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Designs and analyses in structured peer-to-peer systems
KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Peer-to-Peer (P2P) computing is a recent hot topic in the areas of networking and distributed systems. Work on P2P computing was triggered by a number of ad-hoc systems that made the concept popular. Later, academic research efforts started to investigate P2P computing issues based on scientific principles. Some of that research produced a number of structured P2P systems that were collectively referred to by the term ``Distributed Hash Tables'' (DHTs). However, the research occurred in a diversified way leading to the appearance of similar concepts yet lacking a common perspective and not heavily analyzed. In this thesis we present a number of papers representing our research results in the area of structured P2P systems grouped as two sets labeled respectively ``Designs'' and ``Analyses''.

The contribution of the first set of papers is as follows. First, we present the principle of distributed k-ary search (DKS) and argue that it serves as a framework for most of the recent P2P systems known as DHTs. That is, given the DKS framework, understanding existing DHT systems is done simply by seeing how they are instances of that framework. We argue that by perceiving systems as instances of the DKS framework, one can optimize some of them. We illustrate that by applying the framework to the Chord system, one of the most established DHT systems. Second, We show how the DKS framework helps in the design of P2P algorithms by two examples: (a) The DKS(n;k;f) system which is a system designed from the beginning on the principles of distributed k-ary search. (b) Two broadcast algorithms that take advantage of the distributed k-ary search tree.

The contribution of the second set of papers is as follows. We account for two approaches that we used to evaluate the performance of a particular class of DHTs, namely the one adopting periodic stabilization for topology maintenance. The first approach was of an intrinsic empirical nature. In that approach, we tried to perceive a DHT as a physical system and account for its properties in a size-independent manner. The second approach was of a more analytical nature. In this approach we applied the technique of Master equations, which is a widely used technique in the analysis of natural systems. The application of the technique lead to a highly accurate description of the behavior of structured overlays.

Additionally, the thesis contains a primer on structured P2P systems that tries to capture the main ideas that are prevailing in the field and enumerates a subset of the current hot and open research issues.

Place, publisher, year, edition, pages
Stockholm: KTH , 2005. , 229 p.
Series
Trita-IMIT. LECS, ISSN 1651-4076 ; 05:02
Series
SICS Dissertation Series, ISSN 1101-1335 ; 38
Keyword [en]
Datorsystem
Keyword [sv]
Datorsystem
National Category
Computer Engineering
Identifiers
URN: urn:nbn:se:kth:diva-264OAI: oai:DiVA.org:kth-264DiVA: diva2:8306
Public defence
2005-06-10, Sal D, KTH Forum, 10:00
Opponent
Supervisors
Note
QC 20101008Available from: 2005-06-07 Created: 2005-06-07 Last updated: 2010-10-11Bibliographically approved
List of papers
1. A structured P2P overlay networks primer
Open this publication in new window or tab >>A structured P2P overlay networks primer
(English)Manuscript (preprint) (Other academic)
National Category
Computer Engineering
Identifiers
urn:nbn:se:kth:diva-25074 (URN)
Note
QC 20101007. Baserad på: Sameh El-Ansary and Seif Haridi, An Overview of Structured P2P Overlay Networks, Book chapter to appear in the upcoming book: Theoretical and Algorithmic Aspects of Sensor, Ad Hoc Wireless and Peer-to-Peer Networks, (Editor: Prof. JieWu), CRC Press, 2005Available from: 2010-10-07 Created: 2010-10-07 Last updated: 2010-10-11Bibliographically approved
2. A Framework for Peer-To-Peer Lookup Services based on k-ary search
Open this publication in new window or tab >>A Framework for Peer-To-Peer Lookup Services based on k-ary search
2002 (English)Report (Other academic)
Abstract [en]

Locating entities in peer-to-peer environments is a fundamentaloperation. Recent studies show that the concept of distributed hash table can be used to design scalable lookup schemes with good performance (i.e. small routing table and lookup length). In this paper, we propose a simple framework for deriving decentralized lookup algorithms. The proposed framework is simple in that it is based on the well-known concept of k-ary search. To demonstrate the applicability of our framework, we show how it can be used to instantiate Chord. When deriving a generalized Chord from our framework, we obtain better performance in terms of the routing table size (38% smaller than the generalization suggested by the Chord authors).

