Chapter 6
Content
1) Network neutrality = internet service providers (ISPs) allow customers
equal access to content and applications, regardless the source or nature
of the content.
a) Internet backbone carriers must treat all traffic equally on a 1 st come
1st serve basis.
b) Telecommunications & cable companies are not in favor of net
neutrality. But they want to be able to charge differentiated prices
based on the amount of bandwidth.
2) Computer network = system that connects computer and other devices
(e.g., printer) via communication media so data & info can be transmitted
among them.
3) Bandwidth = transmission capacity of network.
a) Bits per second.
b) Faster better.
4) Broadband = network transmission capacities ranging from approx. 1 mill
bits per sec (megabits/s) to 20 megabits/s with fiber to the home.
a) E.g., Digital subscriber line (DSL)
b) Cable
5) Types of computer networks: (from smallest to largest)
a) Personal area networks (PAN): short range (few meters), used for
communication among devices close to one person. Can be wired or
wireless.
b) Local area networks (LAN)
c) Metropolitan area network (MAN): large network.
d) Wide area network (WAN): cover larger geographic area & can span
entire planet.
e) Internet
6) Local area network:
a) Regardless of size, the 3 objectives: speed, distance, & cost.
i) Organization can accept any of the 3 objectives.
(1) E.g., long distance, fast communication higher cost
(2) E.g., cheap slower speeds.
(3) E.g., fast, cheap distance limitations.
b) Connect 2 or more devices in a ltd. Geographical region, usually within
the same building.
c) Every device in the LAN has a network interface card (NIC) that allows
the device to physically connect to the LAN’s communication medium.
This medium is typically unshielded twisted-pair wire (UTP).
d) Have file server or network server.
i) Contains various software & data for the network.
ii) Houses LAN’s network operating system, which manages the server
& routes & manages communications on the network.
7) Wide area networks:
a) Businesses transmit & receive data beyond the confines of the LAN.
b) Cover large geographic area.
c) Connect multiple LANs.
d) Provided by common carriers such as telephone companies &
international networks of global communications services provider.
e) Combine multiple channels, e.g., fiber optic cable, microwave, &
satellites.
f) E.g., of WAN is internet.
g) Contain router. Router = communication processors that routes
messages from a LAN to the Internet, across several connected LAN,
across a wide area network such as internet.
8) Enterprise networks:
a) Multiple LAN and may have multiple WAN, which interconnected to
form an enterprise network.
b) Backbone networks = high speed central networks to which multiple
smaller networks (such as LANs & smaller Wans) connect.
i) LANs are called embedded LANs because they are connect to the
backbone WAN.
9) Network fundamentals:
a) Network transmits info with 2 basic types of signal: analog & digital.
b) Analog signal = continuous waves that transmit info by altering the
characteristics of the waves.
i) 2 parameters: amplitude & frequency.
(1) Amplitude sound
(2) Frequency pitch
c) Digital signal = discrete pulses that are either on or off, representing a
series of bits (0 and 1).
i) Digital signal to convey info in binary form that can be interpreted
by computers.
d) Modems convert digital to analog signal through the process called
modulation.
i) Demodulation = analog to digital signal.
ii) Modem a.k.a. modulator-demodulator.
iii) Modems are used in pair: sending end & receiving end.
iv) 3 types of modem: dial up, cable, DSL
(1) Cable modems operate over coaxial cable. E.g., TV.
(a) Coaxial cables are made of copper.
(b) Offer broadband access to the Internet or corporate intranet.
(c) Speeds wary. More users, cable speed decreases.
(2) DSL (digital subscriber line) modems operate on the same line
as voice telephone and dial up modems.
(a) Always maintain a connection so internet connection is
immediately available.
e) Communications channel: cable & broadcast
i) Cable:
(1) Twisted-pair wire:
(a) Made of copper.
(b) Wire twisted in pairs. Used in telephone.
(c) Inexpensive to purchase, widely available, easy to work with.
(d) Disadvantage: slow for transmitting data, subject to
interference from other electrical sources, & it can be easily
tapped by unintended receivers for gaining unauthorized
access to data.
(2) Coaxial cable:
(a) Insulated copper wire that is much less susceptible to
electrical interference than is twisted pair wire.
(b) Carry more data. Thus, used to carry high speed data traffic
as well as TV signals.
(c) More expensive, more difficult to work with than twisted pair
wire. Inflexible.
(3) Fiber-optic cable:
(a) Made of glass.
(b) Thousands of very thin filaments of glass fibers that transmit
info via light pulses generated by lasers.
(c) Surrounded by cladding, a coating that prevents the light
from leaking out of the fiber.
(d) Smaller and lighter than traditional cable.
(e) Transmit more data & provide greater security from
interference & tapping.
(4) Fiber optic used as backbone of network whereas twisted pair &
coaxial cable connect the backbone to individual devices on
network.
f) Transmission technologies:
i) Enable users to transmit high volume data quickly and accurately
over any type of network.
ii) Digital subscriber line (DSL) = high speed transmission of digital
data from homes & businesses over existing telephone lines.
(1) Existing lines are analog & transmission is digital, thus must
include modems.
(2) Bandwidth = 128Kbps to 3 Mbps
(3) Available only within 18000 feet of providers’ central office.
iii) Asynchronous transfer mode (ATM) = allow users to access almost
unlimited bandwidth on demand.
(1) Support for data, video & voice transmission on single
communications line.
