hello everyone in this video we're going to talk about a couple of different transmission types that are used in networking and those types are half-duplex and full-duplex so let's talk about half-duplex first so in a half-duplex network you have a point-to-point system where two devices are connected to each other using a network cable and these devices can communicate with each other in both directions but in a half-duplex they can only communicate in one direction at a time they cannot communicate in both directions at the same time so if computer a is sending data to computer
B computer B has to wait until computer a is done before it can send data to computer a so data flows in one direction at a time the two computers have to take turns when they send data to each other so half duplex is just like how walkie-talkies work with walkie-talkies a person has to press a button if they want to talk to transmit their voice to the other person and while the button is pressed information is only going in one direction so they can't hear the other person while they're transmitting their voice they would
have to release the button in order to receive the other person's transmission now full duplex is better in a full duplex the two devices can also communicate in both directions with each other but the difference is that they can communicate in both directions at the same time which gives full duplex an advantage over half duplex devices can send and receive data simultaneously so as a result because it sends and receives data at the same time a full duplex system has double the bandwidth of half duplex a good example of a full duplex would be telephone
communication when you talk to somebody on the phone you can talk to and hear the other person at the same time so you don't have to wait to do one or the other you can talk and listen simultaneously so as a comparison between half-duplex and full-duplex you can use an analogy of cars on a highway where you have cars that travel across an area so when a half-duplex the cars would all have to share a single lane on the highway and that lane only allows traffic in one direction at a time the cars on the
opposite sides of the highway would have to wait their turn to use that lane to get to their destination and since it only has one lane collisions do happen from time to time and that's why in a half-duplex network it needs a traffic cop to regulate that lane to tell cars to wait their turn and in networking this traffic cop is called csma/cd or carrier sense multiple access with collision detection and this is an access method that's used to help avoid collisions and to also respond correctly if a collision does happen and if you're not
familiar with what csma/cd does I'll put a link at the end of this video to explain what that is but in a full duplex the cars don't have to wait because you can compare a full duplex as having a two lane highway each Lane is dedicated for a direction the cars that are traveling in the opposite directions have their own dedicated lane as they travel to their destination and so as a result since each direction has their own dedicated Lane it avoids collisions and there is no need for a traffic cop now today we use
full duplex networks a main reason why you would see a half duplex network today is for older legacy equipment that can only be used in half duplex mode for example if a network is still using hubs instead of switches because hubs can only operate in half duplex mode and not full duplex which is a main reason why hubs are obsolete today and you can't even buy them anymore so thank you for watching this tutorial on a difference between half-duplex and full-duplex please subscribe and I'll see you in the next video thank you you
