"Networks and Telecommunications"
Introduction to MIS Networks and Telecommunications Prof. Rushen Chahal Page 1 Outline • What is the value of a single computer? • Why are computer networks so important in today’s businesses? • What components do you need to install to create a network? • Why does it matter how your computer is connected to the network? • How is it possible that you can connect your computer to a network at the office, at home, or while on the road, even overseas? • What is the Internet, how is it controlled, and how does it work? • What problems are you likely to encounter if you need to connect to a supplier in a different country? Page 2 Internal Teamwork Networks Communication Scheduling Internet Sharing Services Applications Research Hosting External Suppliers Customers Banks Page 3 Sharing Data: Transactions Internet Database Management System and Web Server Or Point-of-Sale system Page 4 Sharing Data: Decisions & Decisions & collaboration Collaboration and Database Teamwork & joint authorship File Server Team Document Report and Comments Page 5 Sharing Data: E-mail Internet 2. Message 3. Transferred transferred to via the Internet account on to the server. destination account. 4. Message received when user checks e- 1. User creates e-mail message. mail. Page 6 Sharing Data: Calendars 8:00 Mgt meeting 8:30 (open) 9:00 Staff meeting 9:30 Staff meeting 10:00 new meeting Page 7 Hardware Sharing Printers Storage Corporate or Processors external computer access tape drive (backup) Workstations Server Shared Printer Files are transferred from workstations to the server. Software automatically copies files to tapes. LAN administrator can restore files if needed. Page 8 Network Components • Computers – Servers – Work stations • Media Personal Computer – Cables Personal Computer LAN card – Fiber optic LAN card – Radio – Infrared • Connection devices Internet Router LAN card LAN card Switch Shared Printer Firewall Server Page 9 Server Scalability Server farms distribute the workload. Add more computers for more power. Sun 10000 Increasing performance within a product family. Sun 3800 Rack mount server farm. Compaq Sun Ultra 5 Page 10 Network Transmission Media Fiber Optic Cable Example: Long distance phone lines reflective cladding Twisted Pair Example: Local phone lines glass or plastic Radio or Micro Waves Example: Cellular phones antenna Coaxial Example: Cable TV Page 11 Fiber Optics • Faster • More data • Less magnetic interference • Long stretches without repeaters 900 copper wires can be replaced by one fiber optic line (for telephone connections). Page 12 http://www.jsc.mil/images/speccht.jpg Frequency Spectrum ELF VLF LF MF HF VHF UHF Microwave Optical 100 1K 100K 1M 10M 100M 1G 10G Hertz • All waves behave similarly – Sound – Radio – Micro – Light • Frequency differences – Amount of data – Distance – Interference / Noise http://www.ntia.doc.gov/osmhome/allochrt.pdf Page 13 Wireless Technologies Cellphone or WiMax 2-10 miles, 128 kbps - 3 mbps Bluetooth 10-30 feet 1 mbps Ultra-wideband Wi-Fi 10-30 feet 50-200 feet 1 gbps 11 mbps - 500 mbps Page 14 Local Area Networks Name Format Speed (mbps) 10Base-T Twisted pair 10 100Base-T Transmission Capacity Gigabit Ethernet Twisted pair Twisted pair 100 1000 Wireless LAN 11b,a,g Wireless 11-54 Wireless LAN 11n Wireless 100 LAN/fiber FDDI Fiber optic 100 LAN/fiber ATM Fiber optic 155 LAN/fiber high-end Fiber optic 10,000 Internet Connections Name Format Speed (mbps) Estimated Cost Dial-up Twisted pair 0.05 $24/month DSL Twisted pair 1.5 down/0.13 up $50/month Cable modem Coaxial 2.5 down/0.58 up $50/month Satellite Microwave 1.5 down/0.25 up $50/month Wireless/Wi-Max Microwave 1.5 down/0.25 up $40/month T1-lease Twisted pair 1.544 $400-$700/month T3-lease Fiber optic 45 $2,500-$10,000/month ATM Fiber optic 155 $15,000-30,000/month OC-3 Fiber optic 155 $16,000-$20,000/month