Study On MPLS And Its Application In Quality Of Service And Traffic Engineering

With the rapid expansion of Internet and the data transferring on it, it comes forth manytroublesome problems, especially such as Quality of Service (QoS) and Traffic Engineering(TE). Therefore a lot of new technologies were developed to confront these problems. At thebeginning of ATM technology was bring forward, it was regarded that ATM will replace thetraditional IP technology. But in fact ATM just was not so perfect as people's thought and alsoIP technology will not be replaced by any other new technology. So in 1996 people bringforth the creative notion that was called "IP Switching". The base idea of this notion was tounite the flexible layer-3 IP routing technology and the layer-2 ATM connection-orientedtechnology. After this notion was born, many famous IT Company develop themselvescorrelative technologies. These technologies were very different from each other. For unifythese technologies , IETF found a working group named MPLS(Multiprotocol LabelSwitching)Group to begin the working of standard and finally issue MPLS standard in 1999 .Henceforth the research and application of MPLS was making progress rapidly. By nowalthough MPLS technology had not yet became very perfect, but it had been deployed widelyin real world network and accepted by people more and more.The notion of MPLS is simple, it uses a certain length of label to divide the layer-2 ofdata transmitting and the layer-3 of routing. In this way the router can transmit data onlyaccording to the content of label and need not play the complex processing of route lookup,this will greatly alleviate the burden of routers. Besides, the process of switching of label onlyplay in the first package of data streams and all following package of a data stream will betransmit through the same path as the first package, this will make MPLS network had thecharacteristic of connection-oriented. So MPLS can solute many problems in traditionalInternet very well. It can provide excellent application such as Quality of Service and TrafficEngineering, this two important application are emphasis of our thesis' study. QoS and TEcould meet the increasing demand of diversified applications and optimize the resource ofwholly network.In this thesis we first introduce the history background and basic working mechanism ofMPLS, then we emphasize particularly on its important application in QoS and TE. In contentof QoS portion, We introduce the model of DiffServ over MPLS and found a model withOPNET to play simulation to compare the traffics QoS parameter results on threebackgrounds of ordinary, DiffServ and MPLS&DiffServ;In content of TE portion, We firstintroduce the base function components of MPLS-TE and analyze the SPF algorithm used inIGP network and CSPF algorithm used in MPLS-TE network, then we found a model tosimulate to compare the results of IGP background and MPLS-TE background in the samenetwork topology. Our experimental data show that MPLS could provide excellent applicationin QoS and TE.