Peer-to-Peer and livestreaming10 years of academicresearchGwendal Simon

The Academic Bubble

B. Li et al. Rise and fall of the peer-to-peer empire.

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Academic vs. Industrial World

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What is a Peer ?

px

=

+ +

Ex : PeerJS, Adobe Cirrus Ex : µTP, STUN

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What is a Peer ?

px

=

+ +

Ex : PeerJS, Adobe Cirrus

Ex : µTP, STUN

4 / 14 Gwendal Simon P2P live streaming

What is a Peer ?

px

=

+ +

Ex : PeerJS, Adobe Cirrus Ex : µTP, STUN

4 / 14 Gwendal Simon P2P live streaming

First There Was a Structure

s

source

p1

p2

p3 p4

p5

p6 p7

p8

Leaves do not contribute

Crash affects many peers

Structure is not reactive

WeaknessesNo multi-layer video

Maintaining cost

Structure is not reactive

Weaknesses

5 / 14 Gwendal Simon P2P live streaming

First There Was a Structure

s

source

p1

p2

p3 p4

p5

p6 p7

p8

Leaves do not contribute

Crash affects many peers

Structure is not reactive

WeaknessesNo multi-layer video

Maintaining cost

Structure is not reactive

Weaknesses

5 / 14 Gwendal Simon P2P live streaming

First There Was a Structure

s

source

p1

p2

p3 p4

p5

p6 p7

p8

Leaves do not contribute

Crash affects many peers

Structure is not reactive

Weaknesses

No multi-layer video

Maintaining cost

Structure is not reactive

Weaknesses

5 / 14 Gwendal Simon P2P live streaming

First There Was a Structure

s

source

p1

p2

p3 p4

p5

p6 p7

p8

Leaves do not contribute

Crash affects many peers

Structure is not reactive

WeaknessesNo multi-layer video

Maintaining cost

Structure is not reactive

Weaknesses

5 / 14 Gwendal Simon P2P live streaming

First There Was a Structure

s

source

p1

p2

p3 p4

p5

p6 p7

p8

Leaves do not contribute

Crash affects many peers

Structure is not reactive

Weaknesses

No multi-layer video

Maintaining cost

Structure is not reactive

Weaknesses

5 / 14 Gwendal Simon P2P live streaming

Disruption

cut content into chunks

share chunk map

pull-based downloading

random mesh topology

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Disruption

cut content into chunks

share chunk map

pull-based downloading

random mesh topology

6 / 14 Gwendal Simon P2P live streaming

Disruption

cut content into chunks

share chunk map

pull-based downloading

random mesh topology

6 / 14 Gwendal Simon P2P live streaming

Disruption

cut content into chunks

share chunk map

pull-based downloading

random mesh topology

6 / 14 Gwendal Simon P2P live streaming

Disruption

cut content into chunks

share chunk map

pull-based downloading

random mesh topology

6 / 14 Gwendal Simon P2P live streaming

Mesh Networks

s

source

p1

p2

p3 p4

p5

p6 p7

p8

Every round :

1. Share chunk map

Every round :

1. Share chunk map

2. Request chunks c7

c8

c7

c3

c6

c4

c6

c5

c4

c3 c5

c5

Every round :

1. Share chunk map

2. Request chunks

3. Send chunks

7 / 14 Gwendal Simon P2P live streaming

Mesh Networks

s

source

p1

p2

p3 p4

p5

p6 p7

p8

Every round :

1. Share chunk map

Every round :

1. Share chunk map

2. Request chunks c7

c8

c7

c3

c6

c4

c6

c5

c4

c3 c5

c5

Every round :

1. Share chunk map

2. Request chunks

3. Send chunks

7 / 14 Gwendal Simon P2P live streaming

Mesh Networks

s

source

p1

p2

p3 p4

p5

p6 p7

p8

Every round :

1. Share chunk map

Every round :

1. Share chunk map

2. Request chunks

c7

c8

c7

c3

c6

c4

c6

c5

c4

c3 c5

c5

Every round :

1. Share chunk map

2. Request chunks

3. Send chunks

7 / 14 Gwendal Simon P2P live streaming

Mesh Networks

s

source

p1

p2

p3 p4

p5

p6 p7

p8

Every round :

1. Share chunk map

Every round :

1. Share chunk map

2. Request chunks

c7

c8

c7

c3

c6

c4

c6

c5

c4

c3 c5

c5

Every round :

1. Share chunk map

2. Request chunks

3. Send chunks

7 / 14 Gwendal Simon P2P live streaming

Sliding Windows (example with one peer)

lag. . .

