My 8/02/09 Missoulian column
As I finished last week’s column on packet switching, a “teachable moment” took place (well, more of a “writable moment”), and it serves to illuminate another aspect of the Internet that remains the same from the early days.
Last week, I wrote that packet switching was invented early on by ARPANET in order to make networking over wide areas possible. Packet switching works well in conjunction with the millions of computers and routers and cables that make up the Internet. The interconnected “Web” of the Internet forms an immense network that gets data “packets” – the bits of your e-mails, Web pages, etc. – to their correct destination.
One of the strengths of packet switching is that if a cable is cut or a computer goes down, those data packets will sidestep the damage or accident and keep flowing toward their destination. Traffic may move slower – Web pages will load slower, e-mail will take longer – because more data is trying to fit on a smaller number of routes, but traffic will (in most cases) keep moving.
But the capability to work around network problems is also a very important part of the network itself – the wires, routers, fiber-optic cables and even satellites – and not just the data packets and packet protocols.
During the summer, we’re used to road construction. If a road is closed or traffic is slow, traffic can follow on other roads to get to the same destination, albeit slower. That’s the same with Internet traffic; it can route around problems.
And so last week I was in Choteau, about three hours northeast of Missoula, and one morning I could see the speed of the local Internet service provider was way down. A neighbor said that they’d heard a fiber optic cable had been accidentally cut near Great Falls.
A single fiber-optic cable can carry huge amounts of Internet traffic, and a breakage is a serious problem. But because Internet traffic was finding its way around the broken cable (with some help from the local Internet provider), my e-mail got out, though it took longer to send.
So two technologies of the Internet from the old days were still working well: packet switching, which sends packets however they need to go, and the architecture of the Internet, where millions of computers are interconnected to pass the packets along to their destination. Both work together to ensure the data traffic keeps moving despite problems, and have done so since the early days of the Internet.