(2) Disadvantage: requires fiber optic cable & is 21% more
expensive than DSL.
iv) Synchronous Optical network (SONET) = interface std. designed to
carry large volumes of traffic over relatively long distances using
fiber optic lines.
(1) Defines optical line rates, known as optical carrier (OC) signals.
(2) Base rate is 51.84Mbps (OC-1). Higher rates are multiple of base
rate. E.g., OC-3 = 3 times OC-1 = 155.52Mbps.
v) T-carrier system = digital transmission system that defines circuits
that operate at different rates, all of which are multiples of basic
64Kbps used to transport a single voice call.
(1) Circuits include:
(a) T1 (1.544Mbps, 24 channels)
(b) T2 (6.312Mbps, 96 channels)
(c) T3 (44.736Mbps, 672 channels)
(d) T4 (274.176Mbps, 4032 channels)
g) Network protocols:
i) Devise that are connected to the network must access & share
network to transmit & receive data.
(1) These devices are nodes of network.
(a) Work together by adhering to a common set of rules that
enable them to communicate with one another.
(i) Protocol = set of rules & procedures that govern
transmission across a network.
ii) Ethernet = common LAN protocol. Large corporation use 10-gigabit
per second’s transmission speed. However, 100-gigabit is becoming
the std..
iii) Transmission control protocol/internet protocol (TCP/IP) = protocol of
internet.
(1) TCP perform 3 functions:
(a) Manages movement of packets between computers by
establishing a connection between the computers.
(b) Sequences the transfer of packets.
(c) Acknowledges the packets that have been transmitted.
(2) Internet protocol (IP) = responsible for disassembling, delivering,
& reassembling the data during transmission.
(3) Before data transmitted over internet, they are broken down into
small, fixed bundles of data called packets.
(a) Packet switching = transmission tech that breaks up blocks of
data into packets.
(i) Reliable & fault tolerant.
(ii) Organizations use packet switching to achieve reliable
end-to-end message transmission over sometimes
unreliable network that may have transient (short acting)
or persistent (long-acting) faults.
(b) Each packet carries the info that will help it reach its
destination = the sender’s IP address, intended receiver’s IP
address, # of packets in this message, # of this particular
packet within the message.
(c) Each packet travels independently across the network & can
be routed through diff paths in the network.
(i) When packets reach destination, they are reassembled
into the original message.
(4) TCP/IP functions in 4 layers:
(a) Application layer = enable client application programs to
access the other layers, & defines the protocols that
applications use to exchange data.
(i) One of these application protocols is HTTP (hypertext
transfer protocol).
1. Defines how message are formulated & how they are
interpreted by their receivers.
(b) Transport layer = provides the application layer with
communication & packet services.
(i) Include TCP & other protocol.
(c) Internet protocol (IP) = responsible for addressing, routing, &
packaging data packets.
(d) Network interface layer = places packets on, & receives them
from the network medium, which can be any networking
tech.
(5) After data reached receiver, they travel up the layer.
(6) 2 computers using diff hardware & software can communicate
through TCP/IP.
(7) Enable user to send data across sometimes unreliable networks
with the assurance that the data will arrive in uncorrupted form.
h) Types of network processing:
i) Distributed processing = divides processing work among 2 or more
computers.
(1) Enable computers in different locations to communicate with
one another via telecommunication links.
(2) Common type is client/server processing.
(3) Special type is peer-to-peer processing.
ii) Client/server computing = links 2 or more computers in an
arrangement in which some machines, called servers, provide
computing services for user PCs, called clients.
(1) Client requests applications, data, or processing from the server.
(2) Leads to the idea of fat & thin clients.
(a) Fat clients = large storage & processing power & thus can
run local programs, e.g., Microsoft office application, if
network is down.
(b) Thin clients = no local storage & ltd. Processing power. Thus
must depend on network to run application.
(i) Hence, little value when network is not functioning.
iii) Peer-to-peer (P2P) processing = each computer acts as both client
& server.
(1) Each computer can access all files on all other computers.
(2) 3 types:
(a) Accesses unused CPU power among networked computers.
(i) Well known application is SETI@home that is an open
source projects & can be downloaded free.
(b) Real-time, person-to-person collaboration. E.g., Microsoft
SharePoint Workspace that use buddy lists to establish a
connection.
(c) Advanced search & file sharing = characterized by naturallanguage searches of millions of peer systems.
(i) Enables users to discover other users, not just data & web
pages.
(ii) E.g., BitTorrent that is an open source, free, P2P file
sharing application.
10)
Internet and the World Wide Web.
a) Internet (the Net) is a global WAN.
b) Intranet = network that uses IP so that users can take advantage of
familiar applications & work habits.
i) Support discovery (easy & inexpensive browsing & search),
communication, & collaboration inside an organization.
c) Extranet = connects part of intranets of different organizations.
i) Enables business partners to communicate securely over the
internet using virtual private networks.
ii) Offer ltd. accessibility to the intranets of participating companies,
as well as necessary inter-organizational communications.
iii) Widely used in B2B e-commerce & supply chain mgmt.
d) Accessing the internet:
i) Connecting via online service:
(1) Access internet by opening an account with internet service
provider (ISP).
(2) ISP is a company that offers internet connection for a fee.
(3) Telephone providers & cable companies & computer companies
(e.g., Microsoft) sell internet access too. Need modem & std.
communications software.
