Chapter 8 Communications and Networks

tree network

each device is connected to a central node, either directly or through one or more other devices. The central node is connected to two or more subordinate nodes that in turn are connected to other subordinate nodes, and so forth, forming a treelike structure.

ring network

each device is connected to two other devices, forming a ring.

computer network

is a communication system that connects two or more computers so that they can exchange information and share resources.

physical connections

Physical connections use a solid medium to connect sending and receiving devices. These connections include twisted-pair, coaxial, and fiber-optic cables.

host

any computer system connected to a network that provides access to its resources.

What Does TCP/IP 'do'?

TCP Breaks data transmission into segments Attaches To/From addresses to each segment Ensures reliability that all segments are received IP Identifies where computers are on each network Used for routing the packets

Interpreting RFM Score Results

Ajax: 1, 1, 1 Bloominghams: 5, 1, 1 Caruthers: 5, 4, 5 Davidson: 3, 3, 3 Ajax has ordered recently and orders frequently. M score of 3 indicates it does not order most expensive goods. A good and regular customer but need to attempt to up-sell more expensive goods to Ajax Bloominghams has not ordered in some time, but when it did, ordered frequently, and orders were of highest monetary value. May have taken its business to another vendor. Sales team should contact this customer immediately Caruthers has not ordered for some time; did not order frequently; did not spend much Sales team should not waste any time on this customer Davidson in middle Set up on automated contact system or use the Davidson account as a training exercise

is the activity of representing repeated tasks in an enterprise, so that they may be analyzed, improved, and automated

Business Process Modeling (BPM)

identification

Every computer on the Internet has a unique numeric address called an IP address (Internet protocol address).

Organizations use the following to allow suppliers and others limited access to their networks.

Extranets

Which physical connection is the fastest?

Fiber-optic cable

packetization

Information sent or transmitted across the Internet usually travels through numerous interconnected networks. Before the message is sent, it is reformatted or broken down into small parts called packets. Each packet is then sent separately over the Internet, possibly traveling different routes to one common destination. At the receiving end, the packets are reassembled into the correct order.

Wireless LAN (WLAN)

It uses radio frequencies to connect computers and other devices. All communications pass through the network's centrally located wireless access point or base station. This access point interprets incoming radio frequencies and routes communications to the appropriate devices.

is a diagramming and graphics application for conceptual visualizations that uses stencils to organize like objects for modeling tasks.

Microsoft Visio

modem

Modulation is the name of the process of converting from digital to analog. Demodulation is the process of converting from analog to digital. The modem enables digital personal computers to communicate across different media, including telephone wires, cable lines, and radio waves.

Network Providers

National service providers (NSPs) - Private companies that own and maintain the worldwide backbone that supports the Internet Backbone Regional service providers (RSPs) - Offer Internet service by connecting to NSPs, but they also can connect directly to each other Backhaul Internet service providers (RSPs) - Residential and Commercial endpoint providers; the edge of the network Last Mile

satellite

Satellites orbit at a precise point and speed above the earth. They can amplify and relay microwave signals from one transmitter on the ground to another. Satellites can be used to send and receive large volumes of data.

network administrators

a computer specialist responsible for efficient network operations and implementation of new networks.

coaxial cable

a high-frequency transmission cable, replaces the multiple wires of telephone lines with a single solid-copper core. Coaxial cable is used to deliver television signals as well as to connect computers in a network.

router

a node that forwards or routes data packets from one network to their destination in another network.

client

a node that requests and uses resources available from other nodes. Typically, a client is a user's personal computer.

server

a node that shares resources with other nodes. Dedicated servers specialize in performing specific tasks. Depending on the specific task, they may be called an application server, communication server, database server, file server, printer server, or web server.

directory server

a specialized server that manages resources, such as user accounts, for an entire network.

node

any device that is connected to a network. It could be a computer, printer, or data storage device.

Wide Area Network (WAN)

are countrywide and worldwide networks. These networks provide access to regional service (MAN) providers and typically span distances greater than 100 miles. They use microwave relays and satellites to reach users over long distances

Communication Systems

are electronic systems that transmit data from one location to another. Whether wired or wireless, every communication system has four basic elements. sending and receiving devices connection devices data transmission specifications communication channel

switch

central node that coordinates the flow of data by sending messages directly between sender and receiver nodes. A hub previously filled this purpose by sending a received message to all connected nodes, rather than just the intended node.

microwave

communication uses high-frequency radio waves. It is sometimes referred to as line-of-sight communication because microwaves can only travel in a straight line.

cellular

communication uses multiple antennae (cell towers) to send and receive data within relatively small geographic regions (cells). Most cell phones and mobile devices use cellular networks.

firewall

consists of hardware and software that control access to a company's intranet and other internal networks.

twisted pair cable

consists of pairs of copper wire that are twisted together. Both standard telephone lines and Ethernet cables use twisted pair.

network operating system (NOS)

control and coordinate the activities of all computers and other devices on a network. These activities include electronic communication and the sharing of information and resources.

domain name server

converts text-based addresses to IP addresses.

virtual private networks

create a secure private connection between a remote user and an organization's internal network. Special VPN protocols create the equivalent of a dedicated line between a user's home or laptop computer and a company server.

network architecture

describes how a network is arranged and how resources are coordinated and shared. It encompasses a variety of different network specifics, including network topologies and strategies.

