- Количество слайдов: 50
Telecommunications and Networking
Learning Objectives 1. Understand the concept of a network. 2. Apply Metcalfe’s law in understanding the value of a network. 3. Identify several major developments and trends in the industries, technologies, and business applications of telecommunications and Internet technologies. 4. Examples of the business value of Internet, intranet, and extranet applications.
Learning Objectives 5. Identify the basic components, functions, and types of telecommunications networks used in business. 6. Explain the functions of major components of telecommunications network hardware, software, media, and services. 7. Explain the concept of client/server networking. 8. Understand the two forms of peer-to-peer networking.
Learning Objectives 10. Identify the various transmission media and topologies used in telecommunications networks. 11. Understand the fundamentals of wireless network technologies. 12. Explain the concepts behind TCP/IP. 13. Understand the seven layers of the OSI network model.
Network Concepts § Network – An interconnected chain, group or system § Number of possible connections on a network is N * (N-1)/2 – Where N = number of nodes (points of connections on the network) – Example, if there are 10 computers on a network, there are 10 * 9/2 = 45 possible connections
Telecommunications § Telecommunications – Exchange of information in any form (voice, data, text, images, audio, video) over networks
Basic concepts § Communication protocols (TCP/IP) § Data transmission methods – Asynchronous – Synchronous § Connecting – Modem – Hardwired and remote § Data transmission channels (bps) – – – narrow bands: 5 -30 voice bands: 1, 000 -9, 600 broad bands: 100, 000 § Types of communication lines – – – simplex half-duplex
Networks § Concept – "a group of interconnected computers, workstations, or computer devices (such as printers and data storage systems). ” § Network topology – bus – star – ring § Local-area networks – bus: Ethernet, carrier sense multiple access (CSMA) – ring: token passing method § Distributed data processing – "interconnects sites of one organization not only for communication of data and messages but also for the sharing of resources. "
Open Systems § Information systems that use common standards for hardware, software, applications and networks § Internet networking technologies are a common standard for open systems § Connectivity: – Ability of networked computers to easily access and communicate with each other and share information § Interoperability: – The ability of an open system to enable end user applications to be accomplished using different varieties of computer systems, software packages,
Middleware § Any programming that serves to “glue together” two separate programs
Internet 2 § § § Next generation of the Internet High-performance network In use at 200 universities, scientific institutions, communications corporations
Internet Service Provider § ISP – A company that specializes in providing easy access to the Internet – For a monthly fee, you get software, user name, password and access § ISPs are connect to one another through network access points
An Intranet Also look at fig 6. 8 § A network inside an organization – That uses Internet technologies (such as Web browsers and servers, TCP/IP protocols, HTML, etc. ) – To provide an Internet-like environment within the organization – For information sharing, communications, collaboration and support of business processes – Protected by security measures – Can be accessed by authorized users through the Internet
Extranet (also look at fig 6. 9) § Network links that use Internet technologies – To connect the Intranet of a business – With the Intranets of its customers, suppliers or other business partners
GPS 1. The global positioning system (GPS) is a major technological achievement that has broadreaching implications for business. Using the Internet, – Can find other innovative uses for GPS. – Good places to start familiarizing yourself with current accomplishments are § The GPSWorld site at http: //www. gpsworld. com/gpsworld/ § The GPS Overview at http: //www. colorado. edu/geography/gcraft/notes/gps/ gps_f. html
Telecommunications network § Any arrangement where a sender transmits a message to a receiver over a channel consisting of some type of medium
Types of Networks § § WAN LAN VPN C/S
