internet tv today's and tomorrow's
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TELEFÓNICA I+D
© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Internet TV Today’s and Tomorrow’s Telefonica’s IPTV architecture and workload analysis
© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Pablo Rodriguez (Telefonica Research) Meeyoung Cha (MPI-SWS)
ROADS’08 Keynote
TELEFÓNICA I+D
© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Live content Lower video resolution Tens of channels A few genres Simple channel chagnes A shared experience
Television yesterday
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© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Television today
Live & on-demand High-definition Content diversity Use of channel guides Personalization Mobility
Internet TV has led to many innovations
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TELEFÓNICA I+D
© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Part 1. IPTV basics
Part 2. Architectural alterna6ves
Part 3. TV viewing habits
Part 4. Future challenges
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TELEFÓNICA I+D
© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Internet TV (IPTV)
Delivering television channels over an IP network
Three most popular types
1. Telco’s nation-wide provisioned service
By AT&T, France Telecom, Korea Telecom, Telefonica
2. Over-the-top box-based video-on-demand
Apple TV, Vudu box, Sony’s Internet video link
3. Over-the-top Web TV
Joost, Zattoo, VeohTV, Babelgum, BBC’s iPlayer
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Traffic patterns over the years
Over-the-top videos already generate more traffic than the entire Internet backbone in 2000
Videos will be account for nearly 50% of all Internet traffic by 2012
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© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Internet TV (IPTV)
Delivering television channels over an IP network
Three most popular types
1. Telco’s nation-wide provisioned service
By AT&T, France Telecom, Korea Telecom, Telefonica
2. Over-the-top box-based video-on-demand
Apple TV, Vudu box, Sony’s Internet video link
3. Over-the-top Web TV
Joost, Zatoo, VeohTV, Babelgum, BBC’s iPlayer
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© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Telco IPTV
Major providers worldwide — France (Free, Orange, Neuf Cegetal), Hong Kong (PCCW) — Typically bundled as triple-play (with IP phone and Internet access)
Number of subscribers 2007-2013
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© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Telco’s IPTV FAQs
How is IPTV different from cable or traditional TV? — In traditional TV, all the channels delivered to the TV set — IPTV streams only the channel user requests massive content — Customers assigned unique addresses personalized service
How is IPTV different from Web-based videos? — Web services based on kilobits of end-to-end path
(with high-contention in the backbone) — IPTV requires megabits of steady end-to-end bandwidth
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© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
And multicast finally happened…
Multicast arrived way too soon, in 1988
To make matters worse, we also built the killer applications 20 years too soon (e.g., vic, vat, rat)
…. and we never knew how to monetize them…
Until, Telco’s took it over and implemented IPTV…!
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Set‐top box
TV
DSLAM
customer premise
TV head‐end
IP backbone
All 150 channels
1‐2 channels
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Internet (1 Mb/s)
VoIP
IPTV (5 Mb/s) 1‐2 channels
Last mile (6 Mb/s)
Scenario of watching live TV
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Set‐top box
TV
IP backbone VoD unicast
Scenario of watching VoD
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TV head‐end Regional VoD servers
Access network
TELEFÓNICA I+D
© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Part 1. IPTV basics
Part 2. Architectural alterna6ves
Part 3. TV viewing habits
Part 4. Future challenges
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© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Find paths that connect each destination to TV sources under any failures
TV head-end
Regional Network
Video Hub Office (VHO)
customers
Regional Network
Backbone Distribution Network
TV head-end
VHO
VHO
Broadcast TV VoD
Regional Network
Design goal
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Architectural comparison
IP multicast
TV head-end
IP router
DSLAM
STB
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P2P
Architectural comparison
IP multicast
TV head-end
IP router
DSLAM
STB
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cheaper core &
asynchronous/VCR
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Potential P2P‐TV solution for telcos
Implementation — Home gateways or set-top boxes — Dedicated bandwidth for IPTV (downstream) — Symmetric provisioning (upstream) — Topology-aware peer selection
Goal — Reduce backbone traffic and loads on video servers
while enabling asynchronous and VCR viewing
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User’s channel change input
IGMP messages collected across all 700 DSLAMs
Trace example
Timestamp
DSLAM IP
Set-top box IP
Multicast channel IP
Action (join or leave) set‐top‐box
DSLAM
Collected at IP mul6cast
switching point
Live TV data collection
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Static IP multicast can waste huge bandwidth
Potential problem for serving massive content
Sta6c IP mul6cast (# channels X # DSLAMs)
Actual # streams consumed (on average 17% load of sta6c tree)
High poten6al for p2p IPTV # TV
streams at DSLAMs
Reduction in Edge Links Cost: P2P
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VoD server load without P2P (100%)
VoD load with P2P (5%)
P2P traffic served within DSLAM (80%)
Reduction in VCR server load: P2P
Storing content at peers allow for rewind features P2P can reduce the load on the video servers by 95%
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TELEFÓNICA I+D
© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Part 1. IPTV basics
Part 2. Architectural alterna6ves
Part 3. TV viewing habits
Part 4. Future challenges
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© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Traditional TV research
Nielsen media research — Pick samples (10,000 homes in USA) — Install metering devices at sampled homes — Collect viewing statistics daily — Extrapolate statistics across a nation
Drawbacks — Potential bias in sampling — Awareness of metering alters user behaviours
Challenges: gathering data at a large enough scale
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Collected raw data from a large IPTV system
A quarter million users from a large IPTV system
(entire subscribers within a nation)
150 channels including various genres
(free-to-air, children, sports, movies, music, etc)
Collected traces for 6 months
Largest-scale study of TV viewing patterns!
