Front-End: Call Processing | Major Billing Functions

Major Billing Functions

Billing systems can be divided into two major functions: the front-end and back-end processes. The front-end process accepts messages from a service providers’ own switches or from other telephone or billing company’s systems (called incollects), checks the validity of billing records, matches billing records to customers in a database, and provides billing details to other systems (called outcollects). The front-end process also guides billing records to specific customer accounts. Guiding uses the call detail record identification information such as the calling telephone number to match the billing record to a specific customer account.

The back-end of the billing system aggregates billing records for a specific period (billing cycle), calculates recurring charges (e.g. monthly charges) and total usage charges (minutes or quantity of usage), and produces invoices.

Front-End: Call Processing

Call processing is the steps that are typically associated with the routing and control of the call. When used as part of a billing system, call processing receives call details from various sources (event records), reformats and edits these into call detail records (CDRs), calculates call charges for each CDR, assigns a customer account to the CDR (guiding), and gets the CDR ready for billing.

In a traditional voice telephony environment, Call Processing involves the processing of call detail records in a batch mode (or at best in near real-time). There may be several call detail events and records for each call. For example, a call may be completed from a local switch, translated by an 800 number service, and routed through a long distance switch. All the call detail events are relative to billing the call. Billing and call processing can require a substantial amount of computer processing time because there may be many events for each call.

Each CDR is rated for billing to assign a charge (cost) for each call. This rating process may involve the assignment of a rating band or category first. The actual billing charges may be added or updated after the banding or rate category assignment of the call detail record. After a CDR has been rated and the actual charge for the call is calculated, the call detail record is moved into a “pool” of billing records that are ready to be invoiced (called a bill pool). A bill pool is a group of call records that have been updated by the call processing stage in a billing system to include charging rate information. The bill pool usually contains records that are ready for the final stage of bill processing.

Figure 1 shows the basic functions of the call-processing section. This diagram shows how different event sources are received by the call-processing system. These event sources may be from the network elements or from other companies that have provided services to your customers. These records are reformatted to a common CDR format and duplicate CDRs are eliminated. Identification information in each call detail record is used to guide (match) the record to an account in the customer database. The customer’s information determines the rate plan to use in charge calculation. The rating database uses rate tables, the customers selected rate plan, and possibly other information (e.g. distance, time of day) to calculate the actual charge for each call. All of the information is added to the CDR and it is either placed in the bill pool (ready for billing), or it is sent to another company to be billed if the customer identification is not part of this network’s customer database. If there are any problems with call processing, the call detail records are sent to message investigation for further analysis.

Figure 1: Call Processing.
Source:The Billing College

Rating is the process of guiding call detail records to the correct customer records (locating the customer for the event), identifying the rate plan (from rate tables), and adding this rate information to the call detail record.

Billing systems contain many databases of information. Some of the key databases hold customer information, call detail records, rate tables, and billing records that are ready to be invoiced. A customer database holds unique identification information about the customer. This includes a customer account identification number, telephone number (may be the same as the account number), authorized feature list, rate plan identifier (which rate plan the customer subscribes to), service activation dates, and other information specific to a customer or account. A rating database holds the rate plan identifier codes and charges associated with each rate plan.

It may be necessary to divide the CDR into several components parts. For example, a call from a mobile telephone may be divided into airtime, landline usage, and long distance usage.

CDRs are commonly processed using a single call rating software module. This module uses rate plan identification information found on the CDR (determined after the guiding process) to match to rate tables that allows a per unit increment rate. Rate increments can vary based on the time of day (TOD), day of week (DOW), holidays, and other factors. After the call rate has been determined, the billing system places an initial value on the call. It may be necessary to re-rate the call based on information received after initial rating was calculated. Examples of this include; usage discounts (free minutes), toll free calls (calling party pays), and calls billed using an old rate table after a customer has selected a new rate plan.