Chapter 6 Business Networks and Telecommunications

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Chapter 6 Business Networks andTelecommunications

• Ch 6 Oz (5th ed)

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Telecommunications and Networks

• Telecommunications concerns the movement of
  information between two devices over a distance
• Information includes data, audio, or video
• Networks are collections of devices (nodes) that
  can engage in telecommunications

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The Value of Telecommunications in Business

• Telecommunications has improved business
  efficiency and effectiveness to the point that
  business cannot be conducted without
  telecommunications
• Advantages
• Better business communication
• Geographical distance irrelevant
• Faster communication/instant transaction
• Information becomes immediately available
• Better distribution of data
• Flexible and mobile workforce
• Alternative channels

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Dominant Telecommunications Applications

• Cell phones (local and long distance calls, GPS,
  email, digital cameras)
• Video conferencing
• Fax
• Banking (ATMs and online)
• RFID in warehouse and wireless payments (gas
  pump)
• Peer-to-peer file sharing (Napster)
• Web-empowered commerce
• Buying and selling
• Training and education
• Research
• Marketing

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The Current Business Environment for Large Firms

• The network infrastructure for a large
  corporation consists of three separate
  telecommunications systems
• Data (text, numbers, etc.)
• voice,
• video images.
• The environment is moving towards a common
  Internet foundation for all three (converged
  networks)

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Corporate Networks
Voice
Data
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Pieces in the Corporate Network

• Center piece is a collection of linked LANS that
  support a firm wide corporate network
• A series of servers supporting a corporate web
  site linked to enterprise and legacy systems
  (data)
• Support for a mobile sales force) (voice)
• Separate telephone network (cell and landline)
  (voice)
• Separate video conferencing system (not shown)
  (video)
• Currently no one vendor can supply all of the
  services required
• How does a manager navigate through this complex
  environment and make the right decisions?

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Digital and Analog Signals

• Digital signals (1s and 0s) are represented by
  a discrete non-continuous wave form.
• Analog signals are represented by a sine curve .
  The human voice, music, and noise are examples of
  analog signals
• From a physical point of view, signals can be
  converted to an electric (carried over a wire)
  or electromagnetic (radio) signal
• In telecommunications there is a need to convert
  digital signals to analog signals and vice versa.
  
• Computers emit digital signals but parts of the
  telephone system only transmit analog signals, so
  digital signals must be converted into an analog
  signal and vice versa (need for your modem)

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More on Signals

• All signals can be represented as a sine wave
  (curve).
• The amplitude of a sine wave is the maximum
  height of the sine wave from the x-axis
• The frequency of a sine wave is the number of
  times a sine wave makes a complete cycle within a
  given time frame.
• Cycles per second is referred to as Hertz (Hz)
• Digital data can be converted to a digital signal
  by using two different voltages.
• Digital data can be converted to an analog signal
  by using either two different frequencies or two
  different amplitudes.
• The greater the frequency of a signal, the higher
  the possible data transfer rate the higher the
  desired data transfer rate, the greater the need
  signal frequency.
• Broadband (multiple signals) versus baseband (one
  signal)

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Representation of Signals
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Electromagnetic Frequency Spectrum(Radio Waves)
TV 54M - 216 MHz
TV 220M - 500 MHz
AM 550K - 1650 KHz
FM 88M - 108 MHz
Navy/submarines
ELF
VLF
LF
MF
HF
VHF
UHF
Microwave
Optical
Hertz
100
1K
100K
1M1M
10M
100M
1G
10G

• All waves behave similarly
• Frequency differences
• Amount of data
• Distance
• Interference / Noise

Public Safety 150M - 160 MHz
Public Safety 460M - 500 MHz
Cellular phones 800 MHz
Cordless phones (some) 900 MHz
PCS ET 2 GHz
Pers. Com. Sys (PCS) 1.85 G - 2.2 GHz
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Electromagnetic Signals

• The electromagnetic spectrum can be expressed in
  terms of energy, wavelength, or frequency. Each
  way of thinking about the EM spectrum is related
  to the others in a precise mathematical way.

