1. MSIL Discussion with Industry Steve Wright/Doug Harrison 11 th January 2006 - Issue 1

2. Implementing a 21 st century networkIn Confidence Disclaimer BT makes no warranty or representation as to the accuracy, completeness or reliability of the information contained within this document. BT shall not be under any liability for loss or damage (including consequential loss) whatsoever or howsoever arising as a result of the use of this document, or any of the information contained within it, by you, your employees, agents or any third party. Copyright © British Telecommunications plc, 2005. All rights reserved.

3. Implementing a 21 st century networkIn Confidence These slides reflect current thinking which may change. We can give no assurances that we will implement what these slides describe. The design and activities are part of a wider OFCOM and industry strategic review consultation and therefore any design and implementation must take account of these activities Any slides depicting interconnect with other operators, or statements regarding changes to products should be understood to be proposals pending above. In particular, there is active debate with industry on future interconnect options and the outcome of these discussions will impact the final design. It should be noted that we are driving to provide standards based interfaces to enable full interworking as required with customers, other operators, ISP etc.

4. Implementing a 21 st century networkIn Confidence 20C Customer Sited Handover (CSH) SDH node CP Premises SDH network Fibre or Radio link Core ADM CP ADM CP ADM Splice in external cable chamber- ODF- DDF –CP ADM PPC DataStream Voice

5. Implementing a 21 st century networkIn Confidence 21C Customer Sited Handover (CSH) (SDH/GFP) MSAN node CP Premises 21CN Fibre or Radio link Core ADM CP ADM CP ADM Splice in external cable chamber- ODF- DDF –CP ADM STM1/4 BB/Voice/Ethernet VC4/GFP Standards Based GE

6. Implementing a 21 st century networkIn Confidence In Span (and Extension) Handover (ISH) SDH node CP Premises SDH or 21CN network No BT provided equipment ISH extension handover in footway box (100m from CP premises) ISH handover in footway box (100m from BT premises) Splice in external cable chamber- ODF- DDF –CP ADM CP ADM Core ADM

7. Implementing a 21 st century networkIn Confidence WDM CSH or ISH Fibre TP SDH GE Legacy SDH 21C SDH 21C GE Legacy SDH 2.5G Wavelengths WDM NTE WDM NTE CP BT

8. Implementing a 21 st century networkIn Confidence Ethernet NTE Ethernet NTE GE/FE GE/10GE BTCP