1. Implementation & Migration Working Group 18 th January 2006 Kevin Young Interconnect & Numbering Services The information in this presentation relates to plans currently under development and subject to consultation, and may be subject to change. Detailed implementation depends upon a number of factors including the capabilities of suppliers and the final 21CN network design. NGS Capacity Check Request Process

2. CP Requires Change of Target NGS for 21CN DLE Migration BT Assesses And Agrees Change of Target NGS BT Internal Process To Implement Change NGS Capacity Check Process Completed CP Decides To Use Original Target NGS Original Target NGS Used Alternative Target NGS Used CP Instigates SIA Contract Dispute Procedure No Yes A A BT Accepts Check Request For Assessment? Yes No CP Submits NGS Capacity Check Request CP Escalates to BAU BT Disparity Resolution Team NGS Capacity Check Request Process Flowchart

3. NGS Capacity Check Request Process Milestones DSAN Issued NGS Capacity CR Forms submitted to BT by CPs cut-off – DSAN Issue + 1 week NGS Capacity CR Assessment start – DSAN Issue + 2 weeks (1 week allowed for iteration between BT and CP to ensure CR is accepted for assessment) NGS Capacity CR Assessment complete & CP notified of result – DSAN Issue + 4 weeks NGS Capacity CR Assessment result accepted by CP or escalated to BT Disparity Resolution Team – DSAN + 5 weeks NGS Capacity CR Assessment result escalation to BT Disparity Resolution Team considered and result communicated to CP – DSAN + 6 weeks

4. NGS Capacity Check Request Process Milestones NGS Capacity Check Request Form: ­ Will be a Pro-Forma ­ Should be submitted separately for each DLE in the tranche covered by the DSAN where a change is required ­ Should contain description of change required ­ Should contain detailed reason for request and justification, including diagrammatic representation and ramifications of CR rejection ­ Should be submitted by the cut-off date for the tranche ­ Should contain BT assessment result, including reasons for rejection where appropriate NGS Capacity Check Requests: ­ Will be assessed as a batch for all CPs for a tranche ­ Will be assessed by the BT team responsible for managing NGS Capacity within the 21CN Programme. NGS Capacity Check is managed through the existing TAM/CP relationship