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Transmission Speeds

• Digital signal speeds are usually expressed in
  bits per second (Kbps, Mbps, and Gbps).
• Analog signal speeds are usually expressed in
  frequency per second or Hertz (KHz, MHz, or GHz).
• A simple relationship between bps and frequency
  is found in Nyquists theorem
• C2f(log2)L where f is the frequency, L is the
  number of signal levels (often 2) and C is the
  capacity of the medium in bps
• The range of frequencies accommodated on a
  particular medium is called its bandwidth. For
  example, current cell phones operate in a
  bandwidth between 1.85 GHz and 2.2 GHz

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Measures of Transmission Speeds
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Multiplexing Concept

• A channel is a path followed by a flow of
  information (stream of bits). The information is
  carried by a digital or analog signal.
• Channels and bandwidth cell phone example
• Multiplexing uses a single channel to carry
  simultaneous transmissions from multiple sources.
• Examples
• Frequency division multiplexing divides a high
  speed channel into multiple channels of slower
  speeds (FDMA code division multiple access)
• Time division multiplexing assigns the sender
  transmitter a small slice of time to use the high
  speed channel (TDMA)
• Code division multiplexing assigns each user a
  special code enabling multiple users on a single
  channel (CDMA)

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Transmission Media

• Wire mediums
• twisted pair
• coaxial cable
• fiber optic (each strand carries one signal)
• Next generation optical networks (multiple data
  streams over a single strand)
• Wireless transmissions are based on various types
  of electromagnetic waves (radio frequencies)
• terrestrial microwave
• satellite microwave (GEO)
• low-orbit satellites (LEO)
• Electrical power line (broadband over power lines
  BPL) Duke Energy will be doing this soon

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Media Comparisons
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Transmission Speeds of Typical Mediums
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A Simple Network
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Basic Network Components

• A network consists of two or more connected
  computers.
• A network interface card (NIC) is the connection
  point between one computer and the network
• A network operating system (NOS) routes and
  manages communications on the network and
  coordinates network resources (saving or
  retrieving files on your hard drive versus a
  network drive)

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Basic Network Components (continued)

• Hubs connect network components, sending a packet
  of data to all other connected devices
• A switch has more intelligence than a hub and can
  forward data to a specified device. The switch is
  used within a given network to move information.
• Unlike a switch, a router (or bridge) is a
  special communications processor used to route
  packets of data through different networks,
  ensuring that the message sent gets to the
  correct address. A router connects a LAN to the
  Internet.
• Modems are used to convert digital signals to
  analog signals and vice versa

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Types of Networks

• Geographic scope
• LANs (wired and wireless)
• MANs
• WANs and VANs
• PANs (special type of LAN)
• VPN (virtual private networks)
• Role of server
• Client-server networks
• Peer-to-peer networks

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Local Networks LANs

• Local area network - a network that requires its
  own cabling and encompasses a limited distance
  (one or two buildings) nodes are usually PCs
  and peripherals
• Advantages
• handle high volumes of data
• sharing of hardware, software, files, and data
• unique application (email, video conferencing,
  on-line applications)
• Disadvantages
• expandability
• vendor support or internal expertise

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Wireless LANS

• Benefits
• Easier installation
• Lower initial cost lower operational costs
• Easily expanded (scalability)
• Main drawback is security
• Compared to wired networks wireless networks are
  less secure
• Security measures exist but are not as easy to
  set up as in wired tend to slow down
  transmission

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Large Networks WAN

• Wide area networks nodes
• Corporations can build their own using
  communications service providers
• Switched and dedicated lines
• Individual firm assumes significant role in
  telecommunications management

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Large Networks VANs

• Value-added networks are private data-only
  networks that provide economies in service cost
  and network management because they are used by
  many firms. Many also provide Internet access.
• Value-added means customers do not have to invest
  in network equipment and management
• Disadvantage
• loss of control/expertise
• Security
• Tymnet, SprintNet, and General Electric provide
  VAN services
• An example of a Web based EDI product

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Other Networks

• Metropolitan area network (MAN) links multiple
  LANs within a large city
• Personal area network (PAN) wireless network
  designed for handheld and portable devices
• Used by one or two people
• Transmission speed slower
• Maximum distance 10 meters
• A virtual private network (VPN) enables companies
  to link their LANS to the Internet and protect
  the LAN from unwanted intruders. Used in the
  construction of intranets and extranets

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Client/Server and Peer-to-Peer Networks

• The hardware side
• The client
• The server
• The software side
• Client/server software splits the processing of
  applications between the client and server to
  take advantage of strengths of each machine
• E-mail and browsers are examples
• Client/server computing has largely replaced
  centralized mainframe computing
• Peer-to-peer networks there is no central device
  that controls communication (Napster)

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Switching Techniques

• In packet-switched networks, messages are first
  broken down into small bundles of data called
  packets that are sent along different
  communication paths and reassembled once they
  reach their destinations.
• More efficient use of the networks capacity
• Packets include addressing information and ways
  to check transmission errors along with the data.
  
