Yes... embarrassing. Hubs and Switches. Someone asked me what the difference was between the two network devices, and the only thing that went through my mind was: "A dumb device." The second thought was: "Don't ask me, just Google for it..."
That's when it hit me: Yes, using Google to look up information is great, but should I be so dependent on it that I am unable to answer such a basic networking question?"
And that is why I decided to start writing 'mindupload' notes to myself... So, here's what I learned (re-learned, actually, since I learned this in College, and eventually forgot).
A hub takes data (aka packets) arriving at the incoming port, and transmits it to all outgoing ports with a connected device to it. If more than one computer receives the data and try to respond, it could generate network collisions because they are responding to the same data at the same time, this could slow down your network due to processing of the collision and re-transmission of the data. Related to this same issue, the network devices connected to the hub will be running in half-duplex mode because they have to be constantly listening for data collisions, which means, they can't send and receive data at the same time. Think of it like a walkie-talkie where one person can either talk or listen at a time, instead of full-duplex, which is like a telephone. And the reason for the devices to be running in half-duplex mode is because they have to be listening for collisions on the network.
A network switch on the other hand, uses an internal table that keeps track of the connected network devices addresses and its ports, and by reading the headers of the incoming data it creates temporary connections between the source and destination ports eliminating collisions on the network, and decreasing traffic overhead, therefore allowing network devices to work in full-duplex mode, since they don't have to listen for collisions any longer... Giving you a more efficient (faster) network.
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