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BT\'s work on supporting multicast on its new 21CN next-generation network.
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Consult21 1Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
Multicast
27 February 2007
Broadband Working Group Presentation
Consult21 2Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
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
Consult21 3Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
TR-101 REFERENCE MODEL
Regional BroadbandNetwork
Access Network
AccessNode
(DSLAM)
AccessLoop
MDFEthernet
AggregationIP
BBNetworkGateway
L2TS
IP - QoS
L2TP
Customer Prem. Net
CPE
NSP1
ASP1
A10-ASP
A10-NSP
U
User1
User2T
NIDNSP2
A10-NSP
IP - QoS
A10-NSP
V
NSP/BB Network Gateway
Aggregation Network
ATM-Ethernet interworking
VLAN handling Security QoS Multicast / IGMP OAM
ATM-Ethernet interworking
VLAN handling Security QoS Multicast / IGMP OAM
Ethernet/VLAN aggregation QoS OAM Resiliency
Ethernet/VLAN aggregation QoS OAM Resiliency
PPPoE and/or IP services
Bandwidth/QoS policy enforcement
Security Multicast control OAM
PPPoE and/or IP services
Bandwidth/QoS policy enforcement
Security Multicast control OAM
In 21CNcontext, this could be for primary line voice (H.248) transport to the softswitch
This traffic is analogue POTS on the copper so doesn’t need shaping into the DSL payload
Other traffic is via the BNG hierarchical scheduler to ensure QoS & correct provisioning
In 21CNcontext, this could be for primary line voice (H.248) transport to the softswitch
This traffic is analogue POTS on the copper so doesn’t need shaping into the DSL payload
Other traffic is via the BNG hierarchical scheduler to ensure QoS & correct provisioning
Consult21 4Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
*
WBC Architecture
CPEU
BRAS
Broadband Edge Aggregator
Ethernet*
Aggregation Point(20 Nodes)
*
*
MSAN(5500 Nodes)
DSL AccessADSL2+single VCPPPoE or oA(oE only for multicast) dedicated to EU
Access Aggregationcontended, shared amongst multiple EUsPPPoE with IA
Aggregation PointPhysically shared, logically separate per CPComprehensive QoS features
Customer Access linksuncontended, dedicated to each Communications Provider. L2TP or PTA
Consult21 5Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
TR-101 : QUALITY OF SERVICE OPTIONS
DiffServ based IP QoS at the Routing Gateway and the BNG.
QoS models :
Partitioning of bandwidth among the BNGs
Based on business or application characteristics
Each BNG controls its partition -> inefficient use of capacity
Distributed precedence and scheduling
Ethernet QoS in the Access/Aggregation Network
Lower classes will be dropped under congestion
Fairness between classes but NOT amongst users within a class
Hierarchical Scheduling on the BNG
A sequence of scheduling steps to model downstream congestion points (BNG port, Access Node uplink and DSL synch rate)
Can be used in combination with the above for per user/session control
Consult21 6Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
BRAS downstream QoS - SVLAN view
Realtime
Assured rate (ADQ)
Best-Effort
SVLAN shapedSVLAN shapedto specifiedto specifiedbandwidthbandwidth
• Guaranteed access to SVLAN
• Administrative maximum set for ADQ CAC process
• Guaranteed minimum bandwidth, with access to unused Realtime & ADQ allocations
• Arbitrary mix of Priority & Normal traffic, depending on EU traffic patterns
• Priority access to SVLAN for guaranteed bandwidth & low jitter
• Maximum bandwidth set to protect other classes
Bandwidth poolsBandwidth pools
Realtime
Assured rate (ADQ)
Best-Effort
SVLAN shapedSVLAN shapedto specifiedto specifiedbandwidthbandwidth
• Guaranteed access to SVLAN
• Administrative maximum set for ADQ CAC process
• Guaranteed minimum bandwidth, with access to unused Realtime & ADQ allocations
• Arbitrary mix of Priority & Normal traffic, depending on EU traffic patterns
• Priority access to SVLAN for guaranteed bandwidth & low jitter
• Maximum bandwidth set to protect other classes
Bandwidth poolsBandwidth pools
Consult21 7Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
BRAS downstream QoS - CVLAN view
Realtime
Hi weight
Lo weight
Assured/ADQ
Priority
Normal
Highest priority level
Rate-limit
Rate-limitCVLAN shaped to specified max. bandwidth, and competes for SVLAN
bandwidth with other CVLANs
X
• Weight set higher for Elevated EUs than Standard EUs, to give greater share of SVLAN for BE
Best-Effort
Use of either priority level or weighting to guarantee bandwidth
Realtime
Hi weight
Lo weight
Assured/ADQ
Priority
Normal
Highest priority level
Rate-limit
Rate-limitCVLAN shaped to specified max. bandwidth, and competes for SVLAN
bandwidth with other CVLANs
X
• Weight set higher for Elevated EUs than Standard EUs, to give greater share of SVLAN for BE
Best-Effort
Use of either priority level or weighting to guarantee bandwidth
Consult21 8Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
*
WBC Multicast VLAN Architecture
CPEU
BRAS BEA
Ethernet*
Aggregation Point(20 Nodes)
*
*
MSAN(5500 Nodes)
• Multicast in IPoE • BB & IGMP in PPPoE• 1 VC
• Multicast in IPoE • Snoop IGMP in PPPoE • 1 VC
• Terminate PPPoE• Terminate IGMP• Re-profile EU
Consult21 9Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
*
WBC Replication Points
CPEU
BRAS BEA
Ethernet*
Potential Multicast Replication Points
Aggregation Point(20 Nodes)
*
*
MSAN(5500 Nodes)
Consult21 10Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
Multicast Issues to Consider
21C
Very large L2 domains with multiple tiers
Large number of possible L2 replication points
Use tunnelling as well as routing in the L3 domain
Routers not currently multicast enabled
Have to balance the efficiency of auto-configuration via PIM against stability, management control and the ability to do troubleshooting
IGMP snooping, querying and reporting can produce a significant load on network elements
Need to protect network elements against surges in signalling traffic
Typical CP Requirement
Large number of channels…
Viewing still concentrated in a very small number of channels
The 5 Terrestrial channels still dominate viewing numbers
Channel changing will be correlated in time to a significant degree
Could have up to 500 viewers on an MSAN watching the same programme
Outside the 5 channels, numbers per MSAN per programme will be very much lower
May need a tiered solution….
Consult21 11Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
Phase 1 Multicast Architecture
Multicast across WBC networkIGMPv2 joins to BRASStatic configured Multicast between BEA to cMSANStatic Multicast Routing
Consult21 12Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
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 suppressedNo 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
*
Consult21 13Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
Multicast CAC
CMSAN
BRAS
STB
CPE
IGMP
CACM/C
HeadEnd
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 rateA/S statusM/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 interfacesover single VC
Consult21 14Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
Multicast Proof of Concept
PoC under construction using existing models at Adastral Park Verify vendor capability including interworking
Explore multiple options - Identify technical architecture
Technology Up-skilling
Develop Showcase Capability
Capability for CP’s to take part in PoC to interwork CPE and Head end equipment
Consult21 15Information is subject to change and is for discussion purposes only. Any dates/timings are the current anticipated timescales and may be subject to
change.Broadband
PoC Target Network
Home Access Metro CP
Application / Content
BRAS
Eth SWRouter
Services(RADIUS, ADQ etc.)
Model IP Network
Eth SWRouter
Adastral IP Network
PC
STB
CPE Router
Test Content
Router
(PIM)
MSAN
GE