一种应用于PON接入网的应用层组播优化方案

AN OPTIMISED ALM SCHEME APPLYING IN PON ACCESS NETWORK

在近年来应用层组播业务逐渐兴起的背景下,针对应用层组播本身的拓扑失配、拓扑动荡等问题,提出一种基于重定向与流复制而不修改协议的应用层组播优化承载方案。方案立足于PON接入网的OLT设备,深入探讨了OLT设备中一种软硬件配合实现的部署方法,对此方案进行了仿真验证,结果表明当接入网用户数具有一定规模后,核心网的应用层组播流量负担降低了90%以上;并且,针对OVERLAY拓扑合理性方面,此方案可使节点平均出度降低百分之90以上。此外,还验证了优化效果与PON规模、DPI采样率、视频热门程度等关键因素之间的关系。

With the background of gradual rise of application layer multicast（ALM） in recent years,in this paper we put forward an optimised ALM carrying scheme which is based on redirection and flow replication without modifying the protocol.This scheme aims at solving the problems of topology mismatching and instability of ALM its own,and is based on OLT devices of PON access network.A deployment approach in OLT devices implemented by combining the software with hardware has been discussed in depth.In later part of the paper this scheme is verified with simulation,and the result proves that the flow burden of ALM in core network has a 90% decrease or more when the access network user number achieves to a certain size;Moreover,in light of the rationality of OVERLAY topology,our scheme can reduce the node average outdegree up to 90% and higher.Besides,the relation between the optimisation effect and the key factors of PON size,DPI sampling rate,the popularity of the video,etc.are verified as well.