Chapter 4 IS

analog waves

continuous

packet switching

the transmission technology that divides blocks of text into packets

Internet service provider (ISP

a company that provides access to the internet for a fee

Broadband:

broadband is the transmission capacity of a communications medium (discussed late

Internet Protocol (IP):

A set of rules responsible for disassembling, delivering, and reassembling packets over the Internet.

packets

Before data are transmitted over the Internet, they are divided into small, fixed bundles called packets.

Client/Server Computing

Client/server computing links two or more computers in an arrangement in which some machines, called servers, provide computing services for user PCs, called clients.

cellular

Divide the geographic area into small areas or cells Each cell has transmitter or radio relay antenna to send message from one cell to another

Terrestrial microwave

Earthbound; transmit high-speed radio signals in a line-of-sight path Between relay systems spaced approximately 30-miles apart

TCP performs three basic functions

It manages the movement of data packets between computers by establishing a connection between the computers it sequences the transfer of packets it acknowledges the packets that have been transmitted

extranet

Parts of intranets of multiple companies/locations connected together.

Bluetooth

Radio signals; < 30 feet To connect PC to peripherals such as printer

Wireless LANs (wi-fi)

Radio signals; < 300 feet Connect PCs to networks within home, building

RFID

Radio signals; < 300 feet Tags and readers identify mobile objects (e.g., merchandise, packages, animals)

Communications satellites

Satellite serves as relay stations for communications signals Uses microwave signals

Coaxial Cable

a single strand of insulated copper wire. It is much less susceptible to electrical interference, and it can carry much more data than twisted-pair. It is commonly used to carry high-speed data traffic as well as television signals.

Computer Network

a system that connects computers and other devices via communications media so that data and information can be transmitted among them

Peer-to-Peer (P2P) Processing

a type of client/server distributed processing where each computer acts as both a client and a server. Each computer can access (as assigned for security or integrity purposes) all files on all other computers.

Local Area Network (LAN):

connects two or more devices in a limited geographical region, usually within the same building, so that every device on the network can communicate with every other device.

Fiber-Optic Cable

consists of thousands of very thin filaments of glass fibers that transmit information via light pulses generated by lasers. The fiber-optic cable is surrounded by cladding, a coating that prevents the light from leaking out of the fiber.

Analog Signals

continuous waves that transmit information by altering the characteristics of the waves. Analog signals have two parameters, amplitude and frequency.

Modem (modulator-demodulator):

converts digital signals to analog signals—a process called modulation—and analog signals to digital signals—a process called demodulation. (The name modem is a contraction of modulator-demodulator.)

Virtual Private Networking (VPN)

creates private network connecting two computers together; strong security

Digital Signals

discrete pulses that are either on or off, representing a series of bits (0s and 1s). Th is quality allows digital signals to convey information in a binary form that can be interpreted by computers.

Internet Protocol (IP) address

distinguishes your device from all other computers and consists of sets of numbers, in four parts, separated by dots

Distributed Processing

divides processing work among two or more computers which enables computers in different locations to communicate with one another via telecommunications.

Application Layer

enables client application programs to access the other layers, and it defines the protocols that applications use to exchange data.

Network Access Points (NAPs):

exchange points for Internet traffic. They determine how traffic is routed. NAPs are key components of the Internet backbone.

Communications Media

is the physical media used to send data (e.g., twisted-pair wire, coaxial cable, fiber optic cable, satellite, etc.).

Wide Area Network (WAN)

network that covers a large geographical area. WANs typically connect multiple LANs. They are generally provided by common carriers such as telephone companies and the international networks of global communications services providers. WANs have large capacity, and they typically combine multiple channels (e.g., fiber-optic cables, microwave, and satellite). Th e Internet is an example of a WAN.

Transmission Control Protocol/Internet Protocol (TCP/IP):

the protocol of the Internet. TCP/IP uses a suite of protocols, the main ones being the Transmission Control Protocol (TCP) and the Internet Protocol (IP).

Enterprise Network:

organizational interconnected networks consisting of multiple LANs and may also include multiple WAN's.r in this chapter) faster than 4 megabits per second (Mbps).

Communications Channel

pathway for communicating data from one location to another

Network Interface Layer

places packets on, and receives them from, the network medium, which can be any networking technology.

Transport Layer

provides the application layer with communication and packet services.

digital waves

pulse

Bandwidth:

refers to the transmission capacity of a network; it is stated in bits per second.

Internet Layer

responsible for addressing, routing, and packaging data packets.

intranet

secure network inside an organization that can use Internet infrastructure

Twisted-Pair Wire

the most prevalent form of communications wiring used for almost all business telephone wiring and As the name suggests, it consists of strands of copper wire twisted in pairs. It is relatively inexpensive to purchase, widely available, and easy to work with.