基于无线Mesh网络的移动车地通信技术研究
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摘要
随着信息技术和互联网络的快速发展,人们越来越希望无线网络信号能够覆盖生活的每个角落,甚至是铁路列车。旅客希望能够在列车上高速率地、快捷地接入公共互联网,从而享受网络提供的各种服务。这种铁路列车上的信息服务要求对车地通信技术提出了严峻的挑战,而现有的车地通信技术已经难以满足上述业务需求,因此有必要研究并设计一种更有效的车地通信技术来满足上述业务需求。
为满足新的业务需求,本文提出一种基于无线Mesh网络的车地通信技术实现方案:由车载终端无线节点移动接入沿路布置的无线Mesh网络,从而通过无线Mesh网络连接地面的公共互联网络。同时,车载终端作为网关节点在车厢内部搭建局域网为旅客提供公共互联网络服务。无线Mesh网络在第一、二层采用IEEE802.11b/g协议,在第三层采用TCP/IP协议族中的IP协议。而在无线Mesh网络的二、三层之间,本文增加了无线Mesh层,该层被用实现无线Mesh网络中的车载终端移动接入以及无线Mesh网络路由、代理、快速切换等功能。
本文在分析利用基于无线Mesh网络的车地通信技术解决车地通信问题的可行性后,设计并实现了车地通信所需无线Mesh网络设备的软硬件。之后,对车地通信无线Mesh网络设备性能进行了测试,并搭建了基于无线Mesh网络的车地通信测试环境进行了仿真测试。最后,本文指出了基于无线Mesh网络的接入方案在车地通信应用中的特点。
With the fast development of information technology and Internet, people are expecting that every corner can be covered by wireless network, and even in train. Passengers hope that they can rapidly access to Internet in the train to get various services with high data rate. The passenger's access demand to the public information network on the railway is an austere challenge for vehicle-ground communication technology, and the existing mobile access technology is still difficult to meet the above need. Therefore, it is necessary to research and develop a sort of more effective vehicle-ground communication technology to meet the service demand.
In order to meet the new service demand, this thesis proposes the vehicle-ground communication technology based on wireless mesh network scheme: the vehicle can connect with ground schedule center and ground public Internet network via the wireless node of vehicle-carried terminal accessing to the wireless mesh network which is disposed in roadside in mobile way. The vehicle schedule station communicates with the ground control center through the vehicle-carried terminal; simultaneously the vehicle-carried terminal can do as the gateway node inside the train to build local area network in the compartment interior to provide the public Internet service for the passenger. The wireless mesh network adopts IEEE802.11b/g protocol on layer 1 (L1) and layer 2 (L2), and IP protocol of TCP/IP protocol on layer 3 (L3). And between L2 and L3 in the wireless mesh network, a new layer, named wireless mesh network layer, which is used to implement the mobile access of vehicle-carried terminal, routing, network management and fast handoff function in wireless mesh network.
After analyzing the feasibility to utilize the vehicle-ground communication technology based on wireless mesh network to solve the problem of vehicle communication, this thesis designs and implements the software and hardware of the wireless mesh network equipment which is needed by the vehicle-ground communication. And then, the thesis introduces the test of the wireless mesh network equipment performance, and the simulated environment of the vehicle-ground communication technology based on wireless mesh network. Finally, this thesis conclusion points out the merits and shortcomings of the vehicle-ground communication technology based on wireless mesh network access scheme in vehicle-ground communication application.
为满足新的业务需求,本文提出一种基于无线Mesh网络的车地通信技术实现方案:由车载终端无线节点移动接入沿路布置的无线Mesh网络,从而通过无线Mesh网络连接地面的公共互联网络。同时,车载终端作为网关节点在车厢内部搭建局域网为旅客提供公共互联网络服务。无线Mesh网络在第一、二层采用IEEE802.11b/g协议,在第三层采用TCP/IP协议族中的IP协议。而在无线Mesh网络的二、三层之间,本文增加了无线Mesh层,该层被用实现无线Mesh网络中的车载终端移动接入以及无线Mesh网络路由、代理、快速切换等功能。
本文在分析利用基于无线Mesh网络的车地通信技术解决车地通信问题的可行性后,设计并实现了车地通信所需无线Mesh网络设备的软硬件。之后,对车地通信无线Mesh网络设备性能进行了测试,并搭建了基于无线Mesh网络的车地通信测试环境进行了仿真测试。最后,本文指出了基于无线Mesh网络的接入方案在车地通信应用中的特点。
With the fast development of information technology and Internet, people are expecting that every corner can be covered by wireless network, and even in train. Passengers hope that they can rapidly access to Internet in the train to get various services with high data rate. The passenger's access demand to the public information network on the railway is an austere challenge for vehicle-ground communication technology, and the existing mobile access technology is still difficult to meet the above need. Therefore, it is necessary to research and develop a sort of more effective vehicle-ground communication technology to meet the service demand.
