I wanted to know why do we enable sparse mode in SP cloud when we are using SSM also. (ip ssm default). Since SSM dosent need any RP then why we need the sparse mode together to be used with SSM in the SP cloud.
you can check the mvpn discussion. Hritter answered " SSM uses PIM-SM with a few modifications. RFC4601 section 4.8.1 defines the modifications to the PIM SM protocol to support SSM. Beyond these modifications, all normal PIM SM functionality and messages are required, including periodic join messages.