The chunk genera-ted at the source s

The most recentchunk a peer at 1hop from s can get

The most recentchunk a peer at khops from s can get

The most recentchunk this peer gets

Prioritary chunks

Displayed chunk

Old chunks

8 / 14 Gwendal Simon P2P live streaming

Sliding Windows (example with one peer)

lag. . .

The chunk genera-ted at the source s

The most recentchunk a peer at 1hop from s can get

The most recentchunk a peer at khops from s can get

The most recentchunk this peer gets

Prioritary chunks

Displayed chunk

Old chunks

8 / 14 Gwendal Simon P2P live streaming

Sliding Windows (example with one peer)

lag. . .

The chunk genera-ted at the source s

The most recentchunk a peer at 1hop from s can get

The most recentchunk a peer at khops from s can get

The most recentchunk this peer gets

Prioritary chunks

Displayed chunk

Old chunks

8 / 14 Gwendal Simon P2P live streaming

Sliding Windows (example with one peer)

lag. . .

The chunk genera-ted at the source s

The most recentchunk a peer at 1hop from s can get

The most recentchunk a peer at khops from s can get

The most recentchunk this peer gets

Prioritary chunks

Displayed chunk

Old chunks

8 / 14 Gwendal Simon P2P live streaming

Main AlgorithmsHow to find neighbors ?

Using a tracker- Random pick- Network proximity (IETF ALTO)- Test bandwidth, reputation, etc.

Using a peer-to-peer (trackerless) system- Gossip- Distributed Hash Table

What chunk to send to who ?Random pickRarest chunk to the most contributing peerAccording to urgency

9 / 14 Gwendal Simon P2P live streaming

Main AlgorithmsHow to find neighbors ?

Using a tracker- Random pick- Network proximity (IETF ALTO)- Test bandwidth, reputation, etc.

Using a peer-to-peer (trackerless) system- Gossip- Distributed Hash Table

What chunk to send to who ?Random pickRarest chunk to the most contributing peerAccording to urgency

9 / 14 Gwendal Simon P2P live streaming

Main AlgorithmsHow to find neighbors ?

Using a tracker- Random pick- Network proximity (IETF ALTO)- Test bandwidth, reputation, etc.

Using a peer-to-peer (trackerless) system- Gossip- Distributed Hash Table

What chunk to send to who ?Random pickRarest chunk to the most contributing peerAccording to urgency

9 / 14 Gwendal Simon P2P live streaming

Main AlgorithmsHow to find neighbors ?

Using a tracker- Random pick- Network proximity (IETF ALTO)- Test bandwidth, reputation, etc.

Using a peer-to-peer (trackerless) system- Gossip- Distributed Hash Table

What chunk to send to who ?

Random pickRarest chunk to the most contributing peerAccording to urgency

9 / 14 Gwendal Simon P2P live streaming

Main AlgorithmsHow to find neighbors ?

Using a tracker- Random pick- Network proximity (IETF ALTO)- Test bandwidth, reputation, etc.

Using a peer-to-peer (trackerless) system- Gossip- Distributed Hash Table

What chunk to send to who ?Random pickRarest chunk to the most contributing peerAccording to urgency

9 / 14 Gwendal Simon P2P live streaming

Commercial Success

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The Network Coding Revolution

s

source

p1

p2

p3 p4

p5

p6 p7

p8

c1c2

c1c2

c2

c1

c1 ⊕ c2

c1 ⊕ c2

recall : 1100 ⊕ 1010 = 0110

Cut the content into generations of k blocksb1, b2, . . . , bk .A peer having m blocks in a generationchooses coefficients d1, d2, . . . , dm and encodesa new block : ∑

i≤mdi · bi

When a peer get k blocks, it can re-build thewhole generation.

In practice

c1 ⊕ c2

c1 ⊕ c2

Optimal bandwidth usage

No more request (pushdelivery)

11 / 14 Gwendal Simon P2P live streaming

The Network Coding Revolution

s

source

p1

p2

p3 p4

p5

p6 p7

p8

c1c2

c1c2

c2

c1

c1 ⊕ c2

c1 ⊕ c2

recall : 1100 ⊕ 1010 = 0110

Cut the content into generations of k blocksb1, b2, . . . , bk .A peer having m blocks in a generationchooses coefficients d1, d2, . . . , dm and encodesa new block : ∑

i≤mdi · bi

When a peer get k blocks, it can re-build thewhole generation.

