Implementation of a Peer-to-Peer
Real-time streaming media system
Presenter: Kuei-Yu Hsu
Advisor: Dr. Kai-Wei Ke
2014/6/9
Outline
 Introduction
 Background
 System Architecture
 Packet-Delivery Algorithm
 Push-based System (DMFT and CDMFT)
 Pull-based System (Revised BitTorrent)
 Test and Implementation
 Conclusion
2
Introduction
• Client-Server Network
• Content Delivery Network
• Peer-to-Peer Network
• Hybrid CDN & P2P Network
3
Client-Server Network
 With increasing network
Server
bandwidth, Network transport
are not only text or static
image, but also audio and
video.
 The traditional Client-Server
Client
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architecture can't afford the
number of growing users.
Content Delivery Network
 There are 2 ways to enhance the multimedia
access.
Server Side: Content
Delivery Network (CDN)
1.


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Replicate the content
from the original content
server at its local cache.
Distribute the content
to clients.
CDN Servers
Peer-to-Peer Network
2.
Client Side: Peer-to-Peer (P2P) Network
 Clients become active associates by transmitting
received content to other clients.
Peer-to-Peer
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Hybrid CDN & P2P Network
 Hybrid CDN and P2P Network
CDN Servers
Peer-to-Peer
7
Background
• P2P Streaming System
• ALM Technique
• IPM versus ALM
8
P2P Streaming System
 A system without a central server, where each
participating node, act both as a server and a
client.
 Content to be shared is sourced in parts by each
node – peers.
 Famous Application of P2P Streaming:
 PPStream
 CoolStreaming
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ALM Technique
 Multiple Connections:
 Multiple Unicast
Unicast is the most common way to make connection in
the network. Multiple unicast always produce duplicate
paths.
 IP Multicast (IPM)
Failed due to concerns regarding scalability, deployment,
and support for higher level functionality.
 Application Layer Multicast (ALM)
Dispatcher algorithm potentially avoids redundant
communication in the network.
10
Overlay Network
Conceptual Routing Network
Peer 1
Peer 4
Physical Routing Network
Peer 3
Peer 2
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IPM versus ALM
 IP Multicast
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 Application Layer Multicast
System Architecture
• System Concept Diagram
• Three Subsystems
• System Block Diagram
13
System Concept Diagram
VLC Client
Peer 1
VLC Source
Peer 4
Camera Source
Peer 3
Camera Client
Peer 2
VLC Client
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System Architecture (cont.)
 Three Subsystems:
Streaming Transfer subsystem
1.
 Data Buffering
 Ordering
Algorithm subsystem
2.


Network Management subsystem
3.


