采用经济学方法和定价机制控制用户流量是网络资源分配的一种重要思路.针对软实时应用的带宽需求特性,将面向弹性应用的拥塞定价思想,引入到软实时应用的服务协商和速率控制中来,提出一种拥塞补偿的网络服务定价机制.不同于传统的拥塞定价对所有数据流一视同仁的做法,该定价机制在网络拥塞时,对不同的用户数据流区别对待,向造成网络拥塞的用户收取额外的拥塞费用,而向受到拥塞影响的用户给予适当的价格补偿.探讨了拥塞补偿价格的设置原则,提出与之相适应的拥塞补偿价格动态设置算法.针对服务协商过程中可能存在的用户瞒报或虚报需求的行为,利用博弈论方法,提出了激励相容的网络定价方案和计费策略,并通过实验说明了其有效性.
Soft real-time applications may be rate-adaptive or delay-adaptive, showing much flexibility in bandwidth requirements. For such traffic it is acceptable to allow user's instantaneous rate to be more or less than what he/she requires. Taking this utility characteristics into account, a network pricing mechanism with congestion charge and compensation is proposed, which differs from the traditional congestion pricing in that users traffic is distinguished so as to punish the misbehaving users by extra congestion cost and compensate the innocent users by price discount while network congestion is onset. Following this idea, the rules for setting congestion charge and compensation are examined in detail. By comparing the acquired transmission rate T* with the pre-agreed rate TO negotiated during admission control and the actual arrival rate T, the network users are classified into three kinds so that the basic connection price, congestion charge and compensation could be applied respectively. Then a dynamic pricing algorithm is presented accordingly along with the analysis on the incentive compatibility of charging policy. Simulation results show that the pricing algorithm with congestion charge and compensation is reasonable in that users are charged appropriately in accordance with the pre-agreed service level and actually allocated network resources. With this pricing mechanism, users would like to announce their true requirements through service negotiation while network nodes would like to participate in the pricing game as well to make more profit.