Global Positioning System (GPS)

devices use that information to uniquely determine the geographic location of the device. Available in many automobiles to provide navigational support, these systems are often mounted into the dash with a monitor to display maps and speakers to provide spoken directions.

star network

each device is connected directly to a central network switch. Whenever a node sends a message, it is routed to the switch, which then passes the message along to the intended recipient.

bus network

each device is connected to a common cable called a bus or backbone, and all communications travel along this bus.

mesh network

his topology is the newest type and does not use a specific physical layout (such as a star or a tree). Rather, the mesh network requires that each node have more than one connection to the other nodes.

protocols

https, or hypertext transfer protocol secure, is widely used to protect the transfer of sensitive information. Another widely used Internet protocol is TCP/IP (transmission control protocol/Internet protocol). The essential features of this protocol involve (1) identifying sending and receiving devices and (2) breaking information into small parts, or packets, for transmission across the Internet.

connectivity

is a concept related to using computer networks to link people and resources.

network gateway

is a device that allows one LAN to be linked to other LANs or to larger networks.

bandwidth

is a measurement of the width or capacity of the communication channel. Effectively, it means how much information can move across the communication channel in a given amount of time.

WiMax (Worldwide Interoperability for Microwave Access)

is a new standard that extends the range of Wi-Fi networks using microwave connections. WiMax is commonly used by universities and others to extend the capability of existing Wi-Fi networks.

extranet

is a private network that connects more than one organization. Many organizations use Internet technologies to allow suppliers and others limited access to their networks. The purpose is to increase efficiency and reduce costs.

intranet

is a private network within an organization that resembles the Internet. Like the public Internet, intranets use browsers, websites, and web pages. Typical applications include electronic telephone directories, e-mail addresses, employee benefit information,

bluetooth

is a short-range radio communication standard that transmits data over short distances of up to approximately 33 feet. Bluetooth is widely used for wireless headsets, printer connections, and handheld devices.

uplink

is a term relating to sending data to a satellite.

wireless modem

is also known as a WWAN (wireless wide area network) modem. Almost all computers today have built-in wireless modems. For those that do not, wireless adapter cards are available that plug into USB or special card ports.

cable service

is provided by cable television companies using their existing television cables. These connections are usually faster than DSL.

fiber-optic service

is showing up in some areas, but it is a new technology and not widely available. Current providers of FiOS include Google and Verizon with speeds faster than cable or DSL connections.

voiceband

is used for standard telephone communication. Personal computers with telephone modems and dial-up service use this bandwidth.

medium band

is used in special leased lines to connect midrange computers and mainframes as well as to transmit data over long distances. This bandwidth is capable of very-high-speed data transfer.

broad band

is widely used for DSL, cable, and satellite connections to the Internet. Several users can simultaneously use a single broadband connection for high speed data transfer.

base band

is widely used to connect individual computers that are located close to one another. Like broadband, it is able to support high-speed transmission. Unlike broadband, however, baseband can only carry a single signal at a time.

DSL (digital subscriber line)

modem uses standard phone lines to create a high-speed connection directly to your phone company's offices. These devices are usually external and connect to the system unit using either a USB or an Ethernet port. ADSL (asymmetric digital subscriber line) is one of the most widely used types of DSL. DSL is much faster than dial-up.

peer-to-peer network

nodes have equal authority and can act as both clients and servers. The most common way to share games, movies, and music over the Internet is to use a P2P network.

strategy

or way of coordinating the sharing of information and resources.

downlink

refers to receiving data from a satellite. The major drawback to satellite communication is that bad weather can sometimes interrupt the flow of data.

Metropolitan Area Network (MAN)

span distances up to 100 miles. These networks are frequently used as links between office buildings that are located throughout a city.

network interface cards

these are expansion cards located within the system unit that connect the computer to a network. Sometimes referred to as a LAN adapter.

connection devices

these devices act as an interface between the sending and receiving devices and the communication channel. They convert outgoing messages into packets that can travel across the communication channel. They also reverse the process for incoming messages.

fiber-optic cable

transmits data as pulses of light through tiny tubes of glass. Compared to coaxial cable, it is lighter, faster, and more reliable at transmitting data. Fiber-optic cable is rapidly replacing twisted-pair cable telephone lines.

client/server networks

use central servers to coordinate and supply services to other nodes on the network. The server provides access to resources such as web pages, databases, application software, and hardware.

Satellite connection services

use satellites to provide wireless connections. While slower than DSL and cable modem, satellite connections are available almost anywhere using a satellite-receiving disk.

WiFi (wireless fidelity)

uses high-frequency radio signals to transmit data. A number of standards for Wi-Fi exist, and each can send and receive data at a different speed

cable modem

uses the same coaxial cable as your television. Like a DSL modem, a cable modem creates high-speed connections using the system unit's USB or Ethernet port.

Analog Signal

which are continuous electronic waves.

Intrusion Detection System (IDS)

work with firewalls to protect an organization's network. These systems use sophisticated statistical techniques to analyze all incoming and outgoing network traffic.

Sending and receiving devices

These are often a computer or specialized communication device. They originate (send) as well as accept (receive) messages in the form of data, information, and/or instructions.

data transmission specifications

These are rules and procedures that coordinate the sending and receiving devices by precisely defining how the message will be sent across the communication channel.

communication channel

This is the actual connecting or transmission medium that carries the message. This medium can be a physical wire or cable, or it can be wireless.