Case study on a Telco’s network
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60% of all channel changes happen within 10 seconds
Infrastructure must support fast channel changes
Assist users find interesting programs more quickly
Channel holding times
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Each user is in one of the three states at any given time
Active session: consecutive time spent surfing or viewing
Three user modes
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Gradual audience ramp‐up (asynchronous arrival)
High churn of viewers
Strong membership among users
Per‐program behavior
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90% of online viewers at any given time watch 20% of channels
Behavior well-described by the Pareto principle
Channel popularity
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Channel change probability
Probability of switching to channel y after joining channel x
60% linear
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© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Channel viewing probability
Probability of viewing channel y after viewing channel x
67% non‐linear
60% within genre
17% to the same channel
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© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
3-state Markov model
Cluster users by deviation from the average pattern
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Browse Away
View
0.77 0.19
0.04 0.57
0.35
0.08
0.47
0.32
0.21
Heavy Browser
Focused Viewer
Light User
Average User
40%
25%
15%
20%
Clustering users by channel change patterns
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Clustering users by active times
Used Non-negative matrix factorization (NMF) to find 3 types of users
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Night Owls 25%
Always-On 50%
Early-birds 25%
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IPTV trace methodology — Complete raw data of viewing patterns (no need to sample)
Implications for architecture — Must support for fast channel changes — Must handle high churn during commercials — Can reflect the Pareto channel popularity
Implications for viewing guide — Need to assist channel browsing in the presence of massive content
(10 hours of content uploaded on YouTube every minute!) — Need smart search and personalized suggestions
(based on user clustering studies)
Summary of viewing habits
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TELEFÓNICA I+D
© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Part 1. IPTV basics
Part 2. Architectural alterna6ves
Part 3. TV viewing habits
Part 4. Future challenges
33
TELEFÓNICA I+D
© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Advanced features for the future
Interactivity — User participation on the fly, real-time feedback to broadcasters — Education, games, karaoke on-demand, voting (e.g., American idol)
Time-shifted or asynchronous — Watch content at convenient times
Personalization and search — Program recommendations, target advertisements — More opportunities for accessing long tail content — Synch with mobile TV content — Customization (e.g., local weather and traffic news)
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Challenges
Network capability — Support for end-to-end quality-guaranteed path — Do we have enough bandwidth to carry all asynchronous traffic?
Real-time processing of massive data — Strong need to assist users with content search — Need interdisciplinary research for better understanding users
Privacy issues — Protect user identity — Sensitive viewing data
Content diversity issues — Should Telcos keep walled-garden service?
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TELEFÓNICA I+D
© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Executive summary
IPTV different from Web applications and imposes challenges on backbones — live streaming, planetary coverage, end-to-end bandwidth guarantee
Architectural alternatives — IP multicast — Peer-to-peer (P2)
Workload analysis of TV viewing behaviours — High user churn — Zipf-like channel popularity — Linear channel changes and non-linear viewing — Strong membership per program
Future challenges — Interactivity, time-shifted, long-tail content, personalization
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TELEFÓNICA I+D
© 2007 Telefónica Investigación y Desarrollo, S.A. Unipersonal
Lessons learned from our IPTV research
Exci6ng research ahead!
Future architecture must handle high user churn and support massive content and 6me‐shiWed service
Users will need assistance in program discovery & search
IPTV is the largest networking problem to date
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