With the advances in high-performance network and digital video technology, the large-scale Video-on-demand (Vod) systems have come into practice in recent years. P2P technology is introduced for media streaming system for its scalability and low commercial cost. P2P is a distributed architecture consisting of a collection of resources (e.g. computing power, data, meta-data, network bandwidth) performing a distributed function. And every peer acted as either a client or a server. A general distinction of P2P architectures into three kinds is possible:
• Centralized:
There is a central directory. Each peer contributes its local “table of contents” to the central directory. Peer issues requests to the central directory to discover the most appropriate peer with the desired information. (E.g. Napster)
• Pure:
All peers perform equal functions. Requests of a peer are flooded from the original requestor to their neighbors and so on, recursively, for a number of steps or until the request is satisfied. The flooded-request is manipulated through network connectivity and the appropriate number of steps can result in good request coverage.
• Hybrid:
In pure P2P systems, it caused redundant messages for flooded-requests since the forwarding is performed recursively. Super peers are introduced for efficiency purposes in Kazaa P2P system.
2
Figure 1 Centralized recovery, Flooded-request and super peer model
P2P and multicast are two common transmission manipulations to provide scalable and cost efficient solution for either Video-on-Demand (VoD) or live streaming. P2P technology has been widely adopted in live streaming system. The overlay network is an application level construction that was separated from the physical network. By overlay construction method, they can be roughly classified into three main categories:
• Tree based overlay:
Peers are organized to form a tree-shape overlay network. By IP multicast support, data can transfer from a parent to multiple children as shown in figure 2 Enhance the efficiency of one-to-many and many to many communications over the internet. It concerns the way to build and maintain the tree. The parent peers in tree based overlay have a heavy burden in transferring data while leaf peers become isolation. On the other hand, the leave of parent peers caused tree adjustment which often affects the QoS (Quality of Service) of children peers.
• Mesh-based overlay:
In mesh-based overlay, media data has been split into chunks and drive peers to get from multiple suppliers called partners. Meanwhile, each peer provides data to multiple “children”. The key issues in designing a mesh-based overlay include partnership management and data chunks scheduling algorithms. And a gossip based random algorithm is a solution to multicast message dissemination.
3
• Hybrid overlay:
It divides the transmission of control messages and media data into different overlays in [1]. The mechanisms of peer join, peer leave and peer selection can be optimized in control tree. Through the control tree, peers can easily find their neighbors to construct a transfer mesh.
Figure 2 Network application overlay for live streaming
1.1. Live streaming
There have been significant studies on live video streaming over Internet recently; see the surveys in [2], [3]. System with mesh-based overlay like CoolStreaming [2] is popular for its adaptability to dynamic networks. We now describe some important protocols in mesh-based P2P streaming system:
Gossip-based protocol:
It employs a gossiping protocol in data-driven overlay network (DONet) for partnership management. In a typical gossip algorithm, a node sends a newly generated message to a set of randomly selected nodes; those nodes do similarly in the next round, and so do other nodes until the message is spread to all.
Partner refinement
In mesh-based overlay, a peer can receive media data that has been split into chunks from multiple peers called “partner”, and each peer can provides available chunks for multiple “partner”. Since any node can depart accidentally in DONet, it’s necessary to
3
• Hybrid overlay:
It divides the transmission of control messages and media data into different overlays in [1]. The mechanisms of peer join, peer leave and peer selection can be optimized in control tree. Through the control tree, peers can easily find their neighbors to construct a transfer mesh.
Figure 2 Network application overlay for live streaming
1.1. Live streaming
There have been significant studies on live video streaming over Internet recently; see the surveys in [2], [3]. System with mesh-based overlay like CoolStreaming [2] is popular for its adaptability to dynamic networks. We now describe some important protocols in mesh-based P2P streaming system:
Gossip-based protocol:
It employs a gossiping protocol in data-driven overlay network (DONet) for partnership management. In a typical gossip algorithm, a node sends a newly generated message to a set of randomly selected nodes; those nodes do similarly in the next round, and so do other nodes until the message is spread to all.
