Unicast vs Multicast: Difference and Comparison

Unicast and Multicast are two terms that are widely used in the field of computer networking. They seem to be nothing but jargon for regular software users. Essentially, they are nothing but methods for transmitting information between stations. However, there are several differences that can be useful to know while carrying out various networking processes.

Key Takeaways

1. The unicast transmission sends data packets to a single destination, whereas multicast sends data to multiple destinations simultaneously.
2. Multicast conserves bandwidth by not duplicating data, making it ideal for streaming media and live events.
3. Unicast is better suited for one-to-one communication, like email or file transfers.

Unicast vs Multicast

Unicast refers to a one-to-one communication model in which a single source sends data to a single destination. Multicast refers to a one-to-many communication model in which a single source sends data to multiple destinations at once. Multicast has a complex network infrastructure and management.

Essentially, unicast is the process of transmitting information one-on-one. This means that there can only be one sender and one receiver. It is normally done when the information that is being shared is private or confidential. However, it must be done separately if the sender wants to send multiple messages to different receivers.

Meanwhile, multicast is the process of transmitting information from one to many. This means there can be only one sender but multiple receivers on the other end. It can be looked at as a blend of unicasting and broadcasting. Some common examples of this method are multimedia delivery and forwarding emails.

Comparison Table

Parameters of Comparison	Unicast	Multicast
Meaning	Unicast refers to the method of sending information from one station to another.	Multicast refers to the method of sending information from one station to multiple stations.
Mapping	The mapping is one-on-one.	The mapping is one-to-many.
Topology	This method only works on Single Node Topology.	This method can work on mesh, hybrid, star, and tree topology.
Bandwidth	It uses comparatively large amounts of bandwidth when used for multiple receivers.	It uses bandwidth in an efficient manner.
Scale	It does not work well for large scale networks.	It works well for large scale networks.
Examples	An example of unicasting is surfing the web.	An example of multicasting is a multimedia transmission.

What is Unicast?

Unicast is the method of sending data and information from one point in the network to another point. It is a one-on-one transmission process involving only one sender and receiver. A single unique network address identifies each of them. This is normally done when the information or data that is shared is either private or confidential.

The method is one of the most popular forms of transferring data. It is carried out by most people on their phones on a daily basis. For example, unicasting comes into the picture when a person searches for something on the web. Here, a single source is responsible for sending data to a single device. The mapping is one-on-one.

Multiple Unicasting is a type of unicasting that is used frequently. This is the process of using unicasting to send information to multiple receivers. In this method, a single transmission needs to be carried out multiple times. Each time, the receiving address is different.

This takes up a lot of time and even uses bandwidth recklessly. Moreover, it does not work well when the information needs to be sent over large networks. It is an outdated method that has been replaced by multicasting.

What is Multicast?

Multicast is another method of transmitting information on a network. However, in this process, a single sender transmits the message to multiple receivers at once. The mapping is one-to-many. It can be looked at as a blend of unicasting and broadcasting. However, the bandwidth is used efficiently, and the communication is quick.

In the process of multicasting, a single packet is created, unlike multiple unicasting. This includes the unique addresses of many receivers. The addresses are packed into a group, and the packet is sent at once. The receiver will then receive the packet unanimously.

This kind of communication is very effective over large networks. An example of this is multimedia transmission, in which media is sent from one sender to multiple receivers. It even proves to be cost-effective as compared to other transmitting methods.

In many cases, multicast can even include many-to-many transmission. In this, multiple senders and receivers simultaneously transmit messages through the network. Copies of the information and data are created and stored in network elements such as switches, routers and cellular base stations.

Unlike unicast, that only works on a Single Node topology, multicast works on various topologies, including tree, mesh, star, and hybrid. However, multicast should not be confused with broadcast, which sends messages to all receivers. The message can only be sent to a selected group of receivers by multicasting.

Main Differences Between Unicast and Multicast

1. Unicast refers to sending information from one station to another, whereas multicast refers to sending information from one station to multiple stations.
2. In unicast, the mapping is one-on-one, whereas in multicast, the mapping is one-to-many.
3. Unicast only works on Single Node Topology, whereas multicast can work on mesh, hybrid, star, and tree topology.
4. Unicast uses comparatively large amounts of bandwidth when used for multiple receivers, whereas multicast uses bandwidth in an efficient manner.
5. Unicast does not work well for large-scale networks, whereas multicast works well for large-scale networks.
6. An example of unicasting is surfing the web, whereas an example of multicasting is a multimedia transmission.

References

1. https://ieeexplore.ieee.org/abstract/document/6781293/
2. https://ieeexplore.ieee.org/abstract/document/4801477/