The router will loadsplit based on the source and group addresses if you issue the ip multicast multipath sghash basic command on a router that has multiple equalcost paths to a multicast source. The ip multicast multipath sghash basic command uses the SGhash algorithm so that Protocol Independent Multicast Source Specific Multicast (PIM-SSM) can reply to traffic by using either the Reverse Path Forwarding (RPF) interface or the source group address when equalcost paths exist. The basic SGhash configuration is subject to polarization because the hash is the same no matter which router calculates it.
The router will not send traffic to the Protocol Independent Multicast (PIM) neighbor with the highest IP address. By default, when equalcost paths to a multicast source exist, PIMSSM will send traffic to the neighbor with the highest IP address. However, issuing the ip multicast multipath command with or without keywords enables loadsplitting and disables the default behavior.
The router will not loadsplit based on the source address only. You should issue the ip multicast multipath command to enable Equal Cost Multipath (ECMP) loadsplitting based on only the source address. By issuing the ip multicast multipath command, you can configure PIMSSM to loadsplit traffic between equalcost paths by using the Shash algorithm, which selects the interface on which the traffic arrives as the interface on which to send a response.
The router will not loadsplit based on the source, group, and nexthop addresses. The ip multicast multipath sghash nexthopbased command uses the SGhash algorithm and configures PIMSSM to loadsplit traffic based on the source address, the group address, and the nexthop address. Unlike the ip multicast multipath sghash basiccommand, the nexthopbased SGhash configuration is not subject to polarization.