Consult 21 Interconnect Working Group

1. Consult 21 Interconnect Working Group Ian Self Virtual Capacity Update 5th October 2005 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.

2. Legacy PSTN Interconnect and 21CN end user line migration • Migration of lines to 21CN means DLEs will be closed and legacy interconnect moved to tandem NGS switches • BT proposes charging for legacy interconnect to end user lines as though migration to 21CN had not taken place* * See documented BT Commercial Proposals on Legacy Interconnect

3. Implementation of commercial proposals requires several developments: • Billing of calls at LES rate from NGS Interconnect • Provisional design presented on 12 September • Partitioning of NGS  CP routes and the routing of BT originated calls • Feedback this afternoon • Provision of “Virtual DLE Capacity” between NGS switches and “virtual DLEs” (the number ranges hosted on DLEs prior to migration • VIEC Feasibility completed – update contained in this presentation. • Management of virtual capacity ordered vs. call minutes and the calculation of excess charges • Feasibility Completed • CP input required re algorithm

4. Call Billing (summary of 12 September) • For every selected NGS & Virtual DLE (set of end user number ranges): • Two Options (1) for calls at LES rate (2) : • All calls via NGS • Calls on specific Route ID (3) • EBC files in current format: • All calls – BT provide customised EBC • Route specific – CP uses both customised and standard EBC (4) • Possibility of restriction to selected call types (e.g. CP egress, NTS) • CP selects one option for all interconnect • LES rate subject to rental of qualifying capacity • Route partitioning subject to separate network feasibility study • May suit CPs who bill / verify by route

5. Routing Scenarios (subject to network feasibility) } Tandem Calls DLE A DLE B Virtual Capacity Manage: All Traffic CP Network NGS • Consolidated Route • Tandem / LES partitions (1) Tandem Calls DLE A DLE B Virtual Capacity Manage: LES Traffic (2) CP Network NGS } One DLE Route Individual VIECs • May be replicated for separate traffic streams / CP switches • If CP throttles traffic per DLE for a route dedicated to BT terminating traffic then excess capacity management charges will not occur.

6. Virtual Capacity – product components The VDC component "provisions DLE rate" and has no rental.  The IBC component ensures there is a 2Mbit/s physical port on the NGS The VIEC/virtual CSI charges the distance based rental Two additional migration cases for customers with fibre to non NGS sites

7. Case 1Virtual Capacity – Handover at NGS

8. Virtual Capacity Management • C&W Proposal helpful • ? Need to provision and charge for physical ports • Feas proposes a nominal physical port per E1 VDC – but these ports can carry Tandem traffic. (Alternative would require virtual port component) • CP views requested • ? Assess demand for ppm vs circuit excess charges • Feas recommends ppm as a single simple option • CP choice requested (excess cct option implies requirement to upgrade) • ? Split calculations into day, evening & weekend • Caters for CPs with varying minutes mix e.g. consumer NTS and non friaco dial data • For ST overflow calculate each time band separately • For Circuit overflow use timeband requiring greatest capacity • ? Monthly calculation simplest subject to commercial evaluation • (feas considered hourly / daily calculations) • CP input required re granularity

9. Port / Virtual capacity relationship DLE A = 1 VIEC DLE B = 1 VIEC Tandem Calls require 2 x E1 NGS 3 Physical Ports Required Virtual Port ? • Feas considered 1 physical port per VDC, no Virtual ports • Allows port and CP savings on tandem traffic but not LES traffic • Alternative: Sum of Physical / Virtual ports = sum of virtual capacity required • No port savings but greater opportunity for CP savings since physical ports could be less than sum of VIECs

10. Virtual Capacity – Process permutations: • 3 circuit cases with varying distance / rental components • 2 Routing scenarios (Consolidated NGS or Tandem / LES routes) • Multiple VDC routes per NGS route • Physical capacity less / equal Virtual capacity • 2 excess charge options – circuit+port or ppm • – Single option per CP • Variations by traffic type

11. Conceptual ordering (subject to solution design) • Order relates to: • Specific NGS / Specific CP Switch • All Calls or Specific traffic stream e,g, CPS • Set of end user number ranges / DLE destinations • ISI or CSI • Number of physical E1 ports e.g. 5 (If required then add Virtual ports) • Virtual capacity / VIECs ( = port capacity) • DLE A (remote) = 2 x E1, distance=5km • DLE B (co-located) = 2 x E1, no VIEC charge • Residual Tandem capacity = 1 x E1 • Routing plan entries (may be sent separately) • LES Billing / Excess charges • Route ID / Consolidate NGS • Excess ppm / cct • N.B. • Lead times will take account of need to provision LES rate entries in EBC • Virtual capacity purchased in whole calendar months to align with call billing

12. Additional Slides:

13. Case 2 Virtual Capacity – Co-located DLE / NGS

14. Case 3Virtual Capacity – CSI Circuit