Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 1 PSTN Migration Methodology Simon Rogers 21CN MSAN Transfer Engineering Enquiries about this presentation to 21CN Customer Engagement The following slides provide detail of: PSTN Disconnection transfer activity Selected method Methods considered Impact on end customer service

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 2 PSTN End Customer Migration. - These are the areas we have covered to date / plan to cover PSTN Line disconnection Impact on end customer service Compression & Grooming End customer migration Confirmation of Line disconnection methods Data migration I&MWG February 2006 I&MWG March 21st 2006 PSTN Fallback Line disconnection & data migration I&MWG Nov - Dec 2005 Planned I&MWG April 2006

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 3 Prepare Network Configure + Verify On the night Migration Monitor TE completion and handover Go/No Go Decision Point Decision not to fallback Frames Uplift Customer data Audit Groom Legacy services to retained platform Compression Parallel connect 21CN to customer lines Capture and translate data Load data - start churn process Pre-transfer customer checks & audit 6pm CSS Data freeze 10pm Network Service frozen Activate data Connect to 21CN & Disconnect PSTN Modify PSTN call routing Update BT OSS Post transfer Tests Fault Handling 9am Freeze removed Monitor customer experience Monitor Network - resolve issues Initiate fallback if necessary Hand over to In-Life management TE Workflow Management BT Approach To End Customer Migration Weeks - 12 Weeks + 7 Days

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 4 PSTN End Customer Migration Methodology End customer migration comprises the following steps 1) 21CN parallel connection - the end customers line is connected to 21CN and existing concentrator 2) Data migration – end customer data is transferred from existing digital local exchange (DLE) to 21CN call server and MSAN 3) PSTN disconnection & 21CN connection - the end customers line is moved from existing concentrator to 21CN enabling outgoing call capability 4) PSTN call routing is transferred from existing digital local exchange (DLE) to 21CN call server enabling incoming calls

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 5 Data Migration Activities & Timeline

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 6 E-side MDF Transfer in progress Transfer Activities Command & Control confirm transfer “Go/No Go” Disconnect PSTN concentrator & Switch 21CN TAM Sync with changeover from DLE to Call Server 21CN TAM PSTN CONC Customer lines OVPOVP OVPOVP OVPOVP MDF D E MSAN 21CN T/TH Test Head POTS PSTN DLE 21CN Voice

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 7 PSTN Disconnect Method Evaluation Criteria BT can have a single process that  Minimises risk of mistakes  Is suitable for both System X & AXE10 Minimises impact on end customer service capability  Fast PSTN disconnection method  Fast Fallback re-connection (if required)  Lower risk disconnection & re-connection

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 8 PSTN Disconnection Methods Considered A number of methods were considered to complete the migration of end customer to BT’s 21CN platform that are suitable for both system X and AXE10, these include:  Removing Concentrator Plugs  Line Card Removal  Power Off Line Shelf Groups  Make Service Temporary Out Of Service (TOS)  Test Network Disconnection  Transfer Connectivity Point Disconnect

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 9 PSTN Disconnection Evaluation Results (200 strung) N/ATransfer Connectivity Point Disconnect (Slide 15) N/A System X AXE10 Test Network Disconnection (Slide 14) System X AXE10 System X AXE10 System X AXE10 System X AXE10 Conc. Type Make TOS (Slide 13) 1000 (+ Power reset) 1000 Line Card Removal (Slides 10 & 11) 64 (+30 service delay) Power Off Shelf Group (Slide 12) 126 – – 750 Disconnection (Seconds) Remove Conc. Plug (Slides 8 & 9) MethodFallback (Seconds)

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 10 Selected PSTN Disconnect Method Concentrator Plug Removal System X shelf example 32 pair connector plugs MDF REAR SHELF VIEW Module CModule BModule A 64 pair Slot Position 2 – 5 seconds per plug removal (Variants) 5 seconds per plug replacement

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 11 Selected PSTN Disconnect Method Concentrator Plug Removal AXE10 shelf example 2 – 3 seconds per plug removal 2 – 3 seconds per plug replacement Slot Position LICLIC FRONT SHELF VIEW LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC MDF 128 pair cable (3 x32 pair cables) 8 pair connector per line card 128 pair cable broken down to 8 pairs per connector. LICLIC POUPOU POUPOU TSCTSC BISSBISS CNADCNAD CLSCLS SLCTSLCT ETBETB ETBETB REUREU EPMCEPMC

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 12 Non Preferred Line Card Removal System X shelf example Slot Position S L U (8) S L U (8) S L U (8) S L U (8) S L U (8) S L U (8) S L U (8) S L U (8) Module A (Analogue 64 line) Module B (Digital 32 line) Module C (Digital 16 line) D S L U (8) D S L U (8) D S L U (8) D S L U (8) D S L U (4) D S L U (4) D S L U (4) D S L U (4) FRONT SHELF VIEW LINECNTRLINECNTR LINECNTRLINECNTR LINECNTRLINECNTR PSUPSU PSUPSU PSUPSU SPARESPARE SPARESPARE SPARESPARE SPARESPARE SPARESPARE 4 seconds per line card removal 4 seconds per line card replacement (+ Power reset for some variants)

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 13 Non Preferred Line Card Removal AXE10 shelf example 4 seconds per line card removal 4 seconds per line card replacement Slot Position LICLIC FRONT SHELF VIEW LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC LICLIC MDF 128 pair cable (3 x32 pair cables) 8 pair connector per line card 128 pair cable broken down to 8 pairs per connector. LICLIC POUPOU POUPOU TSCTSC BISSBISS CNADCNAD CLSCLS SLCTSLCT ETBETB ETBETB REUREU EPMCEPMC

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 14 Non Preferred Power Off Line Shelf Groups Removal of power to the concentrator line shelf / line controller module System X  Suitable for providing required PSTN disconnect (2 seconds). However, some variants encountered 30 second delay to service provision on resumption of power. Additionally, faults sometimes raised on resumption of power. AXE10  Suitable for providing required PSTN disconnect (6 seconds). However, resumption of power requires maintenance action before service can be restored (2 – 3 minutes) Note: There is a risk that power supply units will fail when switched on again = Fallback impact

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 15 Non Preferred Make Service Temporary Out Of Service (TOS) Use blocking command to block the service from the customer on the PSTN line System X  Suitable for some variants but failed to provide required PSTN disconnect for some line card variants AXE10  Suitable disconnect for AXE10

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 16 Non Preferred Test Network Disconnection Use ‘test network’ commands to block the service from the customer on the PSTN line System X  Test network failed to provide required PSTN disconnection AXE10  Test network failed to provide required PSTN disconnection

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 17 Non Preferred Transfer Connectivity Point Disconnect MDF TCP Module Only TE disconnect 21CN transfer connection point TE disconnect point Cassette module 1 second per disconnect plug removal 2 – 3 seconds per disconnect plug replacement

Consult21 Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to change. I&M WG 18 End User Experience Outgoing calls  Short break in dial tone at point of 21CN cutover  No service interruption announcement during migration Incoming Calls  Precise detail of service capability will become known upon completion of transfer engineering end to end trials phase.  Incoming call capability will be dependant upon size of number range and customer position within it.  A range of options are being considered as part of the transfer engineering solution to improve these timings.  Principle is to achieve the shortest service capability interruption possible