(4) ISP connects to one another through network access points
(NAPs).
(a) NAPs = exchange points for internet traffic. Determine how
traffic is routed.
(i) Key components of internet backbone.
ii) Connecting via other means:
(1) Terminal known as internet kiosks have been located in public
places for use by ppl who do not have their own computers.
(2) Fiber-to-the-home (FTTH) = connecting fiber optic cable directly
to individual homes.
iii) Addresses on the internet:
(1) Each computer on internet has an assigned address, called IP
address, to distinguish from other computer.
(2) IP address consists of numbers, in 4 parts, separated by dots.
E.g., 145.62.128.91.
(3) Can access internet by typing this number in the address bar of
browser.
(4) 2 IP addressing schemes:
(a) IPv4:
(i) 32 bits, meaning there are 232 possibilities for IP address.
(b) IPv6:
(i) 128 bits, meaning there are 2 128 possibilities for distinct IP
addresses.
(ii) Replace IPv4 to accommodate the rapidly increasing
number of devices that need IP addresses, e.g., smart
phone.
(5) IP address must be unique so computers on internet know where
to find one another.
(a) Internet Corporation for Assigned Names (ICANN) coordinates
these unique addresses throughout world so we have one
global internet.
(6) IP addresses are difficult to remember, thus computers have
name as well.
(a) Companies called registrars will register these names, which
are derived from a system called the domain name system
(DNS).
(b) Domain names consist of multiple parts that are read from
right to left, separated by dots.
(c) Rightmost part of an internet name is top level domain (TLD).
E.g., .com
e) Future of internet:
i) Brownouts = lead computers going offline for several minutes at a
time.
ii) Experts concerned internet users will experience brownouts due to
3 factors:
(1) Increasing number of ppl who work online.
(2) Soaring popularity of websites such as YouTube require large
amounts of bandwidth.
(3) Tremendous demand for high-definition TV delivered over the
internet.
iii) If internet bandwidth is not improved, then internet will be able to
function only at a much reduced speed.
(1) Hence, Internet2 is developed.
(2) Internet2 is designed to be fast, always on, everywhere, natural,
intelligent, easy & trusted.
(a) Not a separate physical network from the internet.
f) WWW:
i) Internet is not equal to WWW.
(1) Internet functions as transport mechanism
(2) WWW is an application that uses those transport functions.
Other applications such as email also run on internet.
ii) WWW (the web or W3) = universally accepted std. for storing,
retrieving, formatting & displaying info via a client/server
architecture.
(1) Handle all types of digital info, including text, hypermedia,
graphics & sound.
(2) Uses graphical user interfaces (GUIs), so easy to navigate.
iii) Organization offer info through the Web must establish a home
page that has a text & graphical screen display that welcomes the
user & lead user to other pages.
(1) Pages of a particular company or individual are collectively
known as website.
(2) Webmaster = person in charge of organization’s website.
iv) To access website, user must specify a uniform resource locater
(URL), which points to the address of a specific resource on the
web.
(1) E.g., URL for Microsoft is http://www.microsoft.com
(a) HTTP = hypertext transport protocol.
(i) Remaining letters in this URL, www.microsoft.com indicate
the domain name that identifies the web server that
stores the website.
v) Users access the Web primarily through software application called
browsers.
(1) Browsers provide a graphical front end that enables users to
point & click their way across the web, a process called surfing.
(2) Web browsers became a means of universal access because
they deliver the same interface on any operating system under
which they run.
11)
Network applications:
a) Discovery:
i) Search engines = computer program that searches for specific info
by key words & then reports the results.
(1) Use index to find pages that match a set of user-specified
keywords.
(a) Indexes are created & uploaded by webcrawlers, which are
computer programs that browse the web and create a copy
of all visited pages.
(i) Search engine index these pages & provide fast searches.
(2) E.g., Google, Yahoo, Bing (Microsoft network, MSN)
ii) Metasearch engine = search several engine at once & integrate the
findings to answer users’ queries.
(1) E.g., surf-wax, metacrawler, mamma, KartOO, Dogpile.
iii) Publication of material in foreign language:
(1) Automatic translation of webpages. E.g., Altavista, Google.
(2) To reach 80% of the world’s internet users, website needs
minimum of 10 languages: English, Chinese, Spanish, Japanese,
German, Korean, French, Italian, Russian, and Portuguese.
(3) Translation services are expensive at 20cents per word.
(4) Portals = web-based, personalized gateway to info & knowledge
that provides relevant info from different IT system & internet
using advanced search & indexing techniques.
(a) 4 types of portal: differentiated by the audiences they serve.
(i) Commercial (public):
1. Most popular portal.
2. Broad & diverse audiences, & offer fairly routine
content, some of it in real time.
(ii) Affinity:
1. Single point of entry to an entire community of
affiliated interests, e.g., hobby group or political party.
2. University usually has it for its alumni.
(iii)Corporate: a.k.a. enterprise portal; info portal; &
enterprise info portal.
1. Personalized, single point of access through a web
browser o critical business info located inside &
outside an organization.
2. To find needed info easier, it also offers customers &
employees self-service opportunities.
(iv)
Industry wide:
1. Serve entire industry.
2. E.g., TruckNet: portal for trucking industry.
(b) Other type of portal is mobile portal: distinguished by its
tech.
(i) Accessible from mobile devices.
(ii) Any of the 4 portals above can be accessed by mobile
devices.