In practice

c1 ⊕ c2

c1 ⊕ c2

Optimal bandwidth usage

No more request (pushdelivery)

11 / 14 Gwendal Simon P2P live streaming

The Network Coding Revolution

s

source

p1

p2

p3 p4

p5

p6 p7

p8

c1c2

c1c2

c2

c1

c1 ⊕ c2

c1 ⊕ c2

recall : 1100 ⊕ 1010 = 0110

Cut the content into generations of k blocksb1, b2, . . . , bk .A peer having m blocks in a generationchooses coefficients d1, d2, . . . , dm and encodesa new block : ∑

i≤mdi · bi

When a peer get k blocks, it can re-build thewhole generation.

In practice

c1 ⊕ c2

c1 ⊕ c2

Optimal bandwidth usage

No more request (pushdelivery)

11 / 14 Gwendal Simon P2P live streaming

The Network Coding Revolution

s

source

p1

p2

p3 p4

p5

p6 p7

p8

c1c2

c1c2

c2

c1

c1 ⊕ c2

c1 ⊕ c2

recall : 1100 ⊕ 1010 = 0110

Cut the content into generations of k blocksb1, b2, . . . , bk .A peer having m blocks in a generationchooses coefficients d1, d2, . . . , dm and encodesa new block : ∑

i≤mdi · bi

When a peer get k blocks, it can re-build thewhole generation.

In practice

c1 ⊕ c2

c1 ⊕ c2

Optimal bandwidth usage

No more request (pushdelivery)

11 / 14 Gwendal Simon P2P live streaming

The Network Coding Revolution

s

source

p1

p2

p3 p4

p5

p6 p7

p8

c1c2

c1c2

c2

c1

c1 ⊕ c2

c1 ⊕ c2

recall : 1100 ⊕ 1010 = 0110

Cut the content into generations of k blocksb1, b2, . . . , bk .A peer having m blocks in a generationchooses coefficients d1, d2, . . . , dm and encodesa new block : ∑

i≤mdi · bi

When a peer get k blocks, it can re-build thewhole generation.

In practice

c1 ⊕ c2

c1 ⊕ c2

Optimal bandwidth usage

No more request (pushdelivery)

11 / 14 Gwendal Simon P2P live streaming

The Network Coding Revolution

s

source

p1

p2

p3 p4

p5

p6 p7

p8

c1c2

c1c2

c2

c1

c1 ⊕ c2

c1 ⊕ c2

recall : 1100 ⊕ 1010 = 0110

Cut the content into generations of k blocksb1, b2, . . . , bk .A peer having m blocks in a generationchooses coefficients d1, d2, . . . , dm and encodesa new block : ∑

i≤mdi · bi

When a peer get k blocks, it can re-build thewhole generation.

In practice

c1 ⊕ c2

c1 ⊕ c2

Optimal bandwidth usage

No more request (pushdelivery)

11 / 14 Gwendal Simon P2P live streaming

It Just Works !

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Toward Peer-Assisted Architectures

s

s0 s1 s2

source

datacenters

p1

p2

p3 p4

p5

p6 p7

p8

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To Conclude

10 years of academic research for technologies that :Reduce control trafficCan cope with a dynamic population

And still some open problemsHow to implement rate-adaptive mechanisms ?Can it be implemented into a smartphone ?

contact : gwendal.simon@telecom-bretagne.eu

14 / 14 Gwendal Simon P2P live streaming

To Conclude

10 years of academic research for technologies that :Reduce control trafficCan cope with a dynamic population

And still some open problemsHow to implement rate-adaptive mechanisms ?Can it be implemented into a smartphone ?

contact : gwendal.simon@telecom-bretagne.eu

14 / 14 Gwendal Simon P2P live streaming

To Conclude

10 years of academic research for technologies that :Reduce control trafficCan cope with a dynamic population

And still some open problemsHow to implement rate-adaptive mechanisms ?Can it be implemented into a smartphone ?

contact : gwendal.simon@telecom-bretagne.eu

14 / 14 Gwendal Simon P2P live streaming