Timeline

26 moments that made networks what it is. Each one is a publication, a first or a decision that can be looked up.

1. 1736Leonhard Euler’s solution of the Königsberg bridges problem, the first result of what became graph theory.
2. 1847Gustav Kirchhoff, who had stated his two circuit laws in 1845, solves the general electrical network by counting its junctions, loops and trees.
3. 1878James Joseph Sylvester introduces the word “graph” in this sense.
4. 1909Agner Krarup Erlang publishes “The Theory of Probabilities and Telephone Conversations”, from which the mathematics of telephone traffic and of queues is usually dated.
5. 1927Kermack and McKendrick publish their mathematical model of epidemics.
6. 1934Jacob Moreno’s book “Who Shall Survive?” sets out his sociograms — drawings of who chooses whom in a group — which he had first shown in public in 1933.
7. 1948Claude Shannon publishes “A Mathematical Theory of Communication”.
8. 1956Lester Ford and Delbert Fulkerson publish the maximum-flow theorem for networks.
9. 1959Paul Erdős and Alfréd Rényi, and independently Edgar Gilbert, publish the theory of random graphs. Dijkstra publishes his shortest-path algorithm.
10. 1964Paul Baran’s reports “On Distributed Communications” propose a network with no centre, carrying messages in blocks.
11. 1965Donald Davies proposes the same idea independently and names the blocks “packets”. Derek de Solla Price publishes “Networks of Scientific Papers”.
12. 1967Stanley Milgram publishes “The Small World Problem”.
13. 1969On 29 October the first message passes between two computers on the ARPANET.
14. 1973Mark Granovetter publishes “The Strength of Weak Ties”. Ethernet is invented at Xerox PARC.
15. 1974Vinton Cerf and Robert Kahn publish the design that becomes TCP/IP.
16. 1983On 1 January the ARPANET switches to TCP/IP. The Domain Name System is specified.
17. 1984Saltzer, Reed and Clark publish the journal version of “End-to-End Arguments in System Design”, first presented in 1981.
18. 1989The Border Gateway Protocol, which joins independent networks into one internet, is specified. Tim Berners-Lee proposes what becomes the World Wide Web.
19. 1998Watts and Strogatz publish the small-world model. Page and Brin describe ranking web pages by their links.
20. 1999Barabási and Albert publish the preferential-attachment model of growing networks.
21. 2000Albert, Jeong and Barabási show that networks with hubs tolerate random failure and are vulnerable to targeted attack.
22. 2001Pastor-Satorras and Vespignani publish the vanishing epidemic threshold. BitTorrent is released.
23. 2003A cascading failure that begins in Ohio cuts electrical power to some fifty million people in the north-eastern and mid-western United States and in Ontario.
24. 2008The Bitcoin paper describes a peer-to-peer network that keeps a shared ledger with no operator.
25. 2011The last blocks of the original internet address space are handed out to the regional registries. A study of 721 million Facebook users finds an average of 4.74 steps between any two.
26. 2019Broido and Clauset report that strictly scale-free networks are rare in real data.