Chapter 8 Communications and Networks computing Essentials 2017 1 Chapter summary  communications o The procedure of share data, programs, and information between two or much more computers including:  E-mail  offers a fast, efficient different to timeless mail by sending and receiving electronic documents.  texting  Provides very efficient direct text communication between individuals using brief electronic messages.  video clip Conferencing  offers a really low-cost alternate to long-distance telephone calls using electronic voice and video clip delivery.  Electronic commerce  Buying and selling products electronically. O Connectivity - using computer system networks to link people and also resources.  Connecting personal computers to other computers and information sources practically anywhere.  To have the ability to efficiently and effectively use computers becomes a matter of …

Chapter 8 Communications and Networks computer Essentials 2017


Chapter Outline

 interactions o The procedure of sharing data, programs, and also information between two or more

computers including:

 E-mail

 provides a fast, efficient alternative to timeless mail by sending and also receiving electronic documents.

You are watching: Fiber-optic cable transmits data as pulses of light through tiny tubes of glass.

 Texting

 Provides really efficient direct text communication in between individuals using brief electronic messages.

 video Conferencing

 provides a really low-cost different to long-distance telephone phone call using digital voice and video clip delivery.

 electronic commerce

 Buying and also selling goods electronically. O Connectivity - using computer system networks to link people and also resources.

 Connecting an individual computers to other computers and also information sources virtually anywhere.

 To be able to efficiently and effectively use computers becomes a matter of knowing about connectivity through networks come personal

computers and also around larger computer systems and also information


o The Wireless transformation -  The single most dramatic readjust in connectivity and also communications

in a decade has actually been the widespread usage of mobile tools like

smartphones and tablets v wireless internet connectivity.

 enables individuals come stay connected with one one more from almost anywhere at any time.

 the is estimated that over 1.5 exchange rate smartphones are in use an international  when wireless modern technology was initially used mainly for voice

communications, countless of today’s cell phones support e-mail, web

access, social networking, and also a selection of internet applications.

 permits a wide range of nearby devices to communicate with one one more without any kind of physical connection

 High speed web wireless an innovation allows people to connect to the Internet and share details from almost anywhere in the


o communications systems - electronic systems that transmit data indigenous one location to another.

o Four basic elements of a interaction system include:  Sending and also receiving gadgets –

 regularly a computer or committed communication device

 originates (send) as well as accept (receive) messages in the kind of data, information, and/or instructions

 link devices –

 act as an interface in between the sending and the receiving devices and communication channel

Chapter 8 Communications and also Networks computing Essentials 2017


 convert outgoing messages into packets that deserve to travel across the interaction channel and reverse the process for

incoming messages

 Data transmission specifications - rules and also procedures the coordinate the sending and also receiving tools by physically defining

how the blog post will it is in sent throughout the communication channel.

 communication channel –

 transmission tool that tote the message

 medium can be a physical wire or cable, or it have the right to be wireless

 Communications channels o Essential facet of every interaction system o carry the data indigenous one computer system to another. O two categories that communication channels that attach sending and receiving

devices encompass physical and wireless connection

o physical Connections- a solid medium to connect sending and also receiving devices. These relationships include:

 Twisted pair cable– bag of copper wires twisted together

 Both standard telephone lines and Ethernet cables use twisted pair, See figure 8-3

o Ethernet cables are frequently used in networks and also to connect a selection of contents to the system unit.

 Coaxial cable - a high-frequency transmission cable consists of a single, solid copper core. See number 8-4.

 used to deliver television signals and to connect computers in a network

 Fiber-optic cable - transmits data together pulses that light v tiny pipe of glass.

 Lighter, faster, and an ext reliable 보다 coaxial cable

 swiftly replacing twisted-pair cable telephone lines. O Wireless relationships o perform not use a solid problem to affix sending and also receiving devices. O Data is moved through the air. O main technologies offered for wireless relationships are Bluetooth, Wi-Fi,

microwave, WiMax, cellular, and also satellite connections.

 Bluetooth is a short-range radio interaction standard that transmits data over short distances of up to about 33 feet.

Bluetooth is widely offered for wireless headsets, press connections,

and handheld devices.

