Multicasting is a communication process that takes place in a network environment. Essentially, a multicast is a message that originates with a single user and is received by multiple end points around the network. In a sense, a multicast is somewhat like sending a single email out to various email addresses. However, the key difference is that a multicast does not rely on any type of email addressing or software, and the transmission is confined to users that are connected to the single network.
There are many different applications that may employ the use of multicast. One common use of the technology is to quickly and easily forward time sensitive announcements out to key people within the organization. Unlike an email transmission, the multicast is not forwarding a message out from a server, across a range of providers and networks, and then terminating in a mailbox. The announcement is delivered to the various points of termination in real time, and will appear as a dialogue box on the screen of each receiver. In the event a recipient is logged out of the network, multicast protocols ensure that the announcement will appear once the person is logged back into the network.
While multicast is ideal for text communications, the process will also work for live video feeds and audio transmissions as well. This means that persons who are unable to attend a live meeting for some reason, but can connect with the network, can still attend by means of a virtual connection. However, this does not mean the remote locations can interact with the home location. Since multicast is a broadcasting tool, some other type of interactive communication, such as a conference call, could be used to allow remote attendees to actively participate.
Other types of broadcast applications also exist. Along with multicast, there is also anycast and unicast. These applications tend to be used for either a general audience of recipients, or for a single point to point network communication. Multicast offers the ability to pick and choose who on the network will receive the communication, and delivers the message to all selected users at one time.