ITIS 1210 Introduction to Web-Based Information Systems Chapter 2. How Computer Networks Send Data Across the Internet

Logistics  Course Web Site  002/ main.htm 002/ main.htm 002/ main.htm  Clickers  Office Hours  MW 3:30-5pm  Woodward Hall 310-F (will change)  TA: Amar Saric

How Networks Link to the Internet  Networks are composed of devices  Computers  Routers  Repeaters  Connected in some way  Telephone lines  Radio waves  Fiber optic lines

How Networks Link to the Internet  Transmissions aren’t continuous  Divided into packets  Packets routed from origin to destination  Across networks  Five major hardware components needed:  Hubs  Bridges  Gateways  Repeaters  Routers

How Networks Link to the Internet  Hubs  Link computer groups together  Bridges  Link local area networks with each other  Local data stays inside its own network  Gateways  Link different types of networks together

How Networks Link to the Internet  Repeaters  Amplify signals that have to travel long distances  Routers  Ensure packets arrive at correct destination REGARDLESS OF ROUTE TAKEN  Used for data transmitted between different networks

How Networks Link to the Internet  Networks communicate in a number of ways  Dedicated telephone lines (56K bps)  T1 telephone lines (1.544 Mbps)  T3 telephone lines ( Mbps)  Cable modems (1-5 Mbps)  Digital Subscriber Lines (6.1 Mbps 640Kbps )  Integrated Services Digital Network (128 Kbps)