Partner refinement
In mesh-based overlay, a peer can receive media data that has been split into chunks from multiple peers called “partner”, and each peer can provides available chunks for multiple “partner”. Since any node can depart accidentally in DONet, it’s necessary to
3
• Hybrid overlay:
It divides the transmission of control messages and media data into different overlays in [1]. The mechanisms of peer join, peer leave and peer selection can be optimized in control tree. Through the control tree, peers can easily find their neighbors to construct a transfer mesh.
Figure 2 Network application overlay for live streaming
1.1. Live streaming
There have been significant studies on live video streaming over Internet recently; see the surveys in [2], [3]. System with mesh-based overlay like CoolStreaming [2] is popular for its adaptability to dynamic networks. We now describe some important protocols in mesh-based P2P streaming system:
Gossip-based protocol:
It employs a gossiping protocol in data-driven overlay network (DONet) for partnership management. In a typical gossip algorithm, a node sends a newly generated message to a set of randomly selected nodes; those nodes do similarly in the next round, and so do other nodes until the message is spread to all.
Partner refinement
In mesh-based overlay, a peer can receive media data that has been split into chunks from multiple peers called “partner”, and each peer can provides available chunks for multiple “partner”. Since any node can depart accidentally in DONet, it’s necessary to
3
• Hybrid overlay:
It divides the transmission of control messages and media data into different overlays in [1]. The mechanisms of peer join, peer leave and peer selection can be optimized in control tree. Through the control tree, peers can easily find their neighbors to construct a transfer mesh.
Figure 2 Network application overlay for live streaming
1.1. Live streaming
There have been significant studies on live video streaming over Internet recently; see the surveys in [2], [3]. System with mesh-based overlay like CoolStreaming [2] is popular for its adaptability to dynamic networks. We now describe some important protocols in mesh-based P2P streaming system:
Gossip-based protocol:
It employs a gossiping protocol in data-driven overlay network (DONet) for partnership management. In a typical gossip algorithm, a node sends a newly generated message to a set of randomly selected nodes; those nodes do similarly in the next round, and so do other nodes until the message is spread to all.
Partner refinement
In mesh-based overlay, a peer can receive media data that has been split into chunks from multiple peers called “partner”, and each peer can provides available chunks for multiple “partner”. Since any node can depart accidentally in DONet, it’s necessary to
3
• Hybrid overlay:
It divides the transmission of control messages and media data into different overlays in [1]. The mechanisms of peer join, peer leave and peer selection can be optimized in control tree. Through the control tree, peers can easily find their neighbors to construct a transfer mesh.
Figure 2 Network application overlay for live streaming
1.1. Live streaming
There have been significant studies on live video streaming over Internet recently; see the surveys in [2], [3]. System with mesh-based overlay like CoolStreaming [2] is popular for its adaptability to dynamic networks. We now describe some important protocols in mesh-based P2P streaming system:
Gossip-based protocol:
It employs a gossiping protocol in data-driven overlay network (DONet) for partnership management. In a typical gossip algorithm, a node sends a newly generated message to a set of randomly selected nodes; those nodes do similarly in the next round, and so do other nodes until the message is spread to all.
Partner refinement
In mesh-based overlay, a peer can receive media data that has been split into chunks from multiple peers called “partner”, and each peer can provides available chunks for multiple “partner”. Since any node can depart accidentally in DONet, it’s necessary to
3
• Hybrid overlay:
It divides the transmission of control messages and media data into different overlays in [1]. The mechanisms of peer join, peer leave and peer selection can be optimized in control tree. Through the control tree, peers can easily find their neighbors to construct a transfer mesh.
Figure 2 Network application overlay for live streaming
1.1. Live streaming
There have been significant studies on live video streaming over Internet recently; see the surveys in [2], [3]. System with mesh-based overlay like CoolStreaming [2] is popular for its adaptability to dynamic networks. We now describe some important protocols in mesh-based P2P streaming system:
Gossip-based protocol:
It employs a gossiping protocol in data-driven overlay network (DONet) for partnership management. In a typical gossip algorithm, a node sends a newly generated message to a set of randomly selected nodes; those nodes do similarly in the next round, and so do other nodes until the message is spread to all.
