Will AT&T's Network Hold Up Under the MMS Strain?

iphones1Will the AT&T (s T) network collapse under the weight of photo-happy iPhone users sending MMS messages? That’s the crucial question behind today’s launch of picture messaging capability on the AT&T network, which has been dogged by criticism since the first iPhone (s aapl) launch. Despite the explanatory video offered up earlier this month by “Seth the Blogger Guy,” which outlined “preparing radio access controllers” and “calibrating base stations all over the country,” sending photos over the iPhone today may not go smoothly.

According to Karl Bode over at DSLReports, AT&T is justifiably nervous. Sources have told him that the carrier estimates traffic will be 40 percent higher on the network as AT&T users get the MMS capability they’ve long been denied. (For AT&T users without the iPhone, this means you, too!) But the network has to work, something Bode’s sources doubt:

According to the source, AT&T is “very” nervous about the launch and is requesting their MMS aggregator partners provide hourly updates on any message delays or problems. AT&T and its MMS partners are already seeing “record traffic during peak hours of the night” with just the users selected for testing.

That early testing has been a little rocky, with AT&T seeing a fairly significant test outage yesterday that has them rushing to beef up their MMSC messaging servers.

Sending an MMS message is different than making a voice call or even accessing data from the Internet. In those cases, the phone sends digital packets over the cell network to either the web — to call on a server, as is the case with data — or to a piece of equipment that will connect it to the circuit switched network in order to call a landline or cell phone. With MMS and SMS messages, the text or photo info is actually sent over the cell network to an AT&T data center.

Once there, a server validates and stores the message. Then it pushes out a notification to the recipient of the message, which contains the sender’s info and a URL to access the content on the server. When the recipient clicks to receive the image, it’s sent. The ability to store the content and wait a bit to push it out to recipients is one reason that texts and MMS can work in a disaster situation, when voice circuit networks are overloaded. Texts may arrive late, but they should get there. So unlike voice calls, there’s a heavy data center component to the MMS capability.

However, Seth Bloom (yes, the guy in the video) emailed me this morning to say, “We expect it to go well today. As previously mentioned, we expect the feature to result in strong usage and record volumes, which is why we took the time to prepare our network so that customers would have an excellent experience from day one.”

Those steps include the aforementioned radio access upgrades, adding MMS-processing servers inside AT&T data centers, adding more cell towers, and allocating the 850 MHz spectrum in major cities to the 3G network — something that was fairly successful at the South By Southwest Interactive show in Austin this year (it had other problems, namely that because of a deal with the city of Austin, only Sprint (s s) was allowed to have its cell gear inside the convention center where SxSW is held, which forced AT&T and other providers to set up their towers farther away).

As AT&T gears up to turn on MMS later this morning on the West Coast and early afternoon on the East Coast, like any web startup about to launch, the carrier is primarily counting on its servers.