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Gradient overlay network 

Gradient overlay network 

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Conference Paper
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This paper presents gradienTv, a distributed, market-based approach to live streaming. In gradienTv, multiple streaming trees are constructed using a market-based approach, such that nodes with increasing upload bandwidth are located closer to the media source at the roots of the trees. Market-based approaches, however, exhibit slow convergence pro...

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... Gradient overlay is a class of P2P overlays that arrange nodes using a local utility function at each node, such that nodes are ordered in descending utility values away from a core of the highest utility nodes [16,17]. As can be seen in Figure 1, the highest utility nodes (darkest colour) are found at the core of the Gradient, and nodes with decreasing utility values (lighter grays) are found at increasing distance from the centre. ...

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... Recently gradient topology comparing to other mentioned adaptive methods has been used in many applications [30][31][32][33] (Fig. 2). That is why it is very important to pay attention to the issue. ...
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... Supernodes are also used to work around connectivity issues [12] by either relaying NAT traversal messages or even actual content when no direct connectivity can be established [1]. In P2P live streaming, supernodes with high upload capacity are tasked to retrieve the streaming data directly from the source of the stream and distribute it to a large number of neighbors [13] In this work, we tackle the supernode selection problem, that is the decision of which peers, among all nodes in the overlay, should become supernodes. This effort is motivated by the needs of a commercial peer-assisted live streaming platform called Hive Streaming [19] 1 , which utilizes supernodes to efficiently deliver content to the viewers. ...
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... However , in overlay networks, nodes have only a relatively small partial view of the system, so preference functions are based only on local state and the state of the node's neighbors. Examples of existing overlay networks that construct their topologies using gossiping and preference functions include Spotify, that preferentially connects nodes with similar music play-lists [8] , Sepidar, that preferentially connects P2P livestreaming nodes with similar upload bandwidth capacity [9], and T-Man, a framework that provides a generic preference function for building such overlays [10]. To the best of our knowledge, there has been no analysis of the convergence properties of such information-carrying gossip-generated topologies built using preference functions. ...
... GLive uses an approximate auction algorithm to match nodes that are willing and able to share the stream with one another. GLive extends our previous work on treebased live-streaming, gradienTv [13] and Sepidar [9], to mesh-based live-streaming. Nodes want to establish connections to other nodes that are as close as possible to the source. ...
... The desired affect of our auction algorithm is that the source will upload to nodes who contribute the most upload bandwidth, who will, in turn, upload to nodes who contribute the next highest amount of bandwidth, and so on until the topology is fully constructed. More details on our approximate assignment algorithm can be found in [9]. One of the main problems with the lack of global information about nodes' upload bandwidths is that it affects the rate of convergence of auction algorithm. ...
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... Finally, we evaluate the convergence of our market model when the node samples are taken from the Gradient overlay compared to a random overlay. Our work is an extension of our previous work on multiple-tree live streaming [17, 16], and the contributions of this paper include: ...
... Many different overlay network topologies have been used for data delivery in P2P media streaming systems, but the two most widely used approaches are multiple-tree [16, 3, 13, 17] and mesh-based overlays [8, 6, 5] . Multipletree overlay networks use push-based content delivery over multiple tree-shaped overlays with the media source as a root of all trees. ...
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... However, the hole punching service can be used by clients of the PSS to establish a direct connection with a sampled private node. NAT hole punching is typically required by applications such as video-on-demand [2] and live streaming [22, 23], where relaying would introduce too much overhead on public nodes. A private node may have several redundant partners. ...
... Finally, we show that if 80% of the nodes are private, and when 50% of the nodes suddenly fail, more than 92% of nodes stay connected. In future work, we will integrate our existing P2P applications with Gozar, such as our work on video streaming [22, 23], and evaluate their behaviour on the open Internet. ...
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... However, the current peer sampling services are not quality-aware as they do not take peer capacity into account when choosing neighbors. The idea of locating higher capacity peers closer to the source than lower capacity peers is similar to the idea of gradient overlays, recently presented in [19], [20]. There are several main differences between these studies and ours. ...
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... Peer sampling services (PSS) have been widely used in large scale distributed applications, such as information dissemination [29], aggregation [30], and overlay topology management [31][32][33][34]. The main purpose of a PSS is to provide the particpating nodes with uniformly random sample of the nodes in the system. ...
... Gossiping algorithms in this case are usually biased towards finding neighbours that have interesting characteristics, e.g. peers with similar playback point and available upload capacity [35] or that are geographically closer to the requester [23]. Upon the discovery of peers, the partnership service is used to establish temporary peering connections with a subset of peers which is considered suitable for the receipt of the stream. ...
... In this dissertation, we present our P2P live media streaming solution in the form of three systems: gradienTv [1], Sepidar [2], and GLive [3]. In gradienTv and Sepidar, we build multiple approximately minimal height overlay trees for content delivery, whereas, in GLive, we build a mesh overlay, such that the average path length between nodes and the media source is approximately minimum. ...
... Therefore, meanwhile the child node, whose father failed, finds an appropriate parent for that stripe, the node misses the content of that stripe. Sepidar [2], gradienTv [1], Orchard [13], ChunkySpread [14], and CoopNet [15] are the solutions in this class. ...
... Many algorithms are proposed based on this model, e.g., NewCoolstreaming [24], DONet/-Coolstreaming [18], PULSE [20] and [21] use a gossip-generated random overlay network to search for the supplying nodes. We use the gossip-generated Gradient overlay [5] for node discovery in gradineTv [1], Sepidar [2], and GLive [3]. In the gossip-based method, each node periodically sends its data availability information to its neighbours, a partial view of nodes in the system, to enable them find appropriate suppliers, who possess data they are looking for. ...