信元调度中的优先级排队研究

Study on Priority Queuing During Cell Scheduling

ATM交换结构通常应具备优先级控制功能,以适应宽带业务的多样性。优先级控制功能是指可以按各类业务的优先级高低来控制服务质量。当不同优先级的信元在争抢资源时,应该保证优先级高的信元先得到服务,优先级低的信元在缓冲器中等待。实际情况是缓冲区的长度是有限的,丢包现象不可避免。但是如何让丢包对于该结构性能影响不大,比较可行的办法便是支持优先级。

To accommodate the diversity of broadband services, ATM switching fabric should possess priority control function. Priority control refers to control the quality of service based on all types of service priority. When the cells with different priorities compete for resources, the cells with high priority should be served first, and the cells with low priority should wait in the buffer. The length of the buffer zone is limited, so packet loss is inevitable. Priority support is a feasible way to reduce the affect of packet loss.