On your early days of study of networking , the topic of topology always discuss about the star topology in which all the computers are connected to a centralized device which was mentioned on your textbook as a hub or switch .
So what is the real difference between the hub and a switch which looks almost identical in every aspects .
First of all hub is just an amplifier or repeater which push the information fed to one port to all other ports , ie we can say hub is just a multi-port repeater . that is if one of the devices connected to the hub is transmitting data , other devices have no other option but to listen to it . Technically we say that hub creates a single collision domain .
The main solution for separating the single collision to two is to use a device called bridge which separates your network into two collision domains . Then come to idea about creating a multi-port bridge device which will look like a hub but is intelligent enough to identify the source and destination port and create a switching path between the source and destination , there by creating multiple collision domains.
The concept was introduced and made popular by a company named kalpana . They created and marketed a device named ether switch . If you are an indian you will guess the name of the company has some Indian connection. The co-founder of this silicon vally based company is Vinod Bhardwaj, and Kalpana is his wife’s name .
Cisco acquired Kalpana back in 1994 and made their products part of the catalyst range of networking switches .The catalyst 3000 range of products are originated from Kalpana ether switches .