MPLS技术实现流量工程及服务质量等问题的研究
摘要
Internet近年来以前所未有的普及速度迅速在全球获得发展，逐渐成为一种面向话音、视频、数据和多媒体应用等多种业务的综合媒体。然而，传统IP网络由于其尽力而为(Best effort)机制无法提供针对特定业务的QoS等问题变得日益尖锐。与传统的IP路由机制相比，L2层的快速交换技术(如ATM)转发算法简单有效，具有一套完整的提供QoS保证的机制。在将IP与ATM进行优势互补的种种尝试中，多协议标签交换(MPLS)应运而生了。这一方案采用类似ATM的“标签交换(LabelSwapping)”，并且不改变现有IP路由协议。MPLS的出现对于网络发展具有革命性的意义。
本文首先介绍了MPLS的基本原理、核心技术和工作流程，接着对MPLS的两个非常重要的关键技术：流量工程和服务质量保证进行了深入的研究，提出了MPLS实现IP流量工程的框架结构，以及MPLS支持IP服务质量和服务等级保证的实现机制——QoS-LSP技术。还对MPLS流量工程的其它方面管理手段，QoS-LSP机制与其它QoS协议的互通等方面也进行了研究和探讨。
由于MPLS技术新、发展迅速，并且制约于实验环境和手段，在本文的研究过程中，我们在实验室中做了部分MPLS实现流量工程机制和QoS保证机制的功能验证测试和性能测试。经过数据分析，证实了MPLS在这两方面有着显著的技术优势。
Recently, Internet has been developed rapidly and was used widely throughout the world, and has gradually become an integrated media facing multi services such as voice, video, data and multimedia application. However, traditional IP network can not provide QoS guarantee to specific service because of its best effort mechanism. L2 fast-switching technology (e.g. ATM) has the simple and effective forwarding algorithm and a set of complete QoS mechanism. When we attempted to combine the advantages of IP and ATM, Multiprotocol Label Switching (MPLS) appeared. This scheme adopt Label Swapping technology like ATM, and do not change current IP routing protocols at the same time. The emergence of MPLS has revolutionary significance to the development of communication network.
First, this paper introduces the basic principle, key technology and working flow of MPLS. Then, two important key technologies of MPLS, i.e., Traffic Engineering (TE) and Quality of Service (QoS) guaranty, are deeply researched. We present MPLS framework of realization for IP-TE, and the mechanism through which IP QoS and CoS are guaranteed by MPLS, namely QoS-LSP technology. Furthermore, other management methods of MPLS TE and interoperability between QOS-LSP mechanism and other QOS protocols have been studied and discussed.
Since MPLS is up-to-date and developed rapidly, and subject to the experimental environment and methods, we did some functional and performance testing to verify MPLS TE and QoS mechanisms in lab during the study. The MPLS's remarkable technological advantages at these two
aspects were proved through the analysis of data.
本文首先介绍了MPLS的基本原理、核心技术和工作流程，接着对MPLS的两个非常重要的关键技术：流量工程和服务质量保证进行了深入的研究，提出了MPLS实现IP流量工程的框架结构，以及MPLS支持IP服务质量和服务等级保证的实现机制——QoS-LSP技术。还对MPLS流量工程的其它方面管理手段，QoS-LSP机制与其它QoS协议的互通等方面也进行了研究和探讨。
由于MPLS技术新、发展迅速，并且制约于实验环境和手段，在本文的研究过程中，我们在实验室中做了部分MPLS实现流量工程机制和QoS保证机制的功能验证测试和性能测试。经过数据分析，证实了MPLS在这两方面有着显著的技术优势。
Recently, Internet has been developed rapidly and was used widely throughout the world, and has gradually become an integrated media facing multi services such as voice, video, data and multimedia application. However, traditional IP network can not provide QoS guarantee to specific service because of its best effort mechanism. L2 fast-switching technology (e.g. ATM) has the simple and effective forwarding algorithm and a set of complete QoS mechanism. When we attempted to combine the advantages of IP and ATM, Multiprotocol Label Switching (MPLS) appeared. This scheme adopt Label Swapping technology like ATM, and do not change current IP routing protocols at the same time. The emergence of MPLS has revolutionary significance to the development of communication network.
First, this paper introduces the basic principle, key technology and working flow of MPLS. Then, two important key technologies of MPLS, i.e., Traffic Engineering (TE) and Quality of Service (QoS) guaranty, are deeply researched. We present MPLS framework of realization for IP-TE, and the mechanism through which IP QoS and CoS are guaranteed by MPLS, namely QoS-LSP technology. Furthermore, other management methods of MPLS TE and interoperability between QOS-LSP mechanism and other QOS protocols have been studied and discussed.
