Telecommunications & Networks Chapter 6 Gerhard Steinke

1. Telecommunications & NetworksChapter 6Gerhard Steinke Identify trends in telecommunication networks. Identify basic components, functions and types of networks. Examine network management issues.

2. We Live in a Networked World… • Telecommunications: The exchange of information over networks • Why? • Share data - Between computers: Email, file-sharing • Share peripheral devices - Printers, Internet connections Server Mainframe Laptop Communications Services Communications Products WAN Local Manager Work Station Server POS Clients Networked Workgroups BUS 3620

3. Networks • Local (LAN) • Wide Area Networks (WAN) • Internet • Intranet • Peer to Peer Network • among computers • sharing resources (printers, internet connection, speakers, etc.) • Client/Server Network • some computers are servers: Email, Database, File, Print, Application, Web servers BUS 3620

4. Client/Server Networks • One (or more) computers are servers • Larger capacity • More memory • More disk space • Connected to shared peripherals • The rest are clients Can be smaller and/or slower BUS 3620

5. Client/Server Networks • Centralized account management • Users need only one password • High-powered servers handle the “big” tasks • Can have huge arrays of disks and large numbers of peripheral devices • Need a dedicated server machine • Higher-end, expensive • Single-point failure • The server is down… • Somebody has to be the administrator • An extra employee? • Administrator controls all configuration and security issues BUS 3620

6. Network Components(Three pieces: sender, medium, receiver) Server Client Cable / Wireless Network Interface Card (NIC) Network Interface Card (NIC) Network Operating System (NOS) BUS 3620

7. Physical Transmission Media • Twisted Pair - similar to phone wire • Coaxial Cable - like cable TV wire, (thick, thin) • Fiber Optics • glass fiber, using light • greater bandwidth • lower attenuation - greater repeater spacing BUS 3620

8. Wireless Transmission Media • Microwave – line of sight • Satellite – microwave signals • HEO - 22,000 mi. up, LEO - 500 mi. up • Cellular, PCS (personal communication services) – radio signals between cell towers • Wireless LANs – IEEE 802.11b,a,g,n • Speeds to 54 Mbps or more (802.11n) • Bluetooth BUS 3620

9. Wireless Technology Advantages Disadvantages • don’t need cabling • mobile • good for • historical buildings • manufacturing environments • real time inventory • hand held devices • Lower speeds • Various standards 802.11a, 802.11b, 802.11g, 802.11n • higher cost • Security • Encryption • Data Compression • Frequency Hopping BUS 3620

10. Network Hardware • Modems – analog, digital • Network Interface Cards (NIC) • Ethernet, Wireless • Repeaters • Hubs • Switches • Routers BUS 3620

11. Network Software • Manage user accounts • Manage performance • Assigning priorities • Detecting and correcting errors • Network management • Traffic, security, capacity planning,… BUS 3620

12. Network Topology • Star - using hubs/switches • Older Topologies: • Bus, e.g. Ethernet • terminators • maximum length • uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) • Ring, e.g. Token Ring • every workstation sends to next • whoever has token, may send • Star-Bus BUS 3620

13. Network Protocols • Set of rules that allow communication • All computers on a network must speak the same “language” • A common protocol • Protocols determine… • When a computer can send a message • If a message is destined for your computer • If your computer should pass a message along to another computer • OSI Model – 7 layer model • TCP/IP BUS 3620

14. Data Management Asset Management Administration Integrated Control Planning & Scheduling Problem Management Network Management Model • Backup & Restore • Media Control & Storage • Database Management • Transaction Data Collect • Security Administration • User/Group Administration • Network Configuration • System Config. • Software Licensing • Distribution & Control • Employee Profile • Resource Accounting • Charge back Services • Inventory Control • Fault Reporting • Problem Escalation • Resolution Assessment • Help Desk Facilities • Remote Store Mgmt. • Workload Scheduling • Performance Monitoring • Performance Analysis • Capacity Planning BUS 3620

15. Internet Service Provider / VoIP • ISP • A company that specializes in providing access to the Internet • For a monthly fee, you get software, user name, password and access • ISPs are connected to one another • VoIP - Voice over IP • Using an Internet connection to pass voice data (telephone calls) using the internet BUS 3620

16. Some Security Concerns • Networks are easy to tap into - many entry points • lots of wires spread throughout • several organizations sharing the same network • use of automated passwords to logon to different systems • access to a workstation  access to the network BUS 3620

17. Telecommunication Trends • Wireless • Cloud Computing / Storage • GPS • Everything connected? • Always connected? • … Information overload!? BUS 3620

18. Business Values / Ethical Issues • Geographic barriers – non digital part? • Time barriers – personal part? • Cost barriers – eliminate air travel? • Structural barriers – relationships? • Public wireless access points BUS 3620