Support Qos, Ipsec Security Gateway Realization

With the development of Internet and services, especially the rapid development of video, voice and other multi-media service, IP network grows from the single data network to the multi-service information networks. The weakness of traditional IP network that is lack of QoS protection is becoming more obviously. So the researchers propose the conception of QoS to offer different QoS protection to different services. IPSec security gateway is a special equipment for encrypting and decrypting. With the appearance of this equipment, it brings some influence on network QoS. Therefore, it is necessary for IPSec security gateway to offer QoS.After analyzing IPSec protocols and correlative technologies of IP-QoS , the effects between IPSec security gateway and network QoS is analysed in detail,include: IPSec tunnel encapsulation, IPSec encryption and decryption, IPSec processing delay and anti-Dos. According to the analysis, specifies the correlative influence to IPSec security gateway, and defines the subject matter of further research.Based on the background of this task, studied on the realization of the existing IPSec security gateways, analyze the situation for IPSec gateway to provide Qos function and finally locate the point to avoid congestion and provide scheduling. Comprehending with the QoS architecture, the classification of QoS and processing characteristics of IPSec security gateway, and got the architecture of IPSec security gateway providing QoS service.On the foundation of these studies, accomplished the design of classifier, congestion avoidance and scheduling, carried out the design in IPSec security gateway, and excogitated the software demo providing the functions of IPSec security gateway with QoS. After testing QoS functions and network performance, IPSec security gateway can provide QoS and meet the requirements of network equipments.