In order to meet the new service demand, this thesis proposes the vehicle-ground communication technology based on wireless mesh network scheme: the vehicle can connect with ground schedule center and ground public Internet network via the wireless node of vehicle-carried terminal accessing to the wireless mesh network which is disposed in roadside in mobile way. The vehicle schedule station communicates with the ground control center through the vehicle-carried terminal; simultaneously the vehicle-carried terminal can do as the gateway node inside the train to build local area network in the compartment interior to provide the public Internet service for the passenger. The wireless mesh network adopts IEEE802.11b/g protocol on layer 1 (L1) and layer 2 (L2), and IP protocol of TCP/IP protocol on layer 3 (L3). And between L2 and L3 in the wireless mesh network, a new layer, named wireless mesh network layer, which is used to implement the mobile access of vehicle-carried terminal, routing, network management and fast handoff function in wireless mesh network.
After analyzing the feasibility to utilize the vehicle-ground communication technology based on wireless mesh network to solve the problem of vehicle communication, this thesis designs and implements the software and hardware of the wireless mesh network equipment which is needed by the vehicle-ground communication. And then, the thesis introduces the test of the wireless mesh network equipment performance, and the simulated environment of the vehicle-ground communication technology based on wireless mesh network. Finally, this thesis conclusion points out the merits and shortcomings of the vehicle-ground communication technology based on wireless mesh network access scheme in vehicle-ground communication application.
引文
[1]胥桓.专用无线Mesh网络原形系统研究与设计.西南交通大学硕士学位论文.2008:7-8
[2]Murray Hughes.The AGV Trains in France.Rly Gaz Intern.2007 No 9:548-550
[3]朱延武,常德远.高速铁路宽带无线接入的几种技术方案分析.铁道通信信号Vol.44 No.3 2008.3:39-45
[4]Bart Lannoo,Didier Colic,Mario Pickavet.Radio-over-fiber-based solution to provide broadband internet access to train passengerts.IEEE Communication Magazine No 22007:56-62
[5]V.Schena.Ceprani FIFTH project solutions demon starting new satellite broadband communication system for high speed train.IEEE Vehicular Technology Conference.Vol 5,2005:2831-2835
[6]Kira Kastell.Improvements in railway communication via GSM-R.IEEE Vehicular Technology Conference.Vol 6,2006:3026-3030
[7]赵庆安.在高速铁路环境下电波传播特性的模型分析.北京铁道部科学研究院.2000:23-26
[8]李进良.对铁路移动通信GSM-R和TETRA两种技术体制选择的思考.铁道通信信号.2001年第31卷第8期:40-43
[9]边灵.采用泄漏电缆的无线电通信.煤炭科学技术.1988,6:34-38
[10]宁滨.中国铁路综合数字移动通信网络与GSM-R的应用[J].中国铁路.2003:15-19
[11]LAN MAN Standards Committee of the IEEE Computer Society.Information technology-Telecommunications and information exchange between systems-Local and metropolitan area networks-Specific requirements-Part 11:Wireless LAN Medium Access Control(MAC)and Physical Layer(PHY)Specifications.1999