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Set routing information (i.e. Build tree structure)
Determine where the streaming packets transport to
Manage socket connection status
Process multiple asynchronous I/O requests
System Architecture
 System Block Diagram
Media Player (Optional)
Play
Stream
Streaming Transfer
subsystem
Control
Messages
Algorithm
subsystem
Routing
Informations
Data
Transport
Network Management
subsystem
Stream
Transport
Operating System Network Transfer (MAC)
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Packet-Delivery Algorithm
• Push-based System
•
•
DMFT
CDMFT
• Pull-based System
•
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Revised BitTorrent
Push-based System
 Nodes are arranged in a tree structure.
 Selected frame is pushed from a parent node to
its child node.
 Delay in the push system occurs when a node
leaves – subsequently leading to rediscovery of
the parent -child relation - Tree is regenerated.
 Moreover there can be redundancy when two
nodes are pushing the same frame to a node.
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DMFT
 DMFT: Distributed Multisource Forwarding Tree
 A multi-source multicast algorithm in application layer
for routing.
 Every member can not only provide source contents
but also can forward data to others.
 Need to maintain some neighbor information.
 NIT (Neighbor Information Table)
 DFT (Data Forwarding Table)
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DMFT Tables
 NIT: Neighbor Information Table
 Record the distance of each member which is in the group
NIT
Field name
Member IP
Hop Count
 DFT: Data Forwarding Table
 Maintain the routing information
DFT
Field name
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Source IP
Next Peers IP
Parent IP
DMFT Flow Chart
A
Start System
No
Input the local ip
(1) Member Join
As a Group Creator?
Yes
Is new member join?
Yes
No
No
Input the one of
The members' ip
Prune Message
Update NIT
(2) Construct
Routing Tree
A
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Member leave
No
Update DFT
Is parent duplicate?
Stream Forward
(5) Inquire at
regular time
A
(3) Prune
Duplicate Path
Yes
(4) Recover
Tree StructureRecovery
CDMFT
 CDMFT: Cluster Distributed Multisource Forwarding
Tree
 An enhanced DMFT algorithm for reducing control
messages.
 With cluster-based group management, all multicast
group members are grouped into different clusters.
 Each cluster has a cluster head which is responsible
for managing cluster members and forwarding
multicast data.
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CDMFT Hierarchical
Cluster Headers
Cluster Members
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Pull-based System
 Peers request neighboring peers for the next frame
needed by them.
 Each peer has a buffer-map of the frames currently
held by it and its neighbors.
 A Peer refers each of its neighbors buffer-map to
decide from whom to pull data.
 Disadvantage: Making requests of pull again and
again and exchanging buffer maps can result in
congestion.
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BitTorrent Network (cont.)
 Common BitTorrent terms:
• Tracker: A server that keeps track of which seeds and
peers are in the swarm.
• Seeder: Refers to a machine possessing some part of
the data.
• Swarm: Together, all peers (including seeds) sharing a
torrent are called a swarm.
• Leech: A peer or any client that does not have 100% of
the data. Also, refers to a peer (or peers) that has a
negative effect on the swarm by having a very poor
share ratio.
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BitTorrent Network
 BitTorrent download Strategies:
1.
Rarest First
• The rarest pieces are transmitted with high priority.
• The strategy can use in the two cases.
2.
Tit for tat
• The strategy is used to optimize the download speed
• Choking Policy: Peers are uploaded to more cooperating
peer.
• Optimistic Unchoking: A peer will upload to other peers
randomly in a period.
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Test and Implementation
• Code Organization
• System Test Cases
• Test Tools
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VLC media player
 A free and open source cross-platform multimedia
player and framework that plays most multimedia
files as well as DVDs, Audio CDs, VCDs, and
various streaming protocols.
 Plays most codecs with
no codec packs needed:
MPEG-2, DivX, H.264,
MKV, WebM, WMV,
MP3...
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http://projects.tano.si/vlc-qt
Implementation
 Organize Codes:
Original Used
IDE
UI
Eclipse C++
wxWidget
wxFormBuilder
Current Used
Qt C++
Qt UI
 Test Respectively:




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IOCP asynchronous transport: Sender, Receiver
Buffering and Ordering
Thread Manager, Memory Manager
Routing Algorithm
Code Organization (cont.)
Original Used IDE:
Eclipse
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Code Organization
Current Used IDE: Qt
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System Test (cont.)
 Test Case:
 Unicast versus Multicast system
 Different bitrate video sources
 Test Range:
 1 peer localhost (127.0.0.1) loopback
 2 peers connect directly
 2 peers connect through network
 3 peers, 4 peers……
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System Test
 Test Environment:
 Localhost
 Self-Contained Network
 Realistic Network
 Test Packets loss tool:
 Wireshark (Telephony)
 Test Transport Stream packets tool:
 TSReader
 MPEG-2 Transport Stream packet analyser
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Wireshark
34
TSReader
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MPEG-2 Transport Stream packet
analyser
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Conclusions
• Future works
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Conclusions
 For enhancing system performance, need to trace the
whole project codes to find where the bug is.
 Will update the prototype to an integrated system.
 Integrate VLC media player into our system.
 Compatible with other kind of media players.
 Find more analysis tools to validate the system results.
 Hope to use real Live sources (i.e.Camera) when
system is stable.
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References (cont.)
 J. Liu, S. Rao, B. Li, and H. Zhang,“Opportunities
and challenges of peer-to-peer internet video
broadcast,” Proc. of the IEEE, vol. 96, no.1, pp.
11-24, Jan. 2008.
 W. Zhanga, Q. Zhenga, H. Lib and F. Tian,“An
overlay multicast protocol for live streaming and
delay-guaranteed interactive media,” Journal of
Network and Computer Applications, vol. 35,
Issue 1, pp. 20-28, Jan. 2012.
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References
 Chia-Hui Huang, “Design and Analysis of Application Layer
Multicast Routing Protocols,” Unpublished doctoral
dissertation, National Taipei University of Technology, April
2013.
 Wen-Neng Tsai,“Design of a live multimedia streaming
system with pull-based P2P transport technology”,
Unpublished master dissertation, National Taipei University
of Technology, July 2013.
 Tzu-Tung Liao,“Design of a multisource multimedia
streaming system with fast recoverable application layer
multicast algorithm”, Unpublished master dissertation,
National Taipei University of Technology, July 2013.
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Thanks for listening
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