OC-12 Fiber optic 622 $20,000- $70,000/month OC-48 Fiber optic 2,488 OC-192 Fiber optic 9,953 OC-768/future Fiber optic 39,813 Page 15 The Importance of Bandwidth Text Image Video-10 sec Bytes 10,000 500,000 15,000,000 Bits 80,000 4,000,000 120,000,000 seconds Dial-up 50 kbps 1.6 80 2400 DSL 1.5 mbps 0.05 2.67 80 LAN 10 mbps 0.008 0.4 12 LAN 100 mbps 0.0008 0.04 1.2 Gigabit 1 gbps 0.00008 0.004 0.12 Page 16 • The need for standards Connecting Networks • A changing environment Internet Backbone fiber optic Routers or Switches Switch Hub Hub Radio-based network Page 17 Enterprise Network Building 1 Building 2 Fiber optic Switch Servers Firewall Workstations/PCs Internet – ISP Subsidiary Page 18 Packet-Switched Networks •All data is converted to packets. •Packet has data, destination, and source address. •Switched services. Voice Sent as packets: 1 2 3 4 5 •Packets routed as needed. B •Reassembled at destination. Chicago 2 New York C 4 A E 1 Atlanta Dallas D 3 5 Computer Sent as packets: A B C D E Page 19 Shared Connections With shared connections, machines have to take turns, and congestion can slow down all connections. With switched connections, each computer has the full bandwidth of the connection at all times. Performance depends on how fast the switch can handle connections. Page 20 Switched Network Switch Servers Workstations/PCs Page 21 Shared-Media Network Tap Shared Media Page 22 Time Division A B A C A C A time C D Computers A and B split their messages into packets and share the transmission medium by taking turns sending the data. Page 23 Frequency Division frequency A B A 3500 Hz C C D Computers A and B split the frequency: A uses a higher spectrum. By listening only to the assigned frequency, multiple transmissions can occur at the same time. Page 24 Spread Spectrum frequency A B C D time Sharing a medium by both frequency and time is one method of spread spectrum transmission. It is efficient for many computers because the full bandwidth can be utilized over time and frequency. Page 25 Wireless Communication Microwave transmissions are used to provide communications for cellular phones and laptop computers. As prices of phones, portable computers, and communication costs decrease, increasing numbers of workers are choosing wireless technologies. Page 26 TCP/IP Reference Model 4. Application Message 3. Transport (TCP) Header 3 Message Trailer 3 2. Internet (IP) Header 2 Header 3 Message Trailer 3 Trailer 2 1. Physical Header 1 Header 2 Header 3 Message Trailer 3 Trailer 2 Trailer 1 Page 27 TCP/IP Reference • Application – Mail, Web, FTP – Authentication, compression, user services • Transport – Packetize data and handle lost packets – Establish connections through numbered ports • Internet Protocol (IP) – Route packets to destination – Requires unique host addresses: IPv4=32-bit; 28 Page Introduction to the Internet • No control • Services – Mail – Telnet The Internet – FTP – WWW • WEB searching – AltaVista – HotBot – Lycos – WebCrawler – Yahoo Page 30 How the Internet Works Network OC3: 155.52 Mbps service OC12: 622 Mbps provider (NSP) T1: 1.544 Mbps Backbone T3: 44.736 Mbps network Internet service provider (ISP) Phone Cable Phone company company company Dial-up: 33.3 - 56 Kbps ISDN: 128 Kbps DSL: 256 Kbps - 6 Mbps Company Individual Cable: 1.5 Mbps Web site Page 31 Internet Connections • Backbone providers – AT&T – Level 3 – MCI (UUNet) • Phone companies – Sprint – Regional Bell operating – Qwest companies (RBOCs) (3) • Network service providers – Competitive local exchange carriers (CLECs) (new) – 1998: 39 – AGIS • Cable companies – AT&T – Cablevision – Cable & Wireless – Comcast – IBM – Regional. – MCI/Worldcom • Satellite – Qwest – Direct Satellite – Sprint – Wild Blue/Starband – UUNet • Internet service providers – America Online – Comcast – SBC Page 32 Colocation and Hosting General Data Centers Equinix Companies