IP承载的移动通信核心网负载模拟的设计与实现
摘要
从20世纪末开始，下一代网络(NGN，Next Generation Network)已经成为当前网络发展的总体趋势。随着下一代网络的发展，移动通信发生了巨大的变革，网络架构演变为以软交换设备为控制核心，业务与控制、接入与承载彼此分离，传输方式逐渐全1P化。在新的架构及传输方式下，面对大话务量的冲击，网络瘫痪时有发生，这就要求我们对网络通信质量进行新的研究。特别是在话务量大的情况，如何对网络负载进行调配、如何进行参数设置、如何进行网络优化等，这些都是值得我们进行研究的新课题。本文以此为背景，研究了基于1P承载的移动通信核心网负载模拟的设计与实现。
本文首先介绍了移动通信核心网的基本知识，分析了七号信令基于IP承载的通信协议栈，介绍了1P承载用到SCTP协议必然性，研究了scTP协议的新特性。然后研究了呼叫及位置更新的常见大话务量数学模型，最后用这些数学模型实现了负载模拟系统输入部分。
本文的核心是负载模拟的功能需求、总体架构及详细设计。负载模拟系统的工作机制是一个不断的取消息，处理消息的消息处理机，其在业务处理部分设计上采用了有限状态机、逻辑线程、逻辑定时器、环形消息队列等技术。并在底层传输部分，采用选择性证实、窗口拥塞控制、慢启动、拥塞避免、快速重传等技术。
本系统经实际测试，输入现网配置信息，不断调整配置参数，能在大话务量的情况下较客观的反映现实网络通信状况，与实际情况较为吻合。通过调整模拟系统网络负载，可以分析现实网络在不同负载下的通信状况，提前发现网络在未来大话务量情况下的隐患，消除潜在的通信事故，也可以用来调整现实网络的配置参数优化，实现一步到位的网络负载优化，节约维护及运行成本。
NGN (Next Generation Network) development has become the generaltrend. With the development of Next Generation Network, mobilecommunications has seen tremendous changes in network architecture andtransmission mode. Soft-Switch is going to play a core role in the call andcontrol of next generation network and IP has become a major means oftransmission. Under the new structure and the means of transmission, thenetwork paralysis occurred due to impact of big traffic. So need a new studyof the quality of the communication network, especially the method to thecase. There are a lot of new issues in the deployment of network load,network optimization, etc. This paper studies the quality of mobil ecommunications based on IP by means of core network simulation.
Signaling is the control signal transmission between communicationsequipment, such as occupation, busy, leisure, etc. Mobile Communicationis the NO.7 Signaling System. IP-based SS7(NO.7 Signaling System)protocol stack used SCTP by the bottom of it. This paper studies many newfeatures of SCTP protocol, such as: Multi -homing, Multi-streaming,Heartbeat mechanism, etc.
Input of Load Simulator is a large number of users call or locationupdating, which is a lot of random events. This paper studies the typicalmathematical model of location call and updating. Call flow is the Poissonprocess model. Location updating has the group mobile model, theindividual mobile model, the time presence m odel and the trajectory model.
The work mechanism of Load Simulation System is a messageprocessor, the constant messages processing. Use the design of finite statemachines to process messages .and the means of design: each receiving arequest message, System will produce a new logical thread. The logicalthread is suspended and set a new status after processing message. At thesame time, it starts a timer, waiting for the response of the equipmentreceiving the messages. when the timer overtime s or it has received theresponse, the thread run again.
System simulation timers use a logic timer technology. Each speciallogical system clock, managing timer function will scan all timers. If a timeris not overtime, it will reduce special value to represent a sp ecial time. If itovertimes, system will run the corresponding logical thread to process thiscase.
In this paper, the load simulation system is based on IP, so IPsimulation is crucial to the simulation results. This paper analyses the datatransmission rules and congestion control. The data transmission involveshow to establish the data transmission couple, how to close the couple oftransmission, and how to avoid deadlock. Congestion Control containsdetailed algorithm analysis and implementation of th e slow start, thecongestion avoiding and the rapid retransmission.
