An Overview of Telecommunications

8/12/2019 An Overview of Telecommunications

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An Overview Of Telecommunications

Telecommunications

Electronic transmission of signals for communications

Telecommunications medium

Any material substance that carries an electronic signal tosupport communications between a sending and receivingdevice

Telecommunications protocol Defines set of rules that governs the exchange of information

over a communications medium


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In information technology, a protocolis the special set of rulesthat end points in a telecommunication connection use when

they communicate.

On the Internet, there are the TCP/IP protocols, consisting of: Transmission Control Protocol (TCP), which uses a set of rules to

exchange messages with other Internet points at the informationpacket level

Internet Protocol (IP), which uses a set of rules to send andreceive messages at the Internet address level

Additional protocols that include the Hypertext Transfer Protocol(HTTP) and File Transfer Protocol (FTP), each with defined sets ofrules to use with corresponding programs elsewhere on the Internet

Wireless protocols, 802.11- applies to wireless LANs and provides 1 or 2 Mbps

transmission in the 2.4 GHz band (referred to as "Wi-Fi") BluetoothA low-cost, short range wireless specification for

connecting mobile products. It is best suited for connectingPDAs, cell phones and PCs over limited distances.

PROTOCOL:


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Basic Telecommunications Channel Characteristics

Coaxial cable

Offers cleaner and crisper data transmission (less noise) than twisted-pair wire

Fiber-optic cable

Transmits signals with light beams

Broadband over power lines

Potential problem: transmitting data over unshielded power lines can interfere

with both amateur (ham) radio broadcasts and police and fire radios


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Basic Telecommunications Channel Characteristics

Wireless communications options

Wireless transmission involves the broadcast ofcommunications in one of three frequency ranges

Radio, microwave, or infrared frequencies


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Short Range Wireless Options

Near Field Communication (NFC)

Short-range wireless connectivity technology designed for cell phonesand credit cards

Bluetooth

Wireless communications specification that describes how cell phones,computers, personal digital assistants, etc., can be interconnected

Ultra wideband (UWB) Transmits large amounts of digital data over short distances of up to

30 feet

Zigbee

Form of wireless communications frequently used in security systems

and heating and cooling control systems


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Medium Range Wireless Options

Wi-Fi (the 802.11 family of protocols)

Wireless telecommunications technology brand owned by the Wi-FiAlliance

Wireless access point

Consists of a transmitter with an antenna, receives the signal, anddecodes it

Wi-Fi access points Have maximum range of about 300 feet outdoors and 100 feet within

a dry-walled building


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Networks and Distributed Processing Computer network

Consists of communications media, devices, and software needed toconnect two or more computer systems or devices

Can transmit and receive information to improve organizationaleffectiveness and efficiency

Bandwidth:

speed at which data are communicated

amount of data that can be transmitted in a fixed time period

Bits per second (bps): unit of measure for bandwidth

Baseband: carry only one transmission at a time

Broadband: carry multiple transmissions simultaneously

Bandwidth and Media

Wave Spectrum Electromagnetic Spectrum
http://science.hq.nasa.gov/kids/imagers/ems/waves3.htmlhttp://missionscience.nasa.gov/ems/01_intro.htmlhttp://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.htmlhttp://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.htmlhttp://science.hq.nasa.gov/kids/imagers/ems/waves3.htmlhttp://missionscience.nasa.gov/ems/01_intro.html


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Network Types Personal area networks

Supports interconnection of information technology within a range of

about 33 feet (Bluetooth)

Local area networks

Connects computer systems and devices within a small area (e.g.,office or home (Wi-Fi)

Metropolitan area networks

Connects users and their devices in a geographical area that spans acampus or city

Wide area networks

Ties together large geographic regions


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Network Types


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Network Types


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Client/Server Systems

Client/server architecture

Multiple computer platforms are dedicated to special functions

Client

Any computer that sends messages requesting services from theservers on the network

File server systems

Users can share data through file server computing


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CLIENT/SERVER

A network architecture in which each computer or process on the network iseither a clientor a server. Servers are powerful computers or processes

dedicated to managing disk drives (file servers), printers (print servers), ornetwork traffic (network servers ). Clientsare applications that run on a PC.Clients rely on servers for resources, such as files, devices, and evenprocessing power.

Another type of network architecture is known as a peer-to-peerarchitecturebecause each node has equivalent responsibilities. Both client/server and

peer-to-peer architectures are widely used, and each has unique advantagesand disadvantages. Client-server architectures are sometimes called two-tierarchitectures.

CLIENT

The client part of a client-server architecture. Typically, a client is anapplication that runs on a personal computer or workstation and relies ona server to perform some operations. For example, an e-mail client is anapplication that enables you to send and receive e-mail.


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A serveris a computer or device on a network that managesnetwork resources. For example, a file server is a computer

and storage device dedicated to storing files. Any user on thenetwork can store files on the server. A print server is acomputer that manages one or more printers, and a networkserver is a computer that manages network traffic. Adatabase server is a computer system that processes

database queries.

Serversare often dedicated, meaning that they perform noother tasks besides their server tasks. On multiprocessingoperating systems, however, a single computer can executeseveral programs at once. A server in this case could refer tothe program that is managing resources rather than theentire computer.

SERVERS


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Cloud Computing

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o With cloud computing, businesses borrow computing

power and storage from independent entities like Amazon.o The reason it is such a growing trend is that computing

becomes more flexible and occurs at a lower cost to thebusiness.

o A business uses cloud-based applications through a web

browser, mobile app or lightweight desktop.o Software and data are stored at a remote location.o Many cloud computing companies advertise themselves as

a greener and more energy-efficient option.o Cloud servers can be up to 80 percent utilized, as opposed

to traditional servers which are 25-30 percent utilized,resulting in fewer total servers needed.

Documents

An Overview of Telecommunications