Multiple high-speed Cybercon Internet connections, Savis power with UPS, air Telecity (Europe) conditioning, and security Specialty Hosting IBM Companies AT&T Individual contracts to EDS perform specific tasks Thousands of small, regional including hosting. providers Page 33 Distributed Content through Akamai Akamai Servers Company Server Internet Content Video By distributing your content to servers at the “edge” of the Internet, customers retrieve data from multiple points, reducing the load on your server and Internet connection. http://www.akamai.com Page 34 Voice Over IP (VoIP) VoIP Provider Telephone Co. Internet Cable modem Voice to IP Page 35 Network Address Translation (NAT) Web Server Translate: 10.1.30.15 10.1.30.15=184.108.40.206 Disallow incoming peer-to-peer Page 36 Domain Name System Internic.org Registration DNS Registration Internet World ISP 220.127.116.11 www.microsoft.com Arin.net Microsoft Corporation One Microsoft Way Net Range Redmond, WA 98052 US 18.104.22.168 – Real World 22.214.171.124 Internet entities Microsoft- are anchored to Global-Net the real world through the DNS registration and through their ISP. If they tell the truth! Page 37 Domain Names Right-to-left Original TLDs Set by ICANN Server.Department.Company.TLD com Optional Required org net edu gov mil accounts.citibank.com.xqioajfm.aka82.com Many more today This address is NOT owned by Citicorp. + When you see it in an e-mail message, Country Codes you know it is a fake. Page 38 M-Commerce Internet access everywhere Cell phones PDAs Laptops Great potential Limited usability Better than voice? Page 39 Cell Phones and Wireless Communication off thework by Wireless cells handing wireless connection to the next tower as the caller moves. Connections to multiple towers at one time enables the system to triangulate to get a fairly precise location of the cellular device--even when it is not in a call. Location knowledge will make it possible (although perhaps not desirable) to offer new business opportunities as people move into range. Page 40 Global Telecommunications • Technical problems – Multiple standards – Language – Developing nations – Time zones – Limits to space & waves • Political complications – Transborder data flows – Taxes – Privacy – Accessibility • Cultural issues – What is an object? – Management & control Page 41 Technology Toolbox: Creating HTML <HTML> Web Pages <HEAD><TITLE>Sample HTML Page</TITLE> <BODY> <H1>Section One</H1> <P>This is a sample paragraph on a sample page.</P> </BODY> </HTML> Tables for Layout Page Editors Images are bitmaps: GIF, JPEG, PNG Adobe PDF Page 42 Quick Quiz: Creating Web Pages Create a document to do the following in HTML: 1. Display a word or phrase in boldface. 2. Link a style sheet to an HTML page. 3. Display a table with three rows and four columns. 4. Display a numbered list of five items. 5. Display an icon in GIF format with a transparent background. Page 43 Technology Toolbox: Connection Transferring Files Strengths Weaknesses FTP Inexpensive and easy to No security. use. FrontPage Very easy to use with Limited availability and users have secure login. to purchase client software. WebDAV Internet standard and Web server security is weaker by can be secure. allowing directory browsing. VPN Very secure. Need to purchase server and client software and requires extra setup steps. Page 44 Quick Quiz: Transferring Files 1. Which methods can you use to transfer files to a university server? 2. Why is FTP considered a security threat? 3. What other objections exist to FrontPage? Page 45 Annual Revenue 7 6 Cases: 5 W.W. Grainger Wholes Billion $ 4 Univar 3 2 Ow ens & Minor ale 1 0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Supplie 0.07 Net Income / Revenue rs 0.06 0.05 0.04 W.W. Grainger 0.03 Univar Ow ens & Minor 0.02 0.01 0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 -0.01 Page 46