Publisher
13 p.
Series
Technical Report, SICS, 2002-06
Keyword
Lookup, peer-to-peer, distributed hash table, k-ary search
National Category
Computer Engineering
Identifiers
urn:nbn:se:kth:diva-25076 (URN)
Note
QC 20101008Available from: 2010-10-07 Created: 2010-10-07 Last updated: 2010-10-08Bibliographically approved
3. DKS(N, k, f): A family of low communication, scalable and fault-tolerant infrastructures for P2P applications
Open this publication in new window or tab >>DKS(N, k, f): A family of low communication, scalable and fault-tolerant infrastructures for P2P applications
2003 (English)In: CCGRID 2003: 3RD IEEE/ACM INTERNATIONAL SYMPOSIUM ON CLUSTER COMPUTING AND THE GRID, PROCEEDINGS / [ed] Titsworth, F.; Azada, D., LOS ALAMITOS: IEEE COMPUTER SOC , 2003, 344-350 p.Conference paper, Published paper (Refereed)
Abstract [en]

In this paper, we present EKS(N,k,f), a family of infrastructures for building Peer-To-Peer applications. Each instance of EKS(N,k,f) is a fully decentralized overlay network characterized by three parameters: N the maximum number of nodes that can be in the network; k the search arity within the network and f the degree of fault-tolerance. Once these parameters are instantiated, the resulting network has several desirable properties. The first property, which is the main contribution of this paper, is that there is no separate procedure for maintaining routing tables; instead, any out-of-date or erroneous routing entry is eventually corrected on-the-fly thereby, eliminating unnecessary bandwidth consumption. The second property is that each lookup request is resolved in at Most log(k)(N) overlay hops under normal operations. Third, each node maintains only (k - 1) log(k)(N) + 1 addresses of other nodes for routing purposes. Fourth, new nodes can join and existing nodes can leave at will with a negligible disturbance to the ability to resolve lookups in logk(N) hops in average. Fifth, any pair key/value that is inserted into the system is guaranteed to be located even in the presence of concurrent joins. Sixth, even if f consecutive nodes fail simultaneously, correct lookup is still guaranteed.

Place, publisher, year, edition, pages
LOS ALAMITOS: IEEE COMPUTER SOC, 2003
National Category
Computer Engineering
Identifiers
urn:nbn:se:kth:diva-25085 (URN)10.1109/CCGRID.2003.1199386 (DOI)000183253300041 ()0-7695-1919-9 (ISBN)
Conference
3rd IEEE/ACM International Symposium on Cluster Computing and the Grid (CCGrid2003)
Note
QC 20101008Available from: 2010-10-08 Created: 2010-10-08 Last updated: 2010-10-08Bibliographically approved
4. Efficient broadcast in structured P2P networks
Open this publication in new window or tab >>Efficient broadcast in structured P2P networks
2003 (English)In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 2735, 304-314 p.Article in journal (Refereed) Published
Abstract [en]

In this position paper, we present an efficient algorithm for performing a broadcast operation with minimal cost in structured DHT-based P2P networks. In a system of N nodes, a broadcast message originating at an arbitrary node reaches all other nodes after exactly N - 1 messages. We emphasize the perception of a class of DHT systems as a form of distributed k-ary search and we take advantage of that perception in constructing a spanning tree that is utilized for efficient broadcasting. We consider broadcasting as a basic service that adds to existing DHTs the ability to search using arbitrary queries as well as dissiminate/collect global information.

National Category
Computer Engineering
Identifiers
urn:nbn:se:kth:diva-25088 (URN)000185936300027 ()
Note
QC 20101008. Ingår i 2nd International Workshop on Peer-to-Peer Systems (IPTPS '03), BERKELEY, CALIFORNIA, FEB 21-22, 2003.Available from: 2010-10-08 Created: 2010-10-08 Last updated: 2017-12-12Bibliographically approved
5. Self-Correcting Broadcast in Distributed Hash Tables
Open this publication in new window or tab >>Self-Correcting Broadcast in Distributed Hash Tables
Show others...
2003 (English)In: Proceedings of the Fifteenth IASTED International Conference on Parallel and Distributed Computing and Systems / [ed] Gonzalez, T., 2003, 93-98 p.Conference paper, Published paper (Refereed)
Abstract [en]

We present two broadcast algorithms that can be used on top of distributed hash tables (DHTs) to perform group communication and arbitrary queries. Unlike other P2P group communication mechanisms, which either embed extra information in the DHTs or use random overlay networks, our algorithms take advantage of the structured DHT overlay networks without maintaining additional information. The proposed algorithms do not send any redundant messages. Furthermore the two algorithms ensure 100% coverage of the nodes in the system even when routing information is outdated as a result of dynamism in the network. The first algorithm performs some correction of outdated routing table entries with a low cost of correction traffic. The second algorithm exploits the nature of the broadcasts to extensively update erroneous routing information at the cost of higher correction traffic. The algorithms are validated and evaluated in our stochastic distributed-algorithms simulator.

