alex bikfalvi universidad carlos iii de madrid imdea networks institute
TRANSCRIPT
Peer-to-Peer Televisionfor the
Next Generation Networks
Alex BikfalviUniversidad Carlos III de Madrid IMDEA Networks Institute
2
Who am I?• Doctoral student at Universidad Carlos III de
Madrid2006
2007
2008
2012
• Engineering degree from Universitatea Tehnică din Cluj-Napoca (Romania)
• Network management, measurements and quality of service• Part of work done at Universitat Politècnica de Catalunya• Research assistant at the IMDEA Networks Institute (Madrid)• Peer-to-peer networks, content distribution
• Master degree from Universidad Carlos III de Madrid• Peer-to-peer video in next generation networks
• Expected doctoral degree at Universidad Carlos III de Madrid• Peer-to-peer television for the IP Multimedia Subsystem• Video-on-demand, peer-to-peer caching, user behavior,
content-centric networks
3
This Talk• It puts together four research topics
Internet Protocol Television
Peer-to-Peer Streaming
Next Generation Networks
Performance Enhancements
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Introduction• What is Internet Protocol television or IPTV?• It begins with broadcast television• Analog or digital (ATSC, DVB)
• Terrestrial, satellite, cable
TV Station
Broadcasting equipment
Broadcast antenna
RF broadcast
Viewers
TV Station
Broadcasting equipment
Broadcast antenna
Receiver antenna
TV set
Set-top box Viewer
6
Internet Protocol Television• IPTV: TV channel audio/video over IP• Content encoded in digital form, transmitted as
packets• Convergence of services: broadcast,
video-on-demand• Economics: only 1-2 channels streamed
to the user
• Bandwidth requirements• Congestion and packet losses• Delay during channel changes: buffering, decoding
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Walled Gardens• Most IPTV providers use a dedicated
infrastructure• Uses IP multicast for all TV channels
Color Key All TV channels 1 or 2 TV channels Physical link
DSLAM
Viewers
Set-top box
IP router with multicast enabled
Telco core network
Broadcast server
TV set
9
The Internet in... 2004• P2P traffic was 60% and rising• ISPs identified P2P as a major challenge in
network design• It affects the QoS for all users• Mostly, file-sharing: BitTorrent, eDonkey, Kad,
Gnutella
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
HTTPP2POtherFTPEmail
Source: Cache Logic “P2P in 2005”
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The Internet in... 2007• Since late 2000’s, web traffic was gaining
share back
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 20042007
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
HTTPP2POtherFTPEmail
Source: Magid Media Futures survey (2007)
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In 2007 and... today
45%
5%14%
36%
Web Audio Other Video
45%
5%14%
20%
16%
Web Audio OtherYouTube Other Video
2007 • More than a third of the HTTP traffic is video streaming
• YouTube is the most popular; counts for around 20%
• That’s about 10% of all Internet traffic
• Internet video, the new broadband killer application?
• More ***Tube service providers?• User generated content and commercial
content
Source: Magid Media Futures survey (2007)
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Today and beyond
20102011
20122013
20142015
0
10000
20000
30000
40000
50000
60000
OtherOnline gamingInternet videoFile sharingVoice over IPVideo callingWeb, email
Peta
byt
es
per
month
2011 • Cisco: Entering the Zettabyte Era• Video surpassed peer-to-peer in 2010• Forecasts fourfold increase over the next
three years
Source: Cisco (2011)
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Peer-to-Peer Streaming• Sending video content is expensive• Applications target many receivers• We need support in the transport network
• What are the options?• Internet Protocol multicast• Content distribution network (servers)• Peer-to-peer
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Peer-to-Peer Streaming• Application layer multicast• Emulates the IP multicast tree• The clients or peers in charge of packet
forwarding
Broadcast server
Peers
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Peer-to-Peer Streaming• Multiple application layer multicast trees• Increases participation and bandwidth
granularity• It coordinates multiple trees
Stream 1 Stream 2
Interior peers
Leaf peers
Broadcast server
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Peer-to-Peer Streaming• Mesh or data-driven• Video stream divided into segments• A unique tree for each segment
Playback buffer
Playback point
Color Key Missing video segment Available video segment
Video segment and buffer-map exchanges
Broadcast server
Peer
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The Next Generation...• One network, many services• Economic reasons: bandwidth is a low margin
business
• Convergence: legacy networks to an all IP
Content providers Telco (ISP) Users
Netflix Skype
YouTube
PSTN
Cable
DSL
UMTS IP core
network
UMTS PSTN DSL
Cable
Common Management, Service, and Control
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IP Multimedia Subsystem• A platform for IP multimedia services• Initially designed by 3GPP as an evolution of
GSM/UMTS• Currently extended to many more access
networks
• Core of a NGN
Service providers
IP Multimedia Core Network Subsystem
Transport Control Functions
Access networks
Core network
Other networks
IMS gateways
IMS terminals
Legacy terminals
3GPP terminals
User equipments
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Quality of Service• Before communication• User equipments establish a multimedia session• Like a handshake, and indicates the session
characteristics• Uses the Session Initiation Protocol
IMS Core
Call Session Control Functions
UE Core
UE Core INVITE INVITE
OK OK
ACK ACK
Media
BYE BYE
OK OK
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IPTV with IP Multimedia Subsystem
Signaling connection
Color Key Media connection
Set-top box (STB)
Viewer
TV set
IPTV provider(s)
Broadcast servers
IP Multimedia Subsystem
Call Session Control Functions
Application Servers
Transport network (telco)
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Peer-to-Peer Television in IMS• User equipments leverage their upload
bandwidth• Available bandwidth not contracted by the user
Computer
TV set and STB
IMS phone
ADSL modem/RGW
DSLAM
IP network Service Level Agreement
Downlink Uplink
Voice Internet P2PTV
Subscriber household
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Business Model• The P2PTV complements other streaming
techniques• A P2PTV provider in charge of coordinating peer
resources IPTV content
providers P2PTV
provider
Transport provider (telco)
Service package
Subscriber
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Streaming Overlay• P2PTV peer coordination example• Three streams belonging to one or more TV
channels
Physical layer
UE UE
UE
BS
Overlay layer
UE
UE
UE
UE UE
UE
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Main Challenges• Signaling delay
• Need to establish a multimedia session between peers• Assures QoS but time expensive
• Peer churn• Departure of a UE peer generates streaming interruptions• In television, amplified by channel changes
• Application server• Coordinates peer participation
Bob
UE CSCFs
UE
Alice
P2PTV-AS
Media stream
Download session
Upload session
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Fast Signaling• Foster peers with established but inactive
sessions• Initiated by the application server• Estimates the necessary number of inactive
sessions based on user demand
Inactive session
Inactive session
Upload Download
UE peer
Stream 1
Stream 2
Stream 3
Uploading neighbors
Downloading neighbors
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Low Churn• Decouple viewing from uploading• Based on a previous work• We adapt the bandwidth allocation algorithm
Upload Download
Primary streams
Secondary streams
Active
Active
Inactive
Inactive
10 20 30 40
10 10 20 30 30 30 40
Current channel 1
2
3
UE peer
TV set
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SummaryInternet Protocol Television• TV channels transmitted as packets with the Internet
Protocol• Pros and cons• Walled gardensPeer-to-Peer Streaming• Rationale given expected increase in video usage• Alternative to IP multicast and content distribution
networks• Tree or meshNext Generation Networks• One network, many services• IP Multimedia Subsystem, an NGN implementation• P2PTV in IMS: rationale, business model & design
Performance Enhancements• Main issues of P2PTV in IMS: delay & churn• Fast signaling• Primary and secondary streams