Getting Connected

1. Getting Connected CECS 5030 with Cathie Norris, Jennifer Smolka & Gerald Knezek

2. The Internet Today • Worldwide network of networks • Government agencies, educational institutions, hospitals, and commercial organizations

3. The Internet Today • Phenomenal growth - 1 million/month • End of 2001 – 500 million users • Largest connection of networks in the world

4. How the Internet Works • Local connection via modem, leased-line, ISDN, etc. • Router at provider’s point-of-presence

5. How the Internet Works • Small providers buy from big providers • NorthwestNet • NorthwestNexus • Big providers interconnect with each other • MCI • Sprint • AT&T MCI AT&T NWNET NWNEXUS

6. The Internet uses TCP/IP • Share common protocol TCP/IP • Transmission Control Protocol/Internet Protocol • “/” means it operates at two levels TCP IP

7. The Internet uses TCP/IP • Created more than thirty years ago by the Department of Defense Advanced Research Projects Agency (DARPA) • TCP/IP is the still the basis for the Internet

8. The Internet uses TCP/IP • IP Address – unique identifier • IP resides in the Network Layer • TCP resides in the Transport Layer

9. TCP/IP • Network Protocols • Internet Protocol (IP) • Every computer on the Internet has a unique number which is the destination point • Where you are and how I get there • Transmission Control Protocol (TCP) • How is my data getting between you and me

10. TCP/IP • Application Protocols • Terminal Emulation (Telnet) • HyperText Transfer Protocol (HTTP) • File Transfer Protocol (FTP) • Simple Mail Transfer Protocol (SMTP) • Simple Network Management Protocol (SNMP) • Domain Name Service (DNS)

11. TCP/IP in the OSI Model Seven Layer Open System Interconnect Model Application Presentation Session Transport Network Logical Link Physical FTP, Telnet SNMP TFTP NFS TCP UDP ARP IP LLC Ethernet, WAN, Token Ring, FDDI

12. TCP/IP in the OSI Model Application Presentation Session Transport Network Logical Link Physical FTP, Telnet SNMP TFTP NFS TCP UDP ARP IP LLC Ethernet, WAN, Token Ring, FDDI

13. Internet Protocol (IP) • IP is a connectionless service that provides basic datagram delivery services. • IP takes care of addressing, or making sure the routers know what to do with your data when it arrives.

14. Internet Protocol (IP) • Not everything is sent over the Internet is not sent as a BATCH – or complete file • Sent over as packet of smaller pieces • 256 characters or 512 characters (maybe longer)

15. Internet Protocol • Every computer on the Internet has a unique address. • Information sent across IP networks is broken up into bite-sized pieces, called packets. • The information within a packet is usually between 1 and about 1500 characters long.

16. DATA From: 192.112.36.5 To: 128.174.5.6 IP Packet IP Envelopes

17. Internet Protocol • Some addressing information goes at the beginning of your message; this information gives your network enough information to deliver the packet of data. • Internet addresses consist of four numbers each less than 256. • 192.112.36.5 • 128.174.5.6

18. Internet Protocol • IP Addresses • Class A Networks: 128.x.x.x • Class B Networks: 146.79.x.x • Class C Networks: 192.100.10.x • IP addresses are running out - Extensions to the current IP address protocol will be required - IPng

19. Transmission Control Protocol • Reliable • TCP takes the information you want to transmit and breaks it into pieces. • TCP numbers each piece so receipt can be verified and the data can be put back in the proper order. • Acknowledgments

20. DATA Bytes 1 to 500 To: 128.174.5.6 TCP Packet From: 192.112.36.5 To: 128.174.5.6 IP Packet TCP Packet Encapsulation

21. SLIP and PPP • Extensions of IP over voice-grade modem lines: • Serial Internet Protocol (SLIP) • Point-to-Point Protocol (PPP) • Allow internet access from the PC in your home by dialing up over modems to an Internet host.

22. TCP/IP Applications/Services • Terminal Emulation (Telnet) • File Transfer Protocol (FTP) • HyperText Transfer Protocol (HTTP) • Simple Mail Transfer Protocol (SMTP) • Simple Network Management Protocol (SNMP) • Domain Name Service (DNS)

23. Terminal Emulation (Telnet) • Telnet is the login and terminal emulation program for TCP/IP environments • Primary function is to allow users to log into remote host systems • Requires username and password

24. How to Telnet • Open your DOS prompt • Type telnet • Your telnet window opens...

25. Uses for Telnet Today • Use of Telnet has diminished in recent years • Still being used to: • Connect to routers • Remote management of servers • Access to home system while traveling

26. File Transfer Protocol (FTP) • Important for building web pages • Primary mode of moving complete file from one computer to another • FTP is a program for transferring files in TCP/IP environments (ASCII or Binary)

27. File Transfer Protocol (FTP) • Client – when you want information • Server – when you have the information • Typically, a user at a client computer downloads files from a remote server

28. FTP Terms: DOS • GET (MGET): You are downloading a file (or files) from another computer to your desktop • PUT (MPUT): You are uploading a file (or files) from your desktop to another computer

29. File Transfer Protocol (FTP) • Must logon to server • Requires username and password to access normal file system • Anonymous FTP allows access to anyone to a special file system (e.g. ftp.microsoft.com)

30. FTP Terms: DOS • CD: Change Directory • Move up or down the directory structure • MD: Make Directory • New storage space

31. FTP Transparent Often FTP commands are transparent through your browser or through a FTP program like WS FTP.

32. HyperText Transfer Protocol • Primary application protocol that underlies the world wide web • Provides user access to the files that make up the web • Anywhere – anyplace – anytime

33. HyperText Transfer Protocol • Defines HOW they get there, not what they look like • Files can be in many different formats (text, graphics, audio, video, etc.) • Hypertext markup language (HTML) is the standardized language for creating web pages

34. Simple Mail Transfer Protocol • SMTP is the electronic mail transfer protocol used in TCP/IP environments • Provides a store-and-forward mail capability between host computer mail systems on the network • MIME (Multimedia Internet Mail Exchange) has become the standard for document attachments

35. Domain Name Service • DNS is a TCP/IP service that maps network address numbers, for example, 123.456.789, to an easy to remember name, such as: • Internet and TCP/IP applications such as telnet, FTP and SMTP access DNS to locate names you’ve specified and resolves them to a numeric address and inserts it into a message for transport. www.microsoft.com

36. Node Node Central Hub Node Node Domain Name Service • The address information is stored at many locations in a hierarchical structure, not at one central depository • Each site has a domain server that maintains information about the local nodes

37. Client/Server Architectures • Two-tier • “Fat” Client: User Interface + Application • Database Server • Example: File servers, SQL Servers

38. Client/Server Architectures • Three-tier • “Thin” Client: User Interface only • Application Server • Database Server • Examples: Mail servers, Business applications

39. Client/Server Architectures • Application Programming Interfaces • SQL, ODBC • APPC • TP Monitors • RPC • Interface Definition Languages • DCE • CORBA • Microsoft OLE

40. From Networking 101Jim Cabral, Puget Technology Group, Inc. & Tammy Ruth, Children’s Hospital and Medical Center cabralje@pugettech.com truth@chmc.org References www.pugettech.com