1. 1 Technologies for EC/EB Walt Scacchi FEMBA 290 Winter 2003

2. Chapter 2 Internet Infrastructure Copyright (C) 2003, Addison-Wesley

3. Figure 2.1 This chapter introduces the technology foundation for EC/EB.

4. Figure 2.2 Communication requires five elements. Message Information/content Transmitter Source or sender Medium Path or pipe Receiver Sink or destination

5. Figure 2.6 Bandwidth. Amount of data a medium can transmit in a given time. Conventions B – bytes b – bits K – 1,000 M – 1,000,000 G – 1,000,000,000 T -- 1,000G P -- 1,000T

6. Networks Network: two or more computers or devices linked by communication lines. Each computer/device is a node Transmitter and receiver are nodes The network is the medium Communication rules are defined by a protocol

7. Protocols Communication protocol An agreed-upon format or procedure for transmitting data. Implemented in software Key issues Deliver message reliably (TCP) or without delay (e.g., UDP, RTSP) Detect and correct message transmission errors (TCP yes, UDP no)

8. Figure 2.7 An electronic message consists of a header, a body, and a trailer. The header carries delivery information Information about the message The trailer is often optional.

9. Message Delivery Broadcast Every message sent to every node Node picks out messages addressed to it Bus and some star networks Point-to-point (Narrowcast) Message moves node-to-node Topology or routing determines path Peer-to-Peer (e.g, Instant messaging) Direct point-to-point connection

10. Figure 2.17 A message’s packets can follow different paths.

11. Figure 2.11 Internetworking. Process of linking two or more networks. A bridge links similar networks A gateway links dissimilar networks

12. Figure 2.12 A client/server network. Server Controls access (view) to served resources Software (e.g., Apache Web Server) Hardware also called server Client Requests resources from server (on demand) Software (e.g., Mozilla Web Browser) Hardware is PC/workstation

13. The Backbone Network Service Provider (NSP) National wide-area network (e.g., WorldCom) Lease bandwidth to Internet Service Providers (ISPs) Network Access Point (NAP) Place where NSPs meet and exchange data Regional ISP Statewide of regional backbones

14. Figure 2.18 The TCP/IP model.

15. Figure 2.20 The application layer protocols support application programs.

16. Open standards TCP/IP is an example Promotes Platform independence Interoperability Open standards make the Internet a true public medium.

17. Figure 2.28 A domain name consists of two to four words separated by dots. Domain: a set of nodes administered as a unit.

18. Figure 2.31 A domain name and an IP address convey the same information. Physical transmission requires IP address Domain name system converts domain name to equivalent IP address

19. Figure 2.35 The e-commerce infrastructure.