AMT Multicast Trials Patricia McCrink pmccrinkattcom 11092009 Outline Page 2 ATampT Trial Activity AMT Multicast Motivation Overview of Trial Technical Learnings Opportunities for Further Discussion ID: 383334
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Slide1
AT&TAMT Multicast Trials
Patricia McCrink
pmccrink@att.com
11/09/2009Slide2
Outline
Page
2
AT&T Trial Activity – AMT Multicast
Motivation
Overview of Trial
Technical Learnings
Opportunities for Further Discussion
Improved standardization & developmentSlide3
AT&T AMT Multicast – Motivation
Multicast will play a critical role in cost-effective delivery of content for both network and content providers
However, the Internet is not currently universally multicast capable – especially broadband access networks and home network equipment such as RGs (Residential Gateways)
As an interim solution, use AMT (Automatic IP Multicast without Explicit Tunnels)
(1)
to tunnel through non-multicast-capable networks
(1) IETF Draft “draft-ietf-mboned-auto-multicast-09”, June 27, 2008
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3Slide4
Automatic Multicast Tunneling
PC
ATM
Broadband Access POPs
Aggregation
Subscriber Premises
Core POPs
Typical Current Network
Access Router
Access Router
Core Router
Core Router
Hub Router
BRAS
DSLAM
RG
HR
CE
CE
Native-Multicast End-to-End
PC
Ethernet
Broadband Access POPs
Aggregation
Subscriber Premises
Core POPs
Multicast Network - Target
Access Router
Access Router
Core Router
Core Router
Hub Router
BRAS
DSLAM
RG
HR
CE
CE
Native-Multicast Backbone
Tunneled-Multicast Access
Multicast Network with AMT
ATM
Broadband Access POPs
Aggregation
Subscriber Premises
Core POPs
Access Router
Access Router
Core Router
Core Router
Hub Router
BRAS
DSLAM
RG
HR
CE
CE
AMT Relay
PC
AMT Client
Multicast capable and ready
Multicast incapable
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4Slide5
AT&T AMT Multicast TrialsOverview
Use PIM-SSM (Protocol Independent Multicast – Source Specific Multicast) over AT&T multicast-capable CBB (Core Backbone) network
AT&T-developed AMT Relay and GW (Gateway)
End-to-end Service delivery perspective
Integrated with AT&T CDN (Content Delivery Network)
Content-request handling/routing logic
Coexistent with unicastService Logic interacting with PC Client
Seamless failover
Service Assurance
Accounting/Reporting
AAA (future)
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5Slide6
AT&T AMT Multicast Trial Architecture
Content Ingest
AT&T Multicast
Enabled Network
Non Multicast
Enabled Networks
AMT
Relay
AMT
Relay
Multicast Media Server
ICDS Unicast Delivery
Unicast delivery to end users without AMT multicast capabilities
AMT
GW
AMT
GW
AMT
GW
AMT
GW
4
3
1
End user requests content and is routed to CDI
2
3
4
CDI scans end user PC for multicast capabilities, enables download of AMT GW, if necessary, and provides multicast source and group address (S,G) to PC
End user PC sets up tunnel with nearest AMT Relay and joins multicast stream to receive content
CDI determines that multicast is an available technology for this content delivery
Content Delivery Intelligence
2
Existing ICDS
(1)
Component
Multicast Service Component
Multicast Network Component
Unicast
Multicast
AMT Multicast
Signaling/Data
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6
1
(1)
ICDS – AT&T Intelligent Content Distribution ServiceSlide7
AT&T AMT Multicast TrialsWhat has worked well
Page
7
Quality of AMT multicast perceived as good as unicast
Pushing GW client, as needed
Pushing appropriate stream to user
Anycast Routing for AMT Relays
Content Ingest
AT&T Multicast
Enabled Network
Non Multicast
Enabled Networks
AMT
Relay
AMT
Relay
Multicast Media Server
ICDS Unicast Delivery
AMT
GW
AMT
GW
AMT
GW
AMT
GW
Content Delivery Intelligence
Unicast
Multicast
AMT Multicast
Signaling/Data
Handling home network environments (e.g. multiple PCs behind NAT, WiFi)
Performance & scalability of Relay (Server-based for Trial)
Tuning MTU on Media Server to accommodate AMT encapsulation and avoid fragmentation
Accounting information uploaded from PCSlide8
AT&T AMT Multicast TrialsFailure Recovery Model
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8
Content Ingest
Non Multicast
Enabled Networks
AMT
Relay
AMT
Relay
Multicast Media Server
ICDS Unicast Delivery
AMT
GW
AMT
GW
AMT
GW
Unicast
Multicast
AMT Multicast
Signaling/Data
1
2
4
AMT Relay
advertises anycast route for Discovery. Once GW discovers Relay, uses its unicast address.
