1. Internet History What is the Internet? Where did it originate? How did it evolve?

2. Objectives Review some of the basic terminolgy. Look at the historical evolution of the internet. Identify some of the major subnets.

3. Advanced Research Projects Agency (ARPA) of the U.S. Dept. of Defense (DOD) Need: In the Cold War Era of the 50s and 60s DOD needed command and control nets which were decentralized and capable of surviving direct hits on centers yet have surviving nodes remain operational. Initially built to provide a platform which would allow for remote login to fast computers and save expense of additional computers.

4. ARPANET served as the experimental platform for many of the protocols which were tested and for developing the concepts of layered protocols first installed in 1969 Initially it did not employ TCP/IP, but used Network Control Protocol (NCP).

5. Packet Routing approaches Circuit switched Packet Switched –datagram –virtual circuit

6. Circuit Switched requires a circuit setup uses a dedicated connection requires reconnection procedure if connection lost

7. Packet Switched data divided into small packets each packet can traverse a different path employs intermediate routers to determine appropriate path dedicated computers traditionally served as the routers uses –datagram –virtual circuit

8. Datagram each packet individually routed adaptable (failure or load variation) connectionless oriented chose by ARPA & used in IP

9. Virtual Circuit all packets use same route efficient alloc of resources (buffers..) connection oriented implemented over IP by TCP

10. Basic Components link - physical connection host - computer connected to network usually only one connection to the network router - computer providing service of determining where to forward packets –multiple connections to net –called InterfaceMessageProcessor (IMP) or PacketSwitchNode (PSN) node - either a router or a host –each has its own unique addres

11. History 1977First implementation of internet packet satellite packet radio ARPANET Ethernet at XEROX research center Development of TCP/IP 1983ARPANET no longer experimental and passed control to another agency (DCA) DCA split it into ARPANET for continued research and MILNET 2 early transcontinental national backbones

12. History Other agencies joined and name changed from ARPA Internet to Federal Research Internet to TCP/IP Internet to Internet 1984 NSF established office for networking 1986 (56Kbps) 1988 (1.544Mbps) 1990 (45Mbps) also provided seed money for NSF regional nets for education, gov. agencies and commercial business now self supporting

13. Other Networks (not internet) 1981CSNET (Computer Science Network) functionally provided only email used dial-up services 1981BITNET (Because Its Time Network) mostly educational for computer center part of IBM VM/370 os 1989CSNET and BITNET merge under mgmt or CREN (Corporation forResearch & Education Networking) BITNET absorbed CSNET. BITNET being absorbed into Internet. 1978 UUCP mail net. dialup service for mail delivery 1979USENET (Users Network) for providing a news service and IS A SERVICE not a net. Originally on UUCP, now on most nets including Internet 1983FidoNet connects MSDOS machines (like UUCP) Now integrated with Internet. (Internet backbone for BITNET) Still have limited direct function of mail/news, some file xfer.

14. Reasons for growth Implementation of TCP/IP in 4.2BSD in 1983 at Univ of Cal at Berkley (UCB) by its Computer Systems Research (CSRG). Public funding dictated it be made available at cost. Lots of startup companies used it. Inexpensive Microprocessors Inexpensive wide-area fiber optic bandwidth NSFNET regional networks DNS for domain name service

15. Responsibility Decentralized Internationally handled in a variety of ways In U.S., the NSF has the leading role in setting policy. Individual organizations can set their own policies. Many organizations participate in Federal Networking Council (FNC) (govt) NSFNET is largest. About a dozen regionals and thousands of connections to each of those exist.

16. Successor to NSFNET is National Research and Education Network (NREN) created by High Perf Computing Act of 1991 International level of organization is loosely structured. Each country/local area manages its own. Some countries have regional orgs (European Commission).

17. API Applications Progamming Interface Procedure calls to access this functionality –Not a protocol! Examples Berkley sockets (WE WILL USE THIS) TLI (Transport Layer Interface) XTI (X/Open Transport Interface) Winsock (windows 95/98/…) RCP (remote procedure calls) POSIX compliance is an attempt to make calls the same from code for ALL OSs. Standards for Protocol Independent Interface (PII) being developed for POSIX compliance.

18. Specifications Internet Drafts –First circulated for discussion. –Online for only 6 months. –When/if it becomes an RFC it is removed. RFC (Request For Comment) –More formal proposal for a standard. –Multiple and even subsequent RFCs associated with STD STD (Internet Standards) –Set required and optional feature support. –One standard might be optional but if adopted would require other standards be adhered to.

19. Standards Bodies ISOC (Internet Society) –International, Non-profit –Appears to be responsible for electing/selecting –members of following bodies, but not clear IAB (Internet Architecture Board) –Recommending body –Chair elected from members and Chair selects members

20. IETF (Internet Engineering Task Force) –Originates all technical work –Sets up working groups for seeking a goal in one of the areas applications, internet, net mgmt, operational reqs, service appllications, routing, security, stds mgmt, transport, user services IRTF (Internet Research Task Force) –areas where outcomes are uncertain but related to internets future Standards Bodies