FIFO(Hierarchical First-In First-Out): A New Frame-based Scheduling Algorithm for Real-time Communications in a Packet Switching Network

초록

In this paper, we propose a new frame-based scheduling algorithm, HFIFO (Hierarchical First-In First-Out), for real-time communications in a packet switching network. HFIFO uses hierarchical frame strategy, in which different levels are allocated to the connections requiring different delays and throughputs, and a hierarchical frame structure is constructed according to these levels. Each time a packet of a connection is arrived, the time slots of the corresponding level frame are reserved for the packet by some ordering rule. Then at the service time, the reserved slots are served sequentially. This scheme enables a flexible bandwidth allocation. The ordering rule, which determines which packet should be scheduled first, has a great effect on the overall delay characteristics of all the served connections. Simulation results shows that the overall delay characteristics, i.e., average delay, maximum delay, and standard deviation, are enhanced with respect to HRR. Furthermore, delay characteristics of HFIFO is proved to be enhanced more by increasing the frame length of each level, which is not possible in HRR.