01Overview
In 1961 Kleinrock analysed packet switching with queueing theory; in 1964 Baran proposed a distributed network for communication under nuclear war. The telephone network set up a dedicated circuit per call; packet switching cuts data into packets, each choosing its own path over shared links.
In 1969 ARPANET connected four machines at UCLA, SRI, UCSB and Utah. The design goal was not efficiency but survivability: with no centre, no single failure can take the network down. That choice later decided the topology and the governance of the Internet.
02History
- 1961
Kleinrock's packet-switching paper
Queueing theory applied to packet networks.
- 1964
Baran's distributed network
Networks designed for survivability.
- 1969
ARPANET's first four nodes
The ancestor of the Internet.
- 1971
Electronic mail
The first killer application.
03Core concepts
Packet
A message cut into bounded chunks, each transmitted independently.
Store and forward
A node receives the whole packet, then picks the next hop.
Distributed routing
No central control; each node keeps its own forwarding table.
04Hands-on
Do it once — it beats reading it ten times
Simulate a 6-node network where one node fails mid-transfer; show the packets rerouting
05Self-check
Say it in your own words first, then open the answer. Whatever you cannot explain is what to review next.
Can you explain "Packet"?
A message cut into bounded chunks, each transmitted independently.
Can you explain "Store and forward"?
A node receives the whole packet, then picks the next hop.
Can you explain "Distributed routing"?
No central control; each node keeps its own forwarding table.
What problem did it solve, and why was there nothing better at the time?
Go back to the history section: how was this done before, and what did it cost?
If you had to build it today, how would you break it down?
Use the hands-on task above: write a plan of at most three steps before you start.
06Key people
Leonard Kleinrock
1934 –
One of the founders of packet-switching theory.
Paul Baran
1926 – 2011
Proposed the distributed communication network.
07Further reading
- Computer Networks
- A Brief History of the Internet