Mgt 20600: IT Management & Applications Telecommuncations and Networks Tuesday March 28, 2006

Reminders  Reading –For today  Fundamentals text, Chapter Four, Telecommunications chapter –For next class on April 4th  Fundamentals text, Chapter Three, Organizing Data and Information  Homework –Homework Three  Networks and Telecommunications  Due Friday, March 31 st  Will need to use outside resources to answer several questions  Next week: Databases

Networking and Telecommunications  Effective communications are essential to organizational success  Why? –Business processes are supported by software that runs over networks –Must choose right software to support business, then design the right network to support the operation of the software –Processing model will help determine what kind of network you need

Basic Processing Strategies  Centralized processing: all processing occurs in a single location or facility  Decentralized processing: processing devices are placed at various remote locations  Distributed processing: computers are placed at remote locations but connected to each other via a network

Distributed Processing Options  Terminal-to-host: the application and database reside on one host computer, and the user interacts with the application and data using a “dumb” terminal

Distributed Processing Options File or Application Server: the application or database reside on the one host computer, called the file server

Distributed Processing Options Client/Server Client: End-user’s computer PC, mobile device, thin client PC, mobile device, thin client Server: Mid-range computer Dedicated to special function such as database server, print server, web server, application server Dedicated to special function such as database server, print server, web server, application server Client and server share in processing task Example, the World Wide Web

Telecommuncations –Telecommunications: the electronic transmission of signals for communications –Telecommunications medium: anything that carries an electronic signal and interfaces between a sending device and a receiving device

Telecommunications and Networks Elements of a Telecommunications System

Transmission Media Wired Transmission Media Types

Wired Media Types

Wireless Transmission Media Types  Radio Waves –Bluetooth  Short distances only  Relatively slow transmission speed  Developed for inter-device communications –Wi-Fi  Standard supports up to 54Mbps  Supports longer distances than bluetooth  Infrared –Signals sent as light waves –Short distance –Unobstructed line of sight  Microwave –High frequency radio signal –Capable of high-speed transmission –Unobstructed line of sight –Susceptible to interference  Cellular

Networks  Computer network: the communications media, devices, and software needed to connect two or more computer systems or devices  Network nodes: the computers and devices on the networks

Network Types  Personal area network (PAN)  Local area network (LAN)  Metropolitan area network (MAN)  Wide area network (WAN)  International network

Network Types A Typical LAN

Network Types A Wide Area Network Is the internet a wide area network?

Communications Software and Protocols  Communications software: software that provides a number of important functions in a network, such as error checking and data security –Network operating system (NOS) –Network management software –Communications protocol: a standard set of rules that controls a telecommunications connection  Example, TCP/IP protocol that underlies the Internet

The Internet  Internet: a collection of interconnected networks, all freely exchanging information  ARPANET –The ancestor of the Internet –A project started by the U.S. Department of Defense (DoD) in 1969

How the Internet Works  Data is passed in chunks called packets –Internet Protocol (IP): communications standard that enables traffic to be routed from one network to another as needed –Transmission Control Protocol (TCP): widely used transport-layer protocol that is used in combination with IP by most Internet applications

How the Internet Works Routing Messages over the Internet

Accessing the Internet Several Ways to Access the Internet

Internet Service Providers  Internet service provider (ISP): any company that provides individuals or organizations with access to the Internet –Most charge a monthly fee –Many ISPs and online services offer broadband Internet access through digital subscriber lines (DSLs), cable, or satellite transmission

Applications that run over the Internet  World Wide Web  Instant Messaging   File Transfer Protocol  Telnet  All of these are –Software applications –Designed for the internet –All assume your computer understands TCP/IP

The World Wide Web  Hypertext Transfer Protocol (HTTP): Protocol that web servers and browsers use to send requests and information  Hypertext Markup Language (HTML): the standard page description language for Web pages  Uniform Resource Locator (URL): an assigned address on the Internet for each computer

Intranets and Extranets  Intranet –Internal corporate network built using Internet and World Wide Web standards and products –Used by employees to gain access to corporate information –Slashes the need for paper

Intranets and Extranets  Extranet –A network based on Web technologies that links selected resources of a company’s intranet with its customers, suppliers, or other business partners  Virtual private network (VPN): a secure connection between two points across the Internet –Intranets and extranets often run over VPN’s

Internet Issues  Privacy –Spyware: hidden files and information trackers that install themselves secretly when you visit some Internet sites –Cookie: a text file that an Internet company can place on the hard disk of a computer system

Net Issues  Security –Cryptography: converting a message into a secret code and changing the encoded message back to regular text –Digital signature: encryption technique used to verify the identity of a message sender for processing online financial transactions –Firewall: a device that sits between an internal network and the Internet, limiting access into and out of a network based on access policies

Net Issues