利用组播树优化VPLS组播功能的研究

Research on using multicast tree to optimize VPLS multicast

RFCs 4761和4762描述了一种基于利用点对点或点对多点单播LSP承载组播流量的VPLS解决方案。对于某些VPLS组播流量配置,这种解决方案有一定局限性。例如,当有大量的组播流量需要传播时,会导致带宽利用严重非最佳化。本文描述的解决方案是为了克服现有VPLS组播解决方案中的一部分局限性。其中描述了在SP网络中利用组播树来实现VPLS组播的过程。该解决方案允许在多个VPLS实例间共享一个这样一棵组播树。此外,本文提出的解决方案还允许SP网络中的一棵单独的组播树承载来自一个或多个VPLS实例的,仅仅属于指定的一个或多个IP组播流集合的流量。

RFCs 4761 and 4762 describe a solution for Virtual Private LAN Self＇ice （VPLS） multicast that relies on the use of point-to-point or nmhipoint-to-point unicast Label Switched Paths （ESPs） for carrying multicast traffic. This solution has certain limitations for certain VPLS multicast traffic profiles. For example, it may result in highly non-optimal bandwidth utilization when a large amount of muhicast traffic is to be transported. This document describes snh,tions for overcoming a subset of the limitations of the existing VPLS multicast solution. It describes procedures for VPLS multicast that utilize muhicast trees in the service provider （SP） network. The solution described in this document allows sharing of one such muhicast tree among muhiple VPLS instances. Furthermore, the solution described in this dueument allows a single multicast tree in the SP network to carry, traffic belonging only to a specified set of one or more IP multicast streams from one or more VPLS instances.