Industry Blog

Reality Check: What is the role of the application function going forward?

We need to update our thinking about the application function, an incredibly powerful yet under-valued element in mobile data networks. The AF could improve the quality of experience for mobile data and revolutionize how operators engage with their subscribers. Yet, to visualize the potential future for the AF we need to understand how the concept and technology evolved.

The application function was created as a concept several years back as part of 3GPP standardization. In IP media subsystem architecture, the traffic generated by services or applications often uses two “planes,” the control plane and the data plane. In this setup, the AF usually sits in the control plane and establishes the quality of service and potentially some charging aspects for a service. Simply put, the AF acts a quality controller for specific applications which resides on the network and interconnects with a policy charging and rules function element.

Outside of IMS architecture, the AF is hardly referenced. In an Internet data world, it is generally not possible to distinguish the two separate planes as there is just one “blended plane” that both serves control and data traffic. That essentially pushes out the intended use of the AF. Now that we are living in an Internet data-centric world, what is the role for the AF going forward?

Part of the difficulty with mobile data is ensuring a good QoS and by extension, a good QoE. This is particularly true of video data because subscribers increasingly judge the quality of their carrier network on their ability to provide smooth and fast video playback. Failing to do that at whatever time of day or location and the carrier will be harshly judged, as subscribers generally do not know or care about time- or location-based congestion.

If the customer experience is the battle cry for service providers in developed markets, then QoE for data is surely the major battleground. Establishing a high-quality experience for voice is not necessarily straightforward, but there is no shortage of experience and technology to handle it within mobile operators. Establishing a high-quality experience for mobile data outside of the IMS domain is a greater challenge, because it is relatively new, it is so subjective and it is tied up with millions of Internet sites and applications.

However, an AF sitting in a modern mobile data network could be a vital hub for service quality. It could do this because it would necessarily be application-aware by seeing both the control and data planes, meaning it understands the application traffic that a subscriber is using and could request that necessary QoS and charging resources be made available to the end-user. It could apply bandwidth parameters for video streaming to ensure a positive experience, provided the network resources were there. Taking that further, assuming an LTE network was in place, it could establish the parameters required to ensure that a user with a new HD video streaming package, for example, got all the resources that were needed for high-quality playback. Similarly on the compression side, it could establish minimum or user-specific requirements for web browsing or video streaming and perform Web and video optimization techniques in concert with the overall 3GPP policy control and charging architecture (PCRF and PGW) when there is congestion on the network.

But there is a potentially much larger win available through the AF. A recent Heavy Reading report suggests that 50% of operators globally now have a policy infrastructure in place. Up until now, the role of policy control has overwhelmingly been focused on enforcement – defensive blocking and tackling and basic traffic management. As PCC solutions find their way into operator networks around the world, there is nevertheless a missing piece in policy infrastructures. That missing link is “policy engagement.”

Operators have traditionally relied on monthly bills and text messages to communicate with their subscribers, but there is a growing sense that they need more context-aware methods of communication in order to increase immediacy and adoption of new services or promotions, as well as make them feel more connected to the operator brand. As policy enforcement edges closer to ubiquity in developed markets and Internet services keep creating instant gratification experiences, policy engagement will start to come to the fore within mobile operators’ networks. Policy engagement means that users are engaged within an interactive and non-disruptive fashion, based on how they interact with content and network services. Essentially, the network will start to act more like a guide, delivering a “curated” experience to subscribers, increasing two-way interactions and delivering better, more relevant options to users. The front-end of this can either be souped-up smartphone apps or in-browser communications, depending upon the capabilities and biases of different operators.

And guess which piece of kit could provide this policy engagement. That’s right, the humble application function. The AF fell off the radar for a little while, but its potential impact is so strong and so fundamental that we truly believe it is ready for the second act. If so, we can look forward to it righting many wrongs, helping to deliver the best QoE and the most natural and comfortable end-user engagement possible.

This blog was published by RCR Wireless on December 4th Click Here