Multicast
Multicast is often employed in Internet Protocol (IP) applications of streaming media, such as IPTV and multipoint videoconferencing.
Multicast uses network infrastructure efficiently by requiring the source to send a packet only once, even if it needs to be delivered to a large number of receivers.
By adding loss detection and retransmission mechanisms, reliable multicast has been implemented on top of UDP or IP by various middleware products, e.g. those that implement the Real-Time Publish-Subscribe (RTPS) Protocol of the Object Management Group (OMG) Data Distribution Service (DDS) standard, as well as by special transport protocols such as Pragmatic General Multicast (PGM).
Internet Relay Chat (IRC) implements a single spanning tree across its overlay network for all conference groups.
[6] Some peer-to-peer technologies employ the multicast concept known as peercasting when distributing content to multiple recipients.
Explicit multi-unicast (Xcast) is another multicast strategy that includes addresses of all intended destinations within each packet.
The Xcast model generally assumes that stations participating in the communication are known ahead of time so that distribution trees can be generated and resources allocated by network elements in advance of actual data traffic.
[7] Wireless communications (with the exception of point-to-point radio links using directional antennas) are inherently broadcasting media.
Wireless networks use electromagnetic waves to transmit data through the air, enabling devices to connect and communicate without physical cables.
This is efficient in scenarios like live streaming, where the data is only sent once but received by multiple devices interested in the same content.
However, they can be affected by interference from physical obstacles, environmental factors, or even other wireless devices, leading to slower speeds or connection issues.
TV gateways converts satellite (DVB-S, DVB-S2), cable (DVB-C, DVB-C2) and terrestrial television (DVB-T, DVB-T2) to IP for distribution using unicast and multicast in home, hospitality and enterprise applications Another similar concept is Cell-TV, and implies TV distribution over 3G cellular networks using the network-assisted multicasting offered by the Multimedia Broadcast Multicast Service (MBMS) service, or over 4G/LTE cellular networks with the eMBMS (enhanced MBMS) service.
