Using Management Information Systems
David Kroenke
Data Communications and Internet Technology
Chapter 5
© 2007 Prentice Hall, Inc.
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Learning Objectives
Know basic telecommunications terminology.
Know the definition and characteristics of LAN,
WANs, and internets.
Understand the nature of processing in a
layered communications protocol.
Know the purpose of the five layers of the
TCP/IP-OSI protocol.
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Learning Objectives (Continued)
Understand Ethernet and wireless LANs.
Understand the characteristics of WANs using
personal computers with modems to the
Internet, networks of leased lines, PSDNs and
virtual private networks.
Know basic concepts involved in the operation of
the Internet.
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Fundamental Networking Concepts
A computer network is a collection of computers
that communicate with one another over
transmission lines.
Three basic types of networks are:



Local area networks (LANs)–connects computers that
reside in a single geographic location on the premises of
the company that operates the LAN.
Wide area networks (WANs)–connects computers at
different geographic sites.
Internets–a network of networks
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Fundamental Networking Concepts (Continued)
The networks that comprise an Internet use a large
variety of communication methods and
conventions, and data must flow seamlessly across
them.
To provide seamless flow, an elaborate scheme
called a layered protocol is used.
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Figure 5-1 Major Network Types
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Figure 5-2 Example Networks
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Figure 5-3 Example of a Grocery Store Protocol
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Communications Protocols
A protocol is a standard means for coordinating an
activity between two or more entities.
A communications protocol is a means for
coordinating activity between two or more
communicating computers.
Two machines must agree on the protocol to use, and
they must follow that protocol as they send messages
back and forth.
Communications protocols are broken into levels of
layers.
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The TCP/IP-OSI Architecture
The International Organization for Standardization
(ISO) developed the Reference Model for Open
Systems Interconnection (OSI), an architecture that
has seven layers.
The Internet Engineering Task Force (IETP),
developed a four-layer scheme called the TCP/IP
(Transmission Control Program Internet Protocol)
architecture.
The most commonly used architecture today is a fivelayer blend of these two architectures called the
TCP/IP-OSI architecture.
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Figure 5-4 TCP/IP – OSI Architecture
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Layer 5
Layer 5 generates and receives email (and
attachments like photos) according to one of the
standard email protocols generated for layer 5


Most likely its Simple Mail Transfer (SMTP)
Hypertext Transfer Protocol (HTTP) is used for the
processing of Web pages.
The Web and the Internet are not the same thing.


The Web, which is a subset of the Internet, consists of sites
and users that process the HTTP protocol.
The Internet is the communications structure that supports
all application-layer protocols, including HTTP, SMTP, and
other protocols.
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Layer 5 (Continued)
FTP, or the File Transfer Protocol is another
application layer protocol.

You can use FTP to copy files from one computer to another.
An architecture is an arrangement of protocol layers in
which each layer is given specific tasks to accomplish.
At each level of the architecture, there are one or
more protocols.

Each protocol is a set of rules that accomplish the tasks
assigned to its layer.
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Layer 5
A program is a specific computer product that
implements a protocol.
Programs that implement the HTTP protocol of the
TCP/IP-OSI architecture are called browsers.
Two common browsers are Netscape and Microsoft
Internet Explorer.
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Figure 5-5 TCP/IP-OSI on Your Computer
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Layer 4
An email program (which uses SMTP) interacts with
another protocol called TCP, or Transmission
Control Program (TCP).
TCP operates at layer 4 of the TCP/IP-OSI
architecture.
The TCP program examines your data (files, email,
pictures, etc.) and breaks these lengthy messages into
pieces called segments.
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Layer 4
TCP places identifying data in front of each segment
that are akin to the To and From addresses that you
would put on a letter for the postal mail.
TCP programs also provide reliability.
If data is sent from a Dell computer to a Macintosh
computer, TCP program translates the segments from
Windows (Dell) to Macintosh format, reassembles the
segments into a coherent whole, and makes that
assembly available to Macintosh computer.
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Layer 3
TCP/IP interacts with protocols that operate at Level 3,
the next layer down.
For the TCP/IP architecture, the layer-3 protocol is the
Internet Protocol (IP).
The chief purpose of IP is to route messages across
an internet.
Routers are special-purpose computers that
implements the IP protocol.
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Layers 1 and 2
Basic computer connectivity is accomplished using
Layers 1 and 2 of the TCP/IP-OSI architecture.
Computing devices called switches facilitate data
communication.
A program implementing a Layer-2 protocol will
package each of your packets into frames, which are
the containers used at Layers 1 and 2 (Segments go
into packets and packets go into frames).
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Local Area Networks
A local area network (LAN) is a group of computers
connected together on a single company site.
Usually the computers are located within a half mile or
so of each other, although longer distances are
possible.

