Research And Implementation Of Terminal Access Technology In Cloud Environment

With the development of cloud platforms,terminal access technologies are widely used.This thesis studies and researches the mainstream terminal access technologies in detail.Among their various implementations,Open VPN has become a popular choice for its low deployment cost and high compatibility.Therefore,this thesis chooses Open VPN as the main research object,and conducts research and analysis on its principles,application scenarios,workflow,and performance,and proposes a DPDK(Data Plane Development Kit)performance optimization scheme.The optimization schemes of data receiving module and data forwarding module are based on DPDK,and respectively designed and implemented on the basis of DPDK combined with Open VPN's own authentication characteristics and special data structure.This thesis studies the workflow of the three main functional modules of Open VPN in detail,and analyzes the impact of their overhead on the performance of Open VPN by means of experiment and literature learning.After obtaining the analysis results,this thesis designs and implements the optimization scheme based on DPDK for the data receiving module and data forwarding module of Open VPN.The optimization scheme of the data receiving module is based on the transceiver platform,the user state protocol stack of F-Stack and the KNI(Kernel NIC Interface)component of DPDK,realizing the high-speed and low overhead reading of data packets by Open VPN and the separation of control plane and data plane combined with the tunnel authentication service of Open VPN at the same time.The optimization scheme of the data forwarding module is also based on the DPDK platform for sending and receiving packets,but in order to be compatible with the special data structure of Open VPN and Open VPN's clients that still use TUN devices,not going through the FStack user mode protocol stack.Therefore,simple ARP and NAT functions are designed and implemented on the basis of DPDK data processing,which reduces the overhead of data forwarding while ensuring communication with the intranet.After optimizing OpenVPN according to the scheme proposed in this thesis,the delay and network throughput are tested.The test results show that,in the same test environment,compared with the Open VPN before optimization,the delay of the Open VPN server optimized by DPDK and other technologies is reduced by 6.3% on the whole,and the network throughput is increased by 16.2%,which improves the performance of the OpenVPN gateway.