Research On Routing Strategy Based On QoS In Aerospace Environment

In aerospace environment, multilevel network nodes coexist such as orbit satellite in various heights, near space platform, ground equipment and so on, with characteristics of big coverage, far transmission distance and high system stability. This system is able to implement a wide range of reliable communication, which is the most development prospect communication network system after ground communication system and satellite communication system.Aerospace network makes satellite and near space platform as backbone network nodes, providing communication service for on ground user and air static user or high-speed mobile user. In order to ensure the reliability of data transmission, multiple relay on data transmission is needed, making transmission path is not the only. On this basis to ensure efficiency of data transmission, a optimal path to meet different business types is need to be selected. In that case, routing strategy based on Qo S is the focus in this paper.First, aerospace network system is generally analyzed. Communication network model is established, confirming topology of entire network, effect of nodes in network and data transmission mode of the link. On this basis, according to the characteristic of space network, appropriate routing mechanism is chosen.Second, in order to solve the problem of high dynamic changing characteristics of communication network topology in air and space environment, a reasonable virtual topology control strategy is designed which is the basis of Qo S strategy. On the basis of the traditional packet header, IP address of source access point and purpose point is added. The method of time slot division is adopted to convert dynamic topology to relatively static virtual topology for the dynamic characteristic of backbone nodes. Within the time slot, Dijkstra algorithm is used with link state as parameter to calculate the optimal path. When time slot switching, soft switching strategy is used to avoid the interruption of transmission. For the dynamic of user nodes, message transmission mechanism is designed when users access and switch backbone nodes. Also, user backbone nodes connection table is built up to seek the connecting node of purpose user.Last, in order to solve the problem of high dynamic changing characteristic of link state, the research on routing mechanism which satisfies the Qo S of different business is made. At first, the transmission business is classified according to the business needs. Then we analyze influencing factors of link-state and describe them in the way of time delay. After that a link-state information table is established to represent the state of whole communication network On the basis of that, based on time-varying link-state and business needs, we get path cost function and constraints,and routing optimization model is established. According to different types of business, the routing optimization algorithm is designed respectively. Queuing delay and the delay caused by packet loss is simulated, whose result illustrates the correctness of the model.By means of designing the routing strategy, Qo S of different business in high dynamic topology and high dynamic link status is guaranteed. Reliability and efficiency of data transmission is guaranteed, and utilization of network resource is improved.