The key distinction, however, is that all of the computers are
located on property controlled by the company that operates
the LAN.
Computers and printers are connected via a switch,
which is a special-purpose computer that receives and
transmits messages on the LAN.
© 2007 Prentice Hall, Inc.
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Local Area Networks (Continued)
Each device on a LAN (computer, printer, etc.) has a
hardware component called a network interface card
(NIC) that connects the device’s circuitry to the cable.


The NIC works with programs in each device to implement
Layer 1 and Layer 2 protocols.
Each NIC has a unique identifier, which is called the (MAC)
media access control address.
The computers, printers, switches, and other devices
on a LAN are connected using one of two media.


Most connections are made using unshielded, twisted pair
(UTP) cable.
A device called an RJ-45 connector is used to connect the
UTP cable into NIC devices on the LAN.
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Local Area Networks (Continued)
The connection between switches can use UTP cable,
but if they carry a lot of traffic or are far apart UTP
cable may be replaced by optical fiber cables.


The signals on such cables are light rays, and they are
reflected inside the glass core of the optical fiber cable.
Optical fiber cable uses special connectors called ST and
SC connectors.
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Figure 5-6 Local Area Network
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Figure 5-7 NIC Interface Card
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Figure 5-8 Unshielded Twisted Pair (UTP) Cable
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Figure 5-9 Optical Fiber Cable
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IEEE 802.3 or Ethernet Protocol
The committee that addresses LAN standards is
called the IEEE 802 Committee. (Institute for Electrical
and Electronics Engineers)

Thus, IEEE LAN protocols always start with the number 802.
Today, the world’s most popular protocol for LAN is the
IEEE 802.3 protocol.



This protocol standard, also called Ethernet, specifies
hardware characteristics such as which wire carries which
signals.
It also describes how messages are to be packaged and
processed for transmission over the LAN.
Ethernet operates at Layers 1 and 2 of the TCP/IP-OSI
architecture.
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IEE 802.3 or Ethernet Protocol (Continued)
Most personal computers today are equipped with an
onboard NIC that supports what is called 10/100/1000
Ethernet.


These products conform to the 802.3 specification and allow
for transmission at a rate of 10, 100, or 1,000 Mbps.
Communications speeds are expressed in bits, whereas
memory sizes are expressed in bytes.
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LANs with Wireless Connections
Wireless connections have become popular with
LANs.
The NIC for wireless devices have been replaced by
wireless NIC (WNIC).

For laptop computers, such devices can be cards that slide
into the PCMA slot or they can be built-in, onboard devices.
Several different wireless standard exist



As of 2005, the most popular is IEEE 802.11g
The current standard, 802.11g allows speeds of up to 54
Mbps.
The WNICs operate according to the 802.11 protocol and
connect to an access point (AP).
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Figure 5-10
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Figure 5-11 Wireless Access Standards
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Figure 5-12 Summary of LAN and WAN Networks
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Wide Area Networks
A wide area network (WAN) connects computers
located at physically separated sites.


A company with offices in Detroit and Atlanta must use a
WAN to connect the computers together.
Because the sites are physically separated, the company
cannot string wire from one site to another.
An Internet service provider (ISP) has three
important functions:
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

It provides you with a legitimate Internet address.
It serves as your gateway to the Internet.
It receives the communication from your computer and
passes them on to the Internet, and it receives
communication from the Internet and passes them on to you.
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Connecting the Personal Computer to an ISP:
Modems
Home computers and those of small businesses are
commonly connected to an ISP in one of three ways:



Using a regular telephone line
Using a special telephone line called a DSL line
Using cable TV line
All three ways require that the digital data in the
computer be converted to an analog, or wavy, signal.
A device called a modem, or modulator/demodulator
performs this conversion.
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Figure 5-13 Analog vs. Digital Signals
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Figure 5-14 Personal Computer (PC) Internet
Access
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Dial-Up Modems
A dial-up modem performs the conversion between
analog and digital in such a way that the signal can be
carried on a regular telephone line.


