基于公平期的循环服务——一种用于ATM网络的简单公平信元调度机制

摘要

为了在ATM网络中简洁及公平地实现信元调度，本文提出了一种新的公平服务规则：基于公平期的循环服务(简称为FCRR)，FCRR将理想的公平服务准则与经典循环服务的简单性有机地相结合，以接近于经典循环服务的代价实现了在每个“公平期”上对各用户业务的公平服务。在给出了“公平基”和“公平期”的概念后，我们证明了FCRR在每个“公平期”上服务的公平性，导出了FCRR的最差公平性和信元时延上界，与转交式循环服务(CORR)相比，FCRR具有更好的公平服务特性。相应的模拟分析进一步表明，FCRR的公平性明显优于CORR，并对高速业务具有比CORR更好的时延特性。%In order to schedule cells fairly and cost-effectively in ATMnetworks，this paper develops a new type of fair service scheme called the “fair-cycle-based”round robin service(FCRR for short below).FCRR combines efficiently the fairness of an ideal fair service with the simplicity of a typical“round-robin”service so that it can provide real fair service over each“fair-allocation-cycle”to all connections at low cost very close to that of a simple round robin.Also，we analyze the worse-case fairness(i.e.the maximum unfairness)，the upper cell delay bound，and the computation complexity of an FCRR server.The analysis presented in this paper shows that FCRR compares favorably with the“carry-over round robin”(CORR for short)in terms of both fairness and computation complexity.The numerical results obtained from a simulation study further support the theoretical analysis，with two main conclusions that FCRR is evidently superior to CORR in terms of fairness and can offer higher-rate connections much better delay properties.