Online Charging: Considerations for Accuracy, Reliability, and Visibility
An Industry Whitepaper
Performing accurate, real-time usage metering is a requirement in most telecommunications markets.
The 3GPP standards specify that the measurement component—in practice the Policy and Charging Enforcement Function (PCEF) or Traffic Detection Function (TDF)— in the data path is a single logical entity that’s connected directly and in real-time to the online charging system (OCS) via Diameter Gy/Gyn; only in this architecture can a CSP avoid revenue leakage.
Many vendors claim that their solutions are 3GPP Gy/Gyn-compliant, even when they aren’t; typically, these non-compliant solutions include an intermediary node that breaks the direct, real-time connection and separates functions within the PCEF/TDF.
Non-compliance makes the charging deployment inaccurate and unreliable; furthermore, in such deployments, attempts to address one shortcoming (e.g., lack of accuracy) make the other one worse (e.g., lower reliability). The ultimate consequences for the CSP include increased cost and complexity, lower subscriber satisfaction, and—critically—revenue leakage.
Beyond architectural compliance, a second consideration for CSPs is the degree to which they have visibility into the charging system’s performance. Deep visibility into the right measurements and metrics satisfies a range of auditability, revenue assurance, and business intelligence use cases.
Understanding the issues at hand and the approaches used by vendors allows CSPs to make an informed decision and to invest in a solution that will actually work as needed.