AMT GWs
can detect Relay failure and “Rediscover” new Relay
1
AMT Relay fails mid-stream
Example:
2
AMT GW detects failure and Rediscovers alternate Relay
Rejoins stream via alternate Relay
3
3
If Media Player times out before stream resumes, should fail over to unicast in playlist
4
AT&T
Multicast
Enabled
Network
Media Player
should allow failover from one stream to another on playlist (last one unicast)
Multicast media servers
could also use anycast for their source address
Unicast media server
redundancy as todaySlide9
AT&T AMT Multicast TrialsTechnical Learnings
Multicast in General
Multicast not universally supported on client devices/players
In particular need IGMP V3
Trials so far limited to:
Windows XP, Vista
Windows Media PlayerPresence of IGMP V2 causes PC with AMT GW, Relay to downgrade from V3 – incompatible with PIM-SSMAMT-RelatedFirewall issues blocking AMT Port in corporate environments - Network & PC based
Allowing native multicast when available (i.e. AMT GW seamlessly turning on/off as needed)
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Technical Learning
IGMP V2 Presence on LAN
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10
AT&T Multicast
Enabled Network
Non Multicast
Enabled Networks
AMT
Relay
AMT
Relay
Multicast Media Server
AMT
GW
AMT
GW
AMT
GW
Unicast
Multicast
AMT Multicast
Signaling/Data
Home router is IGMP V2
PC reverts to V2
Cannot join (S,G) via PIM-SSM without mapping
IGMP V2 Querier
Content Ingest
ICDS Unicast Delivery
1
2
3
4
Causes PC to revert to V2
Though playlist pushed to PC has (S,G), Media Player issues V2 join (*,G)
Unicast delivery is required
Without mapping configured, Relay cannot make PIM-SSM join and AMT fails
1
2
3
4
5
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Technical LearningChanging User Network Environments
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Unicast
Multicast
AMT Multicast
Signaling/Data
Non Multicast
Enabled Networks
Multicast Media Server
User in office
AMT GW should
not
intercept IGMP joins
Corporate
Intranet
(Multicast capable)
User/End Device moves
User/end device moving between environments (native multicast, AMT, unicast-only)
Non Multicast
Enabled Networks
AMT
Relay
AMT
Relay
Multicast Media Server
AMT
GW
User at home
AMT GW pushed for multicast content
AT&T Multicast
Enabled
Network
Don’t want AMT client to intercept and Discover Relay in native multicast capable settingSlide12
Opportunities for Further DiscussionImproved standardization & development
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12
Multicast in general
Support multicast (IGMP V3) in all devices/media players, OS
Media Players should support mid-stream failover in playlist
Ability to override IGMP V2 downgrade or selectively ignore V2 queries
AAA-like function for multicast
Service Assurance
AMT-Related
Firewalls - consistent approach to allowing AMT port
AMT Relay function integrated into network platforms
AMT GW function integrated into end user software and transparent to end user
Where to integrate AMT GW in home environment?
On each client as separate host,
On RG, modem, or home router, or
On “always-on” host acting as GWSlide13
Backup Slides
Page
13Slide14
Opportunities for Further DiscussionHome Network Configurations
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AT&T Multicast
Enabled Network
Non Multicast
Enabled Networks
AMT
Relay
Multicast Media Server
AMT
GW
AMT
GW
Unicast
Multicast
AMT Multicast
Signaling/Data
Variations in home networks:
NAT behind modem/router or DMZ/sharing public ip address
WiFi/Wired
PPPoE on end device or modem, 1483B, etc.
Where to integrate AMT GW in home environment?
On each client as separate host,
On RG, modem, or home router, or
On “always-on” host acting as GW (not shown)
AMT
GW
Web TV
Box
iPhone
Broadband
Modem/Router
RG
AMT
GW
e.g. Android
AMT
GW
AMT GW could be incorporated into end device
AMT GW could be incorporated into home GW device
AMT
GW
AMT
GW
AMT
GW
OR
Broadband
Modem/Router
AMT
Relay
Devices – PCs, TVs, mobile phones/PDAs
Variations in PC OS, Media players, browsers, firewallsSlide15
Glossary
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15
AAA
Authentication, Authorization, and Accounting
AMT
Automatic IP Multicast without Explicit Tunnels
BRAS
Broadband Remote Access Server
CBB
Common Backbone
CDN
Content Delivery Network
GW
Gateway
HR
Home Router
ICDS
AT&T Intelligent Content Distribution Service
IGMP
Internet Group Management Protocol
NAT
Network Address Translation
PIM-SSM
Protocol Independent Multicast-Source Specific Multicast
RG
Residential Gateway
WMP
Windows Media Player