You dial the number for your ISP and connect.
The maximum transmission speed for a switch is 56 kbps.
The way messages are packaged and handled
between your modem and the ISP is governed by a
protocol known as Point-to-Point Protocol (PPP).

This Layer-2 protocol is used for networks that involve just
two computers.
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DSL Modems
A DSL modem is the second modem type.
DSL stands for digital subscriber line.
DSL modems operate on the same lines as voice
telephones and dial-up modems.



They operate so that their signals do not interfere with voice
telephone service.
They provide much faster data transmission speeds than
dial up modems.
They always maintain a connection.
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DSL Modems (Continued)
DSL data transmission and telephone conversations
can occur simultaneously.
DSL modems use their own Layer 1 and Layer 2
protocols for data transmission.
DSL lines that have different upload and download
speeds are called asymmetric digital subscriber
lines (ADSL).
Symmetrical digital subscriber lines (SDSL) offers
the same speed in both directions.
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Cable Modems
A cable modem is the third modem type.
Cable modems provide high-speed data transmission
using cable television lines.
At the maximum, users can download data up to 10
Mbps and can upload data at 256 kbps.
Narrowband lines typically have transmission speeds
less than 56 kbps.
Broadband lines have speeds in excess of 256 kbps.
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Figure 5-15 Wide Area Network Using Leased
Lines
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Networks of Leased Lines
A WAN connects computers located at geographically
distributed company sites.
The lines that connect these sites are leased from
telecommunication companies that are licensed to
provide them.
A variety of access devices connect each site to the
transmission.



These devices are typically special-purposed computers.
The particular devices required depend on the line used and
other factors
Sometimes switches and routers are employed.
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Figure 5-16 Transmission Line Types, Uses, and
Speeds
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Public Switched Data Network
Another WAN alternative is a public switched
network (PSDN), a network of computers and leased
lines that is developed and maintained by a vendor
that leases time on the network to other organizations.
When using a PSDN, each site must lease a line to
connect to the PSDN network.


The location at which this occurs is called a point of
presence (POP); it is the access point into the PSDN.
Once a site has connected to the PSDN POP, the site
obtains access to all other sites connected to the PSDN.
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Public Switched Data Network (Continued)
PSDNs save the setup and maintenance activities
when using leased lines.


They also save costs because a company does not have to
pay for the entire network.
The company can just pay for the traffic that it sends.
Three Layer 1 and 2 protocols are used with PSDNs:



Frame Relay can process traffic in the range of 56 kbps to
40 Mbps.
Asynchronous transfer mode (ATM) can process speeds
from 1 to 156 Mbps (can handle both voice and data).
Ethernet, the protocol developed for LANs
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Figure 5-17 Wide Area Network Using PSDN
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Virtual Private Network
Virtual private network (VPN) is the fourth WAN
alternative.
A VPN uses the Internet or a private internet to create
the appearance of private point-to-point connections.
A VPN uses the public Internet to create the
appearance of a private connection.
A connection called a tunnel, is a virtual pathway over
a public or shared network from the VPN client to the
VPN server.
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Virtual Private Network (Continued)
VPN communications are secure.

The VPN client software encrypts, or codes, the original
messages so that its contents are hidden.
Virtual private networks offer the benefit of point-topoint leased lines, and they enable remote access,
both by employees and by any others who have been
registered with the VPN server.
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Figure 5-18 Remote Access Using VPN: Actual
Connections
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Figure 5-19 Remote Access Using VPN: Apparent
Connection
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Figure 5-20 Wide Area Network Using VPN
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Criteria for Comparing Network Alternatives
Many different computer networking alternatives are
available, each with different characteristics.
There are three types of costs that need to be
considered.

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
Setup costs include the costs of acquiring transmission lines
and necessary equipment, such as switches, routers, and
access devices.
Operational costs include lease fees for lines and
equipment, charges of the ISP, the cost of ongoing training,
etc.
Maintenance costs include those for periodic maintenance,
problem diagnosis and repair, and mandatory upgrades.
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Criteria for Comparing Network Alternatives
(Continued)
There are six considerations with regard to
performance:
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
Speed
Latency
Availability
Loss rate
Transparency
Performance guarantees
Other criteria to consider when comparing network
alternatives include the growth potential (greater
capacity) and the length of contract commitment.
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Figure 5-21 Criteria for Comparing Networking
Alternatives
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Network Addresses: MAC and IP
On most networks, and on every internet, two address
schemes identify computers and other devices.


