Steven E. Czerwinski

Bio: Steven E. Czerwinski is an academic researcher from University of California, Berkeley. The author has contributed to research in topics: Service provider & The Internet. The author has an hindex of 6, co-authored 7 publications receiving 4602 citations.

OceanStore: an architecture for global-scale persistent storage

Abstract: OceanStore is a utility infrastructure designed to span the globe and provide continuous access to persistent information. Since this infrastructure is comprised of untrusted servers, data is protected through redundancy and cryptographic techniques. To improve performance, data is allowed to be cached anywhere, anytime. Additionally, monitoring of usage patterns allows adaptation to regional outages and denial of service attacks; monitoring also enhances performance through pro-active movement of data. A prototype implementation is currently under development.

An architecture for a secure service discovery service

Abstract: The widespread deployment of inexpensive communications technology, computational resources in the networking infrastructure, and network-enabled end devices poses an interesting problem for end users: how to locate a particular network service or device out of hundreds of thousands of accessible services and devices. This paper presents the architecture and implementation of a secure Service Discovery Service (SDS). Service providers use the SDS to advertise complex descriptions of available or already running services, while clients use the SDS to compose complex queries for locating these services. Service descriptions and queries use the eXtensible Markup Language (XML) to encode such factors as cost, performance, location, and deviceor service-specific capabilities. The SDS provides a highlyavailable, fault-tolerant, incrementally scalable service for locating services in the wide-area. Security is a core component of the SDS and, where necessary, communications are both encrypted and authenticated. Furthermore, the SDS uses an hybrid access control list and capability system to control access to service information.

An architecture for secure wide-area service discovery

Abstract: The widespread deployment of inexpensive communications technology, computational resources in the networking infrastructure, and network-enabled end devices poses an interesting problem for end users: how to locate a particular network service or device out of hundreds of thousands of accessible services and devices. This paper presents the architecture and implementation of a secure wide-area Service Discovery Service (SDS). Service providers use the SDS to advertise descriptions of available or already running services, while clients use the SDS to compose complex queries for locating these services. Service descriptions and queries use the eXtensible Markup Language (XML) to encode such factors as cost, performance, location, and device- or service-specific capabilities. The SDS provides a fault-tolerant, incrementally scalable service for locating services in the wide-area. Security is a core component of the SDS: communications are both encrypted and authenticated where necessary, and the system uses a hybrid access control list and capability system to control access to service information. Wide-area query routing is also a core component of the SDS: all information in the system is potentially reachable by all clients.

NinjaMail: the design of a high-performance clustered, distributed e-mail system

Abstract: In today's Internet era, electronic mail is replacing telephony and postal mail as the primary means of communication for hundreds of millions of individuals. Free e-mail services, such as Microsoft's Hotmail and Yahoo's Yahoo Mail, each have tens of millions of subscribers. However, these and other current e-mail systems unfortunately are nor capable of handling the scale of Internet e-mail use, while still providing reliable, high performance and feature-rich services to users. This limitation is the result both of suboptimal use of cluster computing resources, and of highly variable performance of wide-area connections over the Internet. This paper presents NinjaMail, a novel geographically distributed, cluster-based e-mail system built on top of UC Berkeley's Ninja cluster architecture and OceanStore wide-area data storage architecture. NinjaMail is unique in that it uses a collection of clusters distributed through the wide-area to provide users with highly available, scalable and feature-rich services via a wide variety of access methods.

Chord: A scalable peer-to-peer lookup service for internet applications

Abstract: A fundamental problem that confronts peer-to-peer applications is to efficiently locate the node that stores a particular data item. This paper presents Chord, a distributed lookup protocol that addresses this problem. Chord provides support for just one operation: given a key, it maps the key onto a node. Data location can be easily implemented on top of Chord by associating a key with each data item, and storing the key/data item pair at the node to which the key maps. Chord adapts efficiently as nodes join and leave the system, and can answer queries even if the system is continuously changing. Results from theoretical analysis, simulations, and experiments show that Chord is scalable, with communication cost and the state maintained by each node scaling logarithmically with the number of Chord nodes.

Pastry: Scalable, Decentralized Object Location, and Routing for Large-Scale Peer-to-Peer Systems

Abstract: This paper presents the design and evaluation of Pastry, a scalable, distributed object location and routing substrate for wide-area peer-to-peer ap- plications. Pastry performs application-level routing and object location in a po- tentially very large overlay network of nodes connected via the Internet. It can be used to support a variety of peer-to-peer applications, including global data storage, data sharing, group communication and naming. Each node in the Pastry network has a unique identifier (nodeId). When presented with a message and a key, a Pastry node efficiently routes the message to the node with a nodeId that is numerically closest to the key, among all currently live Pastry nodes. Each Pastry node keeps track of its immediate neighbors in the nodeId space, and notifies applications of new node arrivals, node failures and recoveries. Pastry takes into account network locality; it seeks to minimize the distance messages travel, according to a to scalar proximity metric like the number of IP routing hops. Pastry is completely decentralized, scalable, and self-organizing; it automatically adapts to the arrival, departure and failure of nodes. Experimental results obtained with a prototype implementation on an emulated network of up to 100,000 nodes confirm Pastry's scalability and efficiency, its ability to self-organize and adapt to node failures, and its good network locality properties.

A scalable content-addressable network

Abstract: Hash tables - which map "keys" onto "values" - are an essential building block in modern software systems. We believe a similar functionality would be equally valuable to large distributed systems. In this paper, we introduce the concept of a Content-Addressable Network (CAN) as a distributed infrastructure that provides hash table-like functionality on Internet-like scales. The CAN is scalable, fault-tolerant and completely self-organizing, and we demonstrate its scalability, robustness and low-latency properties through simulation.

Dynamo: amazon's highly available key-value store

Abstract: Reliability at massive scale is one of the biggest challenges we face at Amazon.com, one of the largest e-commerce operations in the world; even the slightest outage has significant financial consequences and impacts customer trust. The Amazon.com platform, which provides services for many web sites worldwide, is implemented on top of an infrastructure of tens of thousands of servers and network components located in many datacenters around the world. At this scale, small and large components fail continuously and the way persistent state is managed in the face of these failures drives the reliability and scalability of the software systems.This paper presents the design and implementation of Dynamo, a highly available key-value storage system that some of Amazon's core services use to provide an "always-on" experience. To achieve this level of availability, Dynamo sacrifices consistency under certain failure scenarios. It makes extensive use of object versioning and application-assisted conflict resolution in a manner that provides a novel interface for developers to use.

The Cricket location-support system

Abstract: This paper presents the design, implementation, and evaluation of Cricket, a location-support system for in-building, mobile, location-dependent applications. It allows applications running on mobile and static nodes to learn their physical location by using listeners that hear and analyze information from beacons spread throughout the building. Cricket is the result of several design goals, including user privacy, decentralized administration, network heterogeneity, and low cost. Rather than explicitly tracking user location, Cricket helps devices learn where they are and lets them decide whom to advertise this information to; it does not rely on any centralized management or control and there is no explicit coordination between beacons; it provides information to devices regardless of their type of network connectivity; and each Cricket device is made from off-the-shelf components and costs less than U.S. $10. We describe the randomized algorithm used by beacons to transmit information, the use of concurrent radio and ultrasonic signals to infer distance, the listener inference algorithms to overcome multipath and interference, and practical beacon configuration and positioning techniques that improve accuracy. Our experience with Cricket shows that several location-dependent applications such as in-building active maps and device control can be developed with little effort or manual configuration.