Computer Networks 6 829 Fall 2005 September 8 2005 nms csail mit edu 6 829 Muscle Powered Communications Human messengers on foot or horseback Command and Control between capital and the field 14 AD Roman relays 50 miles per day for regular mail 100 miles per day for express mail 1280 AD Kublai Khan 200 250 mi per day Poste Haste Fast Post riders signal by horns Let us turn now to the system of post horses by which the Great Khan sends his dispatches You must know that the city of Khan balik is a centre from which many roads radiate to many provinces one to each and every road bears the name of the province to which it runs When one of the Great Khan s messengers sets out along any of these roads he has only to go twenty five miles and there he finds a posting station which in their language is called yamb and in our language may be rendered as horse post Here the messengers find no less that 400 horses stationed here by the Great Khan s orders and always kept in readiness for his messengers By this means the Great Khan s messengers travel throughout his dominions and have lodgings and horses fully accoutred for every stage The whole organization is so stupendous and so costly that it baffles speech and writing Marco Polo 1290 The Pony Express 1861 AD The Pony Express 150 200 mi day 1966 mi from Missouri to California 10 13 days Longest ride 14 year old Buffalo Bill Cody 384 mi Record time 7 days 17 hours with President Lincoln s Inaugural Address March 4 1861 Western Union s line puts it out of business October 1861 Visual communications The optical telegraph Pics Proc Symp on the Optical Telegraph Chappe 1763 1805 a defense contractor Stockholm 1st message Junesuccessfully sent in 1794 94 1799 Napoleon seizes power sends Paris is quiet and the good citizens are content 1814 Extends from Paris to Belgium Italy 1840 4000 miles 556 stations 8 main lines 11 sublines each hop 10 km Many advanced techniques switching framing codes redundant relays Scientific Advances Late 18th Early 19th Century Increasing evidence of the close relationship between electricity and magnetism Oersted Copenhagen demonstrated electricity s ability to deflect a needle Sturgeon London 1825 electromagnet demo Joseph Henry 1830 1 mile demo current through long wires causing bell to ring Faraday London 1831 EM induction experiments induction ring basis for motors The Electric Telegraph Cooke and Wheatstone Railroad Telegraph 1837 14 mi installed by 1838 4000 mi by 1852 The Electric Telegraph Samuel Morse Morse Code 18351837 1838 demo d over 2 miles 1844 US sponsored demonstration between Baltimore and Washington DC Dots and Dashes Span the Globe 1852 First international telegram Reuters establishes Telegraph News Network 1858 Cyrus Field lays first transatlantic cable US President Queen Victoria exchange telegrams Line fails in a few months 1866 New cable technology developed by William Thompson Lord Kelvin Dots and Dashes Span The Globe Communications arms race in the Imperial Age No nation could trust its messages to a foreign power 1893 British owned Eastern Telegraph Company and the French crisis in Southeast Asia 1914 British cut the German overseas cables within hours of the start of WW I Germany retaliates by cutting England s Baltic cables and the overland lines to the Middle East through Turkey Strategic necessity circumventing the tyranny of the telegraph lines owned by nation states Wireless James Clerk Maxwell 1831 1879 we have strong reason to conclude that light itself including radiant heat and other radiations if any is an electromagnetic disturbance in the form of waves propagated through the electromagnetic field according to electromagnetic laws Dynamical Theory of the Electromagnetic Field 1864 Heinrich Hertz 1857 1894 Mid 1880s Demonstrated experimentally the wave character of electrical transmission in space Wireless Telegraphy Guglielmo Marconi 1895 21 year old demonstrates communication at distances much greater than thought possible Offers invention to Italian government but they refuse 1897 Demonstrates system on Salisbury Plain to British Royal Navy who becomes an early customer 1901 First wireless transmission across the Atlantic 1907 Regular commercial service commenced Wireless in Warfare Portable radio circa 1915 Airborne radio telephone post WW I The Telegraph Learns to Talk Morse telegraph no multiplexing Only one message sent received at a time Second half of 19th century many researchers work on improving capacity One idea sending messages at different pitches Graham Bell The Telephone Alexander Graham Bell 1876 Demonstrates the telephone at US Centenary Exhibition in Philadelphia Bell and Elisha Gray rush patents to USPTO Bell first by a few hours Bell offers to sell patents to Western Union for 100 000 who refuse Bell Telephone Company founded 9 July 1877 1878 Western Union competes using rival system designed by Thomas Edison and Elisha Gray Bell sues and wins Bell s Early Telephones Most Valuable Patent US Patent 174 465 March 7 1876 Mechanical Telephone Switch Almon Brown Strowger 1839 1902 1889 Invents the girl less cuss less telephone system Ma Bell and the telcos Bell s patents expire in 1890s over 6000 independent operators spring up 1910 Bell System controls 50 of local telephone market 1913 AT T U S government reach Kingsbury Agreement AT T becomes regulated monopoly while promising universal telephone service Controls toll services in U S Long distance interconnection withheld as a competitive weapon 1950 Bell System controls 84 of the local telephone access market 1984 Divesture of Ma Bell Judge Greene 1996 Trivesiture of AT T Bell AT T Lucent NCR Much activitity mergers splits acquisitions over past 10 years Computer Comms Packet Switching ARPA 1957 in response to Sputnik Paul Baran Early 1960s New approaches for survivable comms systems hot potato routing and decentralized architecture 1964 paper Donald Davies early 1960s Coins the term packet Len Kleinrock MIT thesis Information flow in large communication nets 1961 J Licklider W Clark MIT On line Man Computer Communication L Roberts MIT first ARPANET plan for time sharing remote computers SOSP 67 paper ARPANET Internetworking ARPANet 1967 Connect computers at key research sites across the US using pt to pt telephone lines Interface Message Processors IMP ARPA contract to BBN Ted Kennedy telegram on BBN getting contract BBN team that implemented the interface message processor ARPANET Topology in 1969 First