Concerning the excessively high energy consumption, long transmission delay and poor data integrity of nodes in Wireless Sensor Network (WSN),a routing algorithm named MSTSDI (Multi-Sink Time Sensitive Data Integrity) based on multi-mobile sinks considering Quality of Service (QoS) was proposed. Firstly, The density of the nodes was determined by the strength of the signal received from the base station,and the WSN was divided into autonomous areas according to the K-means theory. Secondly, a mobile sink was assigned to each autonomous area, and the trajectory of the mobile sink was determined by using Support Vector Regression (SVR). Finally, the depth and queue potential fields were introduced to transmit data packets with high sensitivity and high data integrity through Improved-IDDR (Integrity and Delay Differentiated Routing) algorithm. Theoretical analysis and simulation results showed that compared with GLRM (Grid-based Load-balanced Routing Method) algorithm and LEACH (Low Energy Adaptive Clustering Hierarchy protocol) algorithm, the energy consumption of routing strategy improved-IDDR was decreased by 21.2% and 23.7%; and the end-to-end delay of the algorithm was decreased by 15.23% and 17.93%; the data integrity was better. Experimental results showed that MSTSDI can effectively improve the performance of the system in real networks.

In order to solve the problem of load balancing in Software Defined Network (SDN) control plane, a Dynamic Switch Migration Algorithm based on Multi-objective optimization (M-DSMA) was proposed. Firstly, the mapping relationship between the switch and the controller was transformed into 0-1 matrix optimization problem. Then, the two conflicting objective functions were simultaneously optimized and controlled by the multi-objective genetic algorithm based on Non-dominated Sorting Genetic Algorithm-Ⅱ (NSGA-Ⅱ), one was the plane load balancing degree and another one was the communication overhead generated by switch migration. In the process of multi-objective optimization, the individuals were selected by using the fitness function for crossover and mutation, and then a rapid non-dominated sorting method was used to elite strategy in population. The next generation population was generated and the whole population was continually evolved, thus the global optimal solution was searched. The simulation results show that, the proposed M-DSMA can effectively balance the control plane load, and reduce the communication overhead by 30% to 50% compared with Dynamic Switch Migration Algorithm (DSMA). The proposed algorithm has the significant advantages in improving the control plane scalability.

Aiming at the problems that the communication overhead between controllers is large and the controller throughput is low during the load balancing process of multi-controller in Software Defined Network (SDN), a hierarchical controller load balancing mechanism was proposed. Based on the hierarchical architecture, the load balancing was completed through the collaboration of super controller and domain controller, and the predefined load threshold was used to reduce the message exchange overhead between domain controller and super controller. At the same time, the most overloaded domain controller was effectively selected. A plurality of switches conforming to the migration standard were selected from the switches controlled by the most overload domain controller. Simultaneously the selected switches were respectively migrated to a plurality of domain controllers with high overall performance, which solving the problem of load imbalance among multiple controllers. The experimental results showed that, compared with the COoperative Load BAlancing Scheme for hierarchical SDN controllers (COLBAS) and the Dynamic and Adaptive algorithm for controller Load Balancing (DALB), the number of messages in the proposed mechanism system was reduced by about 79 percentage points, and the throughput of the proposed system was about 8.57% higher than DALB and 52.01% higher than COLBAS. The proposed mechanism can effectively reduce the communication overhead and improve the system throughput to achieve a better load balancing effect.