(iii)Typically wireless.
b) Communication:
i) E-mail: largest volume application running over the internet.
ii) Web-based call centers: a.k.a. customer care centers.
(1) For effective personalized customer contact.
(2) May be located in foreign country. Companies are moving back
call center back to U.S. because such offshoring is important
issue in U.S. companies due to:
(a) Less control over call center operations.
(i) Must depend on vendor companies & ensure it can uphold
their std., e.g., quality of service.
(ii) Language difficulties can occur.
(iii)Companies that manage sensitive info can run the risk of
breaching customer confidentiality.
(iv)
Vendor companies’ call center representatives
typically work with many companies, thus may not deliver
same lvl of customer services that is require.
iii) Electronic chat rooms:
(1) Electronic chat = arrangement whereby participants exchange
conversational messages in real time.
(2) Chat room = virtual meeting place where many ppl come to
“gab”.
(3) Chat programs allow user to send messages to ppl who are
connected to the same channel of communication at the same
time.
(a) Anyone can this conversation.
(4) 2 types of chat programs:
(a) Web-based chat programs = allow user to send messages to
internet users by visiting a web chat site. E.g., yahoo
messenger.
(b) Internet Relay Chat (IRC) = email based (text only) program.
(i) Business use IRC to interact with customers, provide
online experts’ answers to questions, & so on.
iv) Voice communication:
(1) Internet telephony: a.k.a. Voice over internet Protocol (VoIP)
(a) Phone calls are treated as another kind of data as analog
voice signals are digitized.
(b) Reduced monthly phone bills.
(c) E.g., Skype.
v) Unified communication:
(1) Simplifies & integrate all forms of communications on a common
hardware & software platform.
(2) Unifies all forms of human & computer communications into a
common user experience.
(a) E.g., individual who receive voice mail message can read it in
his email inbox.
c) Collaboration:
i) Efforts by 2 or more entities – that is individuals, teams, groups, or
organizations – who work together to accomplish certain tasks.
ii) Work group = 2 or more individuals who act together to perform
some task.
iii) Workflow = movement of info as it flows through the sequence of
steps that make up an organization’s work procedures.
(1) Makes possible to pass documents, info & tasks from one
participant to another in a way that is governed by the
organization’s rules or procedures.
(2) Tools for automating business processes.
iv) Virtual group = conduct virtual meetings because members are in
diff locations.
v) Virtual collaboration = use of digital tech that enable organizations
or individuals to collaboratively plan, design, develop, manage &
research products, services & innovative applications.
vi) Employees collaborate virtually with one another. Organizations
collaborate virtually with customers, suppliers & other business
partners to improve productivity & competitiveness.
vii) Crowdsourcing = outsourcing a task to an undefined, generally
large group of ppl in the form of an open call.
viii) Synchronous collaboration = all team members meet at the
same time.
(1) Asynchronous = team members cannot meet at the time. Typical
collaboration.
ix) Collaboration software products:
(1) Microsoft SharePoint = provide shared content with version
control.
(2) Google Docs. = free, web-based word processor. Enables user to
create & edit document online while collaborating with other
users. Allow multiple users to open, share, & edit document at
the same time.
(3) IBM Lotus Quickr. = provides shared content with version control
in the form of document directories with check in & out features
based on user privileges.
(4) Jive: newest product is clearspace, which use forum, wiki, & blog
to allow ppl to share content with version mgmt. via discussion
room, calendar & to do list.
(5) Electronic teleconferencing:
(a) Teleconferencing = enable 2 or more ppl at diff locations to
hold
a
simultaneous
conference
using
electronic
communication tech.
(i) Disadvantage = cannot communicate face to face. Cannot
see graphs, charts, & pictures at other locations.
(ii) Video conference overcome disadvantage.
1. Participants in one location can see others & their
documents at other location.
2. Telepresence enables participants to seamlessly share
data, voice, pictures, graphs, & animation by electronic
means.
d) E-learning & distance learning:
i) E-learning = to learning supported by the web. Part of distance
learning.
(1) Benefits:
(a) Online material can deliver up-to-date content that is of high
quality & consistent.
(b) Flexibility to learn at any places, at any time, at own pace.
(c) Reduces training cost as well as expense of renting facility
space.
(2) Disadvantages:
(a) Student must be computer literate.
(b) Miss face-to face interaction with instructor.
(c) Assessing student’s work can be problematic because
instructor do not know who completed the assignment.
ii) Distance learning = any learning situation in which teachers &
students do not meet face-to-face.
e) Virtual universities:
i) Online uni in which student takes classes from home or at an offsite location, via the internet.
f) Telecommuting:
i) Knowledge workers = distributed workforce or digital nomads.
ii) Telecommuting = group of high prized workers work anywhere &
anytime.
iii) Distributed workers = no permanent office at their companies,
prefer to work at home offices.
iv) Advantage:
(1) Employees
(a) Reduced stress & improved family life.
(b) Offer employment opportunities for housebound ppl, e.g.,
single parent & person with disabilities.
(2) Employers:
(a) Improved productivity, ability to retain skilled employees, &
attract employees who live far.
v) Disadvantage:
(1) Employee:
(a) Increased feelings of isolation, possible loss of fringe
benefits, lower pay, no workspace visibility, potential for
slower promotions, & lack of socialization.
(b) Difficulty training their families to understand that they are at
work although they are physically at home.
