Many of today's carriers today operate a mix of network types and frequencies, typically a blend of 2G EDGE, 3G HSPA and 4G LTE services, and some of these underlying services have different subtypes of network and even sometimes operating at a different frequency. Each network type comes from a different era and has a different utility. The older 2G networks were originally designed for voice calling but GPRS and subsequently EDGE data services were engineered into the standard. 2G works offer the least capacity of all of the network types and for today's modern smartphones, the least purpose: navigating most websites or using an application over a GPRS or even EDGE connection is painfully slow. 3G and especially LTE networks offer a much higher capacity – that it, they can handle many more concurrent users, at much higher speeds. And whilst some carriers have carefully deployed their 2G, 3G and LTE networks so as to make best use of available equipment, more and more are looking to shut down their older 2G networks in order to repurpose this spectrum for LTE signals. One such carrier is America's second largest national service provider, AT&T, although we have already seen T-Mobile reuse its 1,900 MHz 2G specrum for LTE networks in 2015. Verizon is planning to close both its 2G and 3G networks by 2021 in favour of LTE.
AT&T has reported that it is moving customers from the older 2G networks to the newer generation networks and has plans to shut down its older 2G network by the end of the year. AT&T's Chief Financial officer, John Stevens, reports that in the last year they have moved six million customers off the 2G network and that the majority of customers still using the 2G network are connected devices. He said that AT&T will "continue to see manageable pressure in the last half of the year from subscribers, mostly connected devices, choosing not to make this migration." In other words, some users or businesses will not want to migrate from their 2G connected device to a more modern technology for a variety of reasons, but cost is likely one of them. AT&T are also expecting that in the short term, any costs of this migration will impact revenues but going forwards, there will be a significant saving to be made through shutting down the 2G network, plus an important increase in network capacity. AT&T have already started reusing some of their existing 2G spectrum for 4G LTE networks where there is little use of the older legacy networks.