Multicasting (explained)

In regular network communication, each data packet is sent from a single sender to a single recipient - a process known as unicasting. But with multicasting you can send a single data packet (from a server) to multiple recipients (clients) within a group. Multicasting can help save bandwidth.

When you use unicasting, the source must transmit one data stream for each recipient.
When you use multicasting, only a single data stream is required on each network segment.

Multicasting as described here is not streaming of video from camera to servers, but from servers to clients.

With multicasting, you work with a defined group of recipients, based on options such as IP address ranges, the ability to enable/disable multicast for individual cameras, the ability to define largest acceptable data packet size (MTU), the maximum number of routers a data packet must be forwarded between (TTL), and so on.

Multicasting should not be confused with broadcasting, which sends data to everyone connected to the network, even if the data is perhaps not relevant for everyone:

Name	Description
Unicasting	Sends data from a single source to a single recipient.
Multicasting	Sends data from a single source to multiple recipients within a clearly defined group.
Broadcasting	Sends data from a single source to everyone on a network. Broadcasting can therefore significantly slow down network communication.