Research On QoS-Based DiffServ Model And Management Mechanism

Along with the rapid expansion of the Internet, as well as the vigorous development of multimedia technical, QoS already became the key question to the normal operation of next generation Internet. Along with it has initiated a series of new technical appearance, like IntServ, DiffServ, CBR as well as MPLS-TE and so on. As the QoS realization model, DiffServ relies on its simplicity and the expandable characteristic, becomes to first choice plan and the research hot spot to realize the IP QoS at present.It's thought "the edge classification, the interior retransmits" helps people go out the IntServ/RSVP model's difficult position, and provide a new mentality for solved IP QoS question .The realization of DiffServ model is safeguard by a series of concrete mechanisms. Queue management and queue scheduling mechanism that function to the system core router make scheduling management and retransmits on data packets according to Different PHB category, but essentially manifests the management and the disposition to the network resources, is the core question for realizes the IP QoS. Therefore, made research to the above two mechanisms have the important theory significance and the practice value for IP QoS.The main work of the thesis as follows:1.Made a thorough research to the DiffServ model, and analyzed the implementation plan about the unify of the DiffServ model and the IntServ model as well as the unify of the DiffServ model and the MPLS model from the technical angle.2.Made an analysis to the shortcomings of the PQM algorithm represent by DropTail as well as the deficiency of several typical AQM algorithms currently like RED, RIO-C, and proposed a new AQM algorithm—PFRIO. This algorithm is for the purpose of solving band width assignment fairness question which initiates by date packets in an identical PHB group but has different priority that sharing buffer queue. And confirmed the feasibility and the validity of the algorithm through the theoretical analysis and the simulation experiment.3. Through analysis and the comparison to many kinds of queue scheduling algorithm, selects the WRR as the scheduling algorithm that guaranteed the QoS plan in the DiffServ model . 4.Considering the QoS guarantee, this thesis article proposed a DiffServ overhead construction model that can simultaneously realize EF, AF, BE PHB and proved this overhead construction model realizes the QoS guarantee validity through the simulation experiment.