Introduction

1. Introduction Chapter 1

2. Part A:The Networking Revolution An overview of trends and the importance of networking to your career

3. The Networking Revolution • The Traditional Career Ladder • Programmer • Systems Analyst • IS (information systems) Management • Chief Information Officer (CIO)

4. The Networking Revolution • Many Factors, including Networking, are Changing this Career Ladder • Networking specialties • User support specialties (combine PC support and networking support groups of) • Programmers create groups of programs that interact by exchanging messages across networks, not just stand-alone programs on single machines.

5. Changes in IT • Transforming the Corporation • Intranets: using Internet technology and applications internally • Many good, standardized applications • Inexpensive, standardized transmission technology • Add security • Extranets: Using Internet technology to reach business partners and customers • Enterprise networks connect any two computers in the organization, even if they are at different sites

6. Changes in IT • Networking • High demand for networking skills • Knowledge beyond wires and bits • TCP/IP standards • Higher-layer standards (applications, etc.) • Systems management (server and client PC management)

7. IS versus CS and EE • Hiring Organizations • CS & EE graduates are trained to work in hardware, software, and networking vendor firms, such as Microsoft, IBM, Oracle, and Cisco Systems. • IS graduates are trained to work in end user organizations, which use IT to enhance business value, such as banks, government agencies, and manufacturing firms--organizations that use IT to get their work done.

8. IS versus CS and EE • Make versus Buy • CS and EE Professionals • Make products for sale • IS Professionals • Buy these products instead of making things • Must select products appropriately • Must integrate these products together

9. Comparing Products • Dimensions for Comparing Products in Purchase Selection • Performance • Whatever is appropriate for specific user needs • In some cases, speed • In other cases, reliability or something else • Feasibility for the firm • Products based on new standards may be too much work to implement • Cost (can never be ignored)

10. Comparing Products • Costs • Total purchase cost for all hardware and software • Typically, “base price” are only a fraction of total cost • Labor costs to plan, install • Often greatly outweigh product purchase costs • Life cycle costs from initial purchase to final abandonment • Often greatly outweigh initial costs

11. Comparing Products • Emphasis: Cost is Always Important • User demands are surging • Budgets are not growing rapidly • You must buy the least expensive technology that will meet user requirements • No comparison of alternatives is complete without a cost analysis

12. User Needs • Drive everything else • Must communicate with users to understand their needs • Must support important user needs without bankrupting the firm

13. Standards • Standards are rules of operation that are followed by most or all vendors. • Standards allow products from different vendors to work together (interoperate) • You are not limited to buying from one firm. • Competition will drive down costs and increase options • You do not have to worry if a single vendor falls behind or fails

14. Part B:Accessing the World Wide Web from Home Many students access the World Wide Web from home. Here is how it works, in terms of standards.

15. Accessing the WWW from Home • A Common and Important Situation • Must be understood • Good way of introducing concepts

16. The Internet • Network • A collection of computers that are interconnected so that any computer can send messages to any other computer simply by giving the receiver’s network address at the start of the message. • Key Ideas • Any-to-any. Fully interconnected • Interact through the exchange of messages • Network delivers messages based on their destination addresses, like the address on a postal envelope

17. The Internet • A Worldwide Group of Networks • Not a single network

18. The Internet • Messages are Broken into Small Packets for Transmission • More efficient than sending long messages Message Packets

19. The Internet • Routers • Connect the Internet’s networks • Cooperate to give an end to end route for each packet Routers Route

20. The Internet • Hosts • Any computer attached to the Internet is a host • Webservers are host • Desktop and notebook PCs are hosts too Host Host

21. The Internet • Host internet addresses • Four number segments separated by dots • For example, 128.171.17.13 • Official addresses for hosts • Also called IP addresses 127.47.17.47 127.18.47.145

22. The Internet • Internet Addresses • Really strings of 32 bits (1s and 0s) • 10000000101010100001000100001101 • For convenience, divide them into four bytes (also called octets) • 10000000 10101010 00010001 00001101 • Both octets and bytes are collections of eight bits

23. The Internet • Internet Addresses • Convert each octet into a decimal number • 10000000 is 128 • 10101011 is 171 • 00010001 is 17 • 00001101 is 13

24. Computing Internet Addresses Position (N) Value (2N) Bit Decimal Binary10100011 = Decimal163 7 128 1 128 6 64 0 0 5 32 1 32 4 16 0 0 3 8 0 0 2 4 0 0 1 2 1 2 Note: Starts with 0 0 1 1 1 163

25. The Internet • Host Names • Easy to remember • www.microsoft.com • voyager.cba.hawaii.edu • Two or more text “labels” separated by dots • No relationship between segments and labels • Like nicknames • Not official names • If have host name, browser can look up internet address of host CNN.COM

