If you've been through this before, you can skip it, but make sure that you have a glance to know what it is .
I) Network Topology :
Network Topology is kind of shape of Network in your house, your office or your school .
1/ Token Ring :
Just one computer can send data at a time .
Data are sent one-way (clockwise or counter clockwise)
Use method called "Token Passing" - it means if a computer want to send data, it needs a token (like a priority) , taken from other computers .
So, data transfer speed is slow ~ 10 Mbps
=> This Topology is oblivion .
2/ Bus :
The two end-points are called Terminators .
Computers connect to the Bus by T-connector .If computer 1 want to send data to computer 4, data must be send to computer 2, computer 3 ... => Not assure for security .
If 2 computers are sending data simultaneously - bandwidth is divided by 2 and so forth .
This topology is easy to expand (just connect a computer to the Bus)
Because of slow speed, it is no longer used in modern Network.
3/ Star :
There is always a central device (called HUB - in this figure) .Every computer becomes a member by connecting to central device .
Speed : 100 Mbps
Easy to deploy and expand .
=> The most popular Network topology is used nowaday .
There're also many topologies, but we just focus on the main ones ; you can find out more about them by doing some Google searches.
II) Network Devices :
1) Network Interface Card (NIC) - or Network Adapter :
- It's a part of your computer (behind a CPU-Case)
- Help computers to communicate to each other, and connect to central device - also .
- To recognise each other, NIC has something called : Address . Imagine that NIC is a house - if I need to send email to you - I need your House's address, right ?
- NIC has 2 types of address :
+ Physical address (MAC address) : Producer provides and cannot be changed - It's unique .
+ Logical address (Netowork address - IP address) : can be changed by administrator .
2/ Central devices :
Today, Hub is no longer used; instead , we use Switch which provides more efficient functions and enhance speed of transfer, also .
Central devices are used in Star Topology as I wrote in previous section.
3/ Cable :
2 types of cable :
- UTP : Unshielded Twisted Pair . Cheap.
- STP : Shielded Twisted Pair . Cover by copper to avoid interferences . Expensive 3 times when compare to UTP cable .
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