Louis Pouzin

Louis Pouzin is the computer scientist who decided that the way to build a network was to accept that the data network itself was basically somewhat unreliable, and then move all the responsibility for reliability into the hosts on the ends (unlike in the ARPANET, where that responsibility was borne by the IMPs). The network that he and his team built, using this approach, CYCLADES, laid the technical groundwork for the Internet.

Advantages

That approach, of having the network provide only unreliable packets (sometimes called datagrams) has several huge advantages:

• The network itself is much simpler, because it does not have to go to any extra work to guarantee that data is not lost. It just does its best (hence another name for the service it provides, 'best effort'), and focuses on its main job - moving data around.

• This approach allows all the intermediate packet switches (routers) in the overall network to carry no state about the connections travelling through them. This has been the single biggest reason why the Internet has been able to grow ('scale', in engineering jargon) to the stupendous size it has.

External links

• Consulting in Paris - Louis learns about the ARPANET