Multicast Address

Last Updated: June 26, 2020

Definition - What does Multicast Address mean?

A multicast address is a specific type of IP address labeling a network location that is used to multicast data packets within a network. It stands in contrast to other IP addresses that only allow for unicast models.

ICANN and IANA and related parties have established the multicast address as part of portioning out IPv4 and IPv6 addresses to serve the global internet community. As the global internet continued to get bigger, the limits of the IPv4 system were stressing the capability of the stakeholders to deliver an adequate volume of new addresses.

The expanded IPv6 system allows for future growth.

Techopedia explains Multicast Address

Multicast Addresses and the OSI 7-layer Model

In the seven-layer OSI model that is used to micromanage device and network data traffic, multicast systems utilize specific layers. Ethernet connections can utilize layer 2 or the data link layer, where wireless router connections can utilize layer 3, which is known as the network or Internet layer.

Each layer of the OSI model has its own functionality and application. This starts with the hardware layer, the data link layer, and the network layer. On top of these are the transport layer, session layer, presentation layer and application layer. Each of these relates to specifically different types of network connections. In total, the model helps to provide a framework for network admin as a whole.

Multicast Addresses in Classful Networks

Part of the utilization of multicast addresses has to do with the original classful network models that administrative bodies created in order to provision IPv4 addresses.

The traditional system involved class A, B, C and D IP addresses. Class D was intended to accommodate multicast address allocation. Classes A through C involve different network sizes.

The apportioning of IP addresses utilizes the high-end bits of the address itself. The range for multicast addresses is from 224.0. 0.0 to 239.255. 255.255.

In addition to multicast addresses, there are higher-level engineering solutions for establishing multicast functionality. Some of these include rendezvous points, bidirectional PIM and source specific multicast.

It’s important to understand that the traditional classful network system used with class A, B and D TCP/IP addresses and multicast designation this way is becoming obsolete due to the emergence of IPv6 syntax and other factors. While stakeholders may still use the classful network system, it has been considered obsolete since the later 1990s.

In the cloud era, though, multicasting is still useful. White papers and other resources go over the unique administrative aspects of multicasting for streaming media, or for enterprise cloud vendor systems, as a working part of delivering functionality over the Internet.

As we can see from both business and consumer systems, people are in general doing more over the Internet, and how the TCP/IP protocols and other associated systems evolve has a lot to do with that change. While administrators have in some ways thrown out the old rulebooks, there are still fundamental structures in terms of original guidance from groups like the IETF to understand in moving forward with this kind of network administration.

This definition was written in the context of IP Address
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