Network
What is network
Communication device and transmission media
| Devices | Description |
|---|---|
| Dial-up Modem | A communications device that can convert digital signals to analog signals and analog signals to digital signals, so that data can travel along an analog telephone line. |
| Digital Modem (ISDN,DSL, Cable Modem) | A communications device that sends and receives data and information to and from a digital line. |
| Wireless Modem | Some mobile users have a wireless modem that uses the cell phone network to connect to the Internet wirelessly from a notebook computer, a smart phone, or other mobile device. |
| Network Card | Sometimes called a network interface card, is a communications device that enables a computer or device that does not have built-in networking capability to access a network. |
| Wireless access point | A central communications device that allows computers and devices to transfer data wirelessly among themselves or to transfer data wirelessly to a wired network . |
| Router | A communications device that connects multiple computers or other routers together and transmits data to its correct destination on a network. |
| Switch | A connection device similar to a hub but more sophisticated, including functionality that allows it to control and manage data transmissions. |
| Hub | A connection device that allows multiple connections to the network. |
What is transmission media
Materials or substances capable of
carrying one or more signals in a communications channel.
Two types
of
transmission media:
1.Physical transmission
media/Guided media/Wired
Twisted-Pair
Cable, Coaxial Cable, Fiber-Optic Cable.
2.Wireless transmission media/Unguided
media/ Wireless:
Infrared, Broadcast Radio, Cellular
Radio, Microwave, communications satellite.
Advantages of network :
Easy Communication and Speed
Advantages of network :
Easy Communication and Speed
1. People
can communicate efficiently by
using a network such as emails,
instant messaging, telephony, video conferencing, chat rooms, etc.
2. Ability
to Share Files, Data and Information
It
can benefit large organizations to
maintain their data in an organized manner.
DISADVANTANGES OF NETWORK
1. Breakdowns
and Possible Loss of Resource
Breakdown of the whole network due to an issue of the server may lead to important data server.
Breakdown of the whole network due to an issue of the server may lead to important data server.
2 Expensive to build
Building
a network for large scale organizations
are very pricey especially to buy and replace cables and other
hardware
Comparisons:LAN,MAN & WAN| CRITERIA | LAN | MAN | WAN |
|---|---|---|---|
| AREA OF COVERAGE | Network cover limited geographical area such as closely positioned group of buildings network , network at home, network inside computer laboratory and network in office building . | A high speed network that connects Local Area Networks in a Metropolitan Area such as a cities or town. | Network cover large geographical area such a countries ,the continents or the world |
NETWORK SIZE | Small size ( in a building) | Larger size ( in a cities or campus) | Largest size (different states or countries) |
| SPEED | Fastest in data transferring and access time | Slower in data transferring and access me | Slowest in data transferring and access time |
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