以太无源光网络中的媒质访问控制研究

以太无源光网络(EPON)借助以太网的简单、易升级等特性,成为一种非常有前途的宽带接入网。EPON是一个点对多点的拓扑结构网络,下行方向利用广播方式传输,而上行方向采用多个ONU共享传输媒质的多址接入方式。为了既能提高传输效率,又避免ONU间的发送冲突,选取一种适当的媒质访问控制机制仲裁各个接入,对维护QoS十分必要。文章重点探讨了动态时隙分配(DBA)机制及其不可或缺的轮询协议设计,使OLT通过轮询动态合理地为每个ONU分配所需的带宽。

Research of media access control (MAC) in EPON

Because of the characteristics of simple,easily upgrading etc.,the Ethernet Passive Optical Network(EPON) has become a promising broadband access network,and has attracted more attention.EPON is a kind of topological structure network of one point to multi-point,the downstream utilizes broadcast way,and the upstream adopts the way that a lot of ONU share the multi-address access.In order to improve the efficiency,prevent the collision between ONU members and safeguard QoS,it is very necessary that choose one proper media access control mechanism to arbitrate the access.This paper probes into dynamic time slot assign mechanism and its indispensable polling protocol especially,and by making use of the polling techniques the OLT can reasonably assign a bandwidth for each ONU.