In telecommunications, we can find multiple terms and characteristics that allow communication to be carried out normally. In this article, we are going to talk about Duplex.
More specifically, we are going to see the differences between Half Duplex and Full Duplex.
We can say that it allows communications to use simultaneous sending and receiving channels.
What Does Duplex Mean in Networking?
First of all, we are going to explain what the term Duplex means. It refers, by itself, to the ability to send and receive data. Duplex is often used when talking about conversations over the phone or computer equipment.
This, therefore, is the system that allows two-way communications to be maintained, something that is essential today, since it is possible to receive and send messages simultaneously.
However, the ability to be able to transmit in Duplex mode is conditioned by different levels.
One of these levels is the physical medium to be able to transmit in both directions, also the transmission system to be able to send and receive at the same time, and finally the protocol or communication standard that it uses.
We can find different possibilities. Let’s see how Full Duplex and Half Duplex differ.
These are two terms that can appear when configuring a network, especially on systems like Windows, and it is good to know exactly what each one means and which one we could choose to get the most out of the available resources.
What are the Differences Between Half Duplex and Full Duplex?
Knowing the difference between Full Duplex and Half duplex is something very important for networks, although currently from the 1000BASE-T standard we always have Full Duplex connectivity.
A) Full Duplex
This term describes the simultaneous transmission and reception of data over a channel. A device that is Full Duplex is capable of bi-directional network data transmissions at the same time. You’re not going to have to wait and see if it’s being broadcast one way.
Full Duplex has a better performance by doubling the use of bandwidth. An example of the use of a Full Duplex is in a telephone. Here the communication is simultaneous and bidirectional. It is also present in network switches.
We can take as an example a two-way highway. Cars can pass through there in both directions. The same happens with the communication in the Full Duplex.
That is why this transmission mode offers better performance.
What this means is that, in this mode, the sender can both send and receive data at the same time and also always makes use of two channels during the transmission of said data because the channels are always split for the simultaneous sending and receiving of data.
Regarding Internet connections, there is a point to take into account and that is that the wired connections, those that connect Ethernet cables, are Full Duplex. This makes it possible to obtain better speeds.
It means that we can send and receive simultaneously, without waiting.
A clear and at the same time quite a simple example could be found in video calls or instant chat rooms, where information, as we have already explained, is sent and received at the same time.
B) Half Duplex
On the other hand, we have the option of a Half Duplex.
We can say that it offers lower performance compared to Full Duplex for what we mentioned.
An example of a mode of use would be a walkie-talkie. The two can talk, but not at the same time. One has to wait for the other to finish.
They could not establish communication at the same time, in both directions, as we could with a mobile phone.
Imagine again a highway with two lanes. Vehicles can go in one direction and also in another, but not both at the same time. In other words, the cars going in one direction would have to wait for all those going in the opposite direction to pass and then continue driving.
These Half Duplex networks will require a mechanism to avoid data collisions. You need to check if anything is streaming before trying to send anything to avoid problems. A device that uses this option is a hub.
It could not serve us in certain cases in which we are going to require that it be a Full Duplex.
Half Duplex or semi-duplex mode is the one present in Wi-Fi networks.
We already know that wireless networks are increasingly present in our daily lives and have improved significantly in recent years, but they still have certain problems in terms of stability.
They are also a requirement in Internet hubs. In this case, we can find the risk of collision.
This can lead to problems, outages, waiting, and certain errors.
This forces the implementation of a system to avoid these collisions and for communication to flow correctly.
Thanks to this system to detect collisions, the devices will detect that there has been a collision and the transmissions will stop for the necessary time and then transmit again.
This will allow both devices to emit at the same time and generate problems as we have mentioned.
Therefore, in a system that allows this problem to be foreseen, it will analyze it before sending the transmission. In case the channel is free, it will continue; if, on the other hand, it is busy, it will wait until it is free and thus does not produce that collision.
Half-Duplex implies less use of the single bandwidth at the time of transmission, so it is more appropriate to use it when we need to carry out data transmission in both directions, but in which it is not necessary for said data to be sent to the same time.
We can also highlight that for example in this mode, each transmitted character is displayed immediately on a monitor while in full-duplex the transmitted data does not appear on the screen until it is received and returned, so you end up saving more time compared to already which also alleviates collisions and frame retransmissions.