[12]IEEE 802.11 Working Group of the LAN/MAN Committee.IEEE P802.11s~(TM)/D0.05Draft Amendment to Standard for Information Technology-Telecommunications and Information Exchange Between Systems-LAN/MAN Specific Requirements-Part 11: Wireless Medium Access Control(MAC)and physical layer(PHY)specifications:Amendment:ESS Mesh Networking[S].2006.3
[13]The Working Group for Wireless LAN,http://www.ieee802.org/11/
[14]樊自甫,万晓榆.新一代宽带无线网络结构—Wireless Mesh.通讯世界.2003.9:43-47
[15]宋文,方旭明.无线网状网研究与发展,铁道学报,Vol.29,No.2,April 2007:96-103
[16]K.Rayner.Mesh wireless networking.Communications Engineer,Vol.1,No.5,Oct.-Nov.2003:44-47
[17]Raffaele Bruno,Marco Conti,Enrico Gregori.Mesh Networks:Commodity Multihop Ad Hoc networks.IEEE Communications Magazine,2005:123-131
[18]方旭明等.下一代无线因特网技术:无线Mesh网络.人民邮电出版社.2006:42-64
[19]刘乃安.无线局域网(WLAN)-原理、技术与应用.西安电子科技大学出版社.2004.4:22-26
[20]方旭明.移动Ad hoc网络研究与发展状况.数据通信.2003年,第4期:15-23
[21]Cong Liu,Jie Wu.Adaptive Routing in Dynamic Ad Hoc Networks.Wireless Communications and Networking Conference,March 31 2008-April 3 2008:2603-2608
[22]方新宇.无线自组织网络中的路由技术研究一种新的多跳无线网路由算法的设计与实现.电子科技大学硕士学位论文.2004:20-23
[23]En Cheng,Yuan Qi,Bo Sun,Ziming Zhuang,Jie Deng.Research on Routing Protocol for Shallow Underwater Acoustic Ad Hoe Network.Computing,Communication,Control,and Management,2008.CCCM'08.ISECS International Colloquium on.Volume 2,2008:533-537
[24]徐静.无线Ad hoc网络路由协议比较.广西通信技术.2004,第2期:29-32
[25]P.Whitehead,Mesh networks.A new architecture for broadband wireless access systems.2000 IEEE Radio and Wireless Conference,10-13 Sept.2000:43-46
[26]Zhimei Jiang,Li Fung Chang,Kim.Incorporating proxy services into wide area cellular IP networks.Wireless Communications and Networking Conference,2000.WCNC.2000 IEEE on Volume 1.2000:246-252
[27]Howard R,Jansen BJ.A proxy server experiment:an indication of the changing nature of the web.Computer Communications,1998.Proceedings.7~(th)International Conference.1998:646-469
[28]Zhimei Jiang,Leung,K.K.Link-condition based proxies for QoS management in wireless networks.Personal,Indoor and Mobile Radio Communications,2001 12~(th)IEEE International Symposium on Volume 1.2001:61-67
[29]方旭明,戚彩霞,向征.IEEE802系列无线网络网状网组网与移动切换技术综述.计算机应用.2006年,第8期:1756-1761
[30]杨仁宗.无线局域网中的结点切换与VoIP应用研究.中国科学院研究生院博士学位论文.2004:43-47
[31]Thavisak Manodham,Luis Loyola,etcl.A Seamless Handoff Scheme with new AP Module for Wireless LANs Support VoIP.International Symposium on Applications and the Internet,Jan,2006:6-7
[32]Mishra et al,M.Shin and W.Arbaugh.An empirical analysis of the IEEE802.11 MAC layer handoff processs.University of Maryland Technical Report.2002:2-4
[33]H(?)ctor Velayos,Gunnar Karlsson.Techniques to Reduce IEEE 802.11b MAC Layer Handover Time.Royal Institute of Technology,April 2003:181-190
[34]S.Shin,A.S.Rawat,H.Schulzrine.Reducing MAC Layer Handoff Latency in IEEE 802.11 Wireless LANs.Proc.ACM MobiWac 2004:4-8
[35]Yong Liao,Lixin Gao.Practical Schemes for Smooth MAC Layer Handoff in 802.11Wireless Networks.World of Wireless,Mobile and Multimedia Networks,June 2006:181-190
[36]Noor Mustafa,Waqar Mahmood,etcl.Pre-Scanning and Dynamic Caching for Fast Handoff at MAC Layer in IEEE 802.11 Wireless LANs.2005.IEEE International Conference on Mobile Ad hoc and Sensor Systems,Nov.2005:8-10.
