Interactive telecommunication between people Analog voice

Transcription

1 History background on Circuit switch and Packet based switch network

2 Telephony Interactive telecommunication between people Analog voice Transmitter/receiver continuously in contact with electronic circuit Electric currentvaries with acoustic pressure Analog/Continuous Signal 2

3 Telephony Milestones 1876: Alexander Bell invented telephone 1878: Public switches installed at New Haven and San Francisco, public switched telephone network is born People can talk without being on the same wire! Without t Switch With Switch 3

4 Telephony Milestones 1878: First telephone directory; White House line 1881: Insulated, balanced twisted pair as local loop 1885: AT&T formed 1892: First automatic commercial telephone switch 1903: 3 million telephones in U.S. 1915: First transcontinental telephone line 1927: First commercial transatlantic commercial service 4

5 Telephony Milestones 1937: Multiplexing introduced for inter city calls One link carries multiple conversations Without Multiplexing With Multiplexing 5

6 Data or Computer Networks Networks designed for computers to computers or devices vs. communication between human beings Digital information vs. analog voice Digital/Discrete it t Signal 6

7 History Story : Early packet switching principles : Internetworking : new protocols, a proliferation of networks 1990, 2000 s: commercialization, the Web, new apps 2009: -7-

8 Early packet switching principles p Background the telephone network uses circuit switching increasing importance of computers and the advent of timeshared computers, "bursty" traffic to access those computers Question An efficient and robust alternative to circuit switching 1961: Kleinrock - queueing theory shows effectiveness of packet-switching 1964: Paul Baran- packetswitching in military nets -8-

9 Major Internet Milestones Basic concept of packet switching was independently developed by Baran (RAND), Kleinrock (MIT) AT&T insisted that packet switching would never work! 1965First timetwocomputers two talked to each other using packets (Roberts, MIT; Marill, SDC) dial-up MIT TX-2 SDC Q32 9

10 Early packet switching principles p 1967: Lawrence Roberts: announces ARPAnet plan, conceived by Advanced Research Projects Agency 1969: first ARPAnet node operational. the early packet switches were known as Interface Message Processors (IMP) ARPA@ : four nodes, UCLA, SRI, UCSB, University it of Utah. The first packetswitched computer network and a direct ancestor of today's public Internet. -10-

11 Major Internet Milestones 1968 BBN group proposed to use Honeywell 516 mini computers for the Interface Message Processors (i.e. packet switches) 1969The first ARPANET message transmitted between UCLA (Kleinrock) and SRI (Engelbart) We sent an L, L, did you get the L? L? Yep! We sent an O, did you get the O? Yep! Crash! We sent a G, did you get the G? 11

12 : Internetworking 1970: The first host-to-host protocol between ARPAnet end systems known as the Network Control Protocol (NCP) was [RFC 001]. 1972: Robert Kahn - ARPAnet public demonstration 1973: Robert Kahn and Vinton Cerf : Transmission Control Protocol (TCP) First , ARPA@1973 ARPA@

13 : Internetworking The architectural principles that Kahn' articulated for creating a socalled "open network architecture" are the foundation on which today's Internet is built minimalism, autonomy: a network should be able to operate on its own, with no internal changes required for it to be internetworked with other networks; best effort service: internetworked networks would provide best effort, end to end endservice. Ifreliable communication wasrequired, this could accomplished by retransmitting lost messages from the sending host; stateless routers: the routers in the internetworked networks would not maintain any per flow state about any ongoing connection decentralized control: there would be no global control over the internetworked networks. -13-

14 : Internetworking The early versions of TCP combined two functions: A reliable in sequence delivery of data via end system retransmission Forwarding functions The separation of IP out of TCP and the development of the UDP protocol Early experimentation with TCP for packetized voice Requirement of an unreliable, non flowcontrolled end end transport service -14-

15 : new protocols, a proliferation of networks 1983: deployment of TCP/IP The new standard dhost protocol for ARPAnet (replacing the NCP protocol) 1982: smtp e mail protocol defined 1983: DNS defined d for name to IP address translation ti 1985: ftp protocol defined 1988: TCP congestion control Important extensions were made to TCP to implement host based congestion control -15-

16 1990, 2000 s: commercialization, the Web, new apps Early 1990 s: ARPAnet decommissioned 1991: NSF lifts restrictions on commercial use of NSFnet (decommissioned, 1995)

17 1990, 2000 s: commercialization, the Web, new apps early 1990s: Web Hypertext, HTML, HTTP 1994: Mosaic, later Netscape late 1990 s: commercialization ation of the Web Late 1990 s 2000 s: more killer apps: instant tmessaging, P2P file sharing network security to forefront est. 50 million host, 100 million+ users backbone links running at Gbps -17-

18 1990, 2000 s: commercialization, the Web, new apps

19 2007, 2009: ~500 million hosts Voice, Video over IP P2P applications: BitTorrent (file sharing) Skype (VoIP), PPLive (video) more applications: YouTube, gaming wireless, mobility -19-

20 Historical Summary on Internet theory university production use commercial broadband prototypes in research early residential home kb/s 1 Mb/s 10 Mb/s 100 Mb/s 1 Gb/s port speeds DNS ATM RIP BGP, OSPF XML UDP Mbone Internet OWL TCP IPsec protocols ftp SIP HTTP SMTP SNMP finger HTML RTP Jabber queuing architecture routing cong. control DQDB, ATM QoS VoD p2p ad-hoc sensor -20-