 Wi-Fi (wireless fidelity) offers high frequency radio signal to transmit data. A number of standards because that Wi-Fi exist, and each can send and

receive data in ~ a various speed. Most home and business wireless

networks usage Wi-Fi, See number 8-6

 Microwave - interaction uses high-frequency radio waves. That is sometimes referred to together line-of-sight interaction because

microwaves have the right to only take trip in a straight line.

 since waves can not bend v the curvature the the planet they deserve to only it is in transmitted over fairly short distances.

 For much longer distances, the waves have to be relayed by method of microwave stations with microwave bowl or antennas.

Chapter 8 Communications and also Networks computing Essentials 2017


 WiMax (Worldwide Interoperability for Microwave Access) is a brand-new standard that extends the variety of Wi-Fi networks using microwave

connections. WiMax is frequently used by universities and others to

extend the capacity of existing Wi-Fi networks.

 Cellular communication uses multiple antennae (cell towers) come send and also receive data within reasonably small geographic regions (cells);

most cell phones and mobile gadgets use moving networks.

 Satellite - magnified microwaves that use point-to-point interaction to relay tools (satellites) orbiting 22,000 miles

above the earth.

 Orbit in ~ a an exact point and also speed over the earth.

 countless are available by Interlsat, the worldwide Telecommunications Satellite Consortium

 Amplify and also relay microwave signals from one transmitter ~ above the ground come another.

 provided to send and also receive big volumes of data.

 Uplink is a hatchet relating to sending data come a satellite

 Downlink describes receiving data native a satellite

 communication interferences can occur in poor weather.

 A network that satellites are owned and also managed by the department of Defense that continuously send location

information to earth

 used by an international positioning mechanism (GPS) devices.

 offered by countless smartphones and tablets

 Infrared uses infrared light waves to interact over quick distances

o have the right to only travel in a directly line and also for brief distances without obstructions

 connection Devices o in ~ one time nearly all computer interaction systems provided telephone lines

and analog signals. Computer systems use digital signals. A modem is required to

convert the digital signal to analog signals and also vice versa.

o Modems (modulator-demodulator) -  Modulation is the name of the procedure of converting from digital to


 Demodulation is the process of converting from analog come digital  Transfer price is in bits-per-second; generally measured in millions of

megabits per second (Mbps)

 Three generally used types of modems include:

 DSL (digital subscriber line) – supplies standard phone present to create a high-speed link directly come the phone call company’s

offices; external and also usually use USB or Ethernet harbor to

connect come system.

 Cable – offers the very same coaxial cable together a tv to create a high-speed connection. Connect using USB or Ethernet port.

 Wireless (also well-known as a WWAN- wireless vast area network modem). Typically a USB or unique card ports that

Chapter 8 Communications and also Networks computer Essentials 2017


provides really portable high-speed connectivity from virtually


o Connection business  T1– distinct high speed lines native telephone companies that assistance all

digital communications.

 T3 or DS3 provide higher capacity options

 used by large companies.

 as well costly for many individuals.

 have largely been replaced with optical carrier (OC) lines which are lot faster.

 Dial-up - provides existing telephones and telephone modems to attach to the Internet. An extremely slow and also has been replaced by various other higher-speed

connection services.

 Digital subscriber heat (DSL) - offers existing telephone currently to carry out high-speed connections. Much faster than dial-up.

 ADSL (asymmetric digital subscriber line) is among the many widely used species of DSL

 Cable business - use existing television cables to carry out high-speed connections. Usually much faster than DSL.

 Fiber Optic service (FiOS) is a brand-new technology in some areas but not commonly available. Existing providers of FiOS incorporate Google and

Verizon v speeds much faster than cable or DSL.

 Satellite link services - use satellites to carry out wireless connections. Slower 보다 DSL and also cable modem but greater availability

 Cellular services - Cellular service providers including Verizon, AT&T, Sprint, and also T-Mobile support voice and data infection to

wireless devices. Cellular services have actually gone v different


 1G (first generation cell phone telecommunications) began in the 1980s using analog radio signal to administer analog voice

transmission service.

