Reference:
PIM dense mode (PIM-DM) uses a push model to flood multicast traffic to every corner of the network. This push model is a brute-force method of delivering data to the receivers. This method would be efficient in certain deployments in which there are active receivers on every subnet in the network. PIM-DM initially floods multicast traffic throughout the network. Routers that have no downstream neighbors prune the unwanted traffic. This process repeats every 3 minutes.
A rendezvous point (RP) is required only in networks running Protocol Independent Multicast sparse mode (PIM-SM).
In PIM dense mode (PIM-DM), multicast traffic is initially flooded to all segments of the network. Routers that have no downstream neighbors or directly connected receivers prune back the unwanted traffic.

As these wireless networks grow especially in remote facilities where IT professionals may not always be onsite, it becomes even more important to be able to quickly identify and resolve potential connectivity issuesideally before the users complain or notice connectivity degradation. To address these issues we have created Cisco's Wireless Service Assurance and a new AP mode called "sensor"mode. Cisco's Wireless Service Assurance platform has three components, namely, Wireless PerformanceAnalytics, Real-time Client Troubleshooting, and Proactive Health Assessment. Using a supported AP ordedicated sensor the device can actually function much like a WLAN client would associating andidentifying client connectivity issues within the network in real time without requiring an IT or technician to beon site.