Improvements by HKTC

Improvements by the ISPs

Background

The Telecommunications Authority (TA) has received a number of complaints from Internet Service Providers (ISP) on the metering system used by Hong Kong Telephone Company Limited (HKTC) on the interconnect lines used by the ISPs. In connection with this, the TA has conducted a preliminary investigation. This report contains a summary of the TA's findings and certain improvements which have been identified during the course of investigation to be technically feasible and which may be implemented readily by the parties concerned.

Nature of the Complaints

2. Some of the more common complaints which the TA has received are:-

   1. malfunction of the end-user equipment causing the holding-up of the interconnect lines but no real connection was established;

   2. malfunction of the HKTC's equipment causing the holding-up of the interconnect lines but no real connection was established;

   3. holding-up of the interconnect lines by unregistered or unwanted customers;

   4. unconnected call attempts from end-users during the period of routine and corrective maintenance of the ISP equipment, including A/C power failure;

   5. repetitive unsuccessful call signals on a busy interconnect line. A complainant said that he was told by a HKTC personnel that these signals are chargeable;

   6. most of the ISPs can only measure the login/logout time of the end-users but cannot record the seizure/release time of each connection. Therefore, they cannot reconcile their records with the telephone bills they get from HKTC; and

   7. the calculation of interconnect charges in terms of occupancy minute might end up in a situation allowing HKTC to issue a bill for a particular interconnect line inclusive of multiple and simultaneous but non-connected signalling time, which theoretically could exceed twenty-four hours per day per line.

   HKTC's Metering System on PNETS Lines

3. Under the current regulatory framework, ISPs are classified as International Value Added Network Services (IVANS) providers, which require them to take out a public non-exclusive telecommunication service (PNETS) licence. The ISPs have to make use of PNETS lines, which begin with the prefix '300' under the Hong Kong Numbering Plan - this requirement applies to the PNETS lines provided by the other three fixed telecommunications network services (FTNS) licensees as well. In addition to the monthly line rental which they have to pay to HKTC for the PNETS lines, the ISPs have to pay to HKTC a usage charge based on the total occupancy minutes of the interconnect lines connecting to their service platforms.

4. There are basically two types of interconnect lines, namely, direct exchange lines (DELs) with hunting facilities and integrated digital access (IDA) trunks (T1 digital lines). The IVANS providers are located mainly in the urban areas connecting to approximately 40 local switches. The occupancy minutes of each connection are measured starting from the seizure signal to the release signal by a Call Detail Recorder (CDR) interface installed on a per line basis in each local switch. The charging information is then sent via these interfaces to the three CDRs located in the Lai Chi Kok (LCK) Exchange I and II for billing purposes (Figure 1).
   

5. HKTC's meters are so designed that the occupancy of each connection would be rounded off to the nearest second and the sum of all connection times of each interconnect line would be rounded off to the nearest minute in each billing cycle i.e. one month. Moreover, under HKTC's current metering system occupancy minute charging would only start when the corresponding interconnect line was seized and that once a line was seized, it could not possibly be seized again by another call before it was released and therefore double or multiple charging on the same line could not occur. Therefore, a bill for a particular interconnect line could not possibly exceed twenty four hours per day per line (in response to item 2(g) above).

6. HKTC has also programmed that the CDR system to report any connection holding for a period of longer than one hour. At present, if such a report was received within office hours, HKTC's duty engineer would immediately carry out a technical check. If the false connection was due to a fault in HKTC's network, HKTC confirmed that it would waive the corresponding interconnect charge. Otherwise, the duty engineer would advise the ISP by facsimile informing him that a prolonged connection had been detected (in response to items 2(a), (b) and (c)). HKTC would then leave it to the ISP to take further corrective measures.

   Comments from ISPs

7. One ISP indicated that it currently did not have the necessary means to measure the seizure-release duration of the interconnect lines and it could not therefore reconcile its internal records with the monthly telephone bills with HKTC. To overcome this problem, it had a plan to install a private automatic branch exchange (PABX) system equipped with station message details recorder (SMDR), which would enable it to measure accurately the seizure-release duration.

8. Another ISP advised that currently it did not have the means to measure the seizure-release duration of the interconnect lines either. It realized however that there was a time lag between the seizure of an interconnect line and the login of the end-subscriber, but this was regarded as inevitable. This ISP was of the view that HKTC's bill might not be absolutely accurate but to reconcile the duration of every call monthly would simply be too time consuming and costly. It opined that it would be HKTC's responsibility to provide for accurate billing and that if there were disputes, it would be better to settle the bills by simple accounting methods (e.g. 5% or 10% discount) instead of an engineering solution.