(2) Employers: difficulties in supervising work & potential data
security problems.
equal access to content and applications, regardless the source or nature
of the content.
a) Internet backbone carriers must treat all traffic equally on a 1 st come
1st serve basis.
b) Telecommunications & cable companies are not in favor of net
neutrality. But they want to be able to charge differentiated prices
based on the amount of bandwidth.
2) Computer network = system that connects computer and other devices
(e.g., printer) via communication media so data & info can be transmitted
among them.
3) Bandwidth = transmission capacity of network.
a) Bits per second.
b) Faster better.
4) Broadband = network transmission capacities ranging from approx. 1 mill
bits per sec (megabits/s) to 20 megabits/s with fiber to the home.
a) E.g., Digital subscriber line (DSL)
b) Cable
5) Types of computer networks: (from smallest to largest)
a) Personal area networks (PAN): short range (few meters), used for
communication among devices close to one person. Can be wired or
wireless.
b) Local area networks (LAN)
c) Metropolitan area network (MAN): large network.
d) Wide area network (WAN): cover larger geographic area & can span
entire planet.
e) Internet
6) Local area network:
a) Regardless of size, the 3 objectives: speed, distance, & cost.
i) Organization can accept any of the 3 objectives.
(1) E.g., long distance, fast communication higher cost
(2) E.g., cheap slower speeds.
(3) E.g., fast, cheap distance limitations.
b) Connect 2 or more devices in a ltd. Geographical region, usually within
the same building.
c) Every device in the LAN has a network interface card (NIC) that allows
the device to physically connect to the LAN’s communication medium.
This medium is typically unshielded twisted-pair wire (UTP).
d) Have file server or network server.
i) Contains various software & data for the network.
ii) Houses LAN’s network operating system, which manages the server
& routes & manages communications on the network.
7) Wide area networks:
a) Businesses transmit & receive data beyond the confines of the LAN.
b) Cover large geographic area.
c) Connect multiple LANs.
d) Provided by common carriers such as telephone companies &
international networks of global communications services provider.
e) Combine multiple channels, e.g., fiber optic cable, microwave, &
satellites.
f) E.g., of WAN is internet.
g) Contain router. Router = communication processors that routes
messages from a LAN to the Internet, across several connected LAN,
across a wide area network such as internet.
8) Enterprise networks:
a) Multiple LAN and may have multiple WAN, which interconnected to
form an enterprise network.
b) Backbone networks = high speed central networks to which multiple
smaller networks (such as LANs & smaller Wans) connect.
i) LANs are called embedded LANs because they are connect to the
backbone WAN.
9) Network fundamentals:
a) Network transmits info with 2 basic types of signal: analog & digital.
b) Analog signal = continuous waves that transmit info by altering the
characteristics of the waves.
i) 2 parameters: amplitude & frequency.
(1) Amplitude sound
(2) Frequency pitch
c) Digital signal = discrete pulses that are either on or off, representing a
series of bits (0 and 1).
i) Digital signal to convey info in binary form that can be interpreted
by computers.
d) Modems convert digital to analog signal through the process called
modulation.
i) Demodulation = analog to digital signal.
ii) Modem a.k.a. modulator-demodulator.
iii) Modems are used in pair: sending end & receiving end.
iv) 3 types of modem: dial up, cable, DSL
(1) Cable modems operate over coaxial cable. E.g., TV.
(a) Coaxial cables are made of copper.
(b) Offer broadband access to the Internet or corporate intranet.
(c) Speeds wary. More users, cable speed decreases.
(2) DSL (digital subscriber line) modems operate on the same line
as voice telephone and dial up modems.
(a) Always maintain a connection so internet connection is
immediately available.
e) Communications channel: cable & broadcast
i) Cable:
(1) Twisted-pair wire:
(a) Made of copper.
(b) Wire twisted in pairs. Used in telephone.
(c) Inexpensive to purchase, widely available, easy to work with.
(d) Disadvantage: slow for transmitting data, subject to
interference from other electrical sources, & it can be easily
tapped by unintended receivers for gaining unauthorized
access to data.
(2) Coaxial cable:
(a) Insulated copper wire that is much less susceptible to
electrical interference than is twisted pair wire.
(b) Carry more data. Thus, used to carry high speed data traffic
as well as TV signals.
(c) More expensive, more difficult to work with than twisted pair
wire. Inflexible.
(3) Fiber-optic cable:
(a) Made of glass.
(b) Thousands of very thin filaments of glass fibers that transmit
info via light pulses generated by lasers.
(c) Surrounded by cladding, a coating that prevents the light
from leaking out of the fiber.
(d) Smaller and lighter than traditional cable.
(e) Transmit more data & provide greater security from
interference & tapping.
(4) Fiber optic used as backbone of network whereas twisted pair &
coaxial cable connect the backbone to individual devices on
network.
f) Transmission technologies:
i) Enable users to transmit high volume data quickly and accurately
over any type of network.
ii) Digital subscriber line (DSL) = high speed transmission of digital
data from homes & businesses over existing telephone lines.
(1) Existing lines are analog & transmission is digital, thus must
include modems.
(2) Bandwidth = 128Kbps to 3 Mbps
(3) Available only within 18000 feet of providers’ central office.
iii) Asynchronous transfer mode (ATM) = allow users to access almost
unlimited bandwidth on demand.
(1) Support for data, video & voice transmission on single
communications line.
