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Selfstabilizing structured ring topology p2p systems
"... We propose a selfstabilizing and modeless peertopeer(P2P) network construction and maintenance protocol, called the Ring Network(RN) protocol. The RN protocol, when started on a network of peers that are in an arbitrary state, will cause the network to converge to a structured P2P system with a di ..."
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Cited by 36 (0 self)
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We propose a selfstabilizing and modeless peertopeer(P2P) network construction and maintenance protocol, called the Ring Network(RN) protocol. The RN protocol, when started on a network of peers that are in an arbitrary state, will cause the network to converge to a structured P2P system with a directed ring topology, where peers are ordered according to their identifiers. Furthermore, the RN protocol maintains this structure in the face of peer joins and departures. The RN protocol is a distributed and asynchronous messagepassing protocol, which fits well the autonomous behavior of peers in a P2P system. The RN protocol requires only the existence of a bootstrapping system which is weakly connected. Peers do not need to be informed of any global network state, nor do they need to assist in repairing the network topology when they leave. We provide a proof of the selfstabilizing nature of the protocol, and experimentally measure the average cost (in time and number of messages) to achieve convergence. 1.
Fast construction of overlay networks
 SPAA
"... An asynchronous algorithm is described for rapidly constructing an overlay network in a peertopeer system where all nodes can in principle communicate with each other directly through an underlying network, but each participating node initially has pointers to only a handful of other participants. ..."
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Cited by 25 (2 self)
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An asynchronous algorithm is described for rapidly constructing an overlay network in a peertopeer system where all nodes can in principle communicate with each other directly through an underlying network, but each participating node initially has pointers to only a handful of other participants. The output of the mechanism is a linked list of all participants sorted by their identifiers, which can be used as a foundation for building various linear overlay networks such as Chord or skip graphs. Assuming the initial pointer graph is weaklyconnected with maximum degree d and the length of a node identifier is W, the mechanism constructs a binary search tree of nodes of depth O(W) in expected O(W log n) time using expected O((d+W)nlog n) messages of size O(W) each. Furthermore, the algorithm has low contention: at any time there are only O(d) undelivered messages for any given recipient. A lower bound of Ω(d + log n) is given for the running time of any procedure in a related synchronous model that yields a sorted list from a degreed weaklyconnected graph of n nodes. We conjecture that this lower bound is tight and could be attained by further improvements to our algorithms.
Asynchronous Resource Discovery
 IN PROCEEDINGS OF THE 22ND ACM SYMPOSIUM ON PRINCIPLES OF DISTRIBUTED COMPUTING (PODC
, 2003
"... Consider a dynamic, largescale communication infrastructure (e.g., the Internet) where nodes (e.g., in a peer to peer system) can communicate only with nodes whose id (e.g., IP address) are known to them. One of the basic building blocks of such a distributed system is resource discovery  efficien ..."
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Cited by 18 (2 self)
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Consider a dynamic, largescale communication infrastructure (e.g., the Internet) where nodes (e.g., in a peer to peer system) can communicate only with nodes whose id (e.g., IP address) are known to them. One of the basic building blocks of such a distributed system is resource discovery  efficiently discovering the ids of the nodes that currently exist in the system. We present both upper and lower bounds for the resource discovery problem. For the original problem raised by HarcholBalter, Leighton, and Lewin [3] we present an # n log n) message complexity lower bound for asynchronous networks whose size is unknown. For this model, we give an asymptotically message optimal algorithm that improves the bit complexity of Kutten and Peleg [4]. When each node knows the size of its connected component, we provide a novel and highly e#cient algorithm with near linear O(n#(n, n)) message complexity (where # is the inverse of Ackerman's function). In addition, we define and study the Adhoc Resource Discovery Problem, which is a practical relaxation of the original problem. Our algorithm for adhoc resource discovery has near linear O(n#(n, n)) message complexity. The algorithm e#ciently deals with dynamic node additions to the system, thus addressing an open question of [3]. We present a # n#(n, n)) lower bound for the Adhoc Resource Discovery Problem, showing that our algorithm is asymptotically message optimal.