Load simulation can be used to analyze real mobile networkcommunications quality under different load conditions. Early foundpotential dangers of network in the future and eliminate it. It also can beused to adjust parameters of network optimization to achieve furtheroptimization of the network load. There is a certain economic value.
In addition, there is a certain theoretical study value. This mathematicalmodel of mobile telecom traffic can be referenced as the other areasresearch foundation about it. And the introduction of logical thread andlogic timer is meaning in the design of other reference. The details of thealgorithm and the realization of SCTP protocol have great referen ce valuefor work or study in this field. The system is also able to verify some of thecore network congestion algorithms, to found problems in advance to avoidproblems left over to the network and avoid leading to a greater loss.
本文首先介绍了移动通信核心网的基本知识，分析了七号信令基于IP承载的通信协议栈，介绍了1P承载用到SCTP协议必然性，研究了scTP协议的新特性。然后研究了呼叫及位置更新的常见大话务量数学模型，最后用这些数学模型实现了负载模拟系统输入部分。
本文的核心是负载模拟的功能需求、总体架构及详细设计。负载模拟系统的工作机制是一个不断的取消息，处理消息的消息处理机，其在业务处理部分设计上采用了有限状态机、逻辑线程、逻辑定时器、环形消息队列等技术。并在底层传输部分，采用选择性证实、窗口拥塞控制、慢启动、拥塞避免、快速重传等技术。
本系统经实际测试，输入现网配置信息，不断调整配置参数，能在大话务量的情况下较客观的反映现实网络通信状况，与实际情况较为吻合。通过调整模拟系统网络负载，可以分析现实网络在不同负载下的通信状况，提前发现网络在未来大话务量情况下的隐患，消除潜在的通信事故，也可以用来调整现实网络的配置参数优化，实现一步到位的网络负载优化，节约维护及运行成本。
NGN (Next Generation Network) development has become the generaltrend. With the development of Next Generation Network, mobilecommunications has seen tremendous changes in network architecture andtransmission mode. Soft-Switch is going to play a core role in the call andcontrol of next generation network and IP has become a major means oftransmission. Under the new structure and the means of transmission, thenetwork paralysis occurred due to impact of big traffic. So need a new studyof the quality of the communication network, especially the method to thecase. There are a lot of new issues in the deployment of network load,network optimization, etc. This paper studies the quality of mobil ecommunications based on IP by means of core network simulation.
Signaling is the control signal transmission between communicationsequipment, such as occupation, busy, leisure, etc. Mobile Communicationis the NO.7 Signaling System. IP-based SS7(NO.7 Signaling System)protocol stack used SCTP by the bottom of it. This paper studies many newfeatures of SCTP protocol, such as: Multi -homing, Multi-streaming,Heartbeat mechanism, etc.
Input of Load Simulator is a large number of users call or locationupdating, which is a lot of random events. This paper studies the typicalmathematical model of location call and updating. Call flow is the Poissonprocess model. Location updating has the group mobile model, theindividual mobile model, the time presence m odel and the trajectory model.
The work mechanism of Load Simulation System is a messageprocessor, the constant messages processing. Use the design of finite statemachines to process messages .and the means of design: each receiving arequest message, System will produce a new logical thread. The logicalthread is suspended and set a new status after processing message. At thesame time, it starts a timer, waiting for the response of the equipmentreceiving the messages. when the timer overtime s or it has received theresponse, the thread run again.
System simulation timers use a logic timer technology. Each speciallogical system clock, managing timer function will scan all timers. If a timeris not overtime, it will reduce special value to represent a sp ecial time. If itovertimes, system will run the corresponding logical thread to process thiscase.
In this paper, the load simulation system is based on IP, so IPsimulation is crucial to the simulation results. This paper analyses the datatransmission rules and congestion control. The data transmission involveshow to establish the data transmission couple, how to close the couple oftransmission, and how to avoid deadlock. Congestion Control containsdetailed algorithm analysis and implementation of th e slow start, thecongestion avoiding and the rapid retransmission.