Programs that implement Layer 2 protocols use physical
addresses, or MAC addresses.
Programs that implement Layer 3, 4, and 5 protocols use
logical addresses, or IP addresses.
Physical Addresses (MAC Addresses)



Each NIC is given an address at the factory that is the
device’s physical address or MAC address.
By agreement among computer manufacturers, such
addresses are assigned in such a way that no two NIC
devices will ever have the same MAC address.
Physical addresses are only known, shared, and used within
a particular network or network segment.
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Network Addresses: MAC and IP (Continued)
Logical Address (IP Addresses)

Internets, including the Internet, and many private networks
use logical addresses, which are also called IP addresses,
for example, 192.168.2.28
Public Versus Private Addresses



Public IP addresses are used on the Internet and assigned
to major institutions in blocks by the Internet Corporation
for Assigned Names and Numbers (ICANN).
Each IP address is unique across all computers on the
Internet.
Private IP addresses are used within private networks and
internets. They are controlled only by the company that
operates the private network or internet
© 2007 Prentice Hall, Inc.
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Network Addresses: MAC and IP (Continued)
Dynamic Host Configuration Protocol



The DHCP server is a computer or router that hosts a
program called Dynamic Host Configuration Protocol
(DHCP).
When the program finds such a device, your computer will
request a temporary IP address from the DNCP server
which is loaned to you while you are connected to the LAN.
When you disconnect, that IP address becomes available,
and the DHCP server will reuse it when needed.
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Figure 5-22 Hotel LAN in Hawaii
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Switches and Routers
Switches work with frames at Layer 2.



They send frames from switch to switch until they arrive at
their destination.
They use MAC addresses.
All switches have a table of data called a switch table.
Routers work with packets at Layer 3.


They send packets from router to router until they arrive at
their destination.
They use IP addresses.
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Figure 5-23 Accessing the (Private) Hotel Web
Server
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Using TCP/IP-OSI Protocols over the Internet
Network Address Translation


For Internet traffic, only public IP addresses can be used.
 These addresses are assigned in blocks to large
companies and organizations like ISPs.
All Internet traffic aimed at any computer within an
organization's LAN will be sent over the Internet using the
router’s IP public address for the given computer.
 The router will receive all packets for all computers for the
organization’s computers.
 When the router receives a packet, it determines the
internal IP address within the LAN for that computer.
 It then changes the address in the packet from the
router’s IP public address to the internal IP address of a
computer in the organization's LAN, the packet’s true
destination.
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Using TCP/IP-OSI Protocols over the Internet
(Continued)
Network Address Translation (continued)

The process of changing public IP addresses into private IP
addresses, and the reverse, is called Network Address
Translation (NAT).
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Figure 5-24 Hawaii Hotel to Ohio Company via
Internet
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Domain Name System
IP addresses are useful for computer-to-computer
communication, but they are not well suited for human
use.
The purpose of the domain name system (DNS) is to
convert user-friendly names into their IP addresses.
Any registered, valid name is called a domain name.
The process of changing a name into its IP address is
called resolving the domain name.
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Domain Name System (Continued)
Every domain name must be unique, worldwide.
To ensure duplicate domain names do not occur, an
agency registers names and records the
corresponding IP addresses in a global directory.
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Domain Name Registration
ICANN is a nonprofit organization that is responsible
for administering the registration of domain names.
ICANN does not register domain names itself; instead
it licenses other organizations to register names.
ICANN is also responsible for managing the domain
name resolution system.
The last letter in any domain name is referred to as
the top-level-domain (TLD).

In the domain www.icann.org the top level domain is .org
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Domain Name Resolution (Continued)
A uniform resource locator (URL) is a document’s
address on the Web.
URLs begin with a domain and then are followed by
optional data that locates a document with that
domain.