Keyword
Distributed Algorithms, Distributed Hash Tables, Group Communication, Peer-to-Peer
National Category
Computer Engineering
Identifiers
urn:nbn:se:kth:diva-25089 (URN)0-88986-392-X (ISBN)
Note
QC 20101008Available from: 2010-10-08 Created: 2010-10-08 Last updated: 2010-10-08Bibliographically approved
6. A component-based P2P simulation environment
Open this publication in new window or tab >>A component-based P2P simulation environment
(English)Manuscript (preprint) (Other academic)
National Category
Computer Engineering
Identifiers
urn:nbn:se:kth:diva-25092 (URN)
Note
QC 20101008Available from: 2010-10-08 Created: 2010-10-08 Last updated: 2010-10-11Bibliographically approved
7. Physics-inspired performance evaluation of DHTs
Open this publication in new window or tab >>Physics-inspired performance evaluation of DHTs
(English)Manuscript (preprint) (Other academic)
Abstract [en]

In the majority of structured peer-to-peer overlay networks a graph with a desirable topology is constructed. In most cases, the graph is maintained by a periodic activity performed by each node in the graph to preserve the desirable structure in face of the continuous change of the set of nodes. The interaction of the autonomous periodic activities of the nodes renders the performance analysis of such systems complex and simulation of scales of interest can be prohibitive. Physicists, however, are accustomed to dealing with scale by characterizing a system using intensive variables, i.e. variables that are size independent. The approach has proved its usefulness when applied to satisfiability theory. This work is the first attempt to apply it in the area of distributed systems. The contribution of this paper is two-fold. First, we describe a methodology to be used for analyzing the performance of large scale distributed systems. Second, we show how we applied the methodology to find two intensive variables that describe the characteristic behavior of the Chord overlay network, the variables are: 1) The density of nodes in the identifier space and 2) The ratio of the magnitude of perturbation of the network (joins/failures) to the magnitude of periodic stabilization of the network.

Keyword
DHT performance, Structured Overlay networks, Data Collapse, Complex Systems
National Category
Computer Engineering
Identifiers
urn:nbn:se:kth:diva-25101 (URN)
Note
QC 20101008. Baserad på följande tre artiklar: Erik Aurell and Sameh El-Ansary A Physics-Style Approach to Scalability of Distributed Systems. LNCS Post-Proceedings of the Global Computing 2004Workshop (March 2004), Rovereto, Italy. Sameh El-Ansary, Erik Aurell, Per Brand and Seif Haridi, Experience with a physics-style approach for the study of self properties in structured overlay networks, In the International Workshop on Self-* Properties in Complex Information Systems, (May 2004), Bertinoro, Italy Sameh El-Ansary, Erik Aurell and Seif Haridi, A Physics inspired Performance Evaluation of a Structured Peer-to-Peer Overlay Networks, In the International Conference on Parallel and Distributed Computing and Networks (PDCN 2005), Innsbruck, Austria, February , 2005 Available from: 2010-10-08 Created: 2010-10-08 Last updated: 2010-10-08Bibliographically approved
8. Analytical study of consistency and performance of DHTs under churn
Open this publication in new window or tab >>Analytical study of consistency and performance of DHTs under churn
(English)Manuscript (preprint) (Other academic)
Abstract [en]

In this paper, we present a complete analytical study of dynamic membership (aka churn) in structured peer-to-peer networks. We use a master-equation-based approach, which is used traditionally in non-equilibrium statistical mechanics to describe steady-state or transient phenomena. We demonstrate that this methodology is infact also well suited to describing structured overlay networks by an application to the Chord system. For any rate of churn and stabilization rates, and any system size, we accurately account for the functional form of: the distribution of inter-node distances, the probability of network disconnection, the fraction of failed or incorrect successor and finger pointers and show how we can use these quantities to predict both the performance and consistency of lookups under churn. Additionally, we also discuss how churn may actually be of different ’types’ and the implications this will have for structured overlays in general. All theoretical predictions match simulation results to a high extent. The analysis includes details that are applicable to a generic structured overlay deploying a ring as well as Chord-specific details that can act as guidelines for analyzing other systems.

Keyword
Peer-To-Peer, Structured Overlays, Distributed Hash Tables, Dynamic Membership in Large- scale Distributed Systems, Analytical Modeling, Master Equations
National Category
Computer Engineering
Identifiers
urn:nbn:se:kth:diva-25104 (URN)
Note
QC 20101008. The work was reported in the following two publications: Sameh El-Ansary, Supriya Krishnamurthy, Erik Aurell and Seif Haridi, An Analytical Study of Consistentcy and Performance of DHTs under Churn. Technical Report TR-2004-12, SICS, October 2004. Supriya Krishnamurthy, Sameh El-Ansary, Erik Aurell and Seif Haridi, A Statistical Theory of Chord under Churn. In the 4th Annual InternationalWorkshop on Peer-To-Peer Systems (IPTPS 05), Ithaca, NY, USA, February 2005 Available from: 2010-10-08 Created: 2010-10-08 Last updated: 2010-10-08Bibliographically approved

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Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
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  • Other style
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  • en-US
  • fi-FI
  • nn-NO
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  • sv-SE
  • Other locale
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Output format
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  • asciidoc
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