The challenges of personalized charging or charging based on applications have generated a lot of discussion lately. The key challenge in any type of service like this is the proper setting of expectations with the customer. There have been a few examples to date of mobile operators attempting to offer prioritized services (mainly gaming) or “enablement” services (i.e., Pay $5 and we will let you use Skype on our mobile broadband.), but application or even site-based charging will require even more techniques. Many GGSNs in the past have offered limited zero-rating capabilities for ringtone downloads, system updates, etc., based on IP addresses or a small number of URLs. There are many cases of IPE systems being used for charging today; however, many of them are volume- or time-based charging to offload existing charging systems, or were installed for future application-based charging use cases.
On the other hand, “application-based” charging or even “site-based” charging in today’s Internet environment brings all new challenges to the table. The biggest challenge is that the user experience on a site is very different than it used to be. Facebook, for example, is now also a container for YouTube videos, ads, games, and chat. YouTube can serve up videos in formats other than flash video for Apple devices. To determine this the operator needs to understand the user experience, and will need to use tools from an IPE to ensure that the user experience is matched through the proper application of signatures, policies, and charging models.
Operators looking to offer new charging models need tools to ensure that the service that they offer matches the user expectations for a site. Operators need the ability to look at a customer’s connectivity in real-time to troubleshoot billing discrepancies, much less to test service ideas in their labs. They need systems that can use properties of applications or sites – for example, the ability to key off the referrer field in http. They need to be able to log user connections to specific sites to have forensic details for value-based or zero-rated charging. They need quickly updated signatures when new versions of applications come out, and the ability to retroactively zero-rate traffic (unknown or incorrectly identified) if a signature changes and is identified as incorrect.
Beyond the features required, another huge challenge for personalized charging looms – signaling load. This is potentially the biggest scaling challenge, and needs to be architected carefully from the beginning. When a user initially accesses the network, the network must be provisioned with the correct service plan for that user, which can require interaction between multiple systems for each service that the customer has purchased. If architected correctly, signaling load can be minimized, and only refreshed as necessary; but, this can also operate on an on-demand basis, which would cause transactions every time a new piece of content is accessed. The IPE, PCRF, and OCS/OFCS systems need to support tens of thousands of sessions per second in a mobile network of any size, and support for less than that will result in severe limitations for any operator that wants to offer mass market personalized charging plans. On the PCRF/OCS side, a new class of product (diameter routers) is designed to allow network signaling to scale. But, on the IPE front, the IPE solutions will need to scale independently, since they are doing both the heavy lifting for charging as well as the reporting.
Personalized charging is one of the most intriguing new services for broadband operators, but will require a system that can adapt rapidly to service changes and can be adjusted in real-time by the operator. It will need to scale on multiple fronts without losing performance or functionality, and certainly without losing accuracy – both for billing and for application identification.