[37]Sangheon Pack,Hakyung Jung,Taekyoung Kwon,and Yanghee Choi.A Selective Neighbor Caching Scheme for Fast Handoff in IEEE 802.11 Wireless Networks.Proc.IEEE ICC Vol.5.May 2005:3599-3603
[38]S.Pack,H.Jung,T.Kwon,and Y.Choi.A Selective Neighbor Caching Scheme for Fast Handoff in IEEE 802.11 Wireless Networks.IEEE International Conference Vol.5,May 2005:3599-3603
[39]J.Montavont,N.Montavont,T.Noel.Enhanced schemes for L2 handover in IEEE 802.11 networks and their evaluations.16th IEEE International Symposium on Personal Indoor and Mobile Radio Communications(PIMRC 2005),Berlin,Germany,Sep.2005:22-24
[40]Min Liu,Zhongcheng Li,Xiaobing Guo,Dutkiewicz E.Performance Analysis and optimization of Handoff Algorithms in heterogeneous Wireless Networks.Mobile Computing,IEEE Transactions on Volume 7 Issue7,July 2008:846-857
[41]V.Hector and K.Gunnar.Techniques to reduce IEEE 802.11b MAC layer handover time.Royal Institute of Technology,April 2003:2-6
[42]Xiaomin Ma,Yun Liu,Trivedi KS.Design and performance Analysis of a New Soft Handoff Scheme for CDMA Cellular Systems.Vehicular Technology,IEEE Transactions on Volume 55,Issue5,Sept.2006:1603-1612
[43]Wang SS,Sridhar S,Green M.Adaptive soft handoff method using mobile location information.Vehicular Technology Conference,2002.VTC Sprint 2002.IEEE 55~(th)Volume 4,6-9 May 2002:1936-1940
[44]Srivatsa,A.M,Jiang Xie.A Performance Study of Mobile Handoff Delay in IEEE 802.11-Based Wireless Mesh Networks.Communications,2008.ICC'08.IEEE International Conference on 19-23 May 2008:2485-2489
[45]杨仁忠,侯紫峰.802.11无线局域网链路层切换机制研究.计算机应用研究.2004.1:97-102
[46]Seastian Speicher,Clemens Cap.Fast Layer 3 Handoffs in AODV-based IEEE 802.11Wireless Mesh Networks,IEEE 2006:3-5
[47]杨仁忠,侯紫峰.基于AP预先转发的802.11无线局域网切换机制研究.计算机研究与发展.2004.8:1376-1380
[48]Li Xu,Bao-yu Zheng.Study on cross-layer design and power conservation in ad hoc network.PDCAT'2003,2003:324-328
[49]W.Richard Stevens.UNIX网络编程第1卷.第二版.清华大学出版社,1997
[50]魏忠,蔡勇,雷红卫.嵌入式开发详解[M].中国电力出版社,2002
[51]Alessandro Rubini.LINUX设备驱动程序,第二版[M].中国电力出版社,2002
[52]Akleman E,Chen J,Srinivasan V.A prototype system for robust,interactive and user-friendly modeling of orientable 2-manifold meshes.Shape Modeling International,2002.Proceedings.2002:43-50
[53]Angrisani L,Narduzzi C.Testing communication and computer networks:an overview.Instrumentation & Measurement Magazine.IEEE Volume 11 2008 Pages(s):12-24
[54]Ionescu B,Ionescu M,Veres S,Ionescu D,Cuervo F,Luiken-Miller M.A testbed and research network for next generation services over next generation networks.Testbeds and Research Infrastructures for the Development of Networks and Communities.2005:22-31
[2]Murray Hughes.The AGV Trains in France.Rly Gaz Intern.2007 No 9:548-550
[3]朱延武,常德远.高速铁路宽带无线接入的几种技术方案分析.铁道通信信号Vol.44 No.3 2008.3:39-45
[4]Bart Lannoo,Didier Colic,Mario Pickavet.Radio-over-fiber-based solution to provide broadband internet access to train passengerts.IEEE Communication Magazine No 22007:56-62
[5]V.Schena.Ceprani FIFTH project solutions demon starting new satellite broadband communication system for high speed train.IEEE Vehicular Technology Conference.Vol 5,2005:2831-2835
[6]Kira Kastell.Improvements in railway communication via GSM-R.IEEE Vehicular Technology Conference.Vol 6,2006:3026-3030
[7]赵庆安.在高速铁路环境下电波传播特性的模型分析.北京铁道部科学研究院.2000:23-26
[8]李进良.对铁路移动通信GSM-R和TETRA两种技术体制选择的思考.铁道通信信号.2001年第31卷第8期:40-43
[9]边灵.采用泄漏电缆的无线电通信.煤炭科学技术.1988,6:34-38
[10]宁滨.中国铁路综合数字移动通信网络与GSM-R的应用[J].中国铁路.2003:15-19
