T ELECOMMUNICATIONS Networks & the Internet. T ELECOMMUNICATIONS Communicating and transmitting...

TELECOMMUNICATIONSNetworks & the Internet

TELECOMMUNICATIONS

Communicating and transmitting information electronically

(includes transmitting data, text, pictures, voice and video over long distance)

HOW DO WE “TELE-”COMMUNICATE? Phone Voice mail Cell phone—also includes texting Fax—a document generated by using a facsimile

machine Email—transmission of messages and files using a

computer network Instant messaging

METHODS OF TELECOMMUNICATION Social networking sites—websites that provide a

virtual community in which people with a shared interest may communicate

Telecommuting—the action of working from home using a computer and telecommunications media

Intranet—a company’s private computer network e-commerce/e-business—buying/selling

merchandise or conducting business on the Internet

METHODS OF TELECOMMUNICATION Audio conferencing—Communication between three

or more sites that are linked by a voice-only telecommunications medium

Video conferencing—Communicate in real time via video with two or more people at different locations

TELECOMMUNICATIONS & NETWORKS

At the heart of telecommunications is the ability to “network” computers together . . .

And at the heart of networks is the media through which communication flows: wires, telephone

lines, or wireless signals.

BENEFITS OF NETWORKS

Instant communication

Information sharing Hardware sharing Software sharing

NETWORK

A group of two or more computers linked together

NETWORK COMPONENTS

Server—the computer at the center of a network that manages network resources; more powerful than a desktop computer

Client—any computer on a network that relies on a server for resources, i.e. email, etc.

computers that are connected and ready to receive and/or transmit data are said to be online,

as opposed to a stand-alone computer: a computer that is not connected to a network

CLASSIFICATION BY COVERAGE Local Area Networks—a network that

spans a relatively small area; typically is confined to a single building or several buildings

WAN—a network that geographically spans a large area; typically includes 2 or more LANs There are several variations of WANs

A popular WAN used by large businesses is the VPN

VIRTUAL PRIVATE NETWORK VPN—a private network that uses a public

network (usually the Internet) to connect remote sites or users together.

Instead of using a dedicated, real-world connection such as leased line, a VPN uses "virtual" connections routed through the Internet from the company's private network to the remote site or employee.

WHAT MEDIA IS USED TO CONNECT COMPUTERS TO A NETWORK OR TO THE INTERNET?

Two categories of media Wired Media Wireless Media

A computer will need a network interface card (NIC)

to connect to a network or the Internet.

WIRED MEDIA

Twisted pair cable—cable that consists of two independently insulated wires twisted around one another. Twisted pair is the least expensive type of wire

Coaxial cable—a type of wire that consists of a center wire surrounded by insulation and then a grounded shield of braided wire

Fiber optic cable—a technology that uses glass (or plastic) threads (fibers) to transmit data. Fiber optics provide the best quality but is expensive to install and the cable is more fragile and difficult to splice

WIRELESS MEDIA

Microwave Satellite Infrared (remote controls)

Cellular Wi-Fi (radio waves)

Bluetooth (short-range radio waves)

HOW IS INFORMATION TRANSMITTED TO AND FROM YOUR COMPUTER ON A NETWORK OR THE INTERNET? Modems—phone, cable, DSL

Satellites—provides high speed access for rural, remote areas or mobile vehicles and boats; transmits electromagnetic signals

T Lines—a digital high-speed long-distance telephone line that is capable of carrying multiple types of signals across the line; T-1 / T-4 lines are currently available; typically large companies and organizations qualify

WHAT IS THE INTERNET?

A global network that connects millions of computers all over the world. The Internet backbone is the central network that

links all the parts of the Internet together.

HOW DO WE GET ACCESS TO THE INTERNET?

Internet Service Providers (ISP)—businesses that sell Internet access to customers

What ISPs are available in our area?

WHERE DO THE ISPS GET ACCESS?

NSP—Network Service Providers supply direct backbone access to ISPs, who then sell access to their customers. Example: AT&T, Verizon, Sprint are major NSPs

in the US

WHAT IS THE WORLD WIDE WEB?

A system of computers that allows you to communicate with other computers talking the same language (using the same protocol)

WHAT IS “PROTOCOL”?

Protocol—rules for communicating between two electronic devices

Internet Protocol (IP)—rules for communicating on the Internet

Hypertext Transfer Protocol (HTTP)—rules for transferring web pages on the Internet

PROTOCOL

Simple Mail Transport Protocol (SMTP)—protocol used for transmitting electronic mail

File Transfer Protocol—a protocol designed to transfer files between an FTP server and a computer—example: downloading software

Voice Over Internet Protocol (VOIP)-- is a digital telephone service that allows you to make and receive phone calls over the internet instead of through the phone lines.

WHAT DOES URL STAND FOR? Uniform Resource Locator

It specifies the internet address of a file stored on a host computer

Example: http://ncaasports.com/basketball/mens/

scoreboard.htm

URL VS DNS

Computers use a domain name system to translate URLs into numeric addresses

WHAT IS THE NUMERIC ADDRESS CALLED?

Internet Protocol address: the numeric address assigned to EVERY computer or device that connects to the Internet

An IP address is a four-part number, each part consisting of a digit from 0 to 255. Example: 207.46.192.254

WHAT IS THE FORMAT OF A URL?

Protocol – host – path – filename

Example: http://www.d1baseball.com/conferences/standings_sec.htm

Protocol: http:// Host: www.d1baseball.com Path: conferences Filename: standings_sec.htm

WHAT IS A TLD:

TLD – Top level domain; suffix at the end of a web address .com—commercial; generic .edu—educational institution—higher ed .gov—state or federal government .mil—U.S. military .net—network service provider (can be used generically) .org—usually nonprofit but can be generic .pro—professional—like physicians, lawyers, CPAs, etc. .name—reserved for individuals

WHAT IS A COUNTRY CODE? A domain name that identifies the location

of a server Example:

.us—United States .jp—Japan .uk—United Kingdom .ca—Canada .mx—Mexico

Find country codes for the following: Brazil, Egypt, Jamaica, Cayman Islands