Resilient Peer-to-Peer StResilient Peer-to-Peer Streamingreaming

Presented by: Yun TengPresented by: Yun Teng

Resilient Peer-to-Peer StreamingResilient Peer-to-Peer Streaming

AuthorsAuthors Venkata N. Padmanabhan Venkata N. Padmanabhan Helen J. Wang Helen J. Wang Philip A. Chou Philip A. Chou

From From MicrosoftMicrosoft

MotivationMotivation

Distributing “live” streaming media content Distributing “live” streaming media content to a potentially large and highly dynamic to a potentially large and highly dynamic population of hosts. population of hosts. ““Live” streaming refer to the simultaneous Live” streaming refer to the simultaneous

distribution of the same content to all clientsdistribution of the same content to all clients

ChallengeChallenge

Peer-to-peer content distribution is attractiPeer-to-peer content distribution is attractive because the bandwidth available to serve because the bandwidth available to serve content scales with demand.ve content scales with demand.

A key challenge: A key challenge: making content distribumaking content distribution robust to peer transiencetion robust to peer transience..

ApproachApproach

Introduce redundancy, both in network patIntroduce redundancy, both in network paths and in data hs and in data

Multiple diverse distribution tree: provide rMultiple diverse distribution tree: provide redundancy in network pathsedundancy in network paths

Multiple description coding (MDC): provide Multiple description coding (MDC): provide redundancy in dataredundancy in data

CoopNet CoopNet

Makes selective use of P2P networking, plMakes selective use of P2P networking, placing minimal demands on the peers acing minimal demands on the peers

Goal: help a server tide over crises such aGoal: help a server tide over crises such as flash crowds rather than replace the servs flash crowds rather than replace the server with a pure P2P systemer with a pure P2P system

AssumptionAssumption

A node participates in and contributes bandwidth A node participates in and contributes bandwidth for content distribution only so long as the user ifor content distribution only so long as the user is interested in the content. It stops forwarding tras interested in the content. It stops forwarding traffic when the user tunes out ffic when the user tunes out

A node only contribute as much upstream bandA node only contribute as much upstream bandwidth as it consumes in the downstream directiowidth as it consumes in the downstream direction (applies to the total bandwidth in and out of a nn (applies to the total bandwidth in and out of a node aggregated over all treesode aggregated over all trees

Nodes in CoopNet are inherently unreliable Nodes in CoopNet are inherently unreliable

Tree managementTree management

GoalsGoals

Short treesShort trees Tree diversity Tree diversity EfficiencyEfficiency Quick join and leaveQuick join and leave ScalabilityScalability

ConflictsConflicts

Tree diversity versus efficiencyTree diversity versus efficiency Quick join and leave versus scalabilityQuick join and leave versus scalability

Feasibility of the Centralized Feasibility of the Centralized ProtocolProtocol

September 11 flash crowd at MSNBCSeptember 11 flash crowd at MSNBC At peak, 18,000 nodes, 1,000 arrivals and At peak, 18,000 nodes, 1,000 arrivals and

departures per seconddepartures per second On average, 10,000 nodes, 180 arrivals and On average, 10,000 nodes, 180 arrivals and

departures per seconddepartures per second

Resource requirementResource requirement Memory: 10 MBMemory: 10 MB Network bandwidth: 8 MbpsNetwork bandwidth: 8 Mbps CPU: 40 ns memory cycle, allow 390 memory CPU: 40 ns memory cycle, allow 390 memory

accesses per insertionaccesses per insertion

Centralized Tree ManagementCentralized Tree Management

Randomized Tree ConstructionRandomized Tree Construction Deterministic Tree ConstructionDeterministic Tree Construction

Tree Efficiency / Topology AwareneTree Efficiency / Topology Awareness ss

Need an efficient way to pick a proximate Need an efficient way to pick a proximate parent for a node without requiring parent for a node without requiring extensive P2P network measurementsextensive P2P network measurements

Each node maintains its “delay Each node maintains its “delay coordinates” of ping times to a small set of coordinates” of ping times to a small set of landmark hostslandmark hosts

Root pick the closest node for incoming Root pick the closest node for incoming node from a set of candidate parentsnode from a set of candidate parents

Tree RepairTree Repair

Due to node leaveDue to node leave Two typesTwo types

Voluntary – Notify the rootVoluntary – Notify the root Failure – Detect failureFailure – Detect failure

Multiple Description CodiMultiple Description Coding (MDC)ng (MDC)

OverviewOverview

Encoding an audio and/or video signal into Encoding an audio and/or video signal into M>1 separate streams, or descriptions, suM>1 separate streams, or descriptions, such that any subset of these descriptions cach that any subset of these descriptions can be received and decoded.n be received and decoded.

The distortion with respect to the original siThe distortion with respect to the original signal is commensurate with the number of gnal is commensurate with the number of descriptions received.descriptions received.

Overview (cont.)Overview (cont.)

MDC incurs a modest performance penalty relatiMDC incurs a modest performance penalty relative to layered coding, which in turn incurs a slight ve to layered coding, which in turn incurs a slight performance penalty relative to single descriptioperformance penalty relative to single description coding.n coding.

The audio and/or video signal is partitioned into The audio and/or video signal is partitioned into groups of frames (GOF), each group having durgroups of frames (GOF), each group having duration of T (such as 1 second). Each GOF is indeation of T (such as 1 second). Each GOF is independently encoded, error protected, and packetipendently encoded, error protected, and packetized into M packets. zed into M packets.

CoopNet MDC System ArchitectureCoopNet MDC System Architecture

Configuring MDCConfiguring MDC

GOF duration G = 1 secondGOF duration G = 1 second M = 16 descriptionsM = 16 descriptions Packet size P = 1250 bytesPacket size P = 1250 bytes T = 8 treesT = 8 trees

Performance evaluationPerformance evaluation

Impact of Number of Distribution Impact of Number of Distribution TreesTrees

Effectiveness of MDCEffectiveness of MDC

Probability distribution of descriptions Probability distribution of descriptions received vs. number of distribution treesreceived vs. number of distribution trees

Root out-degree = 100Root out-degree = 100 Maximum client out-degree = 4Maximum client out-degree = 4

Impact of Repair TimeImpact of Repair Time

Related workRelated work

Related WorkRelated Work

Application-level MulticastApplication-level Multicast Source Coding and Path DiversitySource Coding and Path Diversity

ReferencesReferences

V. N. Padmanabhan, H. J. Wang, and P. A. Chou. V. N. Padmanabhan, H. J. Wang, and P. A. Chou. Resilient Peer-to-Peer Streaming. Technical Report Resilient Peer-to-Peer Streaming. Technical Report MSR-TR-2003-11, Microsoft Research, Redmond, WA, MSR-TR-2003-11, Microsoft Research, Redmond, WA, March 2003. March 2003.

V. N. Padmanabhan, H. J. Wang, P. A. Chou, and K. V. N. Padmanabhan, H. J. Wang, P. A. Chou, and K. Sripanidkulchai. Distributing Streaming Media Content Sripanidkulchai. Distributing Streaming Media Content Using Cooperative Networking. In Using Cooperative Networking. In Proc. NOSSDAVProc. NOSSDAV, May , May 2002. 2002.

Q & AQ & A

Thank you!Thank you!