(2) Disadvantage: requires fiber optic cable & is 21% more
expensive than DSL.
iv) Synchronous Optical network (SONET) = interface std. designed to
carry large volumes of traffic over relatively long distances using
fiber optic lines.
(1) Defines optical line rates, known as optical carrier (OC) signals.
(2) Base rate is 51.84Mbps (OC-1). Higher rates are multiple of base
rate. E.g., OC-3 = 3 times OC-1 = 155.52Mbps.
v) T-carrier system = digital transmission system that defines circuits
that operate at different rates, all of which are multiples of basic
64Kbps used to transport a single voice call.
(1) Circuits include:
(a) T1 (1.544Mbps, 24 channels)
(b) T2 (6.312Mbps, 96 channels)
(c) T3 (44.736Mbps, 672 channels)
(d) T4 (274.176Mbps, 4032 channels)
g) Network protocols:
i) Devise that are connected to the network must access & share
network to transmit & receive data.
(1) These devices are nodes of network.
(a) Work together by adhering to a common set of rules that
enable them to communicate with one another.
(i) Protocol = set of rules & procedures that govern
transmission across a network.
ii) Ethernet = common LAN protocol. Large corporation use 10-gigabit
per second’s transmission speed. However, 100-gigabit is becoming
the std..
iii) Transmission control protocol/internet protocol (TCP/IP) = protocol of
internet.
(1) TCP perform 3 functions:
(a) Manages movement of packets between computers by
establishing a connection between the computers.
(b) Sequences the transfer of packets.
(c) Acknowledges the packets that have been transmitted.
(2) Internet protocol (IP) = responsible for disassembling, delivering,
& reassembling the data during transmission.
(3) Before data transmitted over internet, they are broken down into
small, fixed bundles of data called packets.
(a) Packet switching = transmission tech that breaks up blocks of
data into packets.
(i) Reliable & fault tolerant.
(ii) Organizations use packet switching to achieve reliable
end-to-end message transmission over sometimes
unreliable network that may have transient (short acting)
or persistent (long-acting) faults.
(b) Each packet carries the info that will help it reach its
destination = the sender’s IP address, intended receiver’s IP
address, # of packets in this message, # of this particular
packet within the message.
(c) Each packet travels independently across the network & can
be routed through diff paths in the network.
(i) When packets reach destination, they are reassembled
into the original message.
(4) TCP/IP functions in 4 layers:
(a) Application layer = enable client application programs to
access the other layers, & defines the protocols that
applications use to exchange data.
(i) One of these application protocols is HTTP (hypertext
transfer protocol).
1. Defines how message are formulated & how they are
interpreted by their receivers.
(b) Transport layer = provides the application layer with
communication & packet services.
(i) Include TCP & other protocol.
(c) Internet protocol (IP) = responsible for addressing, routing, &
packaging data packets.
(d) Network interface layer = places packets on, & receives them
from the network medium, which can be any networking
tech.
(5) After data reached receiver, they travel up the layer.
(6) 2 computers using diff hardware & software can communicate
through TCP/IP.
(7) Enable user to send data across sometimes unreliable networks
with the assurance that the data will arrive in uncorrupted form.
h) Types of network processing:
i) Distributed processing = divides processing work among 2 or more
computers.
(1) Enable computers in different locations to communicate with
one another via telecommunication links.
(2) Common type is client/server processing.
(3) Special type is peer-to-peer processing.
ii) Client/server computing = links 2 or more computers in an
arrangement in which some machines, called servers, provide
computing services for user PCs, called clients.
(1) Client requests applications, data, or processing from the server.
(2) Leads to the idea of fat & thin clients.
(a) Fat clients = large storage & processing power & thus can
run local programs, e.g., Microsoft office application, if
network is down.
(b) Thin clients = no local storage & ltd. Processing power. Thus
must depend on network to run application.
(i) Hence, little value when network is not functioning.
iii) Peer-to-peer (P2P) processing = each computer acts as both client
& server.
(1) Each computer can access all files on all other computers.
(2) 3 types:
(a) Accesses unused CPU power among networked computers.
(i) Well known application is SETI@home that is an open
source projects & can be downloaded free.
(b) Real-time, person-to-person collaboration. E.g., Microsoft
SharePoint Workspace that use buddy lists to establish a
connection.
(c) Advanced search & file sharing = characterized by naturallanguage searches of millions of peer systems.
(i) Enables users to discover other users, not just data & web
pages.
(ii) E.g., BitTorrent that is an open source, free, P2P file
sharing application.
10)
Internet and the World Wide Web.
a) Internet (the Net) is a global WAN.
b) Intranet = network that uses IP so that users can take advantage of
familiar applications & work habits.
i) Support discovery (easy & inexpensive browsing & search),
communication, & collaboration inside an organization.
c) Extranet = connects part of intranets of different organizations.
i) Enables business partners to communicate securely over the
internet using virtual private networks.
ii) Offer ltd. accessibility to the intranets of participating companies,
as well as necessary inter-organizational communications.
iii) Widely used in B2B e-commerce & supply chain mgmt.
d) Accessing the internet:
i) Connecting via online service:
(1) Access internet by opening an account with internet service
provider (ISP).
(2) ISP is a company that offers internet connection for a fee.
(3) Telephone providers & cable companies & computer companies
(e.g., Microsoft) sell internet access too. Need modem & std.
communications software.
(4) ISP connects to one another through network access points
(NAPs).
