Congestion Control Strategy For Network Service Providers

Along with the development application and wide spread of network techniques, it is facing several new challenges, mainly including: relative lack of resources, network congestion, service diversity and competition rivalry. Traditional "best effort" service can no longer satisfy the requirements of varying customer applications. Therefore, Internet service provider (ISP) should change current service mode and provide guaranteed services if necessary in this case. But in current Internet service, ISP and customers make decisions that optimize their individual performance. ISP makes the rules and accordingly the customers select their consumption modes. To make more efficient use of sparse network resources, and provide satisfying services as well, it is necessary to investigate ISP's behaviors in network control and competition. To solve the aforementioned problems and challenges, this research focuses on ISP's price control, resource allocation, admission control and equilibrium in supply-demand market with the help of economic methods, in order to maximize customer satisfaction and ISP's profit as well. In this way, network resources would be utilized more efficiently with the precondition of guaranteed services.This paper employs quantitative as well as qualitative method for analyzing congestion control and system equilibrium. Based on customer demand information, congestion policies based on internet pricing, resource allocation and call admission control (CAC) respectively have been discussed. Furthermore, these policies are generalized, then the corresponding equilibrium problem is analyzed as well. This work attempts to suggest a reference benchmark for making specific control.Therefore, this paper can be partitioned into two parts:The first part focused on sinle-ISP network congestion control problem. The discussions lie in chapter 2, 3 and 4. In studying congestion control based on pricing policy, two policies based on customer demand information are presented. To deal with practical choice problem of price control policies, a comparative method for policies choosing based on statistical information of customer demand is suggested. In studying of congestion control based on resource allocation, two different bandwidth allocation policies guaranteeing the Quality of Service based on the demand information of the customers have been proposed.Then the effects of different bandwidth allocation policies on ISP's revenues, customer's benefits and system equilibrium have been analyzed as well. In studying of congestion control based on CAC, the control policy which maximizes the expected rewards under several different service prices is investigated, so as to analyze the ISP's supply characteristics. In the mean time, corresponding simulation algorithm is developed to compare influences caused by different control policies on ISP. This provides a quantitative analyzing method for ISP to choose appreciate resource allocation and admission control policies according to network status.The second part focused on multi-ISP network congestion control problem. The discussion lies in chapter 5. In studying of multi-ISP pricing policy, an analyzing method based on statistical information of customer demand is proposed. In the end, another implication in the sense of game theory is presented for the stability condition of supply-demand equilibrium in traditional economic theory after generalizing the above congestion control policies. It can demonstrate the stability condition for supply-demand equilibrium in economic theory.The innovations of this dissertation are summarized as followed:1. In making pricing policies, customer's utility function, demand information and ISP's revenues are considered; Furthermore, a comparative method for policies choosing based on statistical information of customer demand is suggested. Comparing to the existing pricing policies, these policies achieve ISP's profit maximization and congestion control, at the same time, have the merits of simplicity and fairness.2. Markov decision process (MDP) and Performance Potential theory are applied to the analysis of supply characteristics. Through converting system's long-run expected average reward into steady-state performance in MDP, a policy optimization algorithm under the rule of long-run expected average reward. This algorithm transform M * K-dimension global optimization into K times of M-dimension vector optimization. So the computing complexity brought by high-dimension state decreases evidently.3. By applying game theory and contraction mapping theorem, a sufficient condition for the existence and uniqueness of Nash equilibrium in a multi-person non-cooperative game is proposed. Another implication in the sense of game theory is presented for the stability condition of supply-demand equilibrium in traditional economic theory. It can demonstrate the stability condition for supply-demand equilibrium in economic theory. So the stable supply-demand equilibrium of cobweb model in economics is in fact equivalent to the Nash equilibrium in game theory. That is a brand-new explanation for the conclusion in traditional economic theory.