With multicast, a single video stream is sent across the backbone to all receivers. Packets are replicated at points where the network branches before delivery to the user. Distributed replication eliminates multiple redundant streams from end to end, overcoming a critical limitation of unicast video. Multicasting lets a virtually unlimited number of learners participate. PIM can operate in either sparse or dense mode.
Sparse mode is streamlined for large viewerships because it consumes the lowest bandwidth overhead.
Dense mode works best in small segments that have many receivers. MSDP provides scalability by joining multiple rendezvous points of sparse-mode PIM and advertising them to one another to reduce the amount of overhead traffic in the network. Add Bandwidth Capacity E-learning applications need room to maneuver in the network. This quality uses bandwidth, so capacity planning is a vital step toward enabling e-learning in the network. It's helpful to know the nature of traffic on the link.