Implementation of the load balancing for multiple VPN server

Abstract

This paper proposes a load balancing algorithm for multiple VPN equipments. According to the history flow data of each business node in a period, our algorithm calculates its statistical estimated flow, which is approximate to the real value. And then specifies a special server as a scheduling server. If a business node requests a VPN connection, first, it should communicate with the scheduling server. The scheduling server computed the current load of each VPN server, determines the VPN server the business node should connect, response the request business node with the VPN server's IP address. Finally, the node establishes a connection with the VPN server. Our algorithm not only considers the VPN server's own load condition but also the request business node's flow fluctuations, trying best to avoid the situation that different nodes' flow peak values superimpose in one VPN server at a special time. The experimental results show that our load balancing algorithm improves utilization rate as a whole; at the same time, it avoids the situation that in a period some of the VPN servers overload while others are in the idle condition.