Emergency & Critical numbers Dave Williams - 21CN Common Capability & Voice Service Design

1. Emergency & Critical numbersDave Williams - 21CN Common Capability & Voice Service Design The purpose of this presentation is to: Define the Emergency and critical numbers that will be subject to special attention up to the point of migration. Describe the method to identify calls in progress to emergency and critical numbers and how this activity will be monitored and managed on current voice network prior to transfer. Customer Engagement Contact Alan Turner - e-mail alan.c.turner@bt.com

2. Emergency & Critical Numbers - Introduction • It is BT’s business as usual practice to implement special measures for critical numbers when carrying out planned engineering works • Examples of such engineering works are:- • When re-parenting a Concentrator • When carrying out planned maintenance • BT has a responsibility to ensure that calls to Emergency and Critical numbers are managed appropriately

3. Emergency & Critical Numbers • This is our definition of emergency and critical numbers. • These numbers would be subject to specific checks at the point of transfer to ensure calls are not in progress: • 999 • 112 • 18000 - Text Direct • Child-line - Non-Geographic Number • Samaritans - Non-Geographic Number

4. Emergency & Critical Numbers - Requirements Submission Any requirement for the consideration of additional specific types of Emergency and Critical numbers should be submitted to: Alan Turner 21CN Customer Engagement Manager - Business Continuity Email: alan.c.turner@bt.com or Consult 21 mailbox - consult21@bt.com Responses required by Tuesday 4th April 2006

5. Emergency & Critical Numbers Caveat A significant increase in the number of emergency and critical numbers identified could potentially undermine the capability and process to apply special calls in progress monitoring checks. The definition that should be applied therefore is the commonly accepted categorisation of having ‘life or death’ significance. BT Wholesale reserves the right to negotiate and take the final decision in this matter to avoid jeopardising the integrity of the process to manage calls that fall into this category.

6. Emergency & Critical Numbers - Identification and Monitoring Method NB. This activity will be carried out on the current voice network prior to transfer. Calls from end users routed via a migrating DLE to the identified emergency & critical cumbers will be identified within the ‘on the night’ time window for that DLE migration. The chosen method to monitor calls to the identified emergency and critical numbers will employ the use of Geoprobe™ Signalling Monitors. The Geoprobe™ capacity is dimensioned to accommodate busy hour call attempts

7. Voice Network Architecture and Signalling Interception point 999/112 18000 08XX Trunk Switch DLE 999/112 18000 08XX 999/112 18000 08XX C O N C Signalling monitor (Geoprobe) on all Tandem OA routes Operator Assistance Platform Text Platform Intelligent Network Platform 999/112 18000 08XX • Concentrator – equipment that customer lines are connected to within the existing network. • DLE – provides connectivity between concs and trunk switches. They are either dual or triple parented to the tandem layer. • Trunk Switch – There are a number of types of trunk switches which are all fully interconnected.

8. Description Of Monitored Platforms • OA platform – Operator assistance Platform (of which there are three) has routes from a number of trunk switches. All of these OA-trunk routes have signalling monitors. • Text platform – Text Platform (of which there are two) has routes from a number of trunk switches. All of these Text-trunk routes have signalling monitors. • IN platform – The IN platforms are connected to the trunk switches where calls to the non geographic Childline & Samaritan numbers are triggered. All routes between the trunk switches and the IN platforms have signalling monitors.

9. 999/112 Routing to Emergency Authorities ISPBX DLE B C O N C Trunk Switch EA 1 (Alternative) EA 3 (Primary) ISPBX OA Platform DLE A C O N C Trunk Switch EA 1 (Secondary) Migrating DLE DLE A ISPBX DLE X C O N C Trunk Switch EA 1 (Primary)

10. Primary and secondary routing arrangements on previous diagram • Emergency Authorities (EA) have Primary, Secondary & Alternative numbers. The primary & Secondary numbers are usually served from the same DLE. Where the Primary & Secondary are not available the Alternative number is used. • The 999 Liaison team who manage the OA team have a process to advise/route calls to the Alternative number if the Primary & Secondary are unavailable. • This process will be used to ensure that where an EA is connected to a migrating DLE emergency calls will be routed to an alternative EA.

11. Summary ofEmergency & Critical measures during migration BT Wholesale will proactively identify and monitor calls to Emergency and Critical numbers Communication Providers have the opportunity to suggestadditional ‘Life or Death’ numbers The end user availability of access to the emergency services will be minimised to the period of time when outgoing calls cannot be made.

12. Glossary • Conc – Concentrator • DLE – Digital Local Exchange • EA – Emergency Authorities • IN – Intelligent Network • OA – Operator Assistance