Computer Networks

Computer Networks

Networks A computer network is any system of two or more computers that are linked together.

A computer network is any system of two or more computers that are linked together.

Networks Why is networking important ? Networks enable people to share computer hardware resources, to share data and software and allow people to collaborate in ways that other wise difficult.

Why is networking important ?

Network Classification LAN WAN MAN PAN

LAN

WAN

MAN

PAN

Network Classification LAN (Local Area Network) Computers are physically close to each other, usually in the same building.

LAN (Local Area Network)

Computers are physically close to each other, usually in the same building.

Network Classification LAN hardware Each computer or peripheral in a LAN is called a node ; nodes are connected through hubs or switches . Hubs broadcast messages to all devices connected to a network but one at a time. A switch broadcast the messages only to a destination node and it can carry multiple messages simultaneously.

Network Classification MAN (Metropolitan area network) Links two or more LANs within a city (WAN) Wide area network Extends over a long distance. Each network site is a node on the network. WANs are possible thanks to telephone lines, microwave towers, satellites and fiber-optic cables

MAN (Metropolitan area network)

Links two or more LANs within a city

(WAN) Wide area network

Extends over a long distance.

Each network site is a node on the network.

WANs are possible thanks to telephone lines, microwave towers, satellites and fiber-optic cables

Network Classification Bridges : hardware devices that connect segments of a network. They often translate messages so they can be understood by networks that obey different protocols . Routers : hardware devices or software programs that route messages as they travel between networks. MAN/WAN hardware

Bridges : hardware devices that connect segments of a network. They often translate messages so they can be understood by networks that obey different protocols .

Routers : hardware devices or software programs that route messages as they travel between networks.

Network Classification It is a network that links a variety of personal electronic devices so they can communicate with each other, ( PAN) Personal Area Network generally through bluetooth technology.

It is a network that links a variety of personal electronic devices so they can communicate with each other,

Wireless Technologies Is the transfer of information through the air rather than through cables. Wireless communication may be via: radio frequency communication microwave communication infrared

radio frequency communication

microwave communication

infrared

Modems A modem is a device that converts digital signals from a computer's serial port to the analog signals required for transmission over traditional telephone lines, and vice versa. Conversion is necessary because telephone lines were initially designed to handle the analog nature of the human voice, not data.

A modem is a device that converts digital signals from a computer's serial port to the analog signals required for transmission over traditional telephone lines, and vice versa.

Conversion is necessary because telephone lines were initially designed to handle the analog nature of the human voice, not data.

Protecting the Network The creation of bigger networks, has increased security risks Firewalls : are hardware and software barriers that execute an access control policy among networks.

The creation of bigger networks, has increased security risks

Firewalls : are hardware and software barriers that execute an access control policy among networks.