Can AT&T’s Network Handle the iPhone’s VoIP Traffic?

AT&T’s recent decision to allow iPhone-based internet voice applications (VoIP) on its network begs the question, can the network handle it? In September, the New York Times reported that the increase in data usage related to the iPhone 3GS release has severely impacted AT&T’s service. Customers complain of “dropped calls, spotty service, delayed text and voice messages and glacial download speeds as AT&T’s cellular network strains to meet the demand.” At the same time, AT&T has yet to support tethering on the iPhone as it performs “fine tuning to our systems and networks so that we do deliver a great experience” (Ironically, AT&T does support tethering, or using one’s phone to access the internet by computer, on other devices, for $60 per month). Considering that AT&T also recently began supporting picture messaging (MMS) on the iPhone, how will AT&T’s network respond to the added stress of voice applications?

When VoIP applications such as Skype were first released for the iPhone, the programs were restricted to use over the device’s WiFi connection alone. The same is true for certain video streaming applications, such as Slingplayer Mobile, as AT&T argued that these data-intensive programs would place too great a strain on its network. Recognizing the increased demand the iPhone 3GS would place on its data network, AT&T reportedly performed network upgrades before the new device’s release, just as it had for the two previous iPhone releases. However, the complaints reported by the New York Times all came after the network upgrades were to be completed. While AT&T has announced additional enhancements to its 3G network in limited areas since the iPhone 3GS release, it has made only one major announcement regarding its plans to improve the speed and capability of its data network, but that upgrade will only cover six cities. AT&T has yet to respond to the claims made by the New York Times, or to address the overall coverage issues surrounding its 3G network. The carrier even fails to provide a 3G coverage map on its website, instead providing a list of cities where coverage is available (see How can, on the one hand, AT&T claim a poor customer experience as justification for not offering tethering to some customers while, on the other hand, allowing VoIP applications based on “customers’ expectations and use of the device compared to dozens of others we offer.“? This contradiction may point to weaknesses in AT&T’s network.

In the absence of major network upgrades, AT&T’s decision to allow VoIP applications on the iPhone for reasons that contradict its justification for blocking the device’s tethering abilities could indicate that the carrier’s network is struggling to handle the increased traffic generated by Apple’s latest offering. Given that AT&T also recently enabled MMS for the iPhone, adding VoIP traffic may be all that the network can presently bear.

Incidentally, AT&T’s announcement said nothing specifically about the Google Voice service or application, nor has Apple indicated whether it will now approve the program.

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