Transcript Chapter 1
Internetworking with TCP/IP Fall 2000 Introduction • What is the Internet? – A method of interconnecting physical networks and conventions for allowing the computers on those networks to interact • What is the World Wide Web? • How do all of the computers that have access to Internet communication work together? • What is internetworking? – Connecting different (heterogeneous) physical networks so that they function as a coordinated unit Introduction • How is TCP/IP involved? – Based on ARPA technology which defines: • a set of network standards of how computers communicate • conventions (protocols) for interconnecting networks and routing traffic – connects ~ 170 million individuals in world, as of 2000 – It works at small and large scales – It works with various underlying technologies (OSI) • How have offices and communications changed? Internet Services • Protocols like TCP and IP provide rules for communication – Message formats – Proper response to message arrival – How to handle errors and abnormal conditions • And they hide the low-level details of communication – Why is that good? Internet Services • From a user’s viewpoint, the Internet appears to the user as a set of application programs (accessed by the underlying network technology) • Some of the applications are: – – – – the World Wide Web (~ 80% of Internet traffic?) Electronic Mail File Transfer Remote Login Internet Services • From the application programmer’s viewpoint, an internet provides two types of services: – Connectionless Packet Delivery Service • Small messages are routed from one computer to another based on information carried in the message – Reliable Stream Transport Service • A single stream of much data are sent between two computers as though there was a permanent connection History and Scope of the Internet • ARPA began work mid ‘70’s, to current form in 1977-1979 • Internet Research Group ~ 1979 • Internet Control and Configuration Board til 1983 • In 1980 ARPA converted machines attached to research networks to TCP/IP, ARPANET was backbone • In 1983, the ARPANET was split into two networks, one for military (MILNET) and one for research (kept the name ARPANET) History and Scope of the Internet • Universities were included, Berkeley offered UNIX-like utilities for network services • Berkeley UNIX provided a socket which allowed programmers to use TCP/IP protocols • In late 1970’s NSF funded a project which set up CSNET • In 1986, NSF funded a backbone network, NSFNET which connected to the ARPANET • By 2000, the global Internet reaches ~ 50M computers in 209 countries History and Scope of the Internet • Other companies began connecting to the Internet • Medium and small companies connected in the 1990’s • Rapid expansion caused problems – Originally names and addresses of all computers were kept in a single file which was hand edited and distributed to every site on the Internet – What else? Internet Architecture Board • The IAB provides focus and coordination of research and development underlying TCP\IP protocols – Formed in 1983 as reorganization of ICCB – Generally worked by volunteers – What would likely have changed between 1980 and now? • Reorganized in 1989 into IRTF and IETF • In 1992 a global move generated the Internet Society (ISOC) Requests for Comments (RFCs) • Documentation of protocols, standards and policies are kept on-line and are made available • RFCs are edited by managers of the IETF • The RFC series are numbered sequentially in order they are written • See RFCs 968 and 1180 • Appendix 1 The Future • Evolution of TCP/IP and the Internet continue • The most significant changes seem to come from added traffic - see Figure 1.2 p. 13 (more managers!) • The capacity of the NSFNET backbone was increased 3 times; the current version ANSNET has a capacity 840 times the original • Since 1995, ISPs have built their own backbones • Internet management now spans organizations and countries Summary • What is an internet? • What is the Internet? • What role do TCP and IP play in an internet? The Internet? For Next Time • Read Chapters 1 and 2 • Describe connection-oriented and connectionless networks. What are advantages of each? • Describe the basic Ethernet technology. When are the variations used? • What is the 48-bit address? What are the names it is called? • What are repeaters and bridges? For Next Time • What is FDDI? How does it work? What advantages does it provide? • What is ATM? What advantages does it provide? • Describe ARPANET, NSFNET, ANSNET and vBNS. • What are X.25 networks? What is a point-to-point network? What is dial-up IP? • What is a token ring network? Describe wireless network technology.