[11]LAN MAN Standards Committee of the IEEE Computer Society.Information technology-Telecommunications and information exchange between systems-Local and metropolitan area networks-Specific requirements-Part 11:Wireless LAN Medium Access Control(MAC)and Physical Layer(PHY)Specifications.1999
[12]IEEE 802.11 Working Group of the LAN/MAN Committee.IEEE P802.11s~(TM)/D0.05Draft Amendment to Standard for Information Technology-Telecommunications and Information Exchange Between Systems-LAN/MAN Specific Requirements-Part 11: Wireless Medium Access Control(MAC)and physical layer(PHY)specifications:Amendment:ESS Mesh Networking[S].2006.3
[13]The Working Group for Wireless LAN,http://www.ieee802.org/11/
[14]樊自甫,万晓榆.新一代宽带无线网络结构—Wireless Mesh.通讯世界.2003.9:43-47
[15]宋文,方旭明.无线网状网研究与发展,铁道学报,Vol.29,No.2,April 2007:96-103
[16]K.Rayner.Mesh wireless networking.Communications Engineer,Vol.1,No.5,Oct.-Nov.2003:44-47
[17]Raffaele Bruno,Marco Conti,Enrico Gregori.Mesh Networks:Commodity Multihop Ad Hoc networks.IEEE Communications Magazine,2005:123-131
[18]方旭明等.下一代无线因特网技术:无线Mesh网络.人民邮电出版社.2006:42-64
[19]刘乃安.无线局域网(WLAN)-原理、技术与应用.西安电子科技大学出版社.2004.4:22-26
[20]方旭明.移动Ad hoc网络研究与发展状况.数据通信.2003年,第4期:15-23
[21]Cong Liu,Jie Wu.Adaptive Routing in Dynamic Ad Hoc Networks.Wireless Communications and Networking Conference,March 31 2008-April 3 2008:2603-2608
[22]方新宇.无线自组织网络中的路由技术研究一种新的多跳无线网路由算法的设计与实现.电子科技大学硕士学位论文.2004:20-23
[23]En Cheng,Yuan Qi,Bo Sun,Ziming Zhuang,Jie Deng.Research on Routing Protocol for Shallow Underwater Acoustic Ad Hoe Network.Computing,Communication,Control,and Management,2008.CCCM'08.ISECS International Colloquium on.Volume 2,2008:533-537
[24]徐静.无线Ad hoc网络路由协议比较.广西通信技术.2004,第2期:29-32
[25]P.Whitehead,Mesh networks.A new architecture for broadband wireless access systems.2000 IEEE Radio and Wireless Conference,10-13 Sept.2000:43-46
[26]Zhimei Jiang,Li Fung Chang,Kim.Incorporating proxy services into wide area cellular IP networks.Wireless Communications and Networking Conference,2000.WCNC.2000 IEEE on Volume 1.2000:246-252
[27]Howard R,Jansen BJ.A proxy server experiment:an indication of the changing nature of the web.Computer Communications,1998.Proceedings.7~(th)International Conference.1998:646-469
[28]Zhimei Jiang,Leung,K.K.Link-condition based proxies for QoS management in wireless networks.Personal,Indoor and Mobile Radio Communications,2001 12~(th)IEEE International Symposium on Volume 1.2001:61-67
[29]方旭明,戚彩霞,向征.IEEE802系列无线网络网状网组网与移动切换技术综述.计算机应用.2006年,第8期:1756-1761
[30]杨仁宗.无线局域网中的结点切换与VoIP应用研究.中国科学院研究生院博士学位论文.2004:43-47
[31]Thavisak Manodham,Luis Loyola,etcl.A Seamless Handoff Scheme with new AP Module for Wireless LANs Support VoIP.International Symposium on Applications and the Internet,Jan,2006:6-7
[32]Mishra et al,M.Shin and W.Arbaugh.An empirical analysis of the IEEE802.11 MAC layer handoff processs.University of Maryland Technical Report.2002:2-4
[33]H(?)ctor Velayos,Gunnar Karlsson.Techniques to Reduce IEEE 802.11b MAC Layer Handover Time.Royal Institute of Technology,April 2003:181-190
[34]S.Shin,A.S.Rawat,H.Schulzrine.Reducing MAC Layer Handoff Latency in IEEE 802.11 Wireless LANs.Proc.ACM MobiWac 2004:4-8
[35]Yong Liao,Lixin Gao.Practical Schemes for Smooth MAC Layer Handoff in 802.11Wireless Networks.World of Wireless,Mobile and Multimedia Networks,June 2006:181-190
[36]Noor Mustafa,Waqar Mahmood,etcl.Pre-Scanning and Dynamic Caching for Fast Handoff at MAC Layer in IEEE 802.11 Wireless LANs.2005.IEEE International Conference on Mobile Ad hoc and Sensor Systems,Nov.2005:8-10.
