Both unicast and multicast have their specific advantages. The choice of technology affects not only network capacity but also the end-customer experience. We show you the differences and when each method makes sense.
Today, network operators and utilities need to offer their customers a reliable, scalable and high-quality TV service – and that with growing bandwidth demand. The choice between unicast and multicast affects not only the efficiency of signal distribution but also network utilisation and the economic viability of operations.
What is unicast?
Unicast refers to point-to-point transmission, in which a signal is sent from a sender directly to a single receiver. Each viewer receives an individual data stream, even if several users are watching the same programme.
The challenges for network operators arise mainly from high bandwidth consumption, since each viewer receives their own stream. This can lead to bottlenecks, especially in networks with limited resources. Scalability is also restricted when many users access content at the same time.
Unicast is particularly suitable for applications where individual content is required. Video on demand, replay TV and pay TV offerings rely on this transmission method, as each user receives a tailored programme.
Another important aspect is the type of transmission. Unicast is often based on technologies such as HLS (HTTP Live Streaming) or DASH (Dynamic Adaptive Streaming over HTTP). These streaming protocols divide the video into small segments that the client retrieves and plays one after the other.
A major advantage of unicast is that it works independently of the internet provider’s network. As soon as a consumer leaves the home network and streams via mobile data or another Wi-Fi network, for example, unicast is required.
What is multicast?
Multicast enables point-to-group transmission, in which a single TV signal is sent to a large number of receivers. Instead of generating individual data streams, the signal is sent once and received by multiple endpoints simultaneously.
This method offers network operators clear advantages. Since the signal is only transmitted over the network once, bandwidth consumption remains constant regardless of the number of viewers. This makes multicast highly scalable and particularly suitable for live TV. Lower latency also ensures stable and fast transmission.
A key point with multicast is its network dependency. Multicast can only be used within a defined network, for example in a network operator’s fibre network.
In the classic cable network (DVB-C), the basic offering is almost always provided via multicast, as this method conserves network capacity and enables consistent quality.
Multicast is mainly used to distribute live TV signals in cable or fibre networks. TV transmission in utility networks and corporate TV solutions also benefit from this technology.
Comparing unicast and multicast for TV providers
| Criterion | Unicast | Multicast |
| Transmission type | Point-to-point | Point-to-group |
| Signal receivers | Each receiver gets an individual signal | One signal is sent to several receivers simultaneously |
| Bandwidth use | High bandwidth demand with many viewers | Efficient use of bandwidth |
| Network dependency | Works anywhere, including on mobile | Only within a defined network |
| Scalability | Limited; can lead to bottlenecks under high traffic | Highly scalable; ideal for mass transmission |
| Use cases | Individual content (streaming on demand) | Live events, TV broadcasts |
| Technology | TCP/IP, frequent use of HTTP | IGMP (Internet Group Management Protocol), UDP |
| Latency | Potentially higher latency with many connections | Lower latency, as the signal is only sent once |
| Efficiency | Not very efficient with several viewers | High efficiency through shared transmission |
| Error management | Individual troubleshooting for each user | Can be more difficult with faulty transmissions |
| Public vs. private | Rather private, user-dependent | Rather public, ideal for broadcast applications |
What does this mean for cable network operators and utilities with their own TV offering?
The choice between unicast and multicast depends heavily on the planned use. Multicast is the obvious choice for classic live TV services, as it conserves network capacity and ensures stable transmission. Unicast, on the other hand, is the preferred choice for on-demand content, since individual streams are provided per user.
Many network operators now rely on a combination of both technologies. Live TV is distributed via multicast to use bandwidth efficiently, while replay TV and VoD run via unicast to enable flexible playback times and personalised content.
Netstream supports cable network operators and utilities with a scalable, high-performance TV signal solution. Let’s design the best streaming infrastructure for your network together.
