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22
Associative Search in Peer to Peer Networks: Harnessing Latent Semantics
, 2003
"... The success of a P2P file-sharing network highly depends on the scalability and versatility of its search mechanism. Two particularly desirable search features are scope (ability to find infrequent items) and support for partial-match queries (queries that contain typos or include a subset of keywor ..."
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Cited by 93 (2 self)
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The success of a P2P file-sharing network highly depends on the scalability and versatility of its search mechanism. Two particularly desirable search features are scope (ability to find infrequent items) and support for partial-match queries (queries that contain typos or include a subset of keywords). While centralized-index architectures (such as Napster) can support both these features, existing decentralized architectures seem to support at most one: prevailing unstructured P2P protocols (such as Gnutella and FastTrack) deploy a "blind" search mechanism where the set of peers probed is unrelated to the query; thus they support partial-match queries but have limited scope. On the other extreme, the recently-proposed distributed hash tables (DHTs) such as CAN and CHORD, couple index location with the item's hash value, and thus have good scope but can not effectively support partial-match queries. Another hurdle to DHTs deployment is their tight control of the overlay structure and the information (part of the index) each peer maintains, which makes them more sensitive to failures and frequent joins and disconnects.
Proportional Replication in Peer-to-Peer Networks
, 2006
"... We recently showed for peer-to-peer networks, that having the number of replicas of each object proportional to the request rate for these objects has many per-node advantages. In this paper we complement those results to show that this distribution has network-wide advantages as well. Given these b ..."
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Cited by 36 (0 self)
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We recently showed for peer-to-peer networks, that having the number of replicas of each object proportional to the request rate for these objects has many per-node advantages. In this paper we complement those results to show that this distribution has network-wide advantages as well. Given these benefits of proportional replication, the next issue is achieving proportional replication in a decentralized manner. We show that local storage management algorithms like LRU automatically achieve near-proportional replication and that the system performance with the replica distribution achieved by LRU is very close to optimal. We also show that the LRU responds to a change in user access pattern quickly (the number of accesses taken to reach the new steady-state replica distribution with LRU is close to the minimum possible with any cache replacement algorithm). Analytical models are provided for computing the steady-state network-wide replica distribution and the transient period for LRU.
On the impact of research network based testbeds on wide-area experiments
- In Proceedings of ACM Internet Measurement Conference, Rio de Janeiro
, 2006
"... An important stage of wide-area systems and networking research is to prototype a system to understand its performance when deployed in the real Internet. A key requirement of prototyping is that results obtained from the prototype experiments be representative of the behavior if the system were dep ..."
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Cited by 14 (0 self)
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An important stage of wide-area systems and networking research is to prototype a system to understand its performance when deployed in the real Internet. A key requirement of prototyping is that results obtained from the prototype experiments be representative of the behavior if the system were deployed over nodes connected to commercial ISPs. Recently, distributed testbeds such as PlanetLab and RON have become increasingly popular for performing wide-area experimentation. However, such testbeds typically consist of a significant fraction of nodes with connectivity to research and education networks which potentially hinder their usability in prototyping systems. In this paper, we investigate the impact of testbeds with connectivity to research and education networks on the applications and network services so that such testbeds can be leveraged for evaluation and prototyping. Specifically, we investigate when the representativeness of wide-area experiments deployed on such testbeds is affected by studying the routing paths that applications use over such testbeds. We then investigate how the representativeness of wide-area experiments is affected by studying the performance properties of such paths. We further measure the impact of using such testbeds on application performance via application case studies. Finally, we propose a technique that uses the currently available testbeds but reduces their bias by exposing applications evaluated to network conditions more reflective of the conditions in the commercial Internet.
Just-In-Time Query Retrieval Over Partially Indexed Data on Structured P2P Overlays
"... Structured peer-to-peer (P2P) overlays have been successfully employed in many applications to locate content. However, they have been less effective in handling massive amounts of data because of the high overhead of maintaining indexes. In this paper, we propose PISCES, a Peer-based system that In ..."
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Cited by 9 (4 self)
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Structured peer-to-peer (P2P) overlays have been successfully employed in many applications to locate content. However, they have been less effective in handling massive amounts of data because of the high overhead of maintaining indexes. In this paper, we propose PISCES, a Peer-based system that Indexes Selected Content for Efficient Search. Unlike traditional approaches that index all data, PISCES identifies a subset of tuples to index based on some criteria (such as query frequency, update frequency, index cost, etc.). In addition, a coarse-grained range index is built to facilitate the processing of queries that cannot be fully answered by the tuple-level index. More importantly, PISCES can adaptively self-tune to optimize the subset of tuples to be indexed. That is, the (partial) index in PISCES is built in a Just-In-Time (JIT) manner. Beneficial tuples for current users are pulled for indexing while indexed tuples with infrequent access and high maintenance cost are discarded. We also introduce a light-weight monitoring scheme for structured networks to collect the necessary statistics. We have conducted an extensive experimental study on PlanetLab to illustrate the feasibility, practicality and efficiency of PISCES. The results show that PISCES incurs lower maintenance cost and offers better search and query efficiency compared to existing methods.