Load simulation can be used to analyze real mobile networkcommunications quality under different load conditions. Early foundpotential dangers of network in the future and eliminate it. It also can beused to adjust parameters of network optimization to achieve furtheroptimization of the network load. There is a certain economic value.
In addition, there is a certain theoretical study value. This mathematicalmodel of mobile telecom traffic can be referenced as the other areasresearch foundation about it. And the introduction of logical thread andlogic timer is meaning in the design of other reference. The details of thealgorithm and the realization of SCTP protocol have great referen ce valuefor work or study in this field. The system is also able to verify some of thecore network congestion algorithms, to found problems in advance to avoidproblems left over to the network and avoid leading to a greater loss.
引文
[1] 刘斌, 孙正义, 刘伟彦. 软交换――下一代网络核心技术[J]. 西安邮电学院学报, 2005,(01).
[2] 薛晓红. NGN 现状和关键技术发展趋势[J]. 现代通信, 2005, (03) .
[3] 郑虹. 下一代网络NGN 概述[J]. 电力信息化, 2005,(01) .
[4] 杨艳. 下一代电信网络NGN 及其关键技术综述[J]. 现代电子技术,2005,(10) .
[5] 张园. NGN 国际标准最新进展[J]. 信息网络, 2005,(05) .
[6] 邬贺铨. 第三代移动通信――现代无线技术面向IP 的应用[J]. 中国工程科学 , 2000,(08) .
[7] 张静. WCDMA 核心网信令系统对七号信令网的影响[J]. 世界电信,2002,(08) .
[8] 徐小峰. 基于全IP 的第三代移动通信网[J]. 电信快报, 2000,(08) .
[9] 赵慧玲, 叶华. 以软交换为核心的下一代网络技术. 北京：人民邮电出版社, 2002, 第1 版: 37-40.
[10] 石友康. 下一代网络的核心软交换技术[J]. 电信科学, 2002, 18 (1)：39-44.
[11] S.Deering, R. Hinden. Internet Protocol, Version 6 (IPv6) Specification.IETF RFC 2460, December 1998.
[12] 中国移动通信集团公司研发中心中国移动通信信息资源站实体与互联网短消息网关接口协议. 第2 版_北京:中国移动通信集团公司，2002: 6-9.
[13] 方飞等. SCTP 在移动IP 安全中的应用. 移动通信, 2004 年8 月增刊.
[14] 张蓉, 李健. 基于SCTP 多数据流特性的WEB 传输. 信息技术,2005 Vol.29 No.6: 30-32.
[15] 郭伟, 程时端. 流控制传输协议研究. 中兴通讯技术, 2004 Vol.10No.4: 41-44.
[16] 马严, 金仙力, 邵雯娟. SCTP 数据传输过程的技术研究. 中国数据通信, 2003 Vol.5 No.2: 74-77.
[17] SCTP 的安全特性IETF RFC 3436[10], RFC 3554[9].
[18] L. Ong, J. Yoakum. An Introduction to t he Stream ControlTransmission Protocol (SCTP). IETF RFC 3286, May 2002.
[19] L. Coene. Stream Control Transmission Protocol ApplicabilityStatement. IETF RFC 3257, April 2002.
[20] L. Coene, J.Pastor-Balbas. Telephony Signalling Transport over StreamControl Transmission Protocol (SCTP) Applicability Statement. IETFRFC 4166, February 2006.
[21] J. Rosenberg, H. Schulzrinne,G. Camarillo. The Stream ControlTransmission Protocol (SCTP) as a Transport for the Session InitiationProtocol (SIP). IETF RFC 4168, October 200 5.
[22] R. Stewart, M. Ramalho, Q. Xie, M. Tuexen, P. Conrad. Stream ControlTransmission Protocol (SCTP) Partial Reliability Extension. IETF RFC3758, May 2004.
