Research On Handover Mechanism In Software Defined Networking

Handover of mobile equipment(ME) between different access points(APs) is an inevitable problem in the wireless network. How to satisfy the user's QoS and achieve seamless handover has become a very worth of study in the field of wireless communication network. As users increasingly demanding network environment, it is very essential to improve the mobile equipment's handover efficiency and ensure the handover QoS. It is very difficult that improve the handover efficiency under the existing network architecture, and the emergence of SDN to meet user requirements for the handover performance. The main idea of SDN is removing the control module from the forwarding device, and placing the control plane on a centralized server called “controller”. The controller through open interfaces manages the behavior of all the network devices in the infrastructure layer. The network devices which controlled by controller only keep the simple forwarding capability. Consequently, this paper makes full use of the characteristics of SDN, and proposed a handover mechanism under the SDN architecture. And the proposed mechanism can improve the handover efficiency.This paper studies in depth the SDN architecture. This paper considered selection of the AP and the improvement of QoS. This paper studied the mobile handover mechanism in the SDN environment, and proposed solutions that addressing the problem occurring in the existing network infrastructure. The details are as follows:(1) Research on how to choose the handover AP. This paper proposed a multiple attributes handover algorithm based on fuzzy logic which utilizes RSS, forecasting RSS, available bandwidth and network transmission rate for parameters to design of fuzzy logic controller, and make the parameters quantized and calculate the parameters of membership value. At last the algorithm calculated the values of network performance to make handover decision. The further experiments verified the feasibility of the algorithm in the mobile handover field and the validity of the algorithm. Experiments results showed that the algorithm can effectively avoid the ping-ping effect and improve the network performance.(2) Research on how to ensure the QoS in the process of handover, and then achieve the seamless handover. This paper proposed handover mechanism which based on MPTCP under SDN architecture, and this mechanism can ensure the QoS. In the TCP/IP architecture, the TCP link will be interrupted when the handover delay too long. The MPTCP protocol can overcome poor performance of TCP link. MPTCP is an extension of the TCP; it utilized the multiple transmission paths to transmit data concurrently. The mobile equipment can utilize MPTCP connect multiple APs simultaneously, when a link switching occurs, the rest links continue to maintain communication. It enables to achieve a smooth handover. Experimental results showed that the mechanism can achieve seamless handover, improve handover efficiency. And the handover mechanism improves the network bandwidth utilization and robustness. Thus ensure the user experience during handover.