ppl ive : a m easurement s tudy of p2p iptv s ystem sergio chacon
TRANSCRIPT
PPLIVE: A MEASUREMENT STUDY OF P2P IPTV SYSTEMSergio Chacon
ABSTRACT
IPTV stands for Internet Protocol Television P2P IPTV refers to the delivery of TV over IP
using point-to-point techniques PPLive is one of the most popular IPTV
systems for campus and residential access Hei, et al., Polytechnic University in Brooklyn,
developed a PPLive crawler to carry out in-depth measurements of mesh-pull PPLive
INTRODUCTION
Widespread adoption of broadband (residencial)
Application-level, P2P, mesh-pull P2P Mesh-Pull most successful so far
Rapid deployment @ low cost Minimal infrastructure
BitTorrent Not feasible for real time No fair resource sharing Not for large-scale live streaming
ANSWER TO QUESTIONS
What are the user characteristics? How much overhead and redundant traffic? What are characteristics of peer
partnerships? What are fundamental requirements for
successful mesh pull?
MESH-PULL P2P STREAMING SYSTEMS
Streaming peer node Includes streaming client and server
Channel stream server Converts media to small video chunks
Tracker server Provides streaming channel, peer and chunk
information for each peer node Downloads video chunks from multiple peers
requesting same media content
CHANNEL AND PEER DISCOVERY
PEE’S BUFFER MAP OF VIDEO CHUNKS
MESH-PULL P2P ARCHITECTURE
STREAMING PROCESS MESH-PULL SYSTEMS
GLOBAL VIEW OF USER BEHAVIOR
Peer tracking methodology Evolution of participating users User arrivals and departures User geographic distribution
PEER TRACKING
Peer registration Bootstrap Peer query
PEER REGISTRATION
Peer registration Bootstrap Peer query
NUMBER OF DISCOVERED PEERS
EVOLUTION OF PARTICIPATING USERS
HOW NUMBER OF USERS EVOLVE
USER ARRIVALS AND DEPARTURES
PEER ARRIVAL AND DEPARTURE EVOLUTION
USER GEOGRAPHIC DISTRIBUTION
PEER PLAYBACK DELAY AND LAGS
Start-up delay Video buffering Playback lags among peers
START-UP DELAY
Time interval between channel selection and playback
P2P also have to deal with startup buffering and delay 5-10 seconds from selection to player startup 5-10 seconds from player startup to play
VIDEO BUFFERING
PLAYBACK LAGS AMONG PEERS
CONNECTION + TRAFFIC CHARACTERISTICS
Isolating video traffic Video traffic redundancy Download and upload video traffic Video TCP connections
ISOLATING VIDEO TRAFFIC
VIDEO TRAFFIC REDUNDANCY
DOWNLOAD AND UPLOAD VIDEO
PROPERTIES OF VIDEO TCP CONNECTIONS
Duration of TCP connections Number of partners Dynamic of partners Locality of partners Traffic volume breakdowns Uni-directional or bi-directional traffic?
VIDEO TCP CONNECTIONS
NUMBER OF PARTNERS
DYNAMIC OF PARTNERS
TRAFFIC VOLUME BREAKDOWNS
LOCALITY OF PARTNERS
UNI-DIRECTIONAL OR BI-DIRECTIONAL?
UNI-DIRECTIONAL OR BI-DIRECTIONAL TRAFFIC?
Traffic flows are neither tree-like nor uni-directional (mesh)
Closer in character to BitTorrent Lesson learned: mesh-pull architectures are
more correctly viewed as variations on BitTorrent rather than variations on tree-pull architectures such as end-system multicast
CONCLUSIONS
Current Internet is capable of providing IPTV @ low cost with minimal dedicated infrastructure
Measurements provide understanding of how to architect large-scale P2P IPTV
Areas of improvement: Shorter start-up delay Higher-rate streaming Smaller peer lags Better NAT traversal