   OFTA's Findings

9. From the technical point of view, HKTC should have no difficulty to charge the ISPs based on conversation period starting from answer signal to release signal. However, the current regulatory framework provides that HKTC is to charge the PNETS lines on the basis of occupancy minutes rather than the conversation minutes. The current tariff of 9?per minute was calculated on this basis. This methodology would therefore remain in place pending a further review of the entire regulatory framework as mentioned in the TA's Statement of 2 December 1995.

10. Normally, the modems of the ISPs would be set to answer on the first ring and this would result in a more or less fixed timing difference between the occupancy minutes and conversation minutes of around 1 to 2 seconds per connection. Assuming that an end-user would generally hold more than thirty minutes for each connection, the timing difference between the two charging methods would only account for less than 0.1% of the total chargeable minutes. The TA therefore considers that any charging discrepancy as indicated in item 2(f) should not be as serious as it would appear to be at first sight.

11. The real concern of the ISPs appears to be whether they can exercise some control over the charging of the interconnect lines for unsuccessful calls, false connection calls, malicious calls and unwanted calls during routine & corrective maintenance periods. The TA considers that under such circumstances, it would be fair for the ISPs to be able to exercise control over their lines so that they could stop the meter of HKTC at the far end. This may be achieved technically by activating a remote blocking signal to stop the interconnect line from further charging and/or to force release the connection to clear malicious or false connection calls. The TA considers that the following improvements to the existing metering system to be technically feasible and should be introduced :-

    Improvements by HKTC

    • Remote Blocking facility and Force Release facility to stop charging

      • For IDA trunks, the ISPs are currently able to activate the remote blocking signal at their ends to stop any further charging.

      • For analogue interconnect lines, HKTC confirmed that it is possible to include a remote block facility in the interconnect line by means of a "Don't Disturb" feature so that an ISP may stop the interconnect lines from further charging when the need arises.

      • On ISP may force release an interconnect line by putting "on-hook" the corresponding line. At present, there would be a re-answer supervision time-out of 60 to 70 seconds before the connection was actually released, but OFTA is considering with HKTC to shorten this re-answer supervision timing to around 30 seconds.

      • As HKTC has programmed the CDR system to report any connection holding for a period of longer than one hour, it should consider to use more effective means, e.g. by phone or by pager, instead of sending a fax, to inform the corresponding ISP that a prolonged connection has been detected. HKTC should liaise with the ISPs to sort out the necessary arrangements.

    Improvements by the ISPs

    • False Connection Detection

      To reduce the risk of false connections of interconnect lines, the ISPs may install a monitoring system to detect whether the "no-signal" period of a connection exceeded a threshold value, say 3 minutes, after which the ISPs might then arrange to force release the corresponding interconnect lines. However, the ISPs have to get the necessary consent from HKTC as such monitoring system will have to be installed on the line side of the modems.

    • Call Logs and Meter Accuracy

      • For ISPs who wish to reconcile their telephone bills with HKTC's charges, it is possible for them to install a PABX system with SMDR (refer to item 7 above and Figure 2). However, this kind of arrangement would be relatively expensive and might not be suitable for small ISPs.
        

      • On analogue DEL interconnect lines, it is possible for an ISP to construct a relatively simple device to detect the ring indicator (RI) and data carrier detect (DCD) signals of the V.24 port of their modems. RI will indicate the presence of the seizure signal and DCD will give the actual answer time and the release time of the modems (Figure 3 gives an example of such a device).
        

    Further Review

12. OFTA is currently in the process of engaging a consultant to study the metering and billing accuracies of the public telecommunication carriers. It is expected that the consultancy will be completed by March 1996.

5 December 1995

1. There are two types of interfaces, namely, the analogue line interface and the T1 interface.

2. They include seizure time, answer time and release time. There would be no charging if remote block signal was detected from the T1 trunks of the IVANS provider, but such service would not be provided in analogue DEL interconnect lines because no remote block signal could be activated in the DELs.

3. The ISP might activate the "Don't disturb" feature either on a per line basis or a per hunting group basis. On the per line basis, the ISP has to activate the feature on that particular line. On the per hunting group basis, the ISP has to activate the feature on the prime line but this does not stop the calls to individual interconnect line if the caller dials the DN of that particular line.

4. Either by inputting command in the ISP's equipment to force the corresponding modem on-hook or by physically disconnecting the corresponding interconnect line.

5. For data communications over modems, there is carrier signal on the interconnect lines during the connection established period.