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

4

Internet Protocol TelevisionPart 1

5

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

7

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

8

Peer-to-Peer StreamingPart 2

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”

10

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)

11

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)

12

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)

13

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

14

Peer-to-Peer Streaming• Application layer multicast• Emulates the IP multicast tree• The clients or peers in charge of packet

forwarding

Broadcast server

Peers

15

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

16

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

17

Next Generation NetworksPart 3

18

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

Google

Netflix Skype

YouTube

PSTN

Cable

DSL

UMTS IP core

network

UMTS PSTN DSL

Cable

Common Management, Service, and Control

19

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

20

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

21

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)

22

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

23

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

24

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

25

Performance EnhancementsPart 4

26

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

27

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

28

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

29

Let’s Summarize

30

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

Q&A

Thank You

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Inaglory, flagstaffotos, Greg O'Beirne, Holger Krisp, Kim Hansen, Silvio Tanaka, Berthold Werner