Method for updating flow table and optimizing flow table consistency of software defined satellite network

Abstract

The invention discloses a method for updating a flow table and optimizing flow table consistency of a software defined satellite network, and relates to the field of the software defined satellite network. The method for optimizing the flow table consistency comprises the steps of firstly monitoring a global state of a satellite network in real time through network awareness, maintaining topological graphs at different moments in the satellite network and updating a topological state and events of the network in time; then combining a transmission time delay based routing decision with a path similarity based routing decision, wherein as the needed transmission time delay and the needed write-in time delay are relatively small, the total time delay of the flow table updating process is reduced; and finally, reducing influences from the time delay which is from a switch to a controller to the inconsistency of the flow table through adjusting the transmission sequence of the switch, reducing the number of transmitted flow table items through classifying new and old flow tables so as to reduce the write-in time of the flow table items and accordingly reduce the total time delay for the updating of the flow table. The invention improves the inconsistency problem of the flow table updating of the software defined satellite network in a better way.

Description

technical field [0001] The invention relates to the field of software-defined satellite network (Software Defined Satellite Network, SDSN), in particular to improving the inconsistency problem of updating the flow table of the software-defined satellite network. Background technique [0002] In recent years, software-defined network (Software Defined Network, SDN) has received more and more attention as a new technical concept. It separates the management functions in the network from traditional network devices such as switches or routers, thereby realizing the complete independence of the control plane and the data plane. The control plane in SDN can monitor and collect network information in real time, and provide timely feedback on network status, including network device working status and link connection status. This centralized control function is applied to the satellite network, which can well solve the problems of control information release and poor convergence t...

AI Technical Summary

Problems solved by technology

In the satellite network, the number of satellite nodes is not many, and the traffic volume undertaken by the satellite network is relatively small compared with the ground network. In addition, due to the special network environment of the satellite network, the relative distance between satellite nodes is relatively large, making the satellite network Compared with the ground network, it has a larger network delay

For example, the GEO (High Orbit Satellite Network) node in the satellite network has a delay of more than 100 milliseconds to the ground, and the harsh space environment of the satellite network aggravates the delay problem in the network

At the same time, the dynamic topology of the satellite network makes the network environment unstable. The switching of inter-satellite and inter-satellite links makes the path switching during the service transmission process frequent, which will cause frequent changes in network control rules, and the controller needs to continuously collect network status. , formulate routing policies and update flow table rules

[0006] The inconsistency delay is used to judge whether there is logic inconsistency among the switch nodes in the calculated path. If the delay c from the switch m to the controller is m greater than the delay c from the source switch node to the controller in the path 1 and the sum of the link delays of the first m nodes in the path, it is considered that there is an inconsistent delay in the switch m, and the inconsistent delay △t=c m -c 1 - the sum of the first m node links, then when the network updates the flow table for this path, it takes a long time for the flow table of switch m to take effect, which will happen when the data packet arrives at switch m, the flow table of switch m is still There is no effective situation; if there is no inconsistent delay, △t=0

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