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49
Efficient Routing for Peer-to-Peer Overlays
, 2004
"... Most current peer-to-peer lookup schemes keep a small amount of routing state per node, typically logarithmic in the number of overlay nodes. This design assumes that routing information at each member node must be kept small, so that the bookkeeping required to respond to system membership changes ..."
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Cited by 81 (5 self)
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Most current peer-to-peer lookup schemes keep a small amount of routing state per node, typically logarithmic in the number of overlay nodes. This design assumes that routing information at each member node must be kept small, so that the bookkeeping required to respond to system membership changes is also small, given that aggressive membership dynamics are expected. As a consequence, lookups have high latency as each lookup requires contacting several nodes in sequence. In this paper, we question these...
Corona: A High Performance Publish-Subscribe System for the World Wide Web
- In NSDI
, 2006
"... Despite the abundance of frequently changing information, the Web lacks a publish-subscribe interface for delivering updates to clients. The use of naïve polling for detecting updates leads to poor performance and limited scalability as clients do not detect updates quickly and servers face high loa ..."
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Cited by 57 (5 self)
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Despite the abundance of frequently changing information, the Web lacks a publish-subscribe interface for delivering updates to clients. The use of naïve polling for detecting updates leads to poor performance and limited scalability as clients do not detect updates quickly and servers face high loads imposed by active polling. This paper describes a novel publish-subscribe system for the Web called Corona, which provides high performance and scalability through optimal resource allocation. Users register interest in Web pages through existing instant messaging services. Corona monitors the subscribed Web pages, detects updates efficiently by allocating polling load among cooperating peers, and disseminates updates quickly to users. Allocation of resources for polling is driven by a distributed optimization engine that achieves the best update performance without exceeding load limits on content servers. Large-scale simulations and measurements from PlanetLab deployment demonstrate that Corona achieves orders of magnitude improvement in update performance at a modest cost. 1
Heterogeneity and load balance in distributed hash tables
- In Proc. of IEEE INFOCOM
, 2005
"... Abstract — Existing solutions to achieve load balancing in DHTs incur a high overhead either in terms of routing state or in terms of load movement generated by nodes arriving or departing the system. In this paper, we propose a set of general techniques and use them to develop a protocol based on C ..."
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Cited by 52 (1 self)
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Abstract — Existing solutions to achieve load balancing in DHTs incur a high overhead either in terms of routing state or in terms of load movement generated by nodes arriving or departing the system. In this paper, we propose a set of general techniques and use them to develop a protocol based on Chord, called Y0, that achieves load balancing with minimal overhead under the typical assumption that the load is uniformly distributed in the identifier space. In particular, we prove that Y0 can achieve near-optimal load balancing, while moving little load to maintain the balance, and increasing the size of the routing tables by at most a constant factor. Using extensive simulations based on real-world and synthetic capacity distributions, we show that Y0 reduces the load imbalance of Chord from O(log n) to a less than 4 without increasing the number of links that a node needs to maintain. In addition, we study the effect of heterogeneity on both DHTs, demonstrating significantly reduced average route length as node capacities become increasingly heterogeneous. For a real-word distribution of node capacities, the route length in Y0 is asymptotically less than half the route length in the case of a homogeneous system. Index Terms — System design, Simulations I.
EpiChord: Parallelizing the Chord Lookup Algorithm with Reactive Routing State Management
- IN PROCEEDINGS OF THE 12TH INTERNATIONAL CONFERENCE ON NETWORKS
, 2004
"... EpiChord is a DHT lookup algorithm that demonstrates that we can remove the O(log n)-state-per- node restriction on existing DHT topologies to achieve significantly better lookup performance and resilience using a novel reactive routing state maintenance strategy that amortizes network maintenance c ..."
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Cited by 29 (0 self)
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EpiChord is a DHT lookup algorithm that demonstrates that we can remove the O(log n)-state-per- node restriction on existing DHT topologies to achieve significantly better lookup performance and resilience using a novel reactive routing state maintenance strategy that amortizes network maintenance costs into existing lookups and by issuing parallel queries. Our technique allows us to design a new class of unlimited-state-per-node DHTs that is able to adapt naturally to a wide range of lookup workloads. EpiChord is able to achieve O(1)-hop lookup performance under lookup-intensive workloads, and at least O(log n)- hop lookup performance under churn-intensive workloads even in the worst case (though it is expected to perform better on average). Our reactive
Optimizing peer relationships in a super-peer network
- in: 27th International Conference on Distributed Computing Systems (ICDCS 2007
, 2007
"... Super-peer architectures exploit the heterogeneity of nodes in a P2P network by assigning additional responsibilities to higher-capacity nodes. In the design of a super-peer network for file sharing, several issues have to be addressed: how client peers are related to super-peers, how super-peers lo ..."