Since MPLS is up-to-date and developed rapidly, and subject to the experimental environment and methods, we did some functional and performance testing to verify MPLS TE and QoS mechanisms in lab during the study. The MPLS's remarkable technological advantages at these two
aspects were proved through the analysis of data.
引文
[1] 许继金．MPLS技术及其应用分析．电信技术．2000年9月
[2] 侯立民，郭宇春．MPLS与业务恢复．中国数据通信．2001年4月
[3] 李洪，罗春涛．IP网络中流量工程技术的发展．广东通信技术．2000年7月第20卷第7期
[4] 赵明，刘韵洁．MPLS的技术优势及相关问题．现代电信科技．2000年12月
[5] 石晶林，丁炜．MPLS网络技术及其应用前景．通讯世界．2000年第6期
[6] 徐荣，龚倩．多协议标签交换技术．通讯世界．2000年第4期
[7] 刘嘉，文慧智．浅述多协议标签交换技术．http://www.smiling.com.cn
[8] MPLS技术白皮书．http://www.smiling.com.cn
[9] 周旗，荣波，朱祥华．RSVP与Internet多媒体通信．电信科学．1999年6月
[10] IP QoS离我们有多远．http://www.cnc.net.cn
[11] E.Rosen,A.Viswanathan,R.Callon."Multiprotocol Label Switching Architecture",RFC 3031.IETF.January 2001
[12] Francois Le Faucheur,Liwen Wu,Bruce Davie,Shahram Davari,Pasi Vaananen,Ram Krishnan,Pierrick Cheval,Juha Heinanen."MPLS Support of Differentiated Services",drafi-ietf-mpls-diff-ext-09.txt.April 2001
[13] S.Brim,B.Carpenter,F.Le Faucheur."Per Hop Behavior Identification Codes",RFC 2836.IETF.May 2000
[14] Brim et al. "Per Hop Behavior Identification Codes", draft-ietf-diffserv-2836bis-01． txt. February 2001
[15] Andersson, L., Doolan, P., Feldman, N., Fredette, A. and B. Thomas. "LDP Specification", RFC 3036． January 2001
[16] Awduche et al. "Extensions to RSVP for LSP Tunnels", draft-ietf-mpls-rsvp-lsp-tunnel-09． txt. August 2001
[17] Jamoussi et al. "Constraint-Based LSP Setup using LDP", draft-ietf-mpls-cr-ldp-05． txt. February 2001
[18] Rosen et al. "MPLS Label Stack Encoding", RFC 3032． January 2001
[19] Blake et al. "An architecture for Differentiated Services", RFC 2475． December 1998
[20] Heinanen et al. "Assured Forwarding PHB Group", RFC 2597． June 1999
[21] V. Jacobson, K. Nichols, K. Poduri. "An Expedited Forwarding PHB", RFC 2598． June 1999
[22] Davie et al. "An Expedited Forwarding PHB", draft-ietf-diffserv-rfc2598bis-02． txt. September 2001
[23] Nichols et al. "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC 2474． December 1998
[24] Braden et al. "Resource ReSerVation Protocol (RSVP)-Version 1 Functional Specification", RFC 2205． September 1997
[25] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M. and J. McManus. "Requirements for Traffic Engineering Over MPLS", RFC 2702． September 1999
[26] S. Ganti, N. Seddigh, B. Nandy. "MPLS Support of Differentiated Services using E-LSP", draft-ganti-mpls-diffserv-elsp-00． txt. April 2001
[27] Dan Grossman. "New Terminology for Diffserv", draft-ietf-diffserv-new-terms-05． txt. August 2001
[28] Davie, B., Lawrence, J., McCloghrie, K., Rekhter, Y., Rosen, E., Swallow, G. and P. Doolan. "MPLS using LDP and ATM VC Switching", RFC 3035． January 2001．
[29] "Multiprotocol Label Switching (MPLS)", http://wwww.iec.org
[30] "MPLS-Bringing IP Networks and Connection-Oriented Networks Together". October 2000 issue of Business Communications Review: pp. 84-88
[31] Paul Brittain, Adrian Farrel. "MPLS Traffic Enginneering: A Choice of Signaling Protocols", http://www.dataconnection.com
[32] Xipeng Xiao, Alan Hannan, Brook Bailey, Lionel M. Ni. "Traffic Engineering with MPLS in the Internet", http://www.smiling.com.cn
