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594
Handling Churn in a DHT
- In Proceedings of the USENIX Annual Technical Conference
, 2004
"... This paper addresses the problem of churn---the continuous process of node arrival and departure---in distributed hash tables (DHTs). We argue that DHTs should perform lookups quickly and consistently under churn rates at least as high as those observed in deployed P2P systems such as Kazaa. We then ..."
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Cited by 447 (22 self)
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This paper addresses the problem of churn---the continuous process of node arrival and departure---in distributed hash tables (DHTs). We argue that DHTs should perform lookups quickly and consistently under churn rates at least as high as those observed in deployed P2P systems such as Kazaa. We then show through experiments on an emulated network that current DHT implementations cannot handle such churn rates. Next, we identify and explore three factors affecting DHT performance under churn: reactive versus periodic failure recovery, message timeout calculation, and proximity neighbor selection. We work in the context of a mature DHT implementation called Bamboo, using the ModelNet network emulator, which models in-network queuing, cross-traffic, and packet loss. These factors are typically missing in earlier simulationbased DHT studies, and we show that careful attention to them in Bamboo's design allows it to function effectively at churn rates at or higher than that observed in P2P file-sharing applications, while using lower maintenance bandwidth than other DHT implementations.
An Analysis of Internet Content Delivery Systems
, 2002
"... In the span of only a few years, the Internet has experienced an astronomical increase in the use of specialized content delivery systems, such as content delivery networks and peer-to-peer file sharing systems. Therefore, an understanding of content delivery on the Internet now requires a detailed ..."
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Cited by 316 (9 self)
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In the span of only a few years, the Internet has experienced an astronomical increase in the use of specialized content delivery systems, such as content delivery networks and peer-to-peer file sharing systems. Therefore, an understanding of content delivery on the Internet now requires a detailed understanding of how these systems are used in practice. This paper examines content delivery from the point of view of four content delivery systems: HTTP web traffic, the Akamai content delivery network, and Kazaa and Gnutella peer-to-peer file sharing traffic. We collected a trace of all incoming and outgoing network traffic at the University of Washington, a large university with over 60,000 students, faculty, and staff. From this trace, we isolated and characterized traffic belonging to each of these four delivery classes. Our results (1) quantify the rapidly increasing importance of new content delivery systems, particularly peerto-peer networks, (2) characterize the behavior of these systems from the perspectives of clients, objects, and servers, and (3) derive implications for caching in these systems. 1
Democratizing content publication with Coral
- IN NSDI
, 2004
"... CoralCDN is a peer-to-peer content distribution network that allows a user to run a web site that offers high performance and meets huge demand, all for the price of a cheap broadband Internet connection. Volunteer sites that run CoralCDN automatically replicate content as a side effect of users acc ..."
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Cited by 314 (21 self)
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CoralCDN is a peer-to-peer content distribution network that allows a user to run a web site that offers high performance and meets huge demand, all for the price of a cheap broadband Internet connection. Volunteer sites that run CoralCDN automatically replicate content as a side effect of users accessing it. Publishing through CoralCDN is as simple as making a small change to the hostname in an object's URL; a peer-to-peer DNS layer transparently redirects browsers to nearby participating cache nodes, which in turn cooperate to minimize load on the origin web server. One of the system's key goals is to avoid creating hot spots that might dissuade volunteers and hurt performance. It achieves this through Coral, a latency-optimized hierarchical indexing infrastructure based on a novel abstraction called a distributed sloppy hash table, or DSHT.
A Survey and Comparison of Peer-to-Peer Overlay Network Schemes
- IEEE COMMUNICATIONS SURVEYS AND TUTORIALS
, 2005
"... Over the Internet today, computing and communications environments are significantly more complex and chaotic than classical distributed systems, lacking any centralized organization or hierarchical control. There has been much interest in emerging Peer-to-Peer (P2P) network overlays because they ..."
