mechanism to enhance bandwidth utilization of the IP telephony.展开更多
针对基于SIP协议的SPIT攻击(Spam over Internet Telephony,SPIT),提出一种基于统计的SPIT检测方法。该方法提取用户多个行为属性和采用D-S理论将多个属性进行融合,实现对多种攻击方式的检测。同时,对域进行分类有区别地考虑域发动攻击...针对基于SIP协议的SPIT攻击(Spam over Internet Telephony,SPIT),提出一种基于统计的SPIT检测方法。该方法提取用户多个行为属性和采用D-S理论将多个属性进行融合,实现对多种攻击方式的检测。同时,对域进行分类有区别地考虑域发动攻击的可能性和用户的合法性,提高了检测的准确性。实验及分析表明上述方法具有较好的准确性,能够针对SPIT进行有效的检测。展开更多
This article aims to scale the Brazilian mobile phone market as the number of active lines, carriers participation in the market and teledensity, as well as presenting the main non-quality indicators and rankings of c...This article aims to scale the Brazilian mobile phone market as the number of active lines, carriers participation in the market and teledensity, as well as presenting the main non-quality indicators and rankings of carriers in relation to complaints registered by users. The methodology used was ＂survey＂ with documentary research, enabled through access to the database of the Brazilian National Telecommunications Agency^-ANATEL, and Sindec Report developed by the Brazilian National Secretary of the Consumer--SENACON. The results obtained showed a Brazil of had a teledensity of 132.78 lines every 100 inhabitants, with 261 million mobile lines active, these 19 million enabled in 2012. The leadership of the company ＂Vivo＂ with 29.08% of marketshare and shows the lowest rate of complaints among the big four carriers （Vivo, TIM, Claro, and Oi M6vel） according to the data of Anatel. SENACON data already confirm the big four carriers among the 10 conglomerates more defendants in claims in Brazil. As the indicators of non-quality, the Act of Misappropriation was pointed to by users as the biggest problem in contracted services.展开更多
ITU-T G. 729 is the primarily recommended speech codec by H. 323 standard. This paper describes how to implement G. 729 codec in IP telephony gateway, and goes deep into the programming skills on TMS320C6201 DSP and o...ITU-T G. 729 is the primarily recommended speech codec by H. 323 standard. This paper describes how to implement G. 729 codec in IP telephony gateway, and goes deep into the programming skills on TMS320C6201 DSP and optimizing methods of program code to reduce the speech processing delay time of G. 729 codec. Due to adopting these optimizing methods and programming skills, we have implemented a high-speed speech codec that can process concurrently 20 voice channels with single TMS320C6201 chip in IP telephony gateway. Finally, the paper analyzes the performance results of ITU-T G. 729 codec based on TMS320C6201.展开更多
文摘The brief description and comparison are given to the following two signaling protocol standards that are currently used in Internet: ITU T Recommendation H .323 and IETF Session Initiation Protocol ( SIP ). After the introduction to the latest Distributed Gateway ( DG ) architecture and its internal protocol Media Gateway Control Protocol ( MGCP ), we describe a framework for DG interworking with H.323/SIP . Other topics, such as address translation, relocation of signaling transport protocol architecture and adding components to DG for interworking with H.323/SIP , are also addressed.
文摘Session Initiation Protocol (SIP) is a key technology in the Internettelephony or Voice-over- IP (VoIP), also it is an important signaling technology in the nextgeneration multimedia communications. Based on the comparison between SIP and H. 323 technology,this paper concludes the advantages of SIP. Then grounded on the major components and theirinteraction, it analyzes the mechanism and features of the Internet telephony based on SIP. Finally,it discusses the disadvantages of SIP and provides the emphasis of future work.
文摘The demand for the telecommunication services,such as IP telephony,has increased dramatically during the COVID-19 pandemic lockdown.IP tele-phony should be enhanced to provide the expected quality.One of the issues that should be investigated in IP telephony is bandwidth utilization.IP telephony pro-duces very small speech samples attached to a large packet header.The header of the IP telephony consumes a considerable share of the bandwidth allotted to the IP telephony.This wastes the network's bandwidth and influences the IP telephony quality.This paper proposes a mechanism(called Smallerize)that reduces the bandwidth consumed by both the speech sample and the header.This is achieved by assembling numerous IP telephony packets in one header and use the header'sfields to carry the speech sample.Several metrics have been used to measure the achievement Smallerize mechanism.The number of calls has been increased by 245.1%compared to the typical mechanism.The bandwidth saving has also reached 68%with the G.28 codec.Therefore,Smallerize is a possible mechanism to enhance bandwidth utilization of the IP telephony.
文摘针对基于SIP协议的SPIT攻击(Spam over Internet Telephony,SPIT),提出一种基于统计的SPIT检测方法。该方法提取用户多个行为属性和采用D-S理论将多个属性进行融合,实现对多种攻击方式的检测。同时,对域进行分类有区别地考虑域发动攻击的可能性和用户的合法性,提高了检测的准确性。实验及分析表明上述方法具有较好的准确性,能够针对SPIT进行有效的检测。
文摘This article aims to scale the Brazilian mobile phone market as the number of active lines, carriers participation in the market and teledensity, as well as presenting the main non-quality indicators and rankings of carriers in relation to complaints registered by users. The methodology used was ＂survey＂ with documentary research, enabled through access to the database of the Brazilian National Telecommunications Agency^-ANATEL, and Sindec Report developed by the Brazilian National Secretary of the Consumer--SENACON. The results obtained showed a Brazil of had a teledensity of 132.78 lines every 100 inhabitants, with 261 million mobile lines active, these 19 million enabled in 2012. The leadership of the company ＂Vivo＂ with 29.08% of marketshare and shows the lowest rate of complaints among the big four carriers （Vivo, TIM, Claro, and Oi M6vel） according to the data of Anatel. SENACON data already confirm the big four carriers among the 10 conglomerates more defendants in claims in Brazil. As the indicators of non-quality, the Act of Misappropriation was pointed to by users as the biggest problem in contracted services.
基金Supported by the National Natural Science Foundation of China under grant!69773046
文摘ITU-T G. 729 is the primarily recommended speech codec by H. 323 standard. This paper describes how to implement G. 729 codec in IP telephony gateway, and goes deep into the programming skills on TMS320C6201 DSP and optimizing methods of program code to reduce the speech processing delay time of G. 729 codec. Due to adopting these optimizing methods and programming skills, we have implemented a high-speed speech codec that can process concurrently 20 voice channels with single TMS320C6201 chip in IP telephony gateway. Finally, the paper analyzes the performance results of ITU-T G. 729 codec based on TMS320C6201.
