Networks, telecommunications and the Internet

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Chapter 5

• Networks, telecommunications and the Internet

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Learning objectives

• After this lecture, you will be able to
• specify which components of a communications
  system are necessary to exchange information
  within and between businesses
• explain the basic components and terminology of
  networks, including the Internet
• identify the benefits available through the
  introduction of computer networks
• identify the advantages and disadvantages of the
  client/server architecture in comparison with
  traditional approaches
• explain the broad implications of the Internet on
  the marketplace.

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Management issues

• From a managerial perspective, this lecture
  addresses the following areas
• What are the business benefits of networks?
• What are the basic concepts and terminology
  associated with the Internet and other networks?
• How does the Internet change marketplace
  structures?
• How are network components selected?

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Computer networks defined

• A computer network can be defined as a
  communications system that links two or more
  computers and peripheral devices and enables
  transfer of data between the components.
• Telecommunications The method by which data and
  information are transmitted between different
  locations.
• Local-area network (LAN) A computer network that
  spans a limited geographic area, typically a
  single office or building.
• Wide-area network (WAN) Networks covering a
  large area which connect businesses in different
  parts of the same city, different parts of a
  country or different countries.

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Figure 5.1 Communications links between
different stakeholders in an industry
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Figure 5.2 Polycom video-conferencing system as
used by PepsiCo Source Computer Weekly (2004a)
and Polycom case study press relese.
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Mini case study

• Gill Haggarty, PepsiCo personal productivity
  delivery manager, said,
• The systems were chosen because they are easy to
  use and reliable and they allow us to hold
  multipoint calls. As we work on cross-site
  projects, video conferencing is invaluable to us.
  It has significantly reduced the need for senior
  executives to travel to North America and within
  Europe. The technology has also been used for
  cross-site training, allowing training to be
  rolled out across eight locations in a week. This
  would have taken four weeks before the roll-out
  as we would have had to visit each site.
• Haggarty explains the cost justification of the
  system as follows
• At the Theale headquarters we calculated that if
  only 25 of the potential travel and executive
  time were reduced payback would be within the
  first 6 months of use.  For the manufacturing
  sites, if travel and accommodation costs only are
  used the payback is 3 years, however if the
  savings in man days are added to this, the
  payback is once again less than 6 months.

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Figure 5.3 Components of a client/server system
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Client/server

• Client/server The client/server architecture
  consists of client computers such as PCs sharing
  resources such as a database stored on more
  powerful server computers.
• Benefits
• Faster execution
• Distributed approach
• Customisation and flexibility

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Client/server disbenefits

• Time lost by staff configuration
• Instability caused by clashes with applications
• Maintenance
• Performance
• Cost generally higher TCO

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Server benefits

• Server A server is a powerful computer used to
  control the management of a network. It may have
  a specific function such as storing user files or
  a database or managing a printer.
• Maintain security Access to information in files
  is restricted according to the user name and
  password issued to users of the network.
• Sharing of peripheral devices connected to the
  network, such as printers and tape drives. These
  are often attached directly to the server.
• Sharing of applications such as word processors,
  which do not then need to be stored on the hard
  drive of the end-users computer. The cost of
  buying applications can be reduced through buying
  a site licence.
• Sharing of information Access to this data is
  maintained by the NOS and it is stored within the
  hard drive of a server as files or as part of a
  database.

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Telecommunications equipment

• Modem (modulatordemodulator) A modem is a
  communications device that allows users to
  ordinary telephone line.
• Analogue Analogue data is continuous in that an
  infinite number of values between two given
  points can be represented. As an example, the
  hands of a clock are able to represent every
  single possible time of the day.
• Digital Digital data can only represent a finite
  number of discrete values. For example, at the
  most basic level, a computer recognises only the
  values 0 (zero) and 1. Any values between 0 and
  1, for example 0.15, cannot be represented.
• Hubs Hubs are used to connect up to 20 PCs to a
  network in a convenient way.
• Bridges and routers These are used to connect
  different LANs and transfer data packets from one
  network to the next.

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Selecting broadband issues

• 1. Broadband availability.
• 2. Additional services.
• 3. Limited usage times.
• 4. Limited download or upload speed.
• 5. Maximum download or upload speed.
• 6. Decide the best option using a trial period.

