Dear AT&T, Start Upgrading Backhaul Right Now

Once iPhone 3G lands in customers' hands, I think AT&T is going to have some never-before-experienced issues with saturation of the backhaul supporting its mobile phone network infrastructure. A great example will be what happens at the Moscone Center next January when the Mac user community convenes for Macworld Expo 2009.

At yesterday's WWDC keynote, everybody was worried about the resiliency of services like Twitter and Yahoo! Live which people were using for live blogging. But the mobile data bandwidth needed to support the hundreds of iPhones in the room is a fraction of that which will be required for the iPhone 3Gs that will be present in the same place seven months from now.

I'm not the only one who thinks this is an issue. Over on Gigaom, Om Malik raised this issue in his article Is 3G Ready for the iPhone Stress Test?. Om said:

...With the 3G iPhone, there is little desire to wait for a Wi-Fi connection and hitting the high-speed 3G connection directly for whatever you want to do. It has happened to me: Once I got EVDO, I stopped looking for a hot spot to connect my Lenovo X300, which has a built-in Verizon connection... A flat-rate 3G data plan on iPhone would mean that the usage would start to shift from Wi-Fi to 3G...

Most of the problem, if any, will crop up at the backhaul level. At present, the current 3G networks have a backhaul capacity of between 10-to-15 megabits per second, which is enough for the very short term, but it could become a big issue as more and more 3G iPhones and other new 3G phones go online....

There are some excellent charts in that article that illustrate the potential problems, and compare the per user bandwidth use of EDGE, UMTS, the three flavors of HSDPA (which is what AT&T is calling 3G), and something called LTE which supposedly supports 100 Mbps.

If AT&T has 10 to 15 Mbps backhaul capacity in most places that are 3G capable right now, I'm guessing that 20 concurrent iPhone 3G users consuming an average of 500 kbps could make the wireless data service appear sluggish to everybody using it including iPhone EDGE users, BlackBerry users, and data card users. Not everybody will use the network that intensely, but I'm convinced that quite a few people will find a way to do it.

See the problem? Let me know if you think I'm off base.

The places I think that are going to see this stress first are:

  • Sports arenas, stadiums, and other venues where public events take place in a confined area,
  • Shopping malls and shopping centers designed to look like traditional downtown areas,
  • Office buildings,
  • Certain neighborhoods in cities where lots of technologically savvy people live or work.
I can think of a number of places in Manhattan where this could be an issue soon. I think commuter railroads in places like New Jersey and Long Island will stress AT&T's network across pretty large distances. The bandwidth available on my iPhone when I'm riding New Jersey Transit's Northeast Corridor is already an issue for significant parts of the ride into Penn Station. Airport terminals are another obvious potential choke point.