Scale-free overlay topologies with hard cutoffs for unstructured peer-to-peer networks
- In Proceedings of IEEE ICDCS
, 2007
"... In unstructured peer-to-peer (P2P) networks, the overlay topology (or connectivity graph) among peers is a crucial component in addition to the peer/data organization and search. Topological characteristics have profound impact on the efficiency of search on such unstructured P2P networks as well as ..."
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Cited by 4 (2 self)
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In unstructured peer-to-peer (P2P) networks, the overlay topology (or connectivity graph) among peers is a crucial component in addition to the peer/data organization and search. Topological characteristics have profound impact on the efficiency of search on such unstructured P2P networks as well as other networks. A key limitation of scalefree (power-law) topologies is the high load (i.e. high degree) on very few number of hub nodes. In a typical unstructured P2P network, peers are not willing to maintain high degrees/loads as they may not want to store large number of entries for construction of the overlay topology. So, to achieve fairness and practicality among all peers, hard cutoffs on the number of entries are imposed by the individual peers, which limits scale-freeness of the overall topology. Thus, it is expected that efficiency of the flooding search reduces as the size of the hard cutoff does. We investigate construction of scale-free topologies with hard cutoffs and effect of these hard cutoffs on the search efficiency. 1.
LiPS: Efficient P2P Search Scheme with Novel Link Prediction Techniques
"... Abstract — The usability of peer-to-peer (P2P) file sharing systems highly depends on their search (or query, content routing) efficiency. In this paper, we present LiPS: an efficient P2P search scheme with novel link prediction techniques. LiPS is a natural combination of recent technical thrusts f ..."
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Cited by 3 (0 self)
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Abstract — The usability of peer-to-peer (P2P) file sharing systems highly depends on their search (or query, content routing) efficiency. In this paper, we present LiPS: an efficient P2P search scheme with novel link prediction techniques. LiPS is a natural combination of recent technical thrusts from two different disciplines, namely 1) the exploitation of user interests in P2P search field, and 2) the link prediction in the complex networks field. Based on experiential observation that people’s social circle typically expands through friends ’ friends, we propose a novel neighbors ’ common neighbor link predictor (NCNP) and its two optimized variations. Trace-driven simulation results demonstrate the proposed link predictors and the effectiveness of LiPS. Specifically, the proposed refined and popularity-aware NCNP algorithms can double or even treble the prediction accuracy, as compared with normal common neighbor predictor. LiPS also significantly outperforms (by as large a margin as 15%) the original Shortcuts search method [1] and achieves up to 60% hit rate. Meanwhile, the query traffic is also slightly reduced. I.
Defending P2Ps from Overlay Flooding-based DDoS
"... A flooding-based search mechanism is often used in unstructured P2P systems. Although a flooding-based search mechanism is simple and easy to implement, it is vulnerable to overlay distributed denial-of-service (DDoS) attacks. Most previous security techniques protect networks from network-layer DDo ..."
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Cited by 3 (1 self)
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A flooding-based search mechanism is often used in unstructured P2P systems. Although a flooding-based search mechanism is simple and easy to implement, it is vulnerable to overlay distributed denial-of-service (DDoS) attacks. Most previous security techniques protect networks from network-layer DDoS attacks, but cannot be applied to overlay DDoS attacks. Overlay flooding-based DDoS attacks can be more damaging in that a small number of messages are inherently propagated to consume a large amount of bandwidth and computation resources. We propose a distributed and scalable method, DD-POLICE, to detect malicious nodes in order to defend P2P systems from overlay flooding-based DDoS attacks. We show the effectiveness of DD-POLICE by comprehensive simulation studies. We believe that deploying DD-POLICE will make P2P systems more scalable and robust. 1
rsearch: Ring-based semantic overlay for efficient recall-guaranteed search in p2p networks
- in Parallel Processing Workshops (ICPPW), 2010 39th International Conference on, 2010
"... Providing recall-guaranteed search is critical for P2P networks. While building semantic overlay im-proves search performance, existing designs suffer from a tradeoff between search time and search quality (i.e. high recall). Moreover, they require to use high control overhead for overlay maintenanc ..."
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Cited by 1 (0 self)
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Providing recall-guaranteed search is critical for P2P networks. While building semantic overlay im-proves search performance, existing designs suffer from a tradeoff between search time and search quality (i.e. high recall). Moreover, they require to use high control overhead for overlay maintenance. In this paper, we present rSearch to achieve fast search with guaranteed high recall. The rSearch-enabled overlay topology looks like a ring, augmented with semantic chord links. Given a query, rSearch uses multiple query walkers that traverse on the ring independently to find relevant semantic nodes for answers. The ring structure facilitates fast and low-redundancy query forwarding, while the abundant semantic chord links enable large semantic clusters. Bloom Filter is used to encode and compress node semantic summaries, greatly saving control overhead. rSearch further con-siders churn resilience and network awareness to en-hance system performance. Extensive simulations with real-life file sharing trace and network latency trace show that rSearch greatly outperforms GES. 1.
Supporting Multiple-Keyword Search in A Hybrid Structured Peer-to-Peer Network
"... structured peer-to-peer (P2P) networks only support singlekeyword exact-match lookups. In practice, however, users often have fuzzy information for identifying these items and tend to submit broad queries. The support of searching based on multiple ..."
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structured peer-to-peer (P2P) networks only support singlekeyword exact-match lookups. In practice, however, users often have fuzzy information for identifying these items and tend to submit broad queries. The support of searching based on multiple