26. The Internet • Internet Service Providers (ISPs) • You must have an account with an ISP • Connects you to the Internet • Provides other services (e-mail account, etc.) • Carrier • Connects you to the ISP • You pay for this separately from your ISP charges ISP Carrier Line

27. The Internet • The Internet is Not Free • You pay your ISP around $20 per month • Part of this pays for ISP expenses • Part of this pays the Internet backbone to carry your messages • You Also Pay the Carrier Separately for the Carrier Line ISP Carrier Line

28. The Internet • Internet Backbone • Consists of competing carriers called network service providers (NSPs) • NSPs are all interconnected for any-any communication among hosts Internet Backbone ISP ISP NSPs

29. The Internet • ISPs and NSPs • Began in the United States • Is being copied and adapted by other countries • However, not universal

30. Internet Standards • Framework for standards setting is called TCP/IP • Originally under DARPA (Defense Advanced Research Projects Agency) • Now under an independent body, the IETF (Internet Engineering Task Force)

31. Internet Standards • TCP/IP Standards are Layered • Application • Transport • Internet • Subnet Application Transport Internet Subnet

32. Internet Standards • Application Layer Standards • allow two application programs to work together, even if they come from different vendors • For example, browser on user PC and webserver application program on webserver Webserver Application Program Browser

33. Internet Standards • HTTP (HyperText Transfer Protocol) • World Wide Web standard for browser-webserver application program exchanges Webserver Application Program Browser HTTP

34. Internet Standards • Protocol • A standard to govern communication between peer processes at the same layer on different systems • Browser and webserver programs are at the same layer (application) • Browser and webserver programs are on different machines (user PC and webserver) • So HTTP is a protocol.

35. Internet Standards • Transport Layer Protocols • allow any two computers to exchange messages even if they come from different vendors and even if they are of different platform types • For instance, PC and non-PC webserver PC or Other Computer PC

36. Internet Standards • The Transport Layer Gives Platform Independence • Two computers do not have to be of the same platform type • A PC user does not even know what kind of computer the webserver is ? PC

37. Internet Standards • HTTP Requires the Use of the TCP Transport Standard • Transmission Control Protocol • The TCP in TCP/IP TCP

38. Internet Standards • Internet Layer Protocols • allow packets to be routed across multiple routers from a source host to a destination host, even if the routers come from different vendors Route

39. Internet Standards • The Internet Protocol (IP) is the Main Protocol for Routing Packets Across the Internet. • The IP in “TCP/IP” IP

40. Internet Standards • Subnets • Single networks (LANs, WANs, point-to-point link) • A packet will pass through several subnets along its route across the Internet Subnet Subnet Subnet

41. Internet Standards • Different Subnets Can Have Different Subnet Protocols • IP at the internet layer routes across different protocols at the subnet layer Point-to-Point Subnet Protocol 3 LAN Subnet Protocol 1 WAN Subnet Protocol 2

42. Internet Standards • The IETF Does Not Create Subnet Standards • Uses standards from another architecture, OSI • Reference Model of Open Systems Interconnection Application Transport Internet Subnet: Use OSI Standards

43. Internet Standards • OSI Divides Subnet Standards into Two Layers • Data Link • Physical Application Transport Internet Subnet OSI Standards Data Link Physical

44. Internet Standards • Link • Transmission connection in which there is only one possible path between any two stations • Simplest is a point-to-point link Point- to- Point

45. Internet Standards • Link • Other possibilities for a single possible route between any two stations Ring Multidrop Daisy Chain Hierarchy Star

46. Internet Standards • Data Link Layer Standards • organize transmissions into collections of bits called frames and manage the transmission of these frames within a single network (subnet) Frame 10010001001 Data Link

47. Internet Standards • Data Link Layer Standards • For accessing the Internet from home ... • Point-to-Point Protocol (PPP) dominates • Only used between home and ISP! • Low performance. Other subnets connecting routers are likely to use different subnet protocols! PPP ISP

48. Internet Standards • Physical Layer Standards • standardize connector plugs, transmission media, electrical signaling, and other physical matters you can see and touch, even if they come from different vendors • Work bit by bit. No frame organization.

49. Internet Standards • Physical Layer Standards in Internet Access from Home • Telephone jack (RJ11) • Telephone wire • Serial port connection to external modem • Modem Serial Port Telephone Wire External Modem Wall Jack

50. Internet Standards • Subnet Versus Internet Layer Standards • Internet layer provides routing across multiple subnets • Subnet layer standards (data link and physical) provide for transmission within a single network Internet Layer Subnet Layer