Difference Between Switch, Hubs and switch

Hubs and Switches serve for multiple computers together, and from the outside, they function identically they allow the connected computers to exchange data among themselves. However, the way they handle data internally is very different.

I copy this examples so that you can understand much better:

You can think of a hub like a house with 4 rooms, 4 people, and 4 phones but only one phone number. Each person has the phone to his ear, and they can converse with each other, but if one person speaks, everyone can hear it regardless if the statement was intended for them or not. So, if person 4 wanted to send a message to person 3, he would have to tell everyone to be quiet, say "this message is for person 3" and then say the message.
Figure 1 - 4 port hub.

Imagine the same situation except that each room has its own telephone number. This situation describes a switch. If person 4 wanted to send a message to person 3, he could call directly to that room without disturbing the people in rooms 1 or 2. That means that at the same time 3 and 4 are talking, room 1 and 2 could have a conversation without disrupting any other conversations.

The difference between a switch and a hub is that a switch can handle multiple communications between the computers attached to it whereas a hub handle one at a time. If there are only two computers transmitting data across a network, a hub would perform identically to a switch. However, if more than two computers were trying to transmit across the network at the same time, the switch would perform far better.

While router serves a slightly different function. A router is explicitly designed to connect two networks together, usually a Local Area Network, or LAN (like a single small office) to a Wide Area Network, or WAN (like the Internet). A router also has additional "smart" software with security features that disallow unauthorized access to the computers in the LAN from the outside.