• Always done on the Internet, but restricted to
  data now being used for voice (VoIP)
• Circuit switching creates a dedicated path
  between points in a network. For the duration of
  the communication no other transmissions may use
  this circuit and all transmissions follow a
  dedicated path.
• The telephone system links together media
  segments to create a single unbroken circuit for
  each telephone call.
• Not very efficient for large volumes of data

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Protocols

• Protocols are rules and procedures (virtually
  languages) that govern the transmissions between
  components (devices) in a single network or
  between two networks
• Important protocols
• TCP/IP (Internet protocols)
• HTTP (Internet protocol)
• Ethernet is the most popular protocol for wired
  LANs
• Important wireless protocols
• Wi-Fi
• Bluetooth
• WiMax

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TCP/IP

• TCP/IP is the communications protocol used by the
  Internet and all Internet devices.
• TCP part
• Handles the movement of data between computers
• Establishes a connection between the computers,
  sequences the transfer of packets, and
  acknowledges the packets sent
• IP part
• Responsible for the delivery of packets
• Includes the disassembling and reassembling of
  packets during transmission
• Defines the numeric addressing scheme 4 bytes in
  length 232 potential addresses

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More on TCP/IP

• Adoption by the world of TCP/IP as a standard
  protocol is a major factor in the success of the
  Internet
• Other terms associated with the Internet and
  TCP/IP
• Host and backbone
• IP number (static and dynamic)
• Domain Name System (DNS)

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Internet Protocol Numbers (IPv4)

• Each device attached to the Internet has an IP
  number (some static/some dynamic)
• Each IP number consists of four parts separated
  by periods. Each part contains a number between
  0 and 255 therefore each part can be represented
  by 8 bits or 32 bits for the entire IP number
  (e.g., 146.186.87.220).
• Approximate number of devices able to be on the
  Internet is 232 or
• 210 210 21022103103103221094 (4 billion)
• The process of associating an IP number with a
  character based name is called domain name
  resolution. The domain name system (DNS) is the
  software that associates character based names
  with the IP number. Internet Service Providers
  (ISPs) usually dedicate a server to perform
  domain name resolution (i.e., a DNS server).
• To determine speed of your connection
  http//www.ip-adress.com/speedtest/
• To determine your IP number http//www.What
  ismyIpaddress.com

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Wireless Network Protocols

• Wireless technologies are of interest to business
  because they eliminate the need for expensive
  cables and enable mobility
• Wireless protocols (or Wi-Fi) apply to mobile
  devices (e.g., laptops or PDA)
• Family of standards IEEE 802.11 (the 11 stands
  for the max bit rate supported, 11 Mpbs)
• Most popular is 802.11g which operates in the
  2.4-2.5 GHz range
• Transmission range is about 300 ft (distance is
  likely to increase)
• To make a device wireless requires the device to
  contain a wireless card

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Access Points and Hot Spots

• In order to communicate with a network using a
  wireless device, you must be close enough to an
  access point (AP). The access point is a device
  that is connected to a wired network.
• If a household has a wired connection to the
  Internet (cable or DSL) then wireless devices can
  access the Internet by acquiring a wireless
  router (an AP) that is connected to your cable or
  DSL modem. This enables all your wireless
  devices to link to the Internet.
• Public access points are often called hotspots.
  Winthrop has several hotspots on campus
• Cell phones with dual circuitry can communicate
  with hot spots

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Wireless Issues

• Plus side
• Mobility and low installation cost
• Can be extended by adding access points
• Newer protocols in the 802.11 family offer
  security protocols (WEP, WPA, and WPA2)
• Down side
• Interference from other devices
• The Wi-Fi standard (802.11g is replacing 802.11b)
  is easily penetrated by outsiders with
  appropriate hardware and software
• Competing standards (protocols) Bluetooth is
  another wireless networking standard for creating
  small private networks (range of 30 meters)

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Wireless Applications

• Use of wireless devices in warehouses
• Airlines are equipping their planes with Wi-Fi
  circuitry so passengers can connect to the
  Internet in flight
• Utility companies have installed meters that can
  send signals to the utility company indicating
  customer usage
• Equipping electronic devices such as cell phones,
  digital cameras, game consoles, digital
  camcorders with Wi-Fi circuitry eliminates need
  for a physical connection.

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WiMAX Protocol

• WiMAX (IEEE 802.16)
• Increases range and speed of Wi-Fi to 8-10 miles
  and 100 Mbps
• Enables an entire city to become a hotspot
• Provide low-cost Internet service to masses
• No need for telephone companies
• A nationwide network could be built for less than
  3 billion

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How Wi-MAX Works
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Mobile Broadband Wireless Access (MBWA or IEEE
802.20)

• This protocol will enable cell phones to use cell
  phone towers to get VoIP and access Internet
  resources
• Similarly a laptop with a special MBWA card will
  be able to act as a cell phone
• A device that employs this protocol will be able
  to do everything you currently do with a
  telephone through the Internet (Web browsing,
  file transfer, e-mail, VoIP video telephony,
  videoconferencing, audio streaming, Web based
  gaming, and file sharing).
• Protocol will be compatible with Wi-fi and
  Bluetooth protocols
• Protocol will have high levels of security
• An example from Sprint (http//www.sprint.com/busi
  ness/products/phones/usbU720_allPcsPhones.html )