Asynchronous Resource Discovery in Peer to Peer Networks
 In 21st Symp. on Reliable Distributed Systems, October 2002 Japan
, 2002
"... The resource discovery problem arises in the context of peer to peer (P2P) networks, where at any point of time a peer may be placed at or removed from any location over a general purpose network (e.g., an Internet site). A vertex (peer) can communicate with another vertex directly if and only if it ..."
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Cited by 9 (0 self)
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The resource discovery problem arises in the context of peer to peer (P2P) networks, where at any point of time a peer may be placed at or removed from any location over a general purpose network (e.g., an Internet site). A vertex (peer) can communicate with another vertex directly if and only if it knows a certain routing information to that other vertex. Hence, a critical task is for the peers to convey this routing information to each other. The problem was formalized by HarcholBalter, Leighton and Lewin [13]. The routing information needed for a vertex to reach another peer is that peer’s identifier (e.g., IP address). A logical directed edge represents the fact that the peer at the tail of the edge knows the IP address of the one at its head. A number of algorithms were developed in [13] for this problem in the model of a synchronous network over a weakly connected directed graph. The best of these algorithms was randomized. Subsequently, a deterministic algorithm for the problem on synchronous networks with improved complexity was presented in [15]. The current paper extends the deterministic algorithm of [15] to the environment of asynchronous networks, maintaining similar complexities (translated to the asynchronous model). These are lower than the complexities that would be needed to synchronize the system. The main technical difficulty in a directed, weakly connected system is to ensure that vertices take consistent steps, even if their knowledge about each other is not symmetric, and even if there is no timeout mechanism (which does exist in synchronous systems) to assist in that. (In particular, as opposed to the case in synchronous systems, here an algorithm cannot first
Routing and Resource Discovery in Phoenix GridEnabled Message Passing Library
 IEEE International Symposium on Cluster Computing and the Grid
, 2004
"... We describe design and implementation of a “Gridenabled” message passing library, in the context of Phoenix message passing model. It supports (1) message routing between nodes not directly reachable due to firewalls and/or NAT, (2) resource discovery facilitating ease of configuration that allows n ..."
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We describe design and implementation of a “Gridenabled” message passing library, in the context of Phoenix message passing model. It supports (1) message routing between nodes not directly reachable due to firewalls and/or NAT, (2) resource discovery facilitating ease of configuration that allows nodes without static names (e.g., DHCP nodes) to participate in computation without specific efforts, and (3) nodes dynamically joining/leaving computation at runtime. We argue that, in future Grid environments, all of the above functions, not just routing across firewalls, will become important issues of Gridenabled message passing systems including MPI. Unlike solutions commonly proposed by previous work on a Gridenabled MPI, our system runs a distributed resource discovery and routing table construction algorithm, rather than assuming all such pieces of information are available in a static configuration file or alike. Experimental results using 400 nodes in three LANs indicate that our algorithm is able to dynamically discover participating peers, connect them each other, and calculate a routing table. The elapsed time of our algorithm is only approximately twice as long as that of offline route calculation that just connects nodes based on a fully given configuration. 1.
Discovery through gossip
 In Proc. of 24th ACM SPAA. ACM
, 2012
"... Abstract We study stochastic processes in dynamic networks that are motivated by information discovery in largescale distributed networks such as peertopeer and social networks. A wellstudied problem in peertopeer networks is resource discovery, where the goal for nodes (hosts with IP address ..."
