Research On Quality Of Service In Mobile IPv6 Envirnment Based On NSIS Protocol

In recent years, various mobile devices are widely used. The rapid developing Internet will become a global unified communication network system soon. The continuity of communication and access to Internet for the mobile devices need to be hold in the moving process, so the mobile IP technology become one of the main directions of research in recent years. The IPv6 protocol which resolving the shortage of IP address will replace the IPv4 protocol in the future, this has prepared for the amalgamation of many technologies in IP network. In such circumstance, the mobile IPv6 have emerged, and in the continual development and perfection.With the development of Internet technology, network users and real-time operation are increasing fastly. The real-time business is different from the traditional IP business, in addition to the simple transmission of information is required, the delay and bandwidth are also in required.At the same time, as the rapid development of mobile communication technology, a lot of real-time business were introduced to the mobile network environment, which need better quality of service, so the Quality of Service in the mobile IPv6 network become the focus in current research fields.Now the RSVP protocol in the mobile IPv6 network does not support mobility. As the replacer, the NSIS protocol was born, but it still has many aspects need to be improved. While NSIS protocols suite deals with the specific application of NSLP, it will build entire reservation between two corresponding nodes to guarantee the QoS requirements. When the MN moves frequently across domains, or even occurs Ping-pong type handover, the amount of signaling and the time of building resource reservation will all exponentially increasing. This will affect the QoS of network badly. Therefore, this paper proposes an ameliorative scenario which can resolve the problems effectively. This paper introduce a new thought of transmitting the data packets base on flow table instead of routing table, which can reduce the amount of inquiry and comparison, improve the transmitting speed, reduce the amount of message in network and network congestion rate. At last, this paper proposes how to merge the banding process and the resource reservation process by modifying the format of the banding messages while the mobile node has moved.The main contributions of the paper are listed below:Firstly, research on RSVP and NSIS protocols in mobile IPv6 environment.At present, the main QoS research direction in mobile IPv6 environment is to extend the RSVP protocol with mobile features. However the RSVP protocol didn't support mobility when it was designed, so there are lots of problems in the extension of RSVP. That is why the NSIS work group was established by IETF in 11, 2001. They do some comprehensive, systematic improvement on the RSVP protocol, adding the support for mobilility and bidirectional reservation in reservation process, which can ensure the QoS in mobile environment.Secondly, based on the original simple resource reservation with NSIS protocol, this paper proposes a hierarchical resource reservation mechanism based on the crossover node.This paper gives the concept of crossover node after the data-stream furcating in the mobile process, and proposes a new method about how to find the crossover node. In the NSIS procotol, the search of crossover node by adding message to QoS-NSLP protocol. In the hierarchical resource reservation mechanism, the crossover node was found by comparing the the variety of source address and flow label. Thereby it can avoid the fussy process that intermediate routers deal with the data packets, and reduce the complexity of intermediate node's realization.After the crossover node has been found, a hierarchical resource reservation mechanism based on the crossover node is designed in this paper. After researching on the original reservation process of the NSIS protocol, the mechanism divides reservation path between MN to CN into two parts. That is to say, one is the part from CRN to MN's care-of address, and the second one is from CRN to CN. The same part on the two path will invariable, only reserve the resources on the different path. In this way, we can improve the resource utilization of intermediate nodes. Thirdly, in view of the existing problems that the data packets transmitted based on routing table, a new method that data packet transmitted based on flow table is designed.In the process of transmitting data packets based on routing table need to match the destination address. If the record of the routing table is huge, the transmitting speed will be influenced. So in this paper proposes a new method for data packets transmitting which based on flow label. It gives the definition and structure of the flow table, expatiates the process of data packets transmitting. It can improve the lookup and matching efficiency of transmitting the data packets, and save transmitting time of the data packets.Fourth, this paper proposes a method of merging the binding and resource reservation processes, and modifies the message format carried in the binding process.After the mobile node moved, it will send a binding update message to home agent and correspondent node to bind its'new care-of address with the home address. In this paper, we make use of this process to add resource reservation information to binding update message, so as to complete the process of merging the binding and resource reservation process. The binding update message has NSLP message flag and reservation message type flag to support the merger of the two processes. This mothod can reduce the number of the messages transmitted in the network, save the time of building resource reservation and increase the speed of mobile switching.Fifth, this paper designs the NSIS hierarchical resource reservation mechanism in detail.In the NSIS hierarchical resource reservation mechanism based on the crossover node in mobile IPv6 environment, the operation of every node is the major point in this paper. We describe the packets disposal methods of mobile node, crossover node, correspondent node in the communication process, we also give the data structure reserved in every node, how to find the crossover node and the definition of the flow table which are used for transmitting data packet in every node.Sixth, In the LAN environment of lab, a resource reservation environment is built and simulated by using some computers. An experiment about finding crossover node, the NSIS protocol simple resource reservation process and the hierarchical resource reservation process based on crossover node had been done in the environment. The analysis result of experiment data can prove the feasibility and high efficiency with the hierarchical resource reservation mechanism based on the crossover node. According the experiment's data, this scenario can ensure the QoS requirements by decreasing the time of building reservation process.This paper analysises the mobile IPv6 protocol and NSIS protocol, proposes a mechanism of building the resource reservation path partly, avoiding the waste of repeated reservation, reducing the time for building the reservation path, ensuring the QoS in the process of mobile switch.