VPN § Basically, a VPN is a private network that uses a public network (usually the Internet) to connect remote sites or users together. Instead of using a dedicated, real-world connection such as leased line, a VPN uses "virtual" connections routed through the Internet from the company's private network to the remote site or employee. Source: computer. Howstuffworks. com
Internetwork Processors § Switch – makes connections between telecommunications circuits in a network § Router – intelligent communications processor that interconnects networks based on different protocols § Hub – a port switching communications processor § Gateway – connects networks using different communications architectures
ROUTERS Routers are specialized computers that send your messages and those of every other Internet user speeding to their destinations along thousands of pathways. § Fujitsu Geo. Stream R 980 industrial strength router
ROUTERS configuration table. A configuration table is a collection of information, including: § Information on which connections lead to particular groups of addresses § Priorities for connections to be used § Rules for handling both routine and special cases of traffic A router, then, has two separate but related jobs: § The router ensures that information doesn't go where it's not needed. This is crucial for keeping large volumes of data from clogging the connections of "innocent bystanders. " § The router makes sure that information does make it to the intended destination. Computer. howstuffworks. com
Distributed data processing TSS - Time Sharing Systems PC PC PC MAINFRAME CSS - Client Server Systems PC
Client/Server networks § Clients: End user personal computers or networked computers § Interconnected by LANs § Servers: manage networks § Processing shared between clients and servers
CSS architecture Remote Server File Server Communications Server Print Server LAN PC PC
Peer-to-peer networks (p 209) § Networks that connect from one PC to another PC Peer-to-peer networking enables or enhances the following scenarios: § Real-time communications (RTC) § Collaboration § Content distribution § Distributed processing § Improved Internet technologies Source: www. microsoft. com
Wireless Technologies § Terrestrial microwave – Earthbound microwave systems that transmit high-speed radio signals in a line-of-sight path – Between relay systems spaced approximately 30 -miles apart § Communications satellites – Satellite serves as relay stations for communications signals – Uses microwave radio signals
Wireless Technologies § Cellular and PCS telephone and pager systems – Divide the geographic area into small areas or cells – Each cell has transmitter or radio relay antenna to send message from one cell to another § Wireless LANs – Radio signals within an office or building – Connect PCs to networks § Bluetooth
Bluetooth § Bluetooth is a standard developed by a group of electronics manufacturers that allows any sort of electronic equipment -- from computers and cell phones to keyboards and headphones -- to make its own connections, without wires, cables or any direct action from a user. § Bluetooth can connect up to eight devices simultaneously. With all of those devices in the same 10 -meter (32 -foot) radius
§ http: //www 1. us. dell. com/content/topics/glob al. aspx/solutions/en/truemobile? c=us&cs=0 4&l=en&s=bsd
Cell Phones § GSM (CDMA) vs TDMA § Cell vs Mobile
GSM CDMA Digital YES Network Type P-GSM 900 (primary) 900 MHz band CDMA 800 , 800 MHz band (X 1 is available. . but is not being talked about here) Maximum talk range from a tower (pls. note you will need a carkit for your mobile to achieve these numbers in some cases) 35 KM (stock cell) 70 KM ER , EER 105 KM possible with special towers Approx 110 KM Background Noise suppression YES (Included in EFR) YES Talk Time Higher due to DTX and the "pulse" nature of TDMA. Lower due to CDMA transmitting all the time. Standby Times Higher due the "pulse" nature of TDMA High International Roaming YES (over 138 GSM countries world wide) VERY LOW 15? World wide customers 200 Mil 35 Mil SMS YES Fax + Data YES Built in "Intelligence" HIGH MEDIUM
EDI Concepts § EDI is a mechanism for electronic trading § EDI replaces paper flow with online transactions § EDI architecture ----> see next slide § § § EDI is for trading partners Implementation plan is a key factor Obstacles: – lack of transaction standardization – high start-up costs § EDI third-party suppliers – AT&T, Control Data, EDS, GE, Western Union, IBM, Martin Marietta Data Systems, etc.
