Chapter 6 Business Networks and Telecommunications

1. Chapter 6 Business Networks andTelecommunications Ch 6 Oz (5th ed)

2. 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

3. 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

4. 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

5. 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)

6. Corporate Networks Voice Data

7. 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?

8. Digital and Analog Signals • Digital signals (1’s and 0’s) 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)

9. 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)

10. Figure 6.8 Signal modulation Representation of Signals

11. All waves behave similarly Frequency differences Amount of data Distance Interference / Noise Electromagnetic Frequency Spectrum(Radio Waves) TV: 54M - 216 MHz AM: 550K - 1650 KHz TV: 220M - 500 MHz FM: 88M - 108 MHz Navy/submarines ELF VLF LF MF HF VHF UHF Microwave Optical Hertz 100 1K 100K 1M1M 10M 100M 1G 10G Public Safety: 460M - 500 MHz Public Safety: 150M - 160 MHz Cordless phones (some): 900 MHz Cellular phones: 800 MHz PCS ET: 2 GHz Pers. Com. Sys (PCS): 1.85 G - 2.2 GHz

12. 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.

13. 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 Nyquist’s theorem • C=2*f*(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

14. Measures of Transmission Speeds

15. 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)

16. 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

17. Figure 6.7 Characteristics of channel media Media Comparisons

18. Transmission Speeds of Typical Mediums

19. A Simple Network

20. 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)

21. 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

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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)

29. 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 network’s 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

30. 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

31. 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

32. 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)

33. 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* 210*22~103*103*103*22=109*4 (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

34. 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

35. 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

36. 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)

37. 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.

38. 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

39. How Wi-MAX Works

40. 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/business/products/phones/usbU720_allPcsPhones.html )

41. Protocol Summary

42. 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)

43. 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

44. Internet Networking Services (continued) Figure 6.6: Wireless networking protocols

45. 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

46. 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

47. 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

48. Future of Networking Technologies • Broadband telephoning • Radio Frequency Identification • Convergence of technologies

49. 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 don’t 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

50. 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