Difference between hub, switch and Router

What's the difference between a hub, a switch and a router?

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In a word: intelligence.

Hubs, switches, and routers are all devices that let you connect one
Or more computers to other computers, networked devices, or to other
Networks. Each has two or more connectors called ports into which you
Plug in the cables to make the connection. varying degrees of magic
Happen inside the device, and therein lies the difference. I often see
The terms misused so let's clarify what each one really means.

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AHub
Is typically the least expensive, least intelligent,
And Least Complicated of the three. Its job is very simple:
Anything that comes in one port is sent out to the others. That's
It. Every computer connected to the Hub "sees" Everything that every
Other computer on the hub sees. The Hub itself is blissfully ignorant
Of the data being transmitted. For years, simple hubs have been quick
And easy ways to connect computers in small networks.

ASwitch
Does essentially what a hub does but more
Efficiently. by paying attention to the traffic that comes should SS it,
It can "Learn" where particle ses SSEs are. For example, if it sees
Traffic from machine a coming in on Port 2, it now knows that machine
Is connected to that port and that trafficTo
Machine A needs
To only be sent to that port and not any of the others. The net result
Of using a switch over a hub is that most of the network traffic only
Goes where it needs to rather than to every port. On busy Networks
This can make the network significantly faster.

"Varying degrees of magic happen inside the device, and therein lies the difference ."

ARouter
Is the smartest and most complicated of the bunch.
Routers come in all shapes and sizes from the small four-Port
Broadband routers that are very popular right now to the large
Industrial strength devices that drive the Internet itself. A simple
Way to think of a router is as a computer that can be programmed
Understand, possibly manipulate, and route the data its being asked
Handle. For example, broadband routers include
Ability to "hide" computers behind a type of firewall which involves
Slightly modifying the packets of network traffic as they traverse
Device. All routers include some kind of user interface for handling ing
How the router will treat traffic. The really large routers include
Equivalent of a full-blown programming language to describe how they shocould
Operate as well as the ability to communicate with other routers
Describe or determine the best way to get network traffic from point
To point B.

A quick note on one other thing that you'll often see mentioned
These devices and that's network speed. Most devices now are capable
Both 10mps (10 mega-bits, or million bits, per second) as well as 100mbs and
Will automatically detect the speed. If the device is labeled with only
One speed then it will only be able to communicate with devices that
Also support that speed. 1000mbs or "Gigabit" devices are starting
Slowly become more common as well. Similarly implements devices now also
Include 802.11b or 802.11g wireless transmitters that simply act like
Additional ports to the device.