4-2 MSDP - Anycast RP(2)

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■视频名称：

    《4-2 MSDP - Anycast RP(2)》

■所属专辑：

    《Developing Interdomain Multicast Networks》（跨域组播）

■视频时长：

    9分36秒

■内容简介：

    Anycast RP是一个非常实用的组播部署方案。Anycast RP使用MSDP技术，允许在一个PIM-SM网络中部署多个RP。允许多个RP并存，不仅可以实现RP的冗余备份功能，也可以实现组播流量的负载分担。Anycast RP允许2个或多个RP来分担Source Registration，并且彼此能够做为热备。MSDP是实现Anycast RP的重要协议。所有Anycast RP都配置相同的地址，可以配置成主机地址或环回口地址。

    所有叶路由器都将Anycast RP作为PIM-SM RP，路由协议会自动选择最近的Anycast RP。因此，某些数据源会注册到一台Anycast RP，而接受者会选择另一台Anycast RP作为RPT的根，那么这两台Anycast RP需要建立MSDP邻居以传递数据源信息。当某个Anycast RP失效时，Anycast RP的切换速度取决于IGP的切换速度，因此Anycast RP是一种非常健壮的RP部署方案。

■Abstract：

    Anycast RP is an extremely useful application of MSDP's ability to allow multiple RPs to exist in a PIM-SM network. Allowing more than 1 RP to be active at the same time creates not only a fault tolerant RP method but also a load-sharing mechanism. Anycast RP allows 2 or more RPs to share the load for source registration and to act as hot backup routers for each other. MSDP is the key protocol that makes Anycast RP possible. With Anycast RP, the same unicast address is configured on each RP; this address should be configured as a host address (that is, with a 32-bit mask), and should be configured only on a loopback interface not used for anything other than Anycast RP.

    All the leaf routers are configured so that the host IP address used by Anycast routers is the IP address assigned to be the RP. IP routing automatically selects the topologically closest RP for each source and receiver. Because some sources might choose one physical RP and some receivers a different physical RP, the rendezvous process for PIM-SM cannot operate as designed. With the addition of MSDP and its ability to exchange source-active information, the RP's ability to operate as designed (which is to have knowledge of all active sources) is restored. In the event of a network failure, the speed of RP failover to a backup RP is determined by the speed of the Internal Gateway Protocol (IGP) convergence. Therefore, Anycast RP is an extremely robust method of configuring the RP function within PIM-SM.