The new packet core should simplify networks and let mobile operators roll out new services more quickly, DePuy said. But it could also help carriers prioritize one app over another. PCRF can assign nine different classes of service to applications, four of which can guarantee that app's performance no matter what else it's sharing the network with.

A key advantage of EPC for carriers is the ability to deploy VoLTE (voice over LTE), which is the only way for the new packet-based networks to handle voice calling. VoLTE can be used for better-sounding voice calls, but it benefits carriers in other ways: For one thing, it eventually will let them reuse current 3G spectrum for the 4G network, making better use of their limited resources. Also, VoLTE can help carriers integrate voice with other applications such as instant messaging, offering a class of service called RCS (Rich Communications Services), DePuy said.

Thus, a user could carry on a videoconference with another subscriber and exchange contact information and current location data in the same session, he said. And the carrier could make such a service run over all the phones it sells, regardless of who made each device or what operating system it runs.

But EPC may also help mobile operators to compete with third-party service providers. It lets the carrier use what it knows about the quality of a subscriber's connection to make its own service run better over that link, through priority or other mechanisms, DePuy said. That's something that providers of third-party applications, such as Google or Skype, can't do, he said.

As a third party, "you don't know, when you're running the service, exactly what the status of the connection is," DePuy said. But for carriers, "they're the ones making the connection, and they can monitor the quality of it."