an alliance based peering scheme for p2p live media streaming darshan purandare ratan guha...

An Alliance based Peering An Alliance based Peering Scheme for P2P Live Media Scheme for P2P Live Media

StreamingStreaming

Darshan PurandareDarshan Purandare Ratan GuhaRatan Guha

University of Central FloridaUniversity of Central Florida

August 31, 2007 @ P2P-TV, KyotoAugust 31, 2007 @ P2P-TV, Kyoto

P2P-TV 2007 Darshan Purandare 2

Outline

Chunk based P2P modelsChunk based P2P models

Current Issues

Proposed peering scheme

Discussion and summary

P2P-TV 2007 Darshan Purandare 3

Chunk based P2P models

Server

1

2

5

3

4

…

…

…

…

…

…

…

…

1

3 Stream is split into Stream is split into piecespieces

P2P-TV 2007 Darshan Purandare 4

Working Philosophy

Peers exchange buffer map of data availability

Retrieve the missing pieces and upload pieces to neighbors

Scheduling algorithm finds which pieces to retrieve and from whom

Partnership refinement helps to obtain better

peers in terms of uploading rate

P2P-TV 2007 Darshan Purandare 5

Outline

Chunk based P2P models

Current IssuesCurrent Issues

Proposed peering scheme

Discussion and summary

P2P-TV 2007 Darshan Purandare 6

Current Issues

Quality of Service Quality of Service can improve [Hei et al. 06]Long start up timePeer Lag

Unfairness Unfairness [Ali et al. 06]Uplink bandwidth distribution uneven

Sub-optimal uplink utilizationSub-optimal uplink utilizationMay affect QoS & Scalability

Can we do better ?Can we do better ?

P2P-TV 2007 Darshan Purandare 7

Outline

Chunk based P2P models

Current Issues

Proposed peering schemeProposed peering scheme

Discussion and summary

P2P-TV 2007 Darshan Purandare 8

Proposed Model

Chunk based paradigm but overlay formation using alliances

Nodes cluster in groups of 4-8 to form alliances

Media server relays content to PowerPower nodes

BEAM: Bit strEAMing

P2P-TV 2007 Darshan Purandare 9

BEAM: Working Philosophy

A new node upon arrival obtains peerlist from TrackerPeerlist contains nodes in similar bandwidth range and similar network (if possible)

Contacts peers for stream contentStarts joining alliances or creates one

Server relays stream content to Power nodesPower nodesPower nodes changes periodically based on Utility FactorUtility Factor (UF)A node’s UF computed using: Cumulative share ratio (CSR)

Temporal share ratio (TSR)

P2P-TV 2007 Darshan Purandare 10

Alliance Formation

Peerlist of Node 1:: 6, 17, 236, 17, 23 Peerlist of Node 6: 12, 22, 4312, 22, 43

P2P-TV 2007 Darshan Purandare 11

Alliance Properties

A node can be a member of multiple alliances

HH: Maximum number of nodes in an Alliance

KK: Maximum number of alliances a node can join

Number of neighbors = K(H-1)

P2P-TV 2007 Darshan Purandare 12

Alliance Functionality

H = 5

K = 2

P2P-TV 2007 Darshan Purandare 13

Alliance Functionality

H = 5

K = 2

P2P-TV 2007 Darshan Purandare 14

Why form Alliances ?

Clustering into alliances forms a small world network graph

Short Path Length

Robust to network perturbations such as churn

Close knit group ensures streaming content is

readily available within alliances

Alliance members have common trust & treaty

P2P-TV 2007 Darshan Purandare 15

Small World Network

Dense local clustering (high clustering coefficient)

Some links to other part of the graph (non local)

Overlay distance is near-optimal

Robust to churn

[Watts et al., Nature,98][Watts et al., Nature,98]

P2P-TV 2007 Darshan Purandare 16

Simulator Details

Streaming rate = 512 Kbps

Media Server’s Uplink = 1536 Kbps (3 links)

Heterogeneous bandwidth class

(512,128), (768,256), (1024, 512), (1536,768),

(2048, 1024)

H, K = 4, 2 (6 neighbor nodes)

Each node buffers content for 120 sec

P2P-TV 2007 Darshan Purandare 17

QoS: Average Jitter Rate

P2P-TV 2007 Darshan Purandare 18

QoS: Average Latency

P2P-TV 2007 Darshan Purandare 19

Uplink Utilization

P2P-TV 2007 Darshan Purandare 20

Fairness: Share Ratio Range

P2P-TV 2007 Darshan Purandare 21

Fairness: Jitter Factor Range

P2P-TV 2007 Darshan Purandare 22

Fairness: Latency Range

P2P-TV 2007 Darshan Purandare 23

Summary

Alliance based peering scheme is an effective

technique to group peers

QoS, Uplink throughput and fairness results are at

par or even better than CoolStreaming

Peer lag can be improved using BEAM

Initial buffering time can be slightly improved

Our research is complementary to advance

source and channel coding techniques.

P2P-TV 2007 Darshan Purandare 24

Questions or Comments

Thank You!