 2G (second generation cell phone telecommunications) stared in the 1990s making use of digital radio signals. This generation focused

on voice transmission and was too slow for effective Internet


 3G (third generation mobile telecommunications) started in the 2000s giving services capable of efficient connectivity

to the net and significant the beginning of smartphones.

 4G (fourth generation mobile telecommunications) have begun to change 3G with service providers using WiMax LTE (Long

Term Evolution) relations to carry out faster transmission

speeds. A user’s endure with 4G will rely on several

factors consisting of carrier, geography, and also proximity to cell

towers. 4G technologies can provide accelerates to 10 times

faster than 3G.

 Data transmission

Chapter 8 Communications and also Networks computer Essentials 2017


o Bandwidth – is a measure of the width or capacity of the communication channel. How much information can move throughout the communication channel

in a offered amount of time.

o 4 categories the bandwidth include:  Voiceband (low bandwidth) - offered for typical telephone

communication by an individual computers with telephone modems and

dial-up service. Deserve to transmit text documents but is too sluggish for many

types that transmitting high-quality audio and video.

 tool band - supplied in distinct leased currently to connect midrange computers and also mainframes as well as to transmit data end long

distances. Qualified of an extremely high-speed data transfer.

 Broadband – widely provided by DSL, cable, and also satellite connections; numerous users deserve to simultaneously use a single broadband link for

high-speed data transfer.

 Baseband - widely supplied to attach individual computer systems that are located close to one another.

 like broadband, it is able to assistance high-speed transmission.

 unequal broadband, however, baseband have the right to only lug a single signal in ~ one time.

o Protocols for data infection to be successful, sending and receiving tools must follow a collection of interactions rules because that exchange of

information. Protocols space the rule for trading data between computers.

 https or hypertext transfer protocol secure is a widely provided protocol come protect and transfer perceptible information.

 TCP/IP – Transmission control Protocol/Internet Protocol is the typical protocol for the Internet. Necessary features indicate – sending

and receiving devices and also breaking information into small parts for

transmission across the Internet

 Identification: Every computer on the Internet has actually a distinctive numeric resolve called an IP attend to (Internet protocol

address). Provided to deliver –email and also to situate websites

o uses a domain name server (DNS) that automatically converts text-based addresses to numeric IP addresses

o go into a URL and also a DNS converts it come an IP deal with before a connection can be made

 Packetization: information sent or sent across the web usually travel through countless interconnected

networks. Before a post is sent, the is reformatted or broken

down into small parts referred to as packets. Each packet is climate sent

separately over the Internet, feasible traveling different routes

to one usual destination. In ~ the receiving end, the packets

are reassembled right into the correct order.

 Networks o A computer system network is a interaction system the connects two or more

computers so they deserve to exchange information and also share resources.

o Networks can be set up in different arrangements to fit users’ demands (See figure 8-13) and also may consist of only personal computer or it might integrate

personal computer system or other gadgets with larger computers

o Number of specialized terms that describe computer networks include:  Node—any device that is associated to a network.

Chapter 8 Communications and Networks computer Essentials 2017


 customer —a node the requests and also uses resources obtainable from other nodes. Typically, a customer is a user’s an individual computer.

 Server—a node the shares resources with various other nodes. Devoted servers specialization in performing specific tasks.

 brochure server—specialized server the manages sources such as user account for an entire network.

 Host—any computer system system that deserve to be accessed over a network.  Router —a node the forwards or paths data packets from one

network come their location in an additional network

 Switch—central node that collaborates the flow of data by sending messages directly between sender and receiver nodes. A hub

previously filled this purpose by sending out a received article to all

connected nodes, fairly than simply the plan node.

 Network user interface cards (NIC)—expansion cards located within the mechanism unit that attach the computer to a network. Sometimes

referred to together a LAN adapter.

 Network operating equipment (NOS)—control and also coordinate the tasks of every computers and other devices on a network.

 Network administrator—a computer specialist responsible for effective network operations and also implementation of new networks.

 Network types o local Area Networks (LANs)- Networks v nodes that space in close

physical proximity, frequently spanning much less than a mile and are own and

operated by individual organizations.

 Network gateway - an equipment that permits one LAN to be connected to various other LANs or to larger networks.