[37]Sangheon Pack,Hakyung Jung,Taekyoung Kwon,and Yanghee Choi.A Selective Neighbor Caching Scheme for Fast Handoff in IEEE 802.11 Wireless Networks.Proc.IEEE ICC Vol.5.May 2005:3599-3603
[38]S.Pack,H.Jung,T.Kwon,and Y.Choi.A Selective Neighbor Caching Scheme for Fast Handoff in IEEE 802.11 Wireless Networks.IEEE International Conference Vol.5,May 2005:3599-3603
[39]J.Montavont,N.Montavont,T.Noel.Enhanced schemes for L2 handover in IEEE 802.11 networks and their evaluations.16th IEEE International Symposium on Personal Indoor and Mobile Radio Communications(PIMRC 2005),Berlin,Germany,Sep.2005:22-24
[40]Min Liu,Zhongcheng Li,Xiaobing Guo,Dutkiewicz E.Performance Analysis and optimization of Handoff Algorithms in heterogeneous Wireless Networks.Mobile Computing,IEEE Transactions on Volume 7 Issue7,July 2008:846-857
[41]V.Hector and K.Gunnar.Techniques to reduce IEEE 802.11b MAC layer handover time.Royal Institute of Technology,April 2003:2-6
[42]Xiaomin Ma,Yun Liu,Trivedi KS.Design and performance Analysis of a New Soft Handoff Scheme for CDMA Cellular Systems.Vehicular Technology,IEEE Transactions on Volume 55,Issue5,Sept.2006:1603-1612
[43]Wang SS,Sridhar S,Green M.Adaptive soft handoff method using mobile location information.Vehicular Technology Conference,2002.VTC Sprint 2002.IEEE 55~(th)Volume 4,6-9 May 2002:1936-1940
[44]Srivatsa,A.M,Jiang Xie.A Performance Study of Mobile Handoff Delay in IEEE 802.11-Based Wireless Mesh Networks.Communications,2008.ICC'08.IEEE International Conference on 19-23 May 2008:2485-2489
[45]杨仁忠,侯紫峰.802.11无线局域网链路层切换机制研究.计算机应用研究.2004.1:97-102
[46]Seastian Speicher,Clemens Cap.Fast Layer 3 Handoffs in AODV-based IEEE 802.11Wireless Mesh Networks,IEEE 2006:3-5
[47]杨仁忠,侯紫峰.基于AP预先转发的802.11无线局域网切换机制研究.计算机研究与发展.2004.8:1376-1380
[48]Li Xu,Bao-yu Zheng.Study on cross-layer design and power conservation in ad hoc network.PDCAT'2003,2003:324-328
[49]W.Richard Stevens.UNIX网络编程第1卷.第二版.清华大学出版社,1997
[50]魏忠,蔡勇,雷红卫.嵌入式开发详解[M].中国电力出版社,2002
[51]Alessandro Rubini.LINUX设备驱动程序,第二版[M].中国电力出版社,2002
[52]Akleman E,Chen J,Srinivasan V.A prototype system for robust,interactive and user-friendly modeling of orientable 2-manifold meshes.Shape Modeling International,2002.Proceedings.2002:43-50
[53]Angrisani L,Narduzzi C.Testing communication and computer networks:an overview.Instrumentation & Measurement Magazine.IEEE Volume 11 2008 Pages(s):12-24
[54]Ionescu B,Ionescu M,Veres S,Ionescu D,Cuervo F,Luiken-Miller M.A testbed and research network for next generation services over next generation networks.Testbeds and Research Infrastructures for the Development of Networks and Communities.2005:22-31