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Protocol Summary
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Generations of Mobile Communication (cell phones)

• First generation (1 G)
• Analog signals with circuit switching
• Second generation (2 G)
• Use of multiplexing
• Converted voice to digital signals
• Faster than 1 G
• Third generation (2.5 G)
• Speeds up to 144Kbps
• Limited Internet access
• Packet switching
• Fourth generation (3G)
• Speeds up to 1 Mbps
• Support for video conferencing
• Full Internet access
• Similar to Wi-Fi but more expensive Wi-Fi inside
  3G outside
• Fifth generation (4G)
• Speeds up to 100 Mbps
• Multitasking (listen to music access Internet
  and make calls)

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Internet Networking Services

• Variety of options to choose from when
  subscribing to network services
• Downstream speed of receiving from network
• Upstream speed of transmitting to network

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Internet Networking Services (continued)
Figure 6.6 Wireless networking protocols
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Internet Networking Services Cable and Digital
Subscriber Lines (DSL)

• Cable
• Internet links provided by television cable firms
• At residence, cable split into TV set and
  computer cable modem
• Cable line into a neighborhood is shared by all
  subscribers
• DSL
• Data remains digital through entire transmission
• Uses telephone lines connected to DSL bridge
• Asymmetric versus symmetric DSL
• Transmission rates related to distance from
  telephone company

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Internet Networking Services T1 and T3 Lines and
Satellite

• T1 and T3 lines
• Point-to-point dedicated digital circuits
• T3 lines made of 24 channels of 64 Kbps
• T1 line made of 672 channels of 64 Kbps
• Expensive not for individual consumers
• Satellite (useful in areas that lack DSL or
  cable)
• Service use microwaves
• Service provider installs dish antenna, used as
  communications satellite
• Speeds up to 45 Mbps
• GPS free satellite service
• Uses fixed or mobile antennas

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Internet Networking Services Fixed Wireless and
Optical Carrier

• Fixed wireless
• Point-to-point transmission between two
  stationary devices requires microwave
  transceivers on rooftop
• Wireless Internet service provider (WISP)
• Highly modular and scalable
• Optical Carrier (OC)
• Expensive but high connection speeds
• Uses basic unit of 51.84 Mbps
• Used by ISPs, search engines, and content-rich
  Web sites
• Broadband over Power Lines (BPL)
• Uses electric power lines to carry digital
  signals
• Even if subscriber revenue is low there are
  advantages to utility companies monitor power
  consumption, detect power failure, track power
  outages

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Future of Networking Technologies

• Broadband telephoning
• Radio Frequency Identification
• Convergence of technologies

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Voice over Internet Protocol (VoIP)

• Uses Internet connection to conduct telephone
  conversations
• Can be done with special software or pay firms
  that specialize in the service (Vonnage)
• Possible ways to VoIP (PC to PC, PC-to-telephone,
  or telephone-to-telephone)
• For business users there are significant savings
• For individual consumer
• Often you dont have 911
• No phone when power is out since VoIP requires an
  electric modem
• Future is with advanced cell phones that support
  VoIP big reduction in cell phone costs

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Radio Frequency ID (RFID)

• RFID tags consist of a microprocessor and an
  antenna. Some tags can transmit on their own
  others transmit through activation by a reader
  sending a signal to the chip
• History
• Technology was invented in 1934
• Many different kinds of tags with many different
  capabilities such as range, storage capacity,
  alterability of data
• RFID tag of primary interest are the EPC
  (electronic product code) chips
• Designed to replace UPC codes
• 96-bit storage capacity potential to give
  individual items a unique identifier operate in
  868-965 MHz
• Signals can only be read if within a few feet of
  reader
• Cost of tags is still high 5-10 cents per tag
  limited to large ticket items

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RFID Tags (Continued)

• Major applications of EPC chips (current and
  future)
• Track and locate inventory
• Track items as they move through a firms supply
  chain
• Smart shelves
• Privacy issues (EPC tags)
• Notification of the presence of a tag
• Killing the tag before you leave the store
• Restrictions on the use of tag generated data

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Current Uses of RFID
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Future Uses of RFID
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Convergence of Technologies

• Convergence implies one device or one network
  doing multiple tasks
• Cell phones will double as Internet phones using
  VoIP
• Television sets will be able to function as
  regular TV and connect to the Internet
  concurrently
• PDAs soon will function as a TV and phone
  concurrently
• Portable music players (e.g., IPods) can use
  Wi-Fi to communicate with other Wi-Fi devices
• Local radio stations can use WiMax for digital
  radio you will be able to download songs you
  have listened to and play them back