Cooperation Research On Collaborative Construction And Mapping Method Of Air-Ground Integration Network SFC

In the air-ground integrated network based on software-defined networking(SDN)and network function virtualization(NFV),the virtual network functions(VNFs)required for services are constructed into an ordered service function chain(SFC)and mapped to the physical network,which can achieve flexible network deployment.However,most of the existing SFC construction and mapping studies ignore the impact of the underlying physical network resources distribution on the construction scheme and the load imbalance caused by function aggregation.Aiming at the above problems,this paper firstly proposes an air-ground integrated network architecture based on three-layer collaborative to coordinate management of air-ground network resources,make full use of resources and provide decision support for SFC deployment.Secondly,an SFC construction method based on improved lexicographical order is proposed,which can quickly index in the form of key-value pairs by coding to improve the construction efficiency of SFC.Finally,a selection method of VNFs to be aggregated based on task similarity and a node selection algorithm for SFC mapping based on network resources awareness are proposed,which solves the problem of load imbalance caused by function aggregation in the mapping process.The specific research contents and innovation points are as follows:(1)The existing air-ground integrated network architecture based on SDN and NFV ignores the problem that the resource heterogeneity of the air-ground network is difficult to achieve efficient utilization of resources.This paper constructs a three-layer collaborative air-ground integrated network architecture based on SDN,including the lift-off platform centralized control layer,the ground network centralized control layer and the collaborative management and control layer.Firstly,NFV technology is used to simplify the deployment of air-ground integrated network.Secondly,the centralized control layers of the lift-off platform and the ground network based on SDN technology are respectively deployed on airships and ground network to monitor the network topology and resource status of the air and ground respectively.In order to solve the problem of heterogeneous resources in the air-ground integration,a collaborative management and control layer is introduced in the ground backbone network to supervise and coordinate the lift-off platform and the centralized management and control layer of the ground network,which can collect,monitor and evaluate global information resources.Finally,through the collaborative management and control layer,it provides decision support for on-demand deployment of services and flexible scheduling of resources.(2)In the SFC construction process of air-ground integrated network,the neglect of underlying physical resources distribution and the unknown logical sequence of VNFs constructing service function chain lead to the problem of low efficiency of SFC construction.A SFC construction algorithm based on improved lexicographical order is proposed.Firstly,the VNFs are encoded and arranged in the order of dictionary storage.Secondly,according to the dependencies between VNFs and the resources perception information provided by the collaborative management and control layer,the qualified SFC construction set is obtained by indexing in the form of key-value pairs.Different from the depth and breadth-first search,the SFC construction algorithm based on the improved lexicographical order does not require a tree-shaped storage structure or repeated comparative searches,but indexes in the form of key-value pairs,which reduces the search space and improves construction efficiency of SFC.(3)To solve the load imbalance problem caused by function aggregation in the SFC deployment process of air-ground integrated network,a selection method of VNFs to be aggregated based on task similarity and a selection algorithm of SFC mapping nodes based on network resources awareness are proposed.Before SFC mapping,the network load balancing problem is considered synchronously to balance resources consumption and load balancing.Firstly,a method for selecting VNFs to be aggregated based on task similarity is proposed.The tasks are classified according to the similarity between tasks,and the functions to be aggregated within the class are selected under the limitation of underlying physical resources.Secondly,a selection algorithm of SFC mapping nodes based on network resources awareness is used to obtain the most suitable physical nodes for single-chain and multi-chain mapping according to various attributes of physical network nodes,which make full use of the underlying physical resources to reduce resources consumption and load imbalance.