APPENDIX 12
Memorandum submitted by the Office of
Telecommunications
BT NETWORK: NORTHERN IRELAND ELECTRICITY
SUPPLIES DIFFICULTIES
Oftel takes any failures in BT's network very
seriously and reviews with BT the causes, lessons to be learned
and implementation of improvements to prevent recurrence. I attach
a memorandum on the operation of the BT network during the electricity
supply difficulties over the Christmas/New Year period, which
summarises the position to date.
Our conclusion in this case is that work is
required to ensure that the final overflow mechanism, the network
message facility, is made more robust. We are awaiting BT's report
on how this is to be achieved. Although outside our remit, to
reduce demands on the network in the event of such a failure we
are encouraging consideration of additional means of communication
to be discussed in the dialogue between NIE and BT. For example,
in the case of a similar failure, the use of a publicity campaign
to inform the public of what the utility company knows and provide
other relevant information, e.g., when supply will be restored
in different areas, etc. If this information was available, some
calls would become unnecessary and customers generally would be
better informed.
INTRODUCTION
1. This memorandum addresses the issues raised
by Clerk of the Committee in his letter of 5 March to the Director
General concerning the problems experienced by Northern Ireland
Electricity customers in the period 26 to 31 December 1998. The
information presented is based on analysis of the NIE report into
the incident and meeting with BT.
NETWORK INTEGRITY
2. The SI implementing the Revised Voice Telephony
Directive contains provisions relating to security of network
operations and maintenance of network integrity. Network operators
are expected to take steps to maintain the integrity of their
networks in the face of abnormal conditions. Measures to be applied
in such circumstances could include the use of controls to regulate
traffic flows to specific numbers experiencing abnormal levels
of demand or controls to dampen more general network overload
situations. The philosophy normally applied by network operators
is to restrict traffic as close as possible to its originating
point within the network and provide customers with an appropriate
tone or announcement. Application of controls is a matter of judgment
based on the circumstances of a particular incident and responses
are often adapted as incidents develop. BT has detailed procedures
for this aspect of its operations.
NIE INCIDENT
3. The main points to emerge from OFTEL's review
of the incident are as follows:
— there were very high levels of demand
placed on the BT network in Northern Ireland in the early phases
of the NIE incident;
— BT applied appropriate network traffic
management controls on the NIE reporting number when traffic to
that number became excessive and there was a risk that it could
have adverse implications for other traffic within the BT network;
— BT assisted NIE by providing additional
call handling resources from a BT call centre at periods during
the incident;
— Non-answered calls at high demand
periods were directed to a message facility. However, there were
problems caused by an intermittent fault on that system which
reduced the service capability below an acceptable standard. The
time taken to correct the fault was unacceptable.
ASSESSMENT OF
BT'S HANDLING
OF THE
INCIDENT
4. The application of traffic management controls
in circumstances such as those experienced on this occasion was
a valid response for BT to ensure its network integrity. Such
controls would be applied in response to any situation of this
type at any time of the year to preserve network integrity.
5. The intermittent failure of the Message Link
Facility and the extended repair period are a matter of concern,
OFTEL is reviewing these failures with BT to reduce the risk of
a similar failure in NI or elsewhere, in future. OFTEL has also
noted that BT has commenced a dialogue with NIE on the matter
of restoration priorities for any future incidents and supports
this initiative.
6. There does not appear to be a case for substantial
reinforcement of BT's network as a result of this incident. Inevitably
whenever a situation of this type occurs, more is learnt about
the way in which networks behave and how to improve operational
processes and procedures.
7. OFTEL work on this and other incidents has
identified that BT reviews its operational procedures to ensure
that improvements highlighted in incident reviews are, where practicable,
carried through into practice.
Oftel's investigation of this incident was self
initiated following comments received from Utilities at a regular
meeting between Government, Utilities and Operators. Other than
through this route, Oftel has not received a formal complaint
or any representations from consumers. This is one of a number
of types of network incidents that Oftel investigates on an ad
hoc basis.
18 March 1999
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