Research And Implementation Of On-demand QoS Routing In Active Network

In the traditional IP network, the problem faced in QoS routing algorithm is as follows, firstly, while considering the demand of two or more separate QoS parameters, it is apt to cause NP-Complete problem. Secondly, exisiting QoS routing algorithms are just adapt to specific network applications. What's more, IP network can't simultaneity serve the different network applications with each different QoS requirements. These problems remain to solve in the active network, the reason is that active network has offered a more flexible network platform to user, accelerate the speed that the network upgrades, offer flexible and effective support to various kinds of new-type network application. The essence of active network technology is that it introduce computing function into the network, and serve mode are changed from store-forward to store-compute-forward. active networks nodes not merely has the function of a traditional route's, and can analyse user's customized tactics (active code), in order to control the transmission of the data.This thesis studies some QoS routing algorithms in IP network, and the problem of how to computes route for applications based on their QoS demands and policies in active network. Based on active network technologies, we propose a QoS-Customized Active Routing algorithm which is called QCAR, and correspondingly implement a prototype in active network environment. The research and practice work of this thesis include the following several respect:(1) Have analysed basic route algorithm and QoS route problem in Internet, and discussed more about multi-constrained route algorithm. Make point out that with the diversification and fast development of network applications, network should provide a new and flexible approach to meet applications'QoS demands.(2) Have researched and analysed the active network technology, including system architecture, implementation method and active network encapsulation protocol(ANEP), and analysed the achievements in the domestic and international active network research fields.(3) Have described the network model of QoS routing. Based on active network environment, we proposed two QoS routing algorithms, one is QCAR(ask for compute path) and another is DAQR(compute path in advance). We designed the architecture of the active router,including route compute module and basic QoS policy library, and expand the Capsule formate for the implement of the algorithm.(4) Have studied the active execution environment ANTS, including Capsule programming module, active node mechanism, code distribution and route security problem. Based on above research results, we build a prototype, which can computes route for applications according as their QoS demands and policies actively and flexibly.This thesis's research contents stem from the natural science fund project(BK2001205) in Jiangsu Province, named"The algorithms and protocols used in high performance network routing system", which has been checked and accepted on October 2004.