 The most common standard in which nodes in a LAN can be linked to one one more is well-known as Ethernet.

o residence Networks - networks being used by people in your homes and also apartments. Allow different computers to re-publishing resources, consisting of a

common net connection

 relations in a selection of ways, including electrical wiring, telephone wiring, and special cables

o Wireless LAN (WLAN) - offers radio frequencies to attach computers and other devices. All interactions pass with the network’s centrally

located wireless accessibility point or basic station. This accessibility point interprets

incoming radio frequencies and routes interactions to the appropriate

devices. In public places wireless accessibility points are well-known as hotspots and

typically usage Wi-Fi technology. Many mobile computer devices have an

internal wireless network map to affix to hotspots.

o personal area network (PAN) - type of wireless network that functions within a very tiny area—your prompt surroundings. PANs attach cell phones to

headsets, PDAs to other PDAs, key-boards to cabinet phones, and so on. Most

popular PAN modern technology is Bluetooth, v a maximum selection of around 33


o city Area Networks (MANs)- span distances up come 100 miles. Commonly used links in between office buildings that are situated throughout a

city. Man are typically owned through a group of organizations who jointly own

and operate the network or through a single network organization provider the provides

network services for a fee.

Chapter 8 Communications and also Networks computing Essentials 2017


o broad Area Networks (WANs) - countrywide and worldwide networks. Provide access to local service (MAN) providers and typically span

distances higher than 100 miles. They usage microwave relays and also satellites to

reach customers over lengthy distances. The widest of all WANs in the Internet, which

spans the entire globe.

 The major difference in between a PAN, LAN, MAN, and WAN is the geographic range.

 Network style o defines how a network is arranged and how resources are coordinated and


o Topology – explains the physical plan of a network and how sources are coordinated and shared.

 Bus network

 Each maker is associated to a usual cable referred to as a bus or backbone and also all interactions travel follow me this bus.

 Ring network

 Each machine is linked to two various other devices, forming a ring See figure 8-17;

o when a post is sent, that is passed around the ideal until that reaches the plan destination.

 Star

 Each device is linked directly come a main network move See figure 8-18

 anytime a node sends out a message, it is routed come the switch, which then passes the blog post along to the plan recipient.

 most widely supplied network topology today.

 range of applications includes small networks in the residence to very huge networks in major corporations.

 Tree

 Each maker is connected to a main node, either directly or v one or more other devices.

 main node is associated to two or an ext subordinate nodes that in turn are associated to other subordinate nodes, and so

forth, developing a treelike framework See figure 8-19

 additionally known as a hierarchical network.  Mesh

 Newest form of topology and does not use a details physical layout.

 requires that each node have more than one link to the other nodes. The resulting pattern creates the illustration of a


 If a path in between two nodes is in which method disrupted, data deserve to be instantly rerouted.

 Wireless modern technologies are generally used to build mesh networks.

 tactics o Every network has actually a strategy, or method of coordinating the sharing of

information and also resources. Two of the most usual network methods are

client/server and also peer-to-peer.

Chapter 8 Communications and Networks computing Essentials 2017


 Client/server networks - space widely used on the Internet

 each time a web internet browser is opened the computer system (client) sends out a inquiry for a specific web page; the request is routed over

the web to a server and then the server locates and also send the

requested material ago to the computer

 Client/server networks space widely offered on the Internet.

 advantage of the client/server network strategy include:  ability to manage very big networks efficiently.  accessibility of an effective network management

software to monitor and also control network


 The major disadvantages that the client/server network strategy are the price of installation and maintenance

 Peer-to-peer (P2P) network - nodes have equal authority and can act as both clients and servers. Plenty of current famous games, movies, and

music sharing solutions use this network strategy.

 unique file-sharing, software program such together BitTorrent deserve to be used to achieve files situated on another personal computer.

 benefit of P2P:  Easy and also inexpensive (often free) to collection up and


 Disadvantage that P2P:  lack of defense controls or various other common

management functions.

 business Networks o Intranet Technologies

 A private network in ~ an organization that each other the Internet.  supplies browsers, net sites, and web pages.  organizations use intranets to provide information to your employees

such as electronic telephone directories, e-mail addresses, internal job

openings, and also more.

 easily accessible only to those in ~ the organization.  Easy and intuitive for employees come use.

o Extranet  A personal network the connects more than one organization.  countless organizations use web technologies to allow suppliers and

others limited access to their networks.

 key purpose is to boost efficiency and reduce costs. O Network defense o Securing huge corporate networks requires committed technology. Three

technologies generally used come ensure network protection include:

 Firewalls

 A security device designed to protect an organization network against external threats.

 consists of hardware and software that control access to a company’s intranet or other inner networks.

 sometimes organizational firewalls incorporate a special computer system or software called a proxy server. This device is a gatekeeper.