[33] QoS protocols & architectures, http://www.stardust.com
[34] http://www.techguide.com
[35] http://www.mplsrc.com
[36] http://www.ietf.org/ids.by.wg/mpls.html
[37] http://www.ietf.org/ids.by.wg/diffserv.html
[2] 侯立民，郭宇春．MPLS与业务恢复．中国数据通信．2001年4月
[3] 李洪，罗春涛．IP网络中流量工程技术的发展．广东通信技术．2000年7月第20卷第7期
[4] 赵明，刘韵洁．MPLS的技术优势及相关问题．现代电信科技．2000年12月
[5] 石晶林，丁炜．MPLS网络技术及其应用前景．通讯世界．2000年第6期
[6] 徐荣，龚倩．多协议标签交换技术．通讯世界．2000年第4期
[7] 刘嘉，文慧智．浅述多协议标签交换技术．http://www.smiling.com.cn
[8] MPLS技术白皮书．http://www.smiling.com.cn
[9] 周旗，荣波，朱祥华．RSVP与Internet多媒体通信．电信科学．1999年6月
[10] IP QoS离我们有多远．http://www.cnc.net.cn
[11] E.Rosen,A.Viswanathan,R.Callon."Multiprotocol Label Switching Architecture",RFC 3031.IETF.January 2001
[12] Francois Le Faucheur,Liwen Wu,Bruce Davie,Shahram Davari,Pasi Vaananen,Ram Krishnan,Pierrick Cheval,Juha Heinanen."MPLS Support of Differentiated Services",drafi-ietf-mpls-diff-ext-09.txt.April 2001
[13] S.Brim,B.Carpenter,F.Le Faucheur."Per Hop Behavior Identification Codes",RFC 2836.IETF.May 2000
[14] Brim et al. "Per Hop Behavior Identification Codes", draft-ietf-diffserv-2836bis-01． txt. February 2001
[15] Andersson, L., Doolan, P., Feldman, N., Fredette, A. and B. Thomas. "LDP Specification", RFC 3036． January 2001
[16] Awduche et al. "Extensions to RSVP for LSP Tunnels", draft-ietf-mpls-rsvp-lsp-tunnel-09． txt. August 2001
[17] Jamoussi et al. "Constraint-Based LSP Setup using LDP", draft-ietf-mpls-cr-ldp-05． txt. February 2001
[18] Rosen et al. "MPLS Label Stack Encoding", RFC 3032． January 2001
[19] Blake et al. "An architecture for Differentiated Services", RFC 2475． December 1998
[20] Heinanen et al. "Assured Forwarding PHB Group", RFC 2597． June 1999
[21] V. Jacobson, K. Nichols, K. Poduri. "An Expedited Forwarding PHB", RFC 2598． June 1999
[22] Davie et al. "An Expedited Forwarding PHB", draft-ietf-diffserv-rfc2598bis-02． txt. September 2001
[23] Nichols et al. "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC 2474． December 1998
[24] Braden et al. "Resource ReSerVation Protocol (RSVP)-Version 1 Functional Specification", RFC 2205． September 1997
[25] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M. and J. McManus. "Requirements for Traffic Engineering Over MPLS", RFC 2702． September 1999
[26] S. Ganti, N. Seddigh, B. Nandy. "MPLS Support of Differentiated Services using E-LSP", draft-ganti-mpls-diffserv-elsp-00． txt. April 2001
[27] Dan Grossman. "New Terminology for Diffserv", draft-ietf-diffserv-new-terms-05． txt. August 2001
[28] Davie, B., Lawrence, J., McCloghrie, K., Rekhter, Y., Rosen, E., Swallow, G. and P. Doolan. "MPLS using LDP and ATM VC Switching", RFC 3035． January 2001．
[29] "Multiprotocol Label Switching (MPLS)", http://wwww.iec.org
[30] "MPLS-Bringing IP Networks and Connection-Oriented Networks Together". October 2000 issue of Business Communications Review: pp. 84-88
[31] Paul Brittain, Adrian Farrel. "MPLS Traffic Enginneering: A Choice of Signaling Protocols", http://www.dataconnection.com
[32] Xipeng Xiao, Alan Hannan, Brook Bailey, Lionel M. Ni. "Traffic Engineering with MPLS in the Internet", http://www.smiling.com.cn
[33] QoS protocols & architectures, http://www.stardust.com
[34] http://www.techguide.com
[35] http://www.mplsrc.com
[36] http://www.ietf.org/ids.by.wg/mpls.html
[37] http://www.ietf.org/ids.by.wg/diffserv.html