Basic Concepts of Internet Technology What is a computer network? Isolated computers vs. networked computers internetworking The Internet What’s a protocol?
What is a computer network? An interconnected collection of computers Examples of networks: –Telephone networks –Satellite networks –Mobile telephone networks –Cable TV networks –Intranets and extranets –Internet Computer networks vs. other types networks (general, different types of data vs particular application)
Basic Concepts: Isolated Machines Independent Workstations (Local Processing) How to share data?
Basic Concepts: Networked Machines Computer Network Workstations (Local Processing) File Servers Application Servers Client-Server Model
Classifications of Computer Networks Based on size: –System/Storage area networks (SAN) within the same room connecting processors to storage servers. –Local area networks (LAN) in a close proximity –Metropolitan area networks (MAN) span a city –Wide area networks (WAN) connecting computers situated anywhere Connects many networks together
internetwork A collection of networks
The Internet Topology See for more Internet topologies.
What’s the Internet: a service view communication infrastructure: enables distributed applications: –WWW, , games, e- commerce, database., cyberspace
What’s the Internet: “nuts and bolts” view millions of connected computing devices: hosts, end-systems –pc’s workstations, servers –PDA’s communication links –fiber, copper, radio, satellite routers: forward packets (chunks) of data across networks local ISP company network regional ISP router workstation server mobile
What’s the Internet: “nuts and bolts” view protocols: control sending, receiving of msgs –e.g., TCP, IP, HTTP, FTP Internet: “network of networks” –public Internet versus private intranet –collection(s) of SAN, LAN, MAN, WAN local ISP company network regional ISP router workstation server mobile
What’s a protocol? a human protocol and a computer network protocol: Hi Got the time? 2:00 TCP connection req. TCP connection reply. Get time
What’s a protocol? human protocols: “what’s the time?” “I have a question” introductions … specific messages sent … specific actions taken when messages received, or other events network protocols: machines rather than humans all communication activity in Internet governed by network protocols protocols define format, order of messages sent and received among network entities, and actions taken on message transmission, receipt