Briefly and simply about the complex – charging in “8-800” – Part 2
The very possibility of charging a call to the number 8-800 in the SS7 protocol (OCS7) is realized using the so-called Reverse Charging function. Initially, this function was created for the popular Collect Call service (call at the expense of the called subscriber). In detail from the point of view of the SS7 protocol, the REVC function (such a reduction is often used for Reverse Charging) is described in ITU-T Recommendation Q.736.3.
Consider the scheme of the call from the point of view of charging.
For simplicity, we take the following conventions:
- Subscriber A, “Operator A” makes a call to the number 8-800-ХХХ-ХХ-ХХ, which belongs to “Operator M” (Operator M “- that no one would guess :)).
- According to the rules of routing, a call to number 8-800-XXX-XX-XX is forwarded to Subscriber B of “Operator B” or to Subscriber M of “Operator M” depending on certain conditions (for example, time of day).
So, a call from Subscriber A to number 8-800-ХХХ-ХХ-ХХ is received by the MgMN switch “Operator M”. This switch “Operator M” sends the switch “Operator A” sign REVC (we will not dwell on protocol details), in plain language – informs that the call will be paid by the side of “Operator M”. Further, depending on the rule worked, the call is established with Subscriber B or Subscriber M.
When the call is complete, the corresponding network nodes from the CDR (Charging Data Records) files. In this case, there will be two. The first is the CDR of the so-called “initiation arm” (in Scheme 1) and the second CDR of the so-called “termination arm” (in Scheme 2 or 3).
The first CDR will describe the cost of calling from Subscriber A to “Operator M”, the second CDR will describe the cost from “Operator M” to Subscriber B or to Subscriber M.
The total cost of the call will be equal to the sum of two “shoulders” (CDR1 + CDR2 or CDR1 + CDR3).
Upon completion of the call, the service platform “8-800” generates a resultant CDR containing information about both “arms” of the connection.
And for this example, the call cost for CDR2 and CDR3 will be different, because CDR2 is a termination for “Operator’s” operator’s “alien” network for Operator M, and CDR3 is a termination for its own network.
To simplify the process of charging, the so-called “Tariff Classes” are used, where the directions of initiation and termination are grouped by value and placed in a tariff grid. In this tariff grid, for example, along with the vertical direction of call initiation, and vertically – the direction of termination. At the intersection – in fact, the total cost per minute of the call is indicated. In addition, the tariff grid is collected in minutes packages, in order to provide discounts from the total amount of calls (as usual – the more minutes are reproduced, the cheaper the cost of each minute).
The logical question is how there are tariffs for 8-800 types of “N rub. Minute from any direction? ”
Very simply – this is a conditional “average” of the cost of a minute.
Another question is “How much should the call cost 8-800, which falls on the IVR of Operator M?” At least – the value of the shoulder of initiation (CDR1), and not free, as many believe.
Obviously, it will not be possible to significantly save on the cost of calling to the number 8-800, often the most part of the cost will contain the first “shoulder”.
The cost of the minute of the second “shoulder” (termination) will differ approximately by a penny in case of using the redirection number belonging to the operator-owner of a particular number 8-800 and the “foreign” operator. Conclusion: it is more profitable to buy the number 8-800 from the same operator to which your main phone number is connected. In addition, you can reduce the cost of calls by connecting to the operator on a dedicated line. If this is impossible for some reason, then it is necessary to use the termination on SIP, as it is obviously the cheapest way to deliver traffic to your phone number.
There is another tip for optimizing costs. Numbers 8-800 are sold by many telecom operators. It is also known that most calls to numbers 8-800 are made from mobile numbers. Hence the conclusion suggests: for the mobile operator, the cost of the first “shoulder” will be cheaper since some of the calls to 8-800 (20-40% of all traffic) will come from its own network, therefore, it is not necessary to pay for the interconnect calls. Therefore, hypothetically, a mobile operator can provide a more advantageous offer for the “8-800” service than fixed-line operators. “Operator M”, at least, exactly can.