Supported Platforms
SPT Cutover Control
In some cases, the last-hop router needs to stay on the shared tree to the RP and not transition to a direct SPT to the source. You might not want the last-hop router to transition when, for example, a low-bandwidth multicast stream is forwarded from the RP to a last-hop router. All routers between last hop and source must maintain and refresh the SPT state. This can become a resource-intensive activity that does not add much to the network efficiency for a particular pair of source and multicast group addresses.
In these cases, you configure an SPT threshold policy on the last-hop router to control the transition to a direct SPT. An SPT cutover threshold of infinity applied to a source-group address pair means the last-hop router will never transition to a direct SPT. For all other source-group address pairs, the last-hop router transitions immediately to a direct SPT rooted at the source DR.
