BT multicast plans 2007


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BT\'s work on supporting multicast on its new 21CN next-generation network.

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BT multicast plans 2007

  1. 1. Multicast 27 February 2007 Broadband Working Group Presentation
  2. 2. Technical Roadmap -Q2 Launch Q2 Q4 Q6 Q8 Beta Trial WBC as per product Spec. Improved control over line stability/speed Multicast – IGMP to AP 1024 upstream on ADSL2+ Time table shows Quarters before and after Launch ADSL2+ Annex M Multicast – IGMP to CMSAN
  3. 3. TR-101 REFERENCE MODEL <ul><li>ATM-Ethernet interworking </li></ul><ul><li>VLAN handling </li></ul><ul><li>Security </li></ul><ul><li>QoS </li></ul><ul><li>Multicast / IGMP </li></ul><ul><li>OAM </li></ul><ul><li>Ethernet/VLAN aggregation </li></ul><ul><li>QoS </li></ul><ul><li>OAM </li></ul><ul><li>Resiliency </li></ul><ul><li>PPPoE and/or IP services </li></ul><ul><li>Bandwidth/QoS policy enforcement </li></ul><ul><li>Security </li></ul><ul><li>Multicast control </li></ul><ul><li>OAM </li></ul><ul><li>In 21CNcontext, this could be for primary line voice (H.248) transport to the softswitch </li></ul><ul><li>This traffic is analogue POTS on the copper so doesn’t need shaping into the DSL payload </li></ul><ul><li>Other traffic is via the BNG hierarchical scheduler to ensure QoS & correct provisioning </li></ul>
  4. 4. WBC Architecture CP EU BRAS B roadband E dge A ggregator Ethernet Aggregation Point (20 Nodes) MSAN (5500 Nodes) DSL Access ADSL2+ single VC PPPoE or oA (oE only for multicast) dedicated to EU Access Aggregation contended, shared amongst multiple EUs PPPoE with IA Aggregation Point Physically shared, logically separate per CP Comprehensive QoS features Customer Access links uncontended, dedicated to each Communications Provider. L2TP or PTA * * * *
  5. 5. TR-101 : QUALITY OF SERVICE OPTIONS <ul><li>DiffServ based IP QoS at the Routing Gateway and the BNG. </li></ul><ul><li>QoS models : </li></ul><ul><ul><li>Partitioning of bandwidth among the BNGs </li></ul></ul><ul><ul><ul><li>Based on business or application characteristics </li></ul></ul></ul><ul><ul><ul><li>Each BNG controls its partition -> inefficient use of capacity </li></ul></ul></ul><ul><ul><li>Distributed precedence and scheduling </li></ul></ul><ul><ul><ul><li>Ethernet QoS in the Access/Aggregation Network </li></ul></ul></ul><ul><ul><ul><li>Lower classes will be dropped under congestion </li></ul></ul></ul><ul><ul><ul><li>Fairness between classes but NOT amongst users within a class </li></ul></ul></ul><ul><ul><li>Hierarchical Scheduling on the BNG </li></ul></ul><ul><ul><ul><li>A sequence of scheduling steps to model downstream congestion points ( BNG port, Access Node uplink and DSL synch rate) </li></ul></ul></ul><ul><ul><ul><li>Can be used in combination with the above for per user /session control </li></ul></ul></ul>
  6. 6. BRAS downstream QoS - SVLAN view
  7. 7. BRAS downstream QoS - CVLAN view
  8. 8. WBC Multicast VLAN Architecture CP EU BRAS BEA Ethernet Aggregation Point (20 Nodes) MSAN (5500 Nodes) <ul><li>Multicast in IPoE </li></ul><ul><li>BB & IGMP in PPPoE </li></ul><ul><li>1 VC </li></ul><ul><li>Multicast in IPoE </li></ul><ul><li>Snoop IGMP in PPPoE </li></ul><ul><li>1 VC </li></ul><ul><li>Terminate PPPoE </li></ul><ul><li>Terminate IGMP </li></ul><ul><li>Re-profile EU </li></ul>* * * *
  9. 9. WBC Replication Points CP EU BRAS BEA Ethernet Potential Multicast Replication Points Aggregation Point (20 Nodes) MSAN (5500 Nodes) * * * *
  10. 10. Multicast Issues to Consider <ul><li>21C </li></ul><ul><li>Very large L2 domains with multiple tiers </li></ul><ul><li>Large number of possible L2 replication points </li></ul><ul><li>Use tunnelling as well as routing in the L3 domain </li></ul><ul><li>Routers not currently multicast enabled </li></ul><ul><li>Have to balance the efficiency of auto-configuration via PIM against stability, management control and the ability to do troubleshooting </li></ul><ul><li>IGMP snooping, querying and reporting can produce a significant load on network elements </li></ul><ul><li>Need to protect network elements against surges in signalling traffic </li></ul><ul><li>Typical CP Requirement </li></ul><ul><li>Large number of channels… </li></ul><ul><li>Viewing still concentrated in a very small number of channels </li></ul><ul><li>The 5 Terrestrial channels still dominate viewing numbers </li></ul><ul><li>Channel changing will be correlated in time to a significant degree </li></ul><ul><li>Could have up to 500 viewers on an MSAN watching the same programme </li></ul><ul><li>Outside the 5 channels, numbers per MSAN per programme will be very much lower </li></ul>May need a tiered solution….
  11. 11. Phase 1 Multicast Architecture Multicast across WBC network IGMPv2 joins to BRAS Static configured Multicast between BEA to cMSAN Static Multicast Routing
  12. 12. Phase 2 Multicast Architecture MSAN BRAS AMSAN Dynamic joins via IGMP snooping Static replication PIM-SM or SSM, not DM Dynamic joins via IGMP Green IGMP requests suppressed Red IGMP reports supressed Dynamically send newly requested streams Dynamic joins via IGMP Black IGMP reports suppressed No green IGMP queries - Mixture of statically configured and dynamic paths to get a scalable system – BW and control - Static paths are end to end or partial - Need to optimise where paths, requests, reports and queries originate/terminate * * * *
  13. 13. Multicast CAC C M S A N BRAS STB CPE IGMP CAC M/C Head End Multicast Stream IPoE Multicast IGMP/PPPoE Multicast VLAN Broadband VLAN Video Play Request Multicast Join Authorisation M/C reserve M/C granted D/S line rate A/S status M/C status IGMP CP BTW CP IGMP signals M/C join to BRAS which re-profiles EU CAC function will have to maintain state on EU multicast session so that a subsequent request for an advanced service takes into account the bandwidth already in use for multicast BB Customer Reporting (BBCR) 2 logical interfaces over single VC
  14. 14. Multicast Proof of Concept <ul><li>PoC under construction using existing models at Adastral Park </li></ul><ul><ul><li>Verify vendor capability including interworking </li></ul></ul><ul><ul><li>Explore multiple options - Identify technical architecture </li></ul></ul><ul><ul><li>Technology Up-skilling </li></ul></ul><ul><ul><li>Develop Showcase Capability </li></ul></ul><ul><li>Capability for CP’s to take part in PoC to interwork CPE and Head end equipment </li></ul>
  15. 15. PoC Target Network Home Access Metro CP Application / Content BRAS Eth SW Router Services (RADIUS, ADQ etc.) Model IP Network Eth SW Router Adastral IP Network PC STB CPE Router Test Content Router (PIM) MSAN GE