Chapter 8 Communications and Networks computing Essentials 2017


All communications between the company’s internal networks

and the outside world must pass with it. See number 8-22

 Intrusion detection equipment (IDS)

 Works v firewalls to safeguard an organization network.

 Uses sophisticated statistical techniques to analyze all incoming and outgoing network traffic.

 Uses progressed pattern matching and also heuristics come recognize indicators of a network attack and also disable accessibility before one intruder

can perform damage.

 Virtual private networks (VPN)

 develop a secure private connection in between a remote user and also an organization’s inner network.

 connection is heavily encrypted

 one-of-a-kind VPN protocols develop the equivalent of a committed line between a user’s residence or laptop computer and a company


 Careers In that o Network administrators control a that company LAN and WAN networks. O Duties

 Design, implementation, and maintenance the networks.  maintenance of both hardware and also software related to a company’s

intranet and Internet networks.

 Diagnosing and also repairing troubles with these networks.  Planning and also implementations of network security

o Bachelor’s degree or an advanced associate’s degree in computer system science, computer technology, or information systems and practical networking

experience or technical certification.

o yearly salary the $47,000 come $64,000. O supposed to be amongst the fastest-growing work in the close to future.

 A Look come the Future o Telepresence allows You Be over there without in reality Being over there o Telepresence seeks to produce the illusion the you space actually in ~ a remote

location, seeing, hearing, and someday maybe also feeling as though you

were really there.

o Today’s early telepresence implementations mainly emphasis on an expansion of videoconferencing.

o might be offered to allow people to occupational in hazardous areas from a for sure remote location. Doctors and also medical specialists might have the ability to perform surgeries

on human being unable come travel.

Teaching Tips

 communications o Emphasize in conversation that connectivity is the fastest growing sector the the

computer industry and that The Wireless change is the solitary most

dramatic readjust in connectivity and communications in the past five years.

o comment on why it is referred to as a revolution. O Give an introduction of the different parts that a interaction system that will certainly be


Chapter 8 Communications and Networks computing Essentials 2017


o You have the right to refer come the simple communications version that is debated in public speak classes and also how computer systems work in the very same fashion. View Figure

 Sending and also receiving devices  interaction channel = medium  link devices  Data infection specifications = message

o have students recap how interaction has readjusted during their stays (if girlfriend have various generations attending course students will check out how

communication has actually changed an extremely easily and also how the affects your lives)

 Communications channels o Emphasize that there are two species of channels: o physics (wired) - a solid tool to connect sending and receiving devices.

 point out that twisted pair – supplies copper wires to command electricity, covers the least distance and also is the slowest of the wired channels

 Coaxial cable - a high-frequency infection cable, provides copper cable to conduct electricity, has a medium-range distance capability and


 Fiber-optic cable - transmits data together pulses of light v tiny pipe of glass or plastic, covers the farthest distance and also has the fastest

transmission speed

o bring samples the the physical (wired) channels to class. It gives the college student a clean visual and makes it simpler to open up a conversation on the assorted types.

– it has actually tiny strands the glass that may stick right into their skin. Passing it about is

easier if it is sealed in a plastic freezer bag.>

o Wireless-Give details examples because that each classification or have students comment on which ones work finest for them

 Bluetooth is a short-range radio interaction standard that transmits data over quick distances of up to around 33 feet.

Bluetooth is widely supplied for wireless headsets, press connections,

and handheld devices.

 WiFi - (wireless fidelity) uses high frequency radio signals to transmit data. A variety of standards for Wi-Fi exist, and also each have the right to send and

receive data in ~ a different speed. Many home and business wireless

networks use Wi-Fi.

