1. Chapter Objectives After completing this chapter you will be able to: Describe the history of TCP/IP Describe the history of the Internet Outline the different functions of the Internet organisations (IAB, IETF, IRTF, IANA) Describe Request for Comments (RFCs) Outline the OSI 7-layer model Outline the TCP/IP protocol stack

2. History of TCP/IP 1969: ARPANET went into operation –four packet-switched nodes at three different sites –connected together via 56 kbit/s circuits –using the Network Control Protocol (NCP) –funded by the U.S. Department of Defence 1974: TCP/IP designed by Vinton G. Cerf and Robert E. Kahn 1979: IP version 4 documented

3. History of TCP/IP (Contd) 1979: the Internet Control and Configuration Board (ICCB) formed 1979: BSD Unix with TCP/IP supplied to Universities 1980: ARPA started converting machines to TCP/IP 1983: mandate that all computers connected to ARPANET use TCP/IP 1983 ARPANET split into two separate networks, –ARPANET for further research –MILNET for the military

4. History of the Internet 1985: the ARPANET was heavily used and congested 1986: NSFNET developed to replace ARPANET –universities and research organisations connected to regional networks –regional networks connected to a main backbone –six nationally funded super-computer centres connected to backbone –The original links were 56 kbit/s. 1988: Links upgraded to T1 (1.544 Mbit/s) – The NSFNET T1 backbone connected a total of 13 sites 1991: NSF decided to move the backbone to a private company 1993: New Internet backbone, ANSNET, with T3 (45 Mbit/s) links 1993: Final NSF solicitations

5. Today's Internet Distributed architecture operated by commercial Network Service Providers (NSPs) Connected together at Network Access Points (NAPs) –high-speed switch to which a number of routers can be connected for the purpose of traffic exchange –allows Internet traffic from the customers of one provider to reach the customers of another provider. ISPs provide Internet services to end customers Connection point between a customer and an ISP is called a point of presence (POP) ISP networks exchange information with each other by connecting to NSPs that are connected to NAPs, or by connecting directly to NAPs

6. San Francisco National Center for Atmospheric Research San Diego Supercomputer Center Houston Denver Ameritech NAP Chicago National Center for Supercomputing Applications Cleveland Perryman, MD Sprint NAP MFS NAP Pittsburgh Supercomputing Center Los Angeles Atlanta New York City vBNS Backbone Network Map Boston Washington, DC Seattle R R R R R R R R R R R R R R R R Router ATM Switch NAP R DS-3 OC-3C OC-12C OC-48 R R R

7. Internet Architecture Board (IAB) Organisation The IAB Board IRSGIESG Research groups Working groups IRTFIETF The IAB organisation

8. Active IETF Working Groups Applications Internet Operations and Management Routing Security Transport User services General

9. Internet Research Task Force Active IRTF Research Groups –End-to-End –Information Infrastructure Architecture –Internet Resource Discovery –Network Management –Reliable Multicast –Routing –Secure Multicast –Services Management

10. Internet Assigned Number Authority (IANA) IANA RIPE Reseaux IP Europeen APNIC Asia Pacific Network Information Centre ARIN American Registry for Internet Numbers

11. RFC Standards Track Process Draft Paper RFC Spec Proposed Standard Review by IETF and IESG not to exceed two years IESG recommends promotion to proposed standard. RFC publishes as RFC. Otherwise it is sent back to the IETF work group. Implementation and test for a minimum of 6 months Draft Standard Evaluation of implementation for a minimum of 4 months

12. Important RFCs 12500Internet Official Protocol Standards STD Number RFC Number Name Requirements for IP Version 4 Routers Requirements for Internet hosts Assigned Numbers 3 17002 18124* 1122 1123 www.rfc-editor.org/rfc.html

13. OSI 7- Layer Model PHYSICAL DATA LINK NETWORK TRANSPORT SESSION PRESENTATION APPLICATION Interfaces directly with application programs running on the devices. Provides code conversion and data reformatting. Co-ordinates interaction between end-to-end application processes. Provides end-to-end data integrity and quality of service. Switches and routes information to the appropriate network device. Transfers units of information to the other end of the physical link. Transmits/Receives on the network medium

14. OSI 7- Layer Model and Internetworking Devices Repeater Bridge/Switch Router Data 101100011110101010010 Data T A N S P D 101100011110101010010 Data T A N S P D SYSTEM A SYSTEM B

15. Internet Protocol Suite and OSI Reference Model DATA LINK PHYSICAL NETWORK TRANSPORT SESSION APPLICATION PRESENTATION NETWORK INTERFACE (LAN - ETH, TR, FDDI) (WAN - Serial lines, FR, ATM) INTERNET PROTOCOL (IP) TRANSPORT (TCP or UDP) APPLICATION (FTP, TELNET, SNMP, DNS, SMTP ) ICMP, IGMP ARP, RARP

16. TCP/IP Protocol Stack Based on Data Flow OSPFEGPTCPUDPICMPIGMP IPRARPARP RIPBGP Ethernet, Token Ring, PPP, and so on Telnet, FTP, TFTP,HTTP,SNMP,SMTP, and so on Port Number Protocol Number Type code Application Layer Data Link Layer Internet Layer Transport Layer