[23] ZHENG L, ZHANG L R, XU D. Characteristics of network delay anddelay jitter and its effect on voice over IP (VoIP) [A].
[24] International Conference on Communications IEEE/ICC 2001 [C].St-Petersburg, 2001. 122 -126.
[25] V. W.-S. Wong and V. C. M. Leung, “Location Management for NextGeneration Personal”.
[26] Communications Networks, IEEE network, vol.14, no. 5, pp . 18-24,Sep.-Oct., 2000.
[27] Xie, et al, “A Dynamic Location Area Management and PerformanceAnalysis”, Proc.IEEE 93 Veh. Technol. Conf. May 1993, pp.536-539.
[28] K. K. Leung, et al., “Traffic Models for Wireless CommunicationNetworks”, IEEE J. Select. Areas Commun. Vol.12, No.8, Oct.1994,pp.1353-1364. 114.
[29] Seskar, et al., “Rate of Location Area Updates in Cellular Systems ”,Proc. IEEE VTC 92, May 1992.
[30] G. P. Pollini and Chih-Lin I, “A Profile-Based Location Strategy and ItsPerformance”, IEEE J. Select. Areas Commun. Vol. 15, No. 8, Oct.1997, pp.1415-1424.
[31] Z. Lei and C. Rose, “Wireless Subscriber Mobility Management UsingAdaptive Individual”.
[32] Location Areas for PCS Systems, ICC’98 Conference Record, vol. 3,pp. 1390-1394, 7-11 Jun. 1998.
[33] Yi-Bing Lin, “Modeling Techniques for Large-Scale PCS Networks”,IEEE Communication Magazine , Vol.35, No.2, Feb.1997, pp.102-107.
[34] Bar-Noy, et al, “Mobile Users: To Update or Not to Update? ”,ACM-Baltzer J. Wireless Networks, Vol.1, No.2, July 1995, pp.175- 18
[35] P. V. Orlik, S. S. Rappaport, “Traffic Performance and MobilityModeling of Cellular.
[36] Communications with Mixed Platform and Highly Variable Mobilities ,Proc. of the IEEE, Vol.86, No.7, July 1998, pp.1464-1479.
[37] K. Toh, “Performance Evaluation of Crossover Switch Discover yAlgorithms for Wireless ATM LANs ”, Proc. INFOCOMM, March1996, pp.1380-1387.
[38] D. Hong, S. Rapport, “Traffic Model and Performance Analysis forCellular Mobile Radio”.
[2] 薛晓红. NGN 现状和关键技术发展趋势[J]. 现代通信, 2005, (03) .
[3] 郑虹. 下一代网络NGN 概述[J]. 电力信息化, 2005,(01) .
[4] 杨艳. 下一代电信网络NGN 及其关键技术综述[J]. 现代电子技术,2005,(10) .
[5] 张园. NGN 国际标准最新进展[J]. 信息网络, 2005,(05) .
[6] 邬贺铨. 第三代移动通信――现代无线技术面向IP 的应用[J]. 中国工程科学 , 2000,(08) .
[7] 张静. WCDMA 核心网信令系统对七号信令网的影响[J]. 世界电信,2002,(08) .
[8] 徐小峰. 基于全IP 的第三代移动通信网[J]. 电信快报, 2000,(08) .
[9] 赵慧玲, 叶华. 以软交换为核心的下一代网络技术. 北京：人民邮电出版社, 2002, 第1 版: 37-40.
[10] 石友康. 下一代网络的核心软交换技术[J]. 电信科学, 2002, 18 (1)：39-44.
[11] S.Deering, R. Hinden. Internet Protocol, Version 6 (IPv6) Specification.IETF RFC 2460, December 1998.
[12] 中国移动通信集团公司研发中心中国移动通信信息资源站实体与互联网短消息网关接口协议. 第2 版_北京:中国移动通信集团公司，2002: 6-9.
[13] 方飞等. SCTP 在移动IP 安全中的应用. 移动通信, 2004 年8 月增刊.