 Microwave - interaction through high-frequency radio waves and also provides line-of-sight communication but over short distances.

Bluetooth is a form of microwave transmission

 LTE (Long term Evolution) is one of the newest wireless standards. Currently, LTE and WiMax relationships provide similar performance.

LTE, however, guarantees to administer greater speed and also quality

transmissions in the near future.

 Satellite - enhanced microwaves that usage point-to-point communication to relay tools (satellites) orbiting the earth.

Communication interferences can take place in poor weather.

 general practitioners (global placing system); discuss many applications the GPS and how that is now used in legal events

 Infrared provides infrared irradiate waves to connect over brief distances. Line of sight, remotes

Chapter 8 Communications and also Networks computer Essentials 2017


o together a laboratory exercise task students through interviewing and also identifying which (if any) the the wireless communication channels are provided at your school, work, or


 connection Devices check out o Signals

 Analog – continuous electronic tide  Digital – to represent the existence or absence of an electronic pulse

o You can emphasize the difference between modems and greater speed devices. O many students are familiar with both and also are interested in exactly how you deserve to connect

using the higher speed devices.

o talk about how DSL provides standard phone lines o have actually students identify exactly how each the the simple types of modems are provided o comment on the pros and also cons room each form of connection device

 connections Services o describe the adhering to services and also give examples of each: o DSL, Cable, Satellite, moving o talk about the cellular business generations that mobile communications 1G, 2G,

3G and also 4G.

o have students research and prepare graphs because that 1G-4G rates

 Data infection o Bandwidth can be difficult for students to understand. You can use one analogy

of a highway and the broader the roadway the much more cars deserve to travel on it in a given

amount of time.

o Protocols have the right to be contrasted to international services and also how different nations have various ways come communicate. Mention Internet protocol TCP/IP

o friend can comment on with students how it is possible to recognize which computer system on the internet was offered to send one e-mail or to access a particular web site.

Discussing the concept of the “digital footprint” through students is often


 make IT work-related – the Mobile web should be really exciting to your students; you can have student develop questions for a jeopardy video game for this chapter; working

in pairs

 Networks o You can emphasize the basic parts that make up a network. O watch at all of the components of a network together it makes it simpler for the college student to

grasp the terminology that is supplied to describe computer system networks (node, client,

server, brochure server, host, router, switch, network interface card, network

operating system, and also network administrator)

 Network species o The divisions between the species of networks space not together clear reduced from a

technical perspective since some species of tools that provided to it is in solely

used because that a WAN deserve to be provided in LAN environments. Part students deserve to point

this truth out. It is finest to state that you room taking this native a geographical


o plenty of students have installed or want to download a house network

 Network architecture o how a network is arranged and how resources are coordinated and shared. O Look at the equivalent figures in the book to identify network architecture.

Chapter 8 Communications and also Networks computer Essentials 2017


o anxiety to students the the star network is the many widely supplied network topology today. It is supplied in tiny networks in the home and an extremely large

networks in significant corporations.

 methods o many of the student have had experiences with BitTorrent, and other varieties of

downloading programs. You deserve to use these as an example of how client/server

and peer-to-peer work.

o open up a discussion with students and explore their experiences v the use of this type of downloading and install programs. Why pay for it – as soon as you can acquire it for

free? difficulty with downloading and install viruses from these unsecured sites.

 business internets o Intranet

 Emphasize the it is a personal network within an organization that resembles the Internet and also it offers services obtainable only come those

within the organization.

o Extranet  Emphasize that it is a private network the connects more than one

organization to permit suppliers and also others minimal access to their


 an excellent examples are institutions that use simply In Time inventory.  an excellent discussion on this would be just how Wal-Mart uses this form of

network and also why they are so effective by law so.

o Network defense  Firewalls

 Both hardware and software

 good for house use together well

 have students recognize what form of firewall they are using top top their an individual computers.

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 Intrusion detection systems (NIDS)

 Ask students to search the net for an ext information on just how this system can recognize network attacks and also disable


 Virtual private Network (VPN) – This an innovation is widely used by many people who work-related from home.