Thus, in the URL www.prenhall.com/kroenke , the domain
name is www.prenhall.com , and /kroenke is a directory
within that domain.
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Domain Name Resolution (Continued)
Domain name resolution is the process of converting
a domain name into a public IP address.
The process starts from the TLD and works to the left
across the URL.
As of 2005, ICANN manages 13 special computers
called root servers that are distributed around the
world.
Each root server maintains a list of IP addresses of
servers that each resolve each type of TLD.
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Domain Name Resolution (Continued)
Domain name resolution proceeds quickly because
there are thousands of computers called domain
name resolvers that store the correspondence of
domain names and IP addresses


These resolvers reside at ISPs, academic institutions, large
companies, government organizations, etc.
For example, if a domain name solver is on your campus
and whenever anyone on your campus needs to resolve a
domain name, that resolver will store, or cache, the domain
name and IP address on a local file.
 When someone else on the campus needs to resolve the
same domain name, the resolver can supply the IP
address from the local file.
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Figure 5-25 Top-Level Domains, 2005
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IP Addressing Schemes
Two IP addressing schemes exist: IPv4 and IPv6.
IPv4




IPv4 constructs addresses having 32 bits.
These bits are divided into four groups of 8 bits, and a
decimal number represents each group.
IPv4 addresses appear as 63.224.57.59.
The largest decimal number that can appear between the
period are 255 (0 – 255).
IPv6



Due to growth of the Internet IPv6 was developed.
IPv6 construct addresses having 128 bits.
Currently both IPv4 and IPv6 are used on the Internet.
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Summary
A computer network is a collection of computers
that communicate with one another over
transmission lines.
Three types of computer networks are: LANs,
WANs, and Internets, including the Internet.
A protocol architecture divides communications
activities among several layers.
Each layer has specific functions to perform.
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Summary (Continued)
A protocol is a set of rules for accomplishing the
functions of a particular layer.
LANS consist of computers at a single
organizational site that are connected via UTP or
optical fiber cables.
Each computer has a network interface card
(NIC), which is a special-purpose computer that
connects to the LAN’s cabling.
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Summary (Continued)
A switch is a special-purpose that receives traffic
from one computer and sends it to another
computer.
IEEE 802.3, or Ethernet, is the most popular LAN
standard.
The most popular wireless standard today is IEEE
802.11g.
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Summary (Continued)
Networks of leased lines consist of high-speed
lines that connect two points.
A public switched data network (PSDN) is a
network of computers and leased lines that is
developed and maintained by a vendor that
leases time on the network to other organizations.
A virtual private network (VPN) uses the Internet
or other Internet to create the appearance of
private, point-to-point connections.
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Summary (Continued)
Communicating devices have two addresses:
physical address (MAC) and an IP address (logical
address).
The process of converting IP addresses from
private to public and public to private is called
Network Address Translation (NAT).
The domain name system (DNS) resolves domain
names into IP addresses.
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Key Terms and Concepts
Access device
Access point
Analog signal
Architectures
Asymmetric digital subscriber
line (ADSL)
Asymmetric encryption
Asynchronous transfer mode
(ATM)
Broadband
Cable modem
Cache
Communications protocol
Device access router
Dial-up modem
Domain name
Domain name resolution
Domain name resolver
Domain name system (DSN)
DSL (digital subscriber line)
modem
Dynamic Host Configuration
Protocol (DHCP)
Encryption
Encryption algorithms
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Key Terms and Concepts (Continued)
Ethernet
File Transfer Protocol (FTP)
Frame
Frame relay
HTTPs
Hypertext Transfer Protocol
(HTTP)
IEEE 802.3 protocol
International Organization
for Standardization (ISO)
Internet
Internet Corporation for
Assigned Names and
Numbers (ICANNN)
Internet Engineering Task
Force (IETF)
Internet Protocol (IP)
Internet service provider
(ISP)
IP address
IPv4
IPv6
Key
Layered protocols
Local area network (LAN)
Logical address
MAC address
Modem
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Key Terms and Concepts (Continued)
Narrowband
Network
Network Address
Translation
(NAT)
Network interface card
(NIC)
Network of leased lines
Onboard NIC
Optical fiber cable
Physical address
Point-to-Point protocol
(PPP)
Point of presence (POP)
Private IP Address
Protocol
Public IP address
Public key/private key
Public switched data
network (PSDN)
Reference Model for Open
Systems Interconnection
Root server
Routing table
Secure Socket Layer (SSL)
Segment
Simple Mail Transfer
Protocol (SMTP)
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Key Terms and Concepts (Continued)
SOHO (small office, home
office)
Switch
Switch table
Symmetric encryption
Symmetric digital subscriber
line (SDSL)
TCP/IP-OSI architecture
10/100/1000 Ethernet
Top-level domain (TLD)
Transmission Control
Program (TCP) Protocol
Transmission Control
Program/Internet Protocol
(TCP/IP) architecture
Tunnel
Uniform resource locator
(URL)
Unshielded twisted-pair
(UTP) cable
Virtual private network
Wide area network (WAN)
Wireless NIC (WNIC)
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Problem-Solving Guide–Thinking Exponentially Is
Not Possible, but…
Nathan Myhrvold, the chief scientist at Microsoft
Corporation during the 1990s, once said that
humans are incapable of thinking exponentially.