[14] 张蓉, 李健. 基于SCTP 多数据流特性的WEB 传输. 信息技术,2005 Vol.29 No.6: 30-32.
[15] 郭伟, 程时端. 流控制传输协议研究. 中兴通讯技术, 2004 Vol.10No.4: 41-44.
[16] 马严, 金仙力, 邵雯娟. SCTP 数据传输过程的技术研究. 中国数据通信, 2003 Vol.5 No.2: 74-77.
[17] SCTP 的安全特性IETF RFC 3436[10], RFC 3554[9].
[18] L. Ong, J. Yoakum. An Introduction to t he Stream ControlTransmission Protocol (SCTP). IETF RFC 3286, May 2002.
[19] L. Coene. Stream Control Transmission Protocol ApplicabilityStatement. IETF RFC 3257, April 2002.
[20] L. Coene, J.Pastor-Balbas. Telephony Signalling Transport over StreamControl Transmission Protocol (SCTP) Applicability Statement. IETFRFC 4166, February 2006.
[21] J. Rosenberg, H. Schulzrinne,G. Camarillo. The Stream ControlTransmission Protocol (SCTP) as a Transport for the Session InitiationProtocol (SIP). IETF RFC 4168, October 200 5.
[22] R. Stewart, M. Ramalho, Q. Xie, M. Tuexen, P. Conrad. Stream ControlTransmission Protocol (SCTP) Partial Reliability Extension. IETF RFC3758, May 2004.
[23] ZHENG L, ZHANG L R, XU D. Characteristics of network delay anddelay jitter and its effect on voice over IP (VoIP) [A].
[24] International Conference on Communications IEEE/ICC 2001 [C].St-Petersburg, 2001. 122 -126.
[25] V. W.-S. Wong and V. C. M. Leung, “Location Management for NextGeneration Personal”.
[26] Communications Networks, IEEE network, vol.14, no. 5, pp . 18-24,Sep.-Oct., 2000.
[27] Xie, et al, “A Dynamic Location Area Management and PerformanceAnalysis”, Proc.IEEE 93 Veh. Technol. Conf. May 1993, pp.536-539.
[28] K. K. Leung, et al., “Traffic Models for Wireless CommunicationNetworks”, IEEE J. Select. Areas Commun. Vol.12, No.8, Oct.1994,pp.1353-1364. 114.
[29] Seskar, et al., “Rate of Location Area Updates in Cellular Systems ”,Proc. IEEE VTC 92, May 1992.
[30] G. P. Pollini and Chih-Lin I, “A Profile-Based Location Strategy and ItsPerformance”, IEEE J. Select. Areas Commun. Vol. 15, No. 8, Oct.1997, pp.1415-1424.
[31] Z. Lei and C. Rose, “Wireless Subscriber Mobility Management UsingAdaptive Individual”.
[32] Location Areas for PCS Systems, ICC’98 Conference Record, vol. 3,pp. 1390-1394, 7-11 Jun. 1998.
[33] Yi-Bing Lin, “Modeling Techniques for Large-Scale PCS Networks”,IEEE Communication Magazine , Vol.35, No.2, Feb.1997, pp.102-107.
[34] Bar-Noy, et al, “Mobile Users: To Update or Not to Update? ”,ACM-Baltzer J. Wireless Networks, Vol.1, No.2, July 1995, pp.175- 18
[35] P. V. Orlik, S. S. Rappaport, “Traffic Performance and MobilityModeling of Cellular.
[36] Communications with Mixed Platform and Highly Variable Mobilities ,Proc. of the IEEE, Vol.86, No.7, July 1998, pp.1464-1479.
[37] K. Toh, “Performance Evaluation of Crossover Switch Discover yAlgorithms for Wireless ATM LANs ”, Proc. INFOCOMM, March1996, pp.1380-1387.
[38] D. Hong, S. Rapport, “Traffic Model and Performance Analysis forCellular Mobile Radio”.