Carrier Access Billing can be validated by using SS7 Call Detail Records as a secondary independent source of network activity. The SS7 data is collected by a network probe that records the date, time, call duration, and the calling from and to telephone numbers separate from the information captured by the central office switch or billing process.   An SS7 Probe creates CDRs for all originating and terminating calls for all trunks that utilized the SS7 network for the setup and release of calls. This means CDRs are available for traffic that normally is not recorded by the switch; such as, local EAS trunks, CLEC trunks, Wireless Trunks, and terminating calls from tandem service providers.

There are two major challenges associated with using SS7 CDRs to validate access billing. Before the SS7 CDRs can be utilized, the data has to go through an enhancement process where additional information is added to the records from reference tables. As a minimum, a look up is required to determine the central office CLLI and trunk number. Additional look ups can be performed to identify the OCN, Company Name, OCN Category (RBOC, LEC, CLEC, or Wireless), and Jurisdiction.

The second challenge with SS7 data is the volume of records. Since an SS7 CDR is generated for every call, whether it is billable or not, the quantity of SS7 records is nearly double the number of access billing records.

VeraTeq developed the SkyView Revenue Assurance System to address these two issues and simplify the analysis of network traffic.

The following is a discussion regarding how the SS7 CDRs are used to validate access billing:

• IXC Trunks (Trunks from Long Distance Carriers) – 100% of the originating and terminating traffic should have matching SS7 and billing records.  If non-matching SS7 CDRs exist, an investigation of the switch needs to be conducted to determine while why billing records are not being produced.
• Direct Tandem (DT) Trunks – The challenging aspect of most DT trunks is that they often carry both billable and non-billable traffic.  Different billing rules apply whether a call involves a wireless carrier, is handed off to an IXC, or is transported by the tandem service provider’s network.  If the call is transported by the tandem, then the question is the call jurisdiction local or non-local.

The jurisdiction of an SS7 CDR is performed by a lookup in a Local Calling Area table to determine if a call is local or non-local. This segregates the local traffic from the billable IntraLATA-IntraState traffic. In states where the LECs and Tandems utilize T/O ratios for billing IntraState traffic the SS7 data can be used to validate the ratios.

For local wireless and CLEC traffic the OCN information that is added to the SS7 CDR via a lookup in the LERG can be used to calculate reciprocal compensation ratios and traffic volume.

• CLEC and Wireless Trunks – The SS7 CDRs can be aggregated to provide call volume statistics for reciprocal compensation agreements. If the SS7 CDRs have been categorizes and jurisdictionalized, then the data can be used to investigate possible termination of phantom traffic.