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Protocol-independent multicast

Protocol-independent multicast definition

Protocol-independent multicast (PIM) refers to an advanced computer networking method to route IP packets to multiple destinations simultaneously over a LAN (local area network). Since it’s independent of a specific unicast routing protocol, it’s much more suitable for a wide range of network environments compared to traditional multicast routing protocols. When data needs to be sent to multiple places on a network, PIM finds the best way to deliver it without needing to send it separately each time. However, implementing it can be complex, and PIM’s performance still largely depends on the existing network capabilities.

See also: multicast router

How PIM works

PIM operates in two modes. The sparse mode (PIM-SM) is designed for networks where recipients are widely dispersed, using a “pull” model where data is sent only if requested. The second mode is the dense mode (PIM-DIM). It works best in networks where recipients are densely packed, using a “push” model where data is sent to all nodes initially and then pruned back as necessary.

PIM uses the existing unicast routing information in the network and creates multicast distribution trees. It then uses these trees to route multicast traffic from the source to the receivers efficiently.

Where is PIM used?

  • Video streaming
  • IPTV
  • Cable television
  • Financial trading systems
  • Content delivery networks
  • Multiplayer games
  • Remote education
  • Alert systems