Network Basic

CLASSIFICATION OF NETWORK

Local Area Network(LAN)
-is a network connects computers and devices in a limited geographical area.
-Wireless LAN (WLAN) is a LAN uses no physical wires

Advantages Of LAN:
-Easy to share devices
-Easy to share data
-Low cost

Disadvantages Of LAN:
-Covered a limited area
-Power need to be on all the time for a good LAN
-Can reduce speed for each computer if all computers running at once


Metropolitan Area Network(MAN):
-Is a high speed network that connects local area network in a metropolitan area and handles the bulk of communications activity across that region
-Campus Area Network(CAN) is a type of MAN that made up of an interconnection of local area network(LAN's) within a limited geographical area

Advantages of MAN:
-efficiency and shared access
-All computer-owning residents of an area have equal ability to go on line

Disadvantages of MAN:
-Costly
-Security problems
-Connection can become quite slow


Wide Area Network(WAN):
-Is a network that covers a large geographic area using a communications channel

Advantages Of WAN:
-Increased efficiency
-Ease of communication
-Low costs

Disadvantages Of WAN:
-Security problems
-Training costs
-Maintenance problems


Comparison between LAN,MAN &WAN

LAN: (local area network) A group of computers that share a common connection and are usually in a small area or even in the same building. For example an office or home network. They are usually connected by Ethernet cables and have high speed connections. If it was a wireless setup it would be called a WLAN, which would have a lower connection speed. 

MAN: (metropolitan area network) This is a larger network that connects computer users in a particular  geographic area or region. For example a large university may have a network so large that it may be classified as a MAN. The MAN network usually exist to provide connectivity to local ISPs, cable tv, or large corporations. It is far larger than a LAN and smaller than a WAN. Also large cities like London and Sydney, Australia have metropolitan area networks.

WAN: (wide area network) This is the largest network and can interconnect networks throughout the world and is not restricted to a geographical location. The Internet is an example of a worldwide public WAN. Most WANs exist to connect LANs that are not in the same geographical area. This technology is high speed and very expensive to setup.

All about NETWORK!!!

NETWORK..

WHAT IS A NETWORK???

A network is a collection of computers and devices connected together via communications devices and transmission media

ADVANTAGES OF USING NETWORK??

• Facilitating communication
• Sharing hardware
• Sharing software
• Transferring funds

DISADVANTAGES OF USING A NETWORK??

• Viruses
• Network failure
• Slow service
• Cost
• Expert support required

Network Architecture..

The design of computers, devices, and media on a network is sometimes called the network architecture

Peer to Peer

P2P describes an internet network on which users access each other's hard disks and exchange files directly over the internet..

Client Server

One or more computers act as a server, and the other computers on the network request services from the server..

• Client

----> clients are other computers and mobile devices on the network that rely on the server for its resources

• Server

----> SERVER, sometimes called a host computer, controls access to the hardware, software, and other resources on the network and provides a centralized storage area for program, data and information...

NETWORK TOPOLOGY 

What is topology????

A network topology refers to the layout of the computers and devices in a communication network.

It refers to both the physical and logical layout of a network...

Layout of network..

Physical Topology..

=> The arrangements of a cabling is the physical topology

Logical Topology

=> The path that data travels between computers on a network is the logical topology..

Types of network topology..

Three commonly used network topologies are :

• Bus

• The bus is the physical cable that connects the computers and other devices
• The bus in a bus network transmit data, instructions, and information as a series of signal
• Those signals are sent as electrical pulses that travel along the length of the cable in all directions
• Each devices is connected to the single bus cable through T-Connector.
• A terminator is required at each end of the bus cable to prevent the signal from bouncing back and forth on the bus cable.
• When a sending device transmits data, the address of the receiving device is included with the transmission.
• If the device address does not match the intended address for the data, the device ignores the data.
• If the data does match the device address, the data is accepted.
• All devices receive the data but only the receiving device accept them.

STAR

• All the computers and other devices on the network connect to a central device, thus forming a star
• Two types of devices that provide a common central connection point to all the other devices on the network are a hub and a switch.

RING

• On a ring network, a cable forms a closed loop(ring) with all computers and devices arranged along the ring.
• Data transmitted on a ring network travels from device to device around the entire ring, in one direction (clockwise or counterclockwise)
• Token passing is one method for sending data around a ring
• Each device takes a turn sending and receiving information through the use of a token
• The token along with any data is sent from the first device to the second device which extracts the data addressed to it and adds any data it wishes to send.
• Then second device passes the token and data tothe third device, etc. until it comes back around to the first device again. 
• Only the device with the token is allowed to send data . All other devices must wait for the token to come to them.