Operation Manual – PIMH3C S9500 Series Routing Switches Chapter 2 PIM-SM Configuration2-112.2.15 Disabling RPT-to-SPT SwitchoverRPT is not necessarily the tree that has the shortest path. When the multicast trafficrate becomes high, the forwarding path will be switched from RPT to SPT, which is theshortest forwarding path. If an S9500 series routing switch acts as the receiver-side DR,it initiates an RPT-to-SPT switchover process (by default) upon receiving the firstmulticast packet along the RPT. You can disable the switchover from RPT to SPT.Perform the following operations to disable the RPT-to-SPT switchover:To do… Use the command… RemarksEnter systemview system-view —Enter PIM view pim —DisableRPT-to-SPTswitchoverspt-switch-threshold[ value | infinity ][ group-policy acl-number[ order order-value ] ]RequiredBy default, the device initiatesRPT-to-SPT switchover uponreceiving the first multicast packet.Caution:RPT-to-SPT switchover cannot be disabled on a static RP or C-RP; otherwise, thedevice will fail to forward multicast packets.2.2.16 Configuring SSM MappingIn the SSM model, multicast receivers need to support IGMPv3 so that Layer 3multicast devices on the same subnet can learn the information of multicast sourcesspecified by the receivers. Multicast receivers running IGMPv1 or IGMPv2 cannot meetthe requirements for implementing the SSM model.However, the SSM mapping feature can solve this issue by configuring SSM mappingrules on Layer 3 multicast devices, enabling IGMPv1/v2 receivers to support the SSMmodel.A mapping rule associates a multicast source with a multicast group or group range.Therefore, you can configure multiple rules to map multiple multicast sources to amulticast group or group range.Follow these steps to configure the SSM mapping rulesTo do… Use the command… RemarksEnter systemview system-view —