Partner refinement
In mesh-based overlay, a peer can receive media data that has been split into chunks from multiple peers called “partner”, and each peer can provides available chunks for multiple “partner”. Since any node can depart accidentally in DONet, it’s necessary to
3
• Hybrid overlay:
It divides the transmission of control messages and media data into different overlays in [1]. The mechanisms of peer join, peer leave and peer selection can be optimized in control tree. Through the control tree, peers can easily find their neighbors to construct a transfer mesh.
Figure 2 Network application overlay for live streaming
1.1. Live streaming
There have been significant studies on live video streaming over Internet recently; see the surveys in [2], [3]. System with mesh-based overlay like CoolStreaming [2] is popular for its adaptability to dynamic networks. We now describe some important protocols in mesh-based P2P streaming system:
Gossip-based protocol:
It employs a gossiping protocol in data-driven overlay network (DONet) for partnership management. In a typical gossip algorithm, a node sends a newly generated message to a set of randomly selected nodes; those nodes do similarly in the next round, and so do other nodes until the message is spread to all.
Partner refinement
In mesh-based overlay, a peer can receive media data that has been split into chunks from multiple peers called “partner”, and each peer can provides available chunks for multiple “partner”. Since any node can depart accidentally in DONet, it’s necessary to
3
• Hybrid overlay:
It divides the transmission of control messages and media data into different overlays in [1]. The mechanisms of peer join, peer leave and peer selection can be optimized in control tree. Through the control tree, peers can easily find their neighbors to construct a transfer mesh.
Figure 2 Network application overlay for live streaming
1.1. Live streaming
There have been significant studies on live video streaming over Internet recently; see the surveys in [2], [3]. System with mesh-based overlay like CoolStreaming [2] is popular for its adaptability to dynamic networks. We now describe some important protocols in mesh-based P2P streaming system:
Gossip-based protocol:
It employs a gossiping protocol in data-driven overlay network (DONet) for partnership management. In a typical gossip algorithm, a node sends a newly generated message to a set of randomly selected nodes; those nodes do similarly in the next round, and so do other nodes until the message is spread to all.
Partner refinement
In mesh-based overlay, a peer can receive media data that has been split into chunks from multiple peers called “partner”, and each peer can provides available chunks for multiple “partner”. Since any node can depart accidentally in DONet, it’s necessary to
3
• Hybrid overlay:
It divides the transmission of control messages and media data into different overlays in [1]. The mechanisms of peer join, peer leave and peer selection can be optimized in control tree. Through the control tree, peers can easily find their neighbors to construct a transfer mesh.
Figure 2 Network application overlay for live streaming
1.1. Live streaming
There have been significant studies on live video streaming over Internet recently; see the surveys in [2], [3]. System with mesh-based overlay like CoolStreaming [2] is popular for its adaptability to dynamic networks. We now describe some important protocols in mesh-based P2P streaming system:
Gossip-based protocol:
It employs a gossiping protocol in data-driven overlay network (DONet) for partnership management. In a typical gossip algorithm, a node sends a newly generated message to a set of randomly selected nodes; those nodes do similarly in the next round, and so do other nodes until the message is spread to all.
Partner refinement
In mesh-based overlay, a peer can receive media data that has been split into chunks from multiple peers called “partner”, and each peer can provides available chunks for multiple “partner”. Since any node can depart accidentally in DONet, it’s necessary to
3
• Hybrid overlay:
It divides the transmission of control messages and media data into different overlays in [1]. The mechanisms of peer join, peer leave and peer selection can be optimized in control tree. Through the control tree, peers can easily find their neighbors to construct a transfer mesh.
Figure 2 Network application overlay for live streaming
1.1. Live streaming
There have been significant studies on live video streaming over Internet recently; see the surveys in [2], [3]. System with mesh-based overlay like CoolStreaming [2] is popular for its adaptability to dynamic networks. We now describe some important protocols in mesh-based P2P streaming system:
Gossip-based protocol:
It employs a gossiping protocol in data-driven overlay network (DONet) for partnership management. In a typical gossip algorithm, a node sends a newly generated message to a set of randomly selected nodes; those nodes do similarly in the next round, and so do other nodes until the message is spread to all.
