What multicast is
Multicast is a method of sending data across a network to a group of receivers that are interested in it, all at once. Rather than sending a separate copy to each recipient individually, or sending to everyone on the network, multicast delivers the data to the specific group that wants it. This group-based delivery is what distinguishes multicast from other ways of addressing data.
Unicast, broadcast, and multicast
There are different ways to address network traffic. Unicast sends data to a single specific recipient. Broadcast sends it to all devices on a network. Multicast sits between these: it sends to a defined group of interested receivers. This makes multicast useful when the same information needs to reach many, but not all, devices, without duplicating effort for each one.
Why multicast can be efficient
Multicast can be efficient because it avoids sending a separate copy of the same data to every interested recipient. Instead of the source transmitting many identical copies, the network can deliver the data to the group more economically. When many receivers want the same information at the same time, this approach can save bandwidth compared with sending individual copies to each one.
Receivers joining a group
In multicast, receivers that want to get particular data join the relevant group, signaling their interest. The network then ensures that data sent to that group reaches the members who have joined. Devices that are not part of the group do not receive the data. This selective delivery is central to how multicast targets just the interested receivers rather than everyone.
Where multicast is used
Multicast is useful in situations where the same data needs to go to multiple receivers simultaneously, such as distributing a stream of information to many interested parties at once. Its ability to serve a group efficiently makes it valuable for one-to-many delivery on networks that support it. This role sets it apart from one-to-one and all-recipients communication.
Why it matters
Multicast is an important method of network communication for one-to-many delivery. Understanding what multicast is - sending data to a group of interested receivers at once - clarifies an efficient alternative to sending individual copies. For anyone interested in networking, it is a valuable concept to understand.
Related on Skillo
See also: What is anycast? Explained, What is a packet? Explained.
Sources
Published date reflects the original event date (2025-08-12). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.
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