(a) NAPs = exchange points for internet traffic. Determine how
traffic is routed.
(i) Key components of internet backbone.
ii) Connecting via other means:
(1) Terminal known as internet kiosks have been located in public
places for use by ppl who do not have their own computers.
(2) Fiber-to-the-home (FTTH) = connecting fiber optic cable directly
to individual homes.
iii) Addresses on the internet:
(1) Each computer on internet has an assigned address, called IP
address, to distinguish from other computer.
(2) IP address consists of numbers, in 4 parts, separated by dots.
E.g., 145.62.128.91.
(3) Can access internet by typing this number in the address bar of
browser.
(4) 2 IP addressing schemes:
(a) IPv4:
(i) 32 bits, meaning there are 232 possibilities for IP address.
(b) IPv6:
(i) 128 bits, meaning there are 2 128 possibilities for distinct IP
addresses.
(ii) Replace IPv4 to accommodate the rapidly increasing
number of devices that need IP addresses, e.g., smart
phone.
(5) IP address must be unique so computers on internet know where
to find one another.
(a) Internet Corporation for Assigned Names (ICANN) coordinates
these unique addresses throughout world so we have one
global internet.
(6) IP addresses are difficult to remember, thus computers have
name as well.
(a) Companies called registrars will register these names, which
are derived from a system called the domain name system
(DNS).
(b) Domain names consist of multiple parts that are read from
right to left, separated by dots.
(c) Rightmost part of an internet name is top level domain (TLD).
E.g., .com
e) Future of internet:
i) Brownouts = lead computers going offline for several minutes at a
time.
ii) Experts concerned internet users will experience brownouts due to
3 factors:
(1) Increasing number of ppl who work online.
(2) Soaring popularity of websites such as YouTube require large
amounts of bandwidth.
(3) Tremendous demand for high-definition TV delivered over the
internet.
iii) If internet bandwidth is not improved, then internet will be able to
function only at a much reduced speed.
(1) Hence, Internet2 is developed.
(2) Internet2 is designed to be fast, always on, everywhere, natural,
intelligent, easy & trusted.
(a) Not a separate physical network from the internet.
f) WWW:
i) Internet is not equal to WWW.
(1) Internet functions as transport mechanism
(2) WWW is an application that uses those transport functions.
Other applications such as email also run on internet.
ii) WWW (the web or W3) = universally accepted std. for storing,
retrieving, formatting & displaying info via a client/server
architecture.
(1) Handle all types of digital info, including text, hypermedia,
graphics & sound.
(2) Uses graphical user interfaces (GUIs), so easy to navigate.
iii) Organization offer info through the Web must establish a home
page that has a text & graphical screen display that welcomes the
user & lead user to other pages.
(1) Pages of a particular company or individual are collectively
known as website.
(2) Webmaster = person in charge of organization’s website.
iv) To access website, user must specify a uniform resource locater
(URL), which points to the address of a specific resource on the
web.
(1) E.g., URL for Microsoft is http://www.microsoft.com
(a) HTTP = hypertext transport protocol.
(i) Remaining letters in this URL, www.microsoft.com indicate
the domain name that identifies the web server that
stores the website.
v) Users access the Web primarily through software application called
browsers.
(1) Browsers provide a graphical front end that enables users to
point & click their way across the web, a process called surfing.
(2) Web browsers became a means of universal access because
they deliver the same interface on any operating system under
which they run.
11)
Network applications:
a) Discovery:
i) Search engines = computer program that searches for specific info
by key words & then reports the results.
(1) Use index to find pages that match a set of user-specified
keywords.
(a) Indexes are created & uploaded by webcrawlers, which are
computer programs that browse the web and create a copy
of all visited pages.
(i) Search engine index these pages & provide fast searches.
(2) E.g., Google, Yahoo, Bing (Microsoft network, MSN)
ii) Metasearch engine = search several engine at once & integrate the
findings to answer users’ queries.
(1) E.g., surf-wax, metacrawler, mamma, KartOO, Dogpile.
iii) Publication of material in foreign language:
(1) Automatic translation of webpages. E.g., Altavista, Google.
(2) To reach 80% of the world’s internet users, website needs
minimum of 10 languages: English, Chinese, Spanish, Japanese,
German, Korean, French, Italian, Russian, and Portuguese.
(3) Translation services are expensive at 20cents per word.
(4) Portals = web-based, personalized gateway to info & knowledge
that provides relevant info from different IT system & internet
using advanced search & indexing techniques.
(a) 4 types of portal: differentiated by the audiences they serve.
(i) Commercial (public):
1. Most popular portal.
2. Broad & diverse audiences, & offer fairly routine
content, some of it in real time.
(ii) Affinity:
1. Single point of entry to an entire community of
affiliated interests, e.g., hobby group or political party.
2. University usually has it for its alumni.
(iii)Corporate: a.k.a. enterprise portal; info portal; &
enterprise info portal.
1. Personalized, single point of access through a web
browser o critical business info located inside &
outside an organization.
2. To find needed info easier, it also offers customers &
employees self-service opportunities.
(iv)
Industry wide:
1. Serve entire industry.
2. E.g., TruckNet: portal for trucking industry.
(b) Other type of portal is mobile portal: distinguished by its
tech.
(i) Accessible from mobile devices.
(ii) Any of the 4 portals above can be accessed by mobile
devices.
