I read an incredibly fascinating interview in BoingBoing this week, an interview that explained why cell and wireless networks get swamped during a huge crisis. Network access is tough at SXSW, when thousands of people are hitting a relatively small area with request from their smartphones – but during a natural disaster or a terrorist attack, the whole network can jam.
BoingBoing‘s Maggie Koerth-Baker spoke with Brough Turner, an engineer, and writerwho specializes in phone systems of all kinds. He has some really accessible, fascinating stuff to say about cellular network infrastructure, and what the tradeoffs are between reliability and competitive pricing.
There’s an except below but I recommend reading the entire piece here: Why is it so hard to make a phone call in emergency situations?
In the end, it does come down to trade-offs. That’s true of any network. You’re interested in coverage first and then capacity. If you wanted to guarantee that a network never had an outage your capital investment would have to go up orders of magnitude beyond anything that is rational. So each network is trying to invest their budget in ways that make network appear to perform better.
The cost of providing temporary extra capacity for the Boston Marathon, that’s something that’s in the budget and they plan for that event. But when you get something unexpected like a terrorist event, or an earthquake, or damage from a hurricane or tornado, then you have trade offs between capital and how robust your network is.
Every time you have an event people say, “Oh, they didn’t invest enough.” But you look at New York City after Hurricane Sandy and Southern Manhattan was under 6 feet of water — all the buried infrastructure was lost. Meanwhile, in other places, a significant number of cell sites were knocked out because connections ran on overhead poles and got knocked down by trees. The antenna site literally got destroyed. Interestingly, you can lose 30% of your cells and stil get coverage. Coverage was there in New Jersey after Sandy, even with 1/3 of the network out. The catch is there wasn’t much capacity.