改进的DQDB MAN网络性能分析  

Analysis of Network Performance for M DQDB MAN

作　　者：温燕红[1,2] 应海雄 余松煜[1,2] 

机构地区：[1]上海交通大学图像通信与信息处理研究所 [2]上海通技通讯设备有限公司

出　　处：《上海交通大学学报》1999年第4期398-402,共5页Journal of Shanghai Jiaotong University

基　　金：国家自然科学基金

摘　　要：对比分析了ＤＱＤＢ协议与改进的ＤＱＤＢ协议——具有时隙重用功能和抢占优先功能的、多请求多优先级ＢＷＢ计数器的媒质接入控制机制．分析表明，这种新方法在保持原协议特点的同时，进一步改善了网络带宽分配的性能：时隙重用使网络的吞吐率提高了近１倍；在多优先级网络中ＭＰＢＷＢ机制大大改善了高优先级业务的性能；抢占优先机制使得高优先级业务的性能不受低优先级业务的影响；发送请求窗口值则决定了暂态时间的长短，当它与ＢＷＢ－ＭＯＤ的比值相等时。The basic DQDB protocol was compared with the modified DQDB protocol——slot reused and preemptive Medium Access Control mechanism with multiple requests outstanding and multiple bandwidth balancing counters for different priorities. The new technique not only improves the fairness of network, but also increases the throughput and reduces the delay. In M DQDB, the slot reuse has twice the nominal network bandwidth. The preempty and multiple bandwidth balancing counters for different priorities always guarantee the maximum bandwidth to the highest priority traffic whenever it is requested. The multiple requests outstanding for one node makes the general distributed queue inform the actual situation much more rightly, and reduces the network position dependent characteristics.

关 键 词：计算机通信网 带宽平衡机制 带宽分配 DQDB协议 

分 类 号：TN913.2[电子电信—通信与信息系统] TP393[电子电信—信息与通信工程]