Instead, when something changes exponentially, we
think of the fastest linear change we can imagine and
extrapolate from there.
His point was that no one could then imagine how much
growth there would be in magnetic storage and what we
would do with it.
We have all witnessed exponential growth in a number
of areas: Internet connection, Web pages, and the
amount of data accessible on the Internet.
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Problem Solving Guide–Thinking Exponentially Is
Not Possible, but… (Continued)
Every business, every organization, needs to be
thinking about ubiquitous and cheap connectivity
that is growing exponentially.


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
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What are the new opportunities?
What are the new threats?
How will our competition react?
How should we position ourselves?
How should we respond?
Understand that technology does not drive people
to do things they’re never done before, no matter
how much the technologists suggest it might.
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Opposing Forces Guide–Where’s the OFF Button
We lost our independence with the introduction of
the DSL modem.
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Up until then, you had to dial up, you had to take action,
to get connected.
The default mode was Off, and you had to do something
to get On.
Since DSL, the default mode has been On.
Today, perpetual connectivity is terrific: It is useful,
and it increases productivity.

Have we lost not only the ability to be off line, but also
the desire?
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Opposing Forces Guide–Where’s the OFF Button
(Continued)
Today, we are choosing perpetual connectivity
because we want to. It’s voluntary:
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We connect because we want the services, the
information, the instantaneous gratification.
But in the process, what do we lose?
© 2007 Prentice Hall, Inc.
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Security Guide–Encryption
Encryption is the process of transforming clear
text into coded, unintelligible text for secure storage
or communication.
Considerable research has gone into developing
encryption algorithms that are difficult to break.
A key is a number used to encrypt data.


The encryption algorithm applies the key to the original
message to produce the coded message.
Decoding (decrypting) a message is similar; a key is
applied to code the message to recover the original text.
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Security Guide–Encryption (Continued)
In symmetric encryption, the same key is used to
encode and decode.
In asymmetric encryption, different keys are
used;

One key encodes the message, and the other key
decodes the message.
A special version of asymmetric encryption, public
key/private key, is popular on the Internet.

With this method, each site has a public key for encoding
messages and a private key for decoding them.
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Security Guide–Encryption (Continued)
Most secure communication over the Internet uses
a protocol called HTTPS.
With HTTPS, data are encrypted using a protocol
called the Secure Socket Layer/Transport Layer
Security (SSL/TLS).

SSL uses a combination of public key/private key and
symmetric encryption.
The use of SSL/TLS makes it safe to send sensitive
data like credit card numbers and bank balances.

Just be certain that you see https//: in your browser and
not just http://.
© 2007 Prentice Hall, Inc.
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Ethics Guide–Personal Email at Work
You send a personal email to your friend at his job
that contains both text and a picture (6.2 megabytes
in size).
This email during its transmission from you to your
friend at his job, consumes his company’s entire
computing infrastructure.
Finally, if your friend reads his email during his
working hours, he will be consuming company
resources, his time and attention, which the
company has paid while he is at work.
© 2007 Prentice Hall, Inc.
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Reflection Guide–Human Networks Matter More
The Hungarian writer, Frigyes Karinthy, came up
with the idea that everyone on earth is connected
to everyone else by five or six people.

Today, in fact with the Internet, the number may be
closer to three people than five or six.
Suppose you want to meet your university’s
president.

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The president has a secretary who acts as a
gatekeeper.
If you walk up to that secretary and say, “I’d like a half
hour with President Jones,” you’re likely to be palmed
off to some other university administrator.
What else can you do?
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Reflection Guide–Human Networks Matter More
(Continued)
The problem with the six-degree theory, is that
even though those six people do exist, we don’t
know who they are.

Even worse, we often don’t know who the person is with
whom we want to connect.
Most successful professionals consistently build
personal human networks.


They keep building them because they know that
somewhere there is someone whom they need to know
or will need to know.
They meet people at professional and social situations,
collect and pass out cards, and engage in pleasant
conversation (all part of a social protocol) to expand
their networks.
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