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Measuring data transfer rates

• Baud A simple means of measuring the performance
  of a modem or other device. Early modems operated
  at speeds of 1200 baud, the equivalent of
  approximately 100 characters per second.
• Data transmission rates are more typically
  expressed in bits per second (bps).
• In general, the higher the baud rate or bps
  value, the faster and more efficient the device.
• Bandwidth Bandwidth indicates the data transfer
  rates that can be achieved using given media. It
  is measured in bits per second (size of the
  pipe).

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Network standards which are relevant

• ISDN (integrated services digital network).
• ADSL (asynchronous digital subscribed line).
• SMDS (switched multimegabit data service).
• ATM (asynchronous transfer mode).
• X.25.
• Ethernet network.
• X.400.
• X.500.

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Examples of data transmission
speeds 2005

• Silver 17.99 per month.
• 256 kbps Up to 5 x faster than a modem dialup
  networking or narrowband
• Gold 24.99 per month.
• 512 kbps Up to 10 x faster
• Platinum 29.99 per month.
• 1 Mbps Up to 20 x faster

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Data transmission types

• Broadband A relatively high-capacity, high-speed
  transmission medium such as cable.
• The standard ADSL broadband speed when it was
  first introduced was 512,000 bps, 512 kbps or
  0.512 Mbps and it requires a specific ADSL modem
• ADSL Asynchronous digital subscriber line
  upload and download speeds are different
• ISDN (integrated services digital network) Data
  transfer rates that are up to five times faster
  than a 56,600 bps modem. An ISDN telephone line
  provides two separate channels allowing
  simultaneous voice and data transmissions
  (superseded).

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Activity 5.1 Transmission of data through
different hardware and network components

• Describe the order in which a message passes from
  one piece of hardware to the next when a home
  user in the UK sends an e-mail via the Internet
  to someone in a large corporation in the USA. You
  should refer to the following terms
• (a) mail server
• (b) client PC
• (c) modem
• (d) hub
• (e) network cable
• (f) network card
• (g) gateway server (telecommunications
  processor)
• (h) router.
• Treat the Internet transmission as a single stage.

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Wireless network standards

• Wi-Fi (wireless fidelity)
• A high-speed wireless local-area network enabling
  wireless access to the Internet for mobile,
  office and home users.
• Bluetooth
• A wireless standard for transmission of data
  between devices over short ranges (less than 10 m)

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Communications media characteristics
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Figure 5.4 Infrastructure components of the
Internet Source Chaffey (2004).
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Figure 5.5 An Internet timeline Source Chaffey
(2004).
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Figure 5.6 B2B and B2C interactions between an
organisation, its suppliers and its
customers Source Chaffey (2004).
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Figure 5.7 Summary of transaction alternatives
between businesses and consumers Source Chaffey
(2004).
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Figure 5.8 Disintermediation of a consumer
distribution channel showing (a) the original
situation, (b) disintermediation omitting the
wholesaler and (c) disintermediation omitting
both wholesaler and retailer Source Chaffey
(2004).
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Figure 5.9 Vauxhall e-commerce site Source
www.vauxhall.co.uk.
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Figure 5.10 The move to re-intermediation (a)
original situation,
(b) disintermediation, (c)
re-intermediation Source Chaffey (2004).
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Figure 5.11 Kelkoo.com, a European price
comparison site Source Kelkoo.com.
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Figure 5.12 The relationship between intranets,
extranets and the Internet
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Figure 5.13 Adoption of intranet and
extranet Source DTI (2003).
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Figure 5.14 An example of the use of firewalls
to increase security within an e-business
infrastructure Source Chaffey (2004).
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Figure 5.15 Information exchange between a web
browser and web server Source Chaffey (2004).
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Figure 5.16 The TCP/IP protocol Source Chaffey
(2004).
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Figure 5.17 Home page index.html for an example
company in a web browser showing HTML source in
text editor Source Chaffey (2004).
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Figure 5.18 Hardware and software infrastructure
for WAP system Source Chaffey (2004).
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Figure 5.19 Different protocol layers of the WAP
standard Source Chaffey (2004).
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Figure 5.20 Mobile access technologies Source
Chaffey (2004).
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Figure 5.21 Components of an interactive digital
TV system Source Chaffey (2004).
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Figure 5.23 Businesses that use EDI () Source
DTI survey, 2003.
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Figure 5.24 A small workgroup network connecting
a single server to three PCs and a laser printer
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Figure 5.25 Skype VOIP provider web site Source
(www.skype.com).