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Abstract We study stochastic processes in dynamic networks that are motivated by information discovery in largescale distributed networks such as peertopeer and social networks. A wellstudied problem in peertopeer networks is resource discovery, where the goal for nodes (hosts with IP addresses) is to discover the IP addresses of all other hosts. In social networks, nodes (people) discover new nodes through exchanging contacts with their neighbors (friends). In both cases the discovery of new nodes changes the underlying network new edges are added to the network and the process continues in the changed network. This paper studies and analyzes two natural gossipbased discovery processes. In the push discovery or triangulation process, each node repeatedly chooses two random neighbors and connects them (i.e., "pushes" their mutual information to each other). In the pull discovery process or the twohop walk, each node repeatedly requests or "pulls" a random contact from a random neighbor and connects itself to this twohop neighbor. Both processes are lightweight in the sense that the amortized work done per node is constant per round, local, and naturally robust due to the inherent randomized nature of gossip. Our main result is an almosttight analysis of the time taken for these two randomized processes to converge. We show that in any undirected nnode graph both processes take O(n log 2 n) rounds to connect every node to all other nodes with high probability, whereas Ω(n log n) is a lower bound. We also study the twohop walk in directed graphs, and show that it takes O(n 2 log n) time with high probability, and that the worstcase bound is tight for arbitrary directed graphs, whereas Ω(n 2 ) is a lower bound for strongly connected directed graphs. A key technical challenge that we overcome in our work is the analysis of a randomized process that itself results in a constantly changing network leading to complicated dependencies in every round.
ABSTRACT Fast Construction of Overlay Networks
"... An asynchronous algorithm is described for rapidly constructing an overlay network in a peertopeer system where all nodes can in principle communicate with each other directly through an underlying network, but each participating node initially has pointers to only a handful of other participants. ..."
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An asynchronous algorithm is described for rapidly constructing an overlay network in a peertopeer system where all nodes can in principle communicate with each other directly through an underlying network, but each participating node initially has pointers to only a handful of other participants. The output of the mechanism is a linked list of all participants sorted by their identifiers, which can be used as a foundation for building various linear overlay networks such as Chord or skip graphs. Assuming the initial pointer graph is weaklyconnected with maximum degree d and the length of a node identifier is W, the mechanism constructs a binary search tree of nodes of depth O(W) in expected O(W log n) time using expected O((d+W)nlog n) messages of size O(W) each. Furthermore, the algorithm has low contention: at any time there are only O(d) undelivered messages for any given recipient. A lower bound of Ω(d + log n) is given for the running time of any procedure in a related synchronous model that yields a sorted list from a degreed weaklyconnected graph of n nodes. We conjecture that this lower bound is tight and could be attained by further improvements to our algorithms. Categories and Subject Descriptors
Asynchronous Resource Discovery in Peer to PeerNetworks
"... Abstract The resource discovery problem arises in the context of peer to peer(P2P) networks, where at any point of time a peer may be placed at or removed from any location over a general purpose network (e.g., an Internetsite). A node (peer) can communicate with another node directly if and only if ..."
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Abstract The resource discovery problem arises in the context of peer to peer(P2P) networks, where at any point of time a peer may be placed at or removed from any location over a general purpose network (e.g., an Internetsite). A node (peer) can communicate with another node directly if and only if it knows a certain routing information to that other node. Hence, a criticaltask is for the peers to convey this routing information to each other.
Logan: Automatic Management for Evolvable, LargeScale, Archival Storage
"... Archival storage systems designed to preserve scientific data, business data, and consumer data must maintain and safeguard tens to hundreds of petabytes of data on tens of thousands of media for decades. Such systems are currently designed in the same way as higherperformance, shorterterm storage ..."
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Archival storage systems designed to preserve scientific data, business data, and consumer data must maintain and safeguard tens to hundreds of petabytes of data on tens of thousands of media for decades. Such systems are currently designed in the same way as higherperformance, shorterterm storage systems, which have a useful lifetime but must be replaced in their entirety via a “forklift” upgrade. Thus, while existing solutions can provide good energy efficiency and relatively low cost, they do not adapt well to continuous improvements in technology, becoming less efficient relative to current technology as they age. In an archival storage environment, this paradigm implies an endless series of wholesale migrations and upgrades to remain efficient and up to date. Our approach, Logan, manages node addition, removal, and failure on a distributed network of intelligent storage appliances, allowing the system to gradually evolve as device technology advances. By automatically handling most of the common administration chores—integrating new devices into the system, managing groups of devices that work together to provide redundancy, and recovering from failed devices—Logan reduces management overhead and thus cost. Logan can also improve cost and space efficiency by identifying and decommissioning outdated devices, thus reducing space and power requirements for the archival storage system.