区分服务网络中立即保留请求的接纳控制

Admission control for immediate reservation calls in differentiated service networks

区分服务网络中的资源保留可以分为2类:立即保留和预先保留。当已接纳的预先保留请求开始连接时,一些立即保留连接可能会因带宽不足而被中断。只有当立即保留请求的近似中断概率(实时计算得到)低于某个门限值时,该立即保留请求才被接纳。以往计算立即保留请求的中断概率,皆假设预先保留请求会在预定时间准时建立连接,但一般用户可能提前或延后建立其预定的连接。因此在允许预先保留请求提前或延后建立连接的环境下,提出了一个更准确地评估其立即保留连接中断概率的非准时连接近似法和其接纳控制方法。实验结果证实该方法可以更准确地计算立即保留连接的中断概率,降低其实际中断情况的发生,确保其所要求的服务质量。

The Quality of Service （QoS） reservation in Differentiated Service （DiffServ） networks can be classified into two sets： Immediate Reservation calls （IR calls） and Advance Reservation calls （AR calls）. When an admitted AR call became active, some ongoing IR calls were interrupted when the bandwidth was insufficient to support both IR and AR calls. Thus an IR call would be admitted by admission control scheme only if its approximate interrupt probability （computed in real time） was below a threshold. In many previous studies, the interrupt probability of IR calls was under the assumption that AR calls started their connections at the time they reserved. However, users may establish advance or postponed their connections. Thus, a more accurate Approximation under Inexact Connection Arriving Times （AICA） way was proposed to estimate the interrupt probability of IR calls in the environment where AR calls were admitted with inexact connection arriving times. The results showed that our calculation could get a higher and more correct interrupt probability of an IR call so that its actual interrupt probability was lower and its QoS was guaranteed.