Partner refinement
In mesh-based overlay, a peer can receive media data that has been split into chunks from multiple peers called “partner”, and each peer can provides available chunks for multiple “partner”. Since any node can depart accidentally in DONet, it’s necessary to
3
• Hybrid overlay:
It divides the transmission of control messages and media data into different overlays in [1]. The mechanisms of peer join, peer leave and peer selection can be optimized in control tree. Through the control tree, peers can easily find their neighbors to construct a transfer mesh.
Figure 2 Network application overlay for live streaming
1.1. Live streaming
There have been significant studies on live video streaming over Internet recently; see the surveys in [2], [3]. System with mesh-based overlay like CoolStreaming [2] is popular for its adaptability to dynamic networks. We now describe some important protocols in mesh-based P2P streaming system:
Gossip-based protocol:
It employs a gossiping protocol in data-driven overlay network (DONet) for partnership management. In a typical gossip algorithm, a node sends a newly generated message to a set of randomly selected nodes; those nodes do similarly in the next round, and so do other nodes until the message is spread to all.
Partner refinement
In mesh-based overlay, a peer can receive media data that has been split into chunks from multiple peers called “partner”, and each peer can provides available chunks for multiple “partner”. Since any node can depart accidentally in DONet, it’s necessary to
4
detect node failure for partnership refinement. It helps each node maintain a stable number of available partners by calculating a score for each partner. Let node j be the partner of node i. for node i, the score of partner node j is denoted byScorei,j.
is the average number of segment that node i retrieved from node j. A partner that detects the failure will issue the departure message on behalf the failed node. And then the message is gossiped.
Chunk distribution protocol:
Every node periodically exchanges data availability information with a set of partners.
The data availability information can be described as a buffer map.
Peer’s buffer map of video chunks:
As figure 3 shows the buffer map message includes the offset that the ID of the first chunk, the length of the buffer map, and a string of zeros and ones indicating which chunks are available. The BM playable video indicates the number of continuous chunks in the buffer map, beginning from the offset
Figure 3 buffer map format
1.2. Video on Demand
Several approaches have been explored in the past to tackle scalability issues faced by VoD service. IP multicast has been proposed to enhance the efficiency of
4
detect node failure for partnership refinement. It helps each node maintain a stable number of available partners by calculating a score for each partner. Let node j be the partner of node i. for node i, the score of partner node j is denoted byScorei,j.
is the average number of segment that node i retrieved from node j. A partner that detects the failure will issue the departure message on behalf the failed node. And then the message is gossiped.
Chunk distribution protocol:
Every node periodically exchanges data availability information with a set of partners.
The data availability information can be described as a buffer map.
Peer’s buffer map of video chunks:
As figure 3 shows the buffer map message includes the offset that the ID of the first chunk, the length of the buffer map, and a string of zeros and ones indicating which chunks are available. The BM playable video indicates the number of continuous chunks in the buffer map, beginning from the offset
Figure 3 buffer map format
1.2. Video on Demand
Several approaches have been explored in the past to tackle scalability issues faced by VoD service. IP multicast has been proposed to enhance the efficiency of
4
detect node failure for partnership refinement. It helps each node maintain a stable number of available partners by calculating a score for each partner. Let node j be the partner of node i. for node i, the score of partner node j is denoted byScorei,j.
is the average number of segment that node i retrieved from node j. A partner that detects the failure will issue the departure message on behalf the failed node. And then the message is gossiped.
Chunk distribution protocol:
Every node periodically exchanges data availability information with a set of partners.
The data availability information can be described as a buffer map.
Peer’s buffer map of video chunks:
As figure 3 shows the buffer map message includes the offset that the ID of the first chunk, the length of the buffer map, and a string of zeros and ones indicating which chunks are available. The BM playable video indicates the number of continuous chunks in the buffer map, beginning from the offset
Figure 3 buffer map format
1.2. Video on Demand
Several approaches have been explored in the past to tackle scalability issues
Several approaches have been explored in the past to tackle scalability issues