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Cited by 21 (2 self)
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Super-peer architectures exploit the heterogeneity of nodes in a P2P network by assigning additional responsibilities to higher-capacity nodes. In the design of a super-peer network for file sharing, several issues have to be addressed: how client peers are related to super-peers, how super-peers locate files, how the load is balanced among the super-peers, and how the system deals with node failures. In this paper we introduce a self-organizing super-peer network architecture (SOSPNet) that solves these issues in a fully decentralized manner. SOSPNet maintains a super-peer network topology that reflects the semantic similarity of peers sharing content interests. Super-peers maintain semantic caches of pointers to files which are requested by peers with similar interests. Client peers, on the other hand, dynamically select super-peers offering the best search performance. We show how this simple approach can be employed not only to optimize searching, but also to solve generally difficult problems encountered in P2P architectures such as load balancing and fault tolerance. We evaluate SOSPNet using a model of the semantic structure derived from the 8-month traces of two large file-sharing communities. The obtained results indicate that SOSPNet achieves close-to-optimal file search performance, quickly adjusts to changes in the environment (node joins and leaves), survives even catastrophic node failures, and efficiently distributes the system load taking into account peer capacities. 1
Discovery of stable peers in a self-organising peer-to-peer gradient topology. In:
- Proceedings of the 6th IFIP international conference distributed applications and interoperable systems (DAIS’06),
, 2006
"... Abstract. Peer-to-peer (P2P) systems are characterised by a wide disparity in peer resources and capabilities. In particular, a number of measurements on deployed P2P systems show that peer stability (e.g. uptime) varies by several orders of magnitude between peers. In this paper, we introduce a pe ..."
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Cited by 18 (8 self)
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Abstract. Peer-to-peer (P2P) systems are characterised by a wide disparity in peer resources and capabilities. In particular, a number of measurements on deployed P2P systems show that peer stability (e.g. uptime) varies by several orders of magnitude between peers. In this paper, we introduce a peer utility metric and construct a self-organising P2P topology based on this metric that allows the efficient discovery of stable peers in the system. We propose and evaluate a search algorithm and we show that it achieves significantly better performance than random walking. Our approach can be used by certain classes of applications to improve the availability and performance of system services by placing them on the most stable peers, as well as to reduce the amount of network traffic required to discover and use these services. As a proof-of-concept, we demonstrate the design of a naming service on the gradient topology.
D1HT: A Distributed One Hop Hash Table
- in Proc. of IPDPS, Apr 2006. [Online]. Available: http://www.lcp.coppe.ufrj.br
"... Distributed Hash Tables (DHTs) have been used in a variety of applications, but most DHTs so far have opted to solve lookups with multiple hops, which sacrifices performance in order to keep little routing information and minimize maintenance traffic. In this paper, we introduce D1HT, a novel single ..."
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Cited by 15 (2 self)
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Distributed Hash Tables (DHTs) have been used in a variety of applications, but most DHTs so far have opted to solve lookups with multiple hops, which sacrifices performance in order to keep little routing information and minimize maintenance traffic. In this paper, we introduce D1HT, a novel single hop DHT that is able to maximize performance with reasonable maintenance traffic overhead even for huge and dynamic peer-to-peer (P2P) systems. We formally define the algorithm we propose to detect and notify any membership change in the system, prove its correctness and performance properties, and present a Quarantine-like mechanism to reduce the overhead caused by volatile peers. Our analyses show that D1HT has reasonable maintenance bandwidth requirements even for very large systems, while presenting at least twice less bandwidth overhead than previous single hop DHT. 1.
Using aggregation for adaptive super-peer discovery on the gradient topology
- In IEEE International Workshop on Self-Managed Networks, Systems and Services
, 2006
"... Abstract. Peer-to-peer environments exhibit a very high diversity in individual peer characteristics ranging by orders of magnitude in terms of uptime, available bandwidth, and storage space. Many systems attempt to exploit this resource heterogeneity by using the best performing and most reliable p ..."
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Cited by 13 (3 self)
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Abstract. Peer-to-peer environments exhibit a very high diversity in individual peer characteristics ranging by orders of magnitude in terms of uptime, available bandwidth, and storage space. Many systems attempt to exploit this resource heterogeneity by using the best performing and most reliable peers, called super-peers, for hosting system services. However, due to inherent decentralisation, scale, dynamism, and complexity of P2P environments, self-managing super-peer selection is a challenging problem. In this paper, decentralised aggregation techniques are used to reduce the uncertainty about system properties by approximating the peer utility distribution allowing peers to calculate adaptive thresholds in order to discover appropriate super-peers. Furthermore, a heuristic search algorithm is described that allows super-peers, above a certain utility threshold, to be eOEciently discovered and utilised by any peer in the system.1
Achieving One-Hop DHT Lookup and Strong Stabilization by Passing Tokens
- PROCEEDINGS OF THE 12TH INTERNATIONAL CONFERENCE ON NETWORKS 2004 (ICON 2004), SINGAPORE, NOVEMBER 2004.
, 2004
"... Recent research has demonstrated that if network churn is not excessively high, it becomes entirely reasonable for a Distributed Hash Table (DHT) to store a global lookup table at every node to achieve one-hop lookup. We present a novel algorithm for maintaining global lookup state in a DHT with a C ..."
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Cited by 13 (0 self)
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Recent research has demonstrated that if network churn is not excessively high, it becomes entirely reasonable for a Distributed Hash Table (DHT) to store a global lookup table at every node to achieve one-hop lookup. We present a novel algorithm for maintaining global lookup state in a DHT with a Chord-like circular address space. In our DHT, events are disseminated with a parallelized token-passing algorithm using dynamically-constructed dissemination trees rooted at the source of the events. We show that we are able to achieve good one- and two-hop routing performance at a modest cost in bandwidth. Furthermore, our scheme is bandwidth-adaptive, and automatically detects and repairs global address space inconsistencies.
