MSAN access & interconnection Consult21 Industry Working Group 10 Jan 2005

1. MSAN access & interconnection Consult21 Industry Working Group 10 Jan 2005

2. AIMS AND AGENDA • Positioning of this Industry Working Group and of this specific meeting • Architecture presentation and discussion (BT) • in response to industry input • Industry presentation(s) and discussion • Summary and next steps

3. SCOPE OF MEETING • To explore platform implications of ‘MSAN interconnect’ to inform scheduled product working group discussions • To reach a shared understanding of: • possible architectures • platform implications • relative cost impact on products • Consultation in parallel with Ofcom consultation • BT believes this to be a product cost management rather than an engineering problem

4. CONSULT21 FEEDBACK • Views of infrastructure players: • don’t wish to be restricted by BT’s design or preferences • for any site, want prices for MSAN access or interconnect products for all services (broadband, PPCs, PSTN voice) • where they have their own backhaul, they want to use it for all services (LLU, broadband, PPCs, PSTN voice) • ‘Equivalence of input’ regulatory principle • Scenarios drawn up with infrastructure players • BT to provide cost implications of scenarios to give a feel for viability

5. What is Interconnect? What is Access? • ‘Interconnect’ is between peer-level service control and switching / routing functions • the control protocol needs to be defined (eg, ISUP, SIP-I) • ‘Access’ is the media and control protocol paths between the end user and the service PoP Example of dial IP Content Content provider - access to end user End user Router BRAS ISP - access to end user Router Service control Service control PSTN provider - access to end user Switch Switch Interconnect For discussion purposes only.No implementation assurance implied or intended

6. ACCESS & INTERCONNECT PLATFORM SCENARIOS BT OCP To Core Soft Switch Soft Switch Metro site L3 Metro interconnect BRAS Router L3 Metro Router L2 Metro access Switch L2 switch L3 Aggregator access L3 Aggregation Router Router Aggregator site L2 Aggregator access MSAN L2 Aggregator Switch Copper shelf DSLAM Physical media access (LLU) Main Distribution Frame HDF Subtended aggregator site Remote MSAN End user End user For discussion purposes only.No implementation assurance implied or intended

7. SOFT LLU - OFCOM DIAGRAM Logical Schematic of Proposed Soft LLU from OFCOM

8. INTERCONNECT REALITIES • What are the realities of today’s interconnect? • Regulatory drive for infrastructure competition and build-out • LLU provides ultimate opportunity for infrastructure competition for current and next-generation network applications • OCPs typically apply a logical process to make ‘build versus buy’ decisions in network expansion

9. RELATIVE COSTINGS Base case • No access • Broadband / data-only access • Broadband / data and PSTN voice access • Relative cost cf with overall network Cost of additional ports for OCP connect + cost of L2 switching As (2) + L3 routing + MGW at MSAN

10. COSTING SCENARIOS • Need to recognise that all sites are not equal… • Scenarios addressed: • MSAN is one of top 100 (Metro location) • NB No commercial advantage if co-located ! • MSAN is in range 100-2000 (Likely LLU site) • The most critical to understand • MSAN is in range 2000+ (unlikely LLU site) • Costs likely to be disproportionately larger • Build as incremental cost on a nominal “base case” • potentially very low for L2 access • Higher for L3 access (Router, MGW, etc) • For each scenario – assume a realistic number of customer lines, and OCP interconnects (5 OCPs at each MSAN ?)

11. LOGICAL FUNCTIONS INSIDE MSAN - NO ACCESS • Copper Shelf & Fibre Shelf – Currently proposed MSAN components • No OCP connection direct to MSAN, no additional gateways • OCP connection at Metro node – with “connectivity” provided by MSAN if needed • Relative cost of providing this = 1 unit • Costing scenarios: • MSAN is one of top 100 • MSAN is in range 100-2000 • MSAN is in range 2000+ MSAN Copper Shelf Copper Shelf Fibre Shelf To BT

12. LOGICAL FUNCTIONS INSIDE MSAN - BROADBAND / DATA-ONLY ACCESS • Layer 2 switch - at MSAN sites that would otherwise only offer basic SDH functionality – this could be a separate device or fully functional fibre box • L2 OCP connection at MSAN • L2 turnaround within MSAN infrastructure • Relative cost of providing this = 1+x units • Costing scenarios: • MSAN is one of top 100 • No additional functionality required - apart from additional ports. • MSAN is in range 100-2000 • No additional functionality required - apart from additional ports. • MSAN is in range 2000+ • Will require L2 switching capability – requires additional fully functional Fibre box at some locations. MSAN Copper Shelf Copper Shelf L2 switch Fibre Shelf To BT To OCP Indicates additional component required(over and above current 21CN Architecture) For discussion purposes only.No implementation assurance implied or intended

13. LOGICAL FUNCTIONS INSIDE MSAN - PSTN VOICE ACCESS • Router – capable of handling ALL voice traffic at an MSAN, call by call routing required • IP BGW – Border Gateway. Provided as one per OCP. Shown connected via Fibre Shelf, but could be a direct GE connection to an OCP • Media Server – provides announcement capabilities – including 3 party call with one BT & one OCP parties (Otherwise, traffic would need to be backhauled to Metro node for these services – which defeats the lowest backhaul cost argument). BT is also required to provide a specific announcement when OCP connections are busy, indicating that the call is unable to be connected due to congestion on the BT network. Connected to fibre box due to port and functionality limitations within copper element. MSAN Copper Shelf Copper Shelf Media Server Ethernet interface aggregating all voice traffic. Router Fibre Shelf IP BGW To BT To OCP Indicates additional component required(over and above current 21CN Architecture) For discussion purposes only.No implementation assurance implied or intended

14. COSTING SCENARIO - PSTN VOICE ACCESS • L2 OCP connection at MSAN • L2 turnaround within MSAN infrastructure • No requirement to support local call control under MSAN isolation • NB: L2 switching component removed for clarity – still required for Data and Broadband access • Relative cost of providing this = 1+x+y units • Costing scenarios: • MSAN is one of top 100 • Capability should already be available at Metro node ie no additional cost (?) • MSAN is in range 100-2000 • Will require capability highlighted in orange plus fibre MSAN ports • MSAN is in range 2000+ • Will require capability highlighted in orange plus fibre MSAN capability at some locations plus ports MSAN Copper Shelf Copper Shelf Media Server Router Fibre Shelf IP BGW To BT To OCP Indicates additional component required(over and above current 21CN Architecture) For discussion purposes only.No implementation assurance implied or intended

15. RELATIVE COSTS FOR PSTN VOICE ACCESS • The following is capex only • covers costs of router and session border control with redundancy • excludes media server and OCP fibre ports • based on indications from vendors - subject to change • Does not include opex costs For discussion purposes only.No implementation assurance implied or intended

16. CONCLUSION • MSAN interconnect is technically possible, commercial issues dominate • Broadband / data-only access needs no additional functionality for the top 2000 MSAN sites, apart from additional fibre ports • PSTN voice access needs significant additional functionality, adding over 50% to the capital costs of MSANs for 30000-line sites For discussion purposes only.No implementation assurance implied or intended