Network Topologies (p 219) § Topology: structure of a network § Star: ties end user computers to a central computer § Ring: ties local computer processors together in a ring on a relatively equal basis § Bus: local processors share the same communications channel
Network Architectures & Protocols § Protocol: standard set of rules and procedures for the control of communications in a network § Network Architecture: – Master plan of standard protocols, hardware, software and interfaces between end users and computer systems – Goal of promoting an open, simple, flexible, and efficient telecommunications environment
OSI & TCP/IP Models (p 221) § Open Systems Interconnection (OSI) Model – A seven-layer model that serves as a standard model for network architectures – Model for how messages should be transmitted between two points in a network – Each layer adds functions § Transmission Control Protocol / Internet Protocol (TCP/IP) – A five layer telecommunications protocol used by the Internet
IP Internet protocol § Each system connected to the internet is identified by a 32 -bit IP address § Four numbers separated by a decimal Each represented by octal (8 bits; hence 0 -255) § Ex: 168. 212. 226. 204 Binary format: 10101000. 11010100. 11100010. 1100. A new protocol IPv 6 allows for 128 bit IP addresses to look up an IP address : http: //www. kloth. net/services/nslookup. php to find info: http: //www. geobytes. com/Ip. Locator. htm
Basic Communications Model Standards are needed at all Layers User Layer Application Layer Computer (Transport) Layer Transmission Layer
Internet Telephony § Using an Internet connection to pass voice data using IP § Voice over IP (Vo. IP) § Skips standard long-distance phone charges
VOIP (source www. fcc. gov)
Bandwidth § Bandwidth – Frequency range of a telecommunications channel – Determines transmission rate – Classified in bits per second (bps) § Transmission Rates: – Narrow-band – low-speed – Broadband – high-speed
Wi. Fi § WIreless FIdelity (Wi. Fi)-- used generically when referring of any type of 802. 11 "Wi-Fi Certified" (a registered trademark) by the Wi-Fi Alliance are interoperable with each other, even if they are from different manufacturers. A user with a "Wi-Fi Certified" product can use any brand of access point with any other brand of client hardware that also is certified http: //www. webopedia. com/TERM/W/Wi_Fi. html
Additional Readings § § § § § Voice over data networks Networking Hardware Quiz abc of wireless LAN ISDN Tutorial Ethernet tutorial Internet Protocol Thin clients UNIX/NT integration Cell phones
RWC 1: SAIC, Hewlett-Packard, GE, and Others: Wireless, Wireless Everywhere What are some of the business benefits associated with using wireless networks to collect and transmit data? Benefits would include” § Superfast wireless connections to the Web. § Cost is about one-fourth of existing costs for connection to the Web. § Productivity gains such as a 45% gain at UPS.
What are some of the challenges being faced in this use of wireless technologies? What solutions can you offer? § Having everyone online in a meeting can be toxic to productivity. “No laptop” policies for important meetings. § Enormous pressure within companies to provide Wi-Fi in all areas of the company. Which employees have compelling needs for Wi-Fi access § Cost exceeds the benefit to be gained by providing Wi-Fi such as in a manufacturing plant that would require numerous additional access points than usual. § Security of information available via the Wi-Fi system. Delay implementation until security assurances are met.
The use of wireless networking as described in the case is both innovative and useful. What other business uses can you envision for this approach?
RWC 2: Maryland Colorado: Serving Its Citizens Without Using Wires 1. What is the business value of advanced mobile technologies to Maryland’s emergency management services? § Direct agents toward places where their presence is required § Give notice of impending natural disasters with forecasts and instructions on how to proceed. § Improve information gathering on the extent and magnitude of devastation. § Reduce the amount of manual data-entry, leading to improved response times and reduction of errors (i. e. address is automatically captured and pop-up menus limit possible answers).
In what other government services could GPS serve to provide business value? Give some examples. § States’ National Guards, to monitor and direct personnel in case of an emergency. § Emergency Services, to direct ambulances, firefighters, etc. § Department of Treasury / Federal Reserve, to track the location of armored trucks both for regular traffic and in case of a hijacking. § The military in general, given that it has one of the largest manpower and logistics network in the country.
Are there disadvantages or risks associated with the deployment of GPS systems to monitor the location of people? Explain. § Invasions of privacy § Limitation on the freedom of movement § Could allow not only the government but also private individuals to monitor other people’s movements.