(iii)Typically wireless.
b) Communication:
i) E-mail: largest volume application running over the internet.
ii) Web-based call centers: a.k.a. customer care centers.
(1) For effective personalized customer contact.
(2) May be located in foreign country. Companies are moving back
call center back to U.S. because such offshoring is important
issue in U.S. companies due to:
(a) Less control over call center operations.
(i) Must depend on vendor companies & ensure it can uphold
their std., e.g., quality of service.
(ii) Language difficulties can occur.
(iii)Companies that manage sensitive info can run the risk of
breaching customer confidentiality.
(iv)
Vendor companies’ call center representatives
typically work with many companies, thus may not deliver
same lvl of customer services that is require.
iii) Electronic chat rooms:
(1) Electronic chat = arrangement whereby participants exchange
conversational messages in real time.
(2) Chat room = virtual meeting place where many ppl come to
“gab”.
(3) Chat programs allow user to send messages to ppl who are
connected to the same channel of communication at the same
time.
(a) Anyone can this conversation.
(4) 2 types of chat programs:
(a) Web-based chat programs = allow user to send messages to
internet users by visiting a web chat site. E.g., yahoo
messenger.
(b) Internet Relay Chat (IRC) = email based (text only) program.
(i) Business use IRC to interact with customers, provide
online experts’ answers to questions, & so on.
iv) Voice communication:
(1) Internet telephony: a.k.a. Voice over internet Protocol (VoIP)
(a) Phone calls are treated as another kind of data as analog
voice signals are digitized.
(b) Reduced monthly phone bills.
(c) E.g., Skype.
v) Unified communication:
(1) Simplifies & integrate all forms of communications on a common
hardware & software platform.
(2) Unifies all forms of human & computer communications into a
common user experience.
(a) E.g., individual who receive voice mail message can read it in
his email inbox.
c) Collaboration:
i) Efforts by 2 or more entities – that is individuals, teams, groups, or
organizations – who work together to accomplish certain tasks.
ii) Work group = 2 or more individuals who act together to perform
some task.
iii) Workflow = movement of info as it flows through the sequence of
steps that make up an organization’s work procedures.
(1) Makes possible to pass documents, info & tasks from one
participant to another in a way that is governed by the
organization’s rules or procedures.
(2) Tools for automating business processes.
iv) Virtual group = conduct virtual meetings because members are in
diff locations.
v) Virtual collaboration = use of digital tech that enable organizations
or individuals to collaboratively plan, design, develop, manage &
research products, services & innovative applications.
vi) Employees collaborate virtually with one another. Organizations
collaborate virtually with customers, suppliers & other business
partners to improve productivity & competitiveness.
vii) Crowdsourcing = outsourcing a task to an undefined, generally
large group of ppl in the form of an open call.
viii) Synchronous collaboration = all team members meet at the
same time.
(1) Asynchronous = team members cannot meet at the time. Typical
collaboration.
ix) Collaboration software products:
(1) Microsoft SharePoint = provide shared content with version
control.
(2) Google Docs. = free, web-based word processor. Enables user to
create & edit document online while collaborating with other
users. Allow multiple users to open, share, & edit document at
the same time.
(3) IBM Lotus Quickr. = provides shared content with version control
in the form of document directories with check in & out features
based on user privileges.
(4) Jive: newest product is clearspace, which use forum, wiki, & blog
to allow ppl to share content with version mgmt. via discussion
room, calendar & to do list.
(5) Electronic teleconferencing:
(a) Teleconferencing = enable 2 or more ppl at diff locations to
hold
a
simultaneous
conference
using
electronic
communication tech.
(i) Disadvantage = cannot communicate face to face. Cannot
see graphs, charts, & pictures at other locations.
(ii) Video conference overcome disadvantage.
1. Participants in one location can see others & their
documents at other location.
2. Telepresence enables participants to seamlessly share
data, voice, pictures, graphs, & animation by electronic
means.
d) E-learning & distance learning:
i) E-learning = to learning supported by the web. Part of distance
learning.
(1) Benefits:
(a) Online material can deliver up-to-date content that is of high
quality & consistent.
(b) Flexibility to learn at any places, at any time, at own pace.
(c) Reduces training cost as well as expense of renting facility
space.
(2) Disadvantages:
(a) Student must be computer literate.
(b) Miss face-to face interaction with instructor.
(c) Assessing student’s work can be problematic because
instructor do not know who completed the assignment.
ii) Distance learning = any learning situation in which teachers &
students do not meet face-to-face.
e) Virtual universities:
i) Online uni in which student takes classes from home or at an offsite location, via the internet.
f) Telecommuting:
i) Knowledge workers = distributed workforce or digital nomads.
ii) Telecommuting = group of high prized workers work anywhere &
anytime.
iii) Distributed workers = no permanent office at their companies,
prefer to work at home offices.
iv) Advantage:
(1) Employees
(a) Reduced stress & improved family life.
(b) Offer employment opportunities for housebound ppl, e.g.,
single parent & person with disabilities.
(2) Employers:
(a) Improved productivity, ability to retain skilled employees, &
attract employees who live far.
v) Disadvantage:
(1) Employee:
(a) Increased feelings of isolation, possible loss of fringe
benefits, lower pay, no workspace visibility, potential for
slower promotions, & lack of socialization.
(b) Difficulty training their families to understand that they are at
work although they are physically at home.
(2) Employers: difficulties in supervising work & potential data
security problems.