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Cited by 300 (1 self)
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Over the Internet today, computing and communications environments are significantly more complex and chaotic than classical distributed systems, lacking any centralized organization or hierarchical control. There has been much interest in emerging Peer-to-Peer (P2P) network overlays because they provide a good substrate for creating large-scale data sharing, content distribution and application-level multicast applications. These P2P networks try to provide a long list of features such as: selection of nearby peers, redundant storage, efficient search/location of data items, data permanence or guarantees, hierarchical naming, trust and authentication, and, anonymity. P2P networks potentially offer an efficient routing architecture that is self-organizing, massively scalable, and robust in the wide-area, combining fault tolerance, load balancing and explicit notion of locality. In this paper, we present a survey and comparison of various Structured and Unstructured P2P networks. We categorize the various schemes into these two groups in the design spectrum and discuss the application-level network performance of each group.
Designing a DHT for low latency and high throughput
- IN PROCEEDINGS OF THE 1ST NSDI
, 2004
"... Designing a wide-area distributed hash table (DHT) that provides high-throughput and low-latency network storage is a challenge. Existing systems have explored a range of solutions, including iterative routing, recursive routing, proximity routing and neighbor selection, erasure coding, replication, ..."
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Cited by 189 (15 self)
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Designing a wide-area distributed hash table (DHT) that provides high-throughput and low-latency network storage is a challenge. Existing systems have explored a range of solutions, including iterative routing, recursive routing, proximity routing and neighbor selection, erasure coding, replication, and server selection. This
Boxwood: Abstractions as the Foundation for Storage Infrastructure
, 2004
"... Writers of complex storage applications such as distributed file systems and databases are faced with the challenges of building complex abstractions over simple storage devices like disks. These challenges are exacerbated due to the additional requirements for faulttolerance and scaling. This paper ..."
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Cited by 132 (8 self)
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Writers of complex storage applications such as distributed file systems and databases are faced with the challenges of building complex abstractions over simple storage devices like disks. These challenges are exacerbated due to the additional requirements for faulttolerance and scaling. This paper explores the premise that high-level, fault-tolerant abstractions supported directly by the storage infrastructure can ameliorate these problems. We have built a system called Boxwood to explore the feasibility and utility of providing high-level abstractions or data structures as the fundamental storage infrastructure. Boxwood currently runs on a small cluster of eight machines. The Boxwood abstractions perform very close to the limits imposed by the processor, disk, and the native networking subsystem. Using these abstractions directly, we have implemented an NFSv2 file service that demonstrates the promise of our approach.
Survey of Research towards Robust Peer-to-Peer Networks: Search Methods
- COMPUTER NETWORKS
, 2004
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The design and implementation of a next generation name service for the internet
- In SIGCOMM
, 2004
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Shark: Scaling File Servers via Cooperative Caching
"... Network file systems offer a powerful, transparent interface for accessing remote data. Unfortunately, in current network file systems like NFS, clients fetch data from a central file server, inherently limiting the system’s ability to scale to many clients. While recent distributed (peer-topeer) sy ..."
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Cited by 105 (3 self)
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Network file systems offer a powerful, transparent interface for accessing remote data. Unfortunately, in current network file systems like NFS, clients fetch data from a central file server, inherently limiting the system’s ability to scale to many clients. While recent distributed (peer-topeer) systems have managed to eliminate this scalability bottleneck, they are often exceedingly complex and provide non-standard models for administration and accountability. We present Shark, a novel system that retains the best of both worlds—the scalability of distributed systems with the simplicity of central servers. Shark is a distributed file system designed for largescale, wide-area deployment, while also providing a dropin replacement for local-area file systems. Shark introduces a novel cooperative-caching mechanism, in which mutually-distrustful clients can exploit each others ’ file caches to reduce load on an origin file server. Using a distributed index, Shark clients find nearby copies of data, even when files originate from different servers. Performance results show that Shark can greatly reduce server load and improve client latency for read-heavy workloads both in the wide and local areas, while still remaining competitive for single clients in the local area. Thus, Shark enables modestly-provisioned file servers to scale to hundreds of read-mostly clients while retaining traditional usability, consistency, security, and accountability.
