基于效用EPON分布式动态带宽分配实现机制  

Implement Mechanism on Distributed EPON DBA Based on Utility

作　　者：张晋豫[1] 刘犁 

机构地区：[1]北京交通大学计算机与信息技术学院,北京100044 [2]Computer Department,New Jersey's Science and Technology University,Newark,N.J.07102,USA

出　　处：《软件学报》2008年第7期1693-1706,共14页Journal of Software

基　　金：the National High-Tech Research and Development Plan of China under Grant No.2007AA01Z203(国家高技术研究发展计划(863));the National Basic Research Program of China under Grant No.2007CB307101-4(国家重点基础研究发展计划(973))

摘　　要：EPON(Ethernet-based passive optical network)作为基于光纤的宽带网络接入技术,已经成为下一代接入网络的关键技术之一,但是IEEE 802.3ah EPON的Polling机制存在带宽使用率不高的问题,其DBA(dynamic bandwidth allocation)算法产生UWR(unused window remainder),USR(unused slot remainder),UQR(unused queue remainder)和UPR(unused package remainder),浪费了许多带宽资源.IPACT(interleaved polling with adaptive cycle time)EPON提出了一个带宽使用率较高的新的Poling机制,但没有解决DBA算法存在的缺点.在IPACT基础上,提出了一个基于效用的分布式EPON DBA实现机制,实现了对不同SLA(service level agreement)用户的相同业务类应用的差分处理.通过一种集中递归效用算法,有效地消除了再生UWR,通过一种分布式递归效用算法,有效地消除了UQR,通过一个分布式UPR消除机制,减少了UPR.提出了一个基于交织接力棒的USR消除机制,提高了消除USR条件满足的概率,通过将交棒者的USR追加到接棒者的授权中,提高了带宽的使用效率.仿真结果很好地验证了该机制的优点.EPON （Ethernet-based passive optical network） is optical-fiber-based access technology and is becoming a primary one for the next generation access network. But the Polling mechanism of IEEE 802.3ah EPON has low bandwidth efficiency, and many available bandwidths are wasted through UWR （unused window remainder）, USR （unused slot remainder）, UQR （,unused queue remainder）, and UPR （unused package remainder） produced by its DBA （dynamic bandwidth allocation） algorithm. IPACT （interleaved Polling with adaptive cycle time） EPON presents a new Polling mechanism with high bandwidth efficiency, but its DBA algorithm has the same disadvantages as IEEE 802.3ah. Based on IPACT, this paper presents an implement mechanism on distributed EPON utility DBA, it can provide user service different treatment according to his SLA （service level agreement）. By a concentrated and a distributed recursive utility algorithms, it effectively diminishes UWR-reproduced and UQR. By a distributed UPR diminishing mechanism, it reduces UPR. By putting forward a USR diminish mechanism based on interleaved baton, it increases the success probability of diminishing USR, and by adding the USR of baton-sender to the grant of his baton-receiver, it improves the bandwidth efficiency. The simulation results verify it merits well.

关 键 词：以太无源光网络 动态带宽分配 服务质量 服务等级协议 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]