T ELECOMMUNICATIONS Networks & the Internet

T ELECOMMUNICATIONS Communicating and transmitting information electronically (includes transmitting data, text, pictures, voice and video over long distance)

H OW D O W E “T ELE -”C OMMUNICATE ? Phone Voice mail Cell phone— also includes texting Fax— a document generated by using a facsimile machine — transmission of messages and files using a computer network Instant messaging

M ETHODS OF T ELECOMMUNICATION 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

M ETHODS OF T ELECOMMUNICATION 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

T ELECOMMUNICATIONS & N ETWORKS 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.

B ENEFITS OF N ETWORKS Instant communication Information sharing Hardware sharing Software sharing

N ETWORK A group of two or more computers linked together

N ETWORK C OMPONENTS 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. , 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

C LASSIFICATION BY C OVERAGE 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 WAN There are several variations of WANs A popular WAN used by large businesses is the VPN

V IRTUAL P RIVATE N ETWORK VPN— a private network that uses a public network (usually the Internet) to connect remote sites or users together. VPN 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.

W HAT MEDIA IS USED TO CONNECT COMPUTERS TO A NETWORK OR TO THE I NTERNET ? 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.

W IRED M EDIA Twisted pair cable— cable that consists of two independently insulated wires twisted around one another. Twisted pair is the least expensive type of wire Twisted pair cable Coaxial cable— a type of wire that consists of a center wire surrounded by insulation and then a grounded shield of braided wire Coaxial cable 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 Fiber optic cable

W IRELESS M EDIA Microwave Satellite Infrared (remote controls) Cellular Wi-Fi (radio waves) Bluetooth (short-range radio waves)

H OW IS INFORMATION TRANSMITTED TO AND FROM YOUR COMPUTER ON A NETWORK OR THE I NTERNET ? Modems — phone, cable, DSL Satellites —provides high speed access for rural, remote areas or mobile vehicles and boats; transmits electromagnetic signals Satellites 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 T Lines

W HAT IS THE I NTERNET ? 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.

H OW DO WE GET ACCESS TO THE I NTERNET ? Internet Service Providers (ISP)—businesses that sell Internet access to customers What ISPs are available in our area?

W HERE DO THE ISP S 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

W HAT 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)

W HAT IS “P ROTOCOL ”? 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

P ROTOCOL 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.

W HAT DOES URL STAND FOR ? Uniform Resource Locator It specifies the internet address of a file stored on a host computer Example: scoreboard.htm

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

W HAT 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:

W HAT IS THE FORMAT OF A URL? Protocol – host – path – filename Example: Protocol: Host: Path: conferences Filename: standings_sec.htm

W HAT 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

W HAT 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