Proceedings. 19th IEEE International Conference on Distributed Computing Systems (Cat. No.99CB37003)

This paper discusses the startup phase of a TDMA protocol intended for safety-critical real-time systems using a broadcast bus. The protocol contains sender id in each message, and nodes send messages of equal size in a fixed order. A single channel media is used and data and synchronization information must therefore share the same channel. Synchronization is challenging, since clocks must be syn... View full abstract»

The application of optimal search strategies to scheduling for distributed real-time systems is, in general, plagued by an inherent computational complexity. This has effectively prevented the integration of strategies such as branch-and-bound (B&B) in scheduling frameworks and tools used in practice today. To show that optimal scheduling is, in fact, a viable alternative for many real-time sc... View full abstract»

We describe imprecise calendars, a way to organize and schedule clusters of nodes in a computation grid. Imprecise calendars permit the easy and efficient sharing of resources between different clusters of computers that are part of a computational grid. In addition, they can be used to provide specific time reservations for applications. We describe the algorithms and policies for manipulation of... View full abstract»

The movement based dynamic location update scheme is studied. An analytical model is applied to formulate the costs of location update and paging in the movement based location update scheme. The problem of minimizing the total cost is formulated as an optimization problem that finds the optimal threshold in the movement based location update scheme. We prove that the total cost function is a conv... View full abstract»

One use of mobile agents is support for itinerant computation (D. Chess et al., 1995). An itinerant computation is a program that moves from host to host in a network. Which hosts the program visits is determined by the program. The program can have a pre-defined itinerary or can dynamically compute the next host to visit as it visits each successive host; it can visit the same host repeatedly or ... View full abstract»

In this paper we examine the problem of balancing load in a large-scale distributed system when information about server loads may be stale. It is well known that sending each request to the machine with the apparent lowest load can behave badly in such systems, yet this technique is common in practice. Other systems use round-robin or random selection algorithms that entirely ignore load informat... View full abstract»

This paper evaluates the Dynamic Boundary Restricted protocol with phase-checking (DBRpc). DBRpc is a highly-adaptable extension of DBR that can respond to changes in the network environment and application workload. DBRpc is suitable for reliable shared memory systems that require rapid and complete response to site failures and phase changes. In this paper, we compare DBRpc with traditional prot... View full abstract»

Replication of information among multiple World Wide Web servers is necessary to support high request rates to popular Web sites. A clustered Web server organization is preferable to multiple independent mirrored servers because it maintains a single interface to the users and has the potential to be more scalable, fault-tolerant and better load-balanced. In this paper, we propose a Web cluster ar... View full abstract»

This paper examines the problem of building scalable, fault-tolerant distributed systems from collections of communicating process groups, while maintaining well-defined end-to-end delivery semantics. We propose a new architecture which supports modular group composition by providing a distinction between intra-group and inter-group communication. With this architecture, multiple group communicati... View full abstract»

The paper proposes a protocol suite for dynamic replication and migration of Internet objects. It consists of an algorithm for deciding on the number and location of object replicas and an algorithm for distributing requests among currently available replicas. Our approach attempts to place replicas in the vicinity of a majority of requests, while ensuring at the same time that no servers are over... View full abstract»

Mockingbird is a prototype tool for developing interlanguage and distributed applications. It compiles stubs from pairs of interface declarations, allowing existing data types to be reused on both sides of every interface. Other multilanguage stub compilers impose data types on the application, complicating development. Mockingbird supports C/C++, Java, and CORBA IDL, and can be extended to other ... View full abstract»

In this paper, we develop efficient admission control tests for member join/leave and its associated state refresh and update procedures for receiver-initiated core-based multicast routing, e.g., core based tree (CBT) protocol, to allow construction of QoS-capable multicast trees, while making the minimum possible impact on the existing infrastructure. Specifically, we (i) derive sufficient condit... View full abstract»

Detecting and resolving performance problems in distributed systems often requires measurements of end-to-end (“finger tip to eyeball”) response times. Existing approaches embed transaction definitions in instrumentation codes. As a result, service providers (e.g., ISPs) cannot tailor transaction definitions to the usage patterns of their customers. We propose a new approach-ETE (end-t... View full abstract»

Describes the design and implementation of a middleware system named the Possession System. The system is designed based on the “possession model”, which provides users with a consistent view of application components, networked sensors and distributed devices by introducing two separate abstractions: “body” and “soul”. The Possession System realizes a simple fr... View full abstract»

A software RAID file system is defined as a system that distributes data redundantly across an array of disks attached to each of the workstations connected to a high-speed network. This configuration provides higher throughput and availability compared to conventional file systems. In this paper, we consider two specific issues, namely the distribution of data among the cluster (i.e. striping) an... View full abstract»

The paper analyzes threats and attacks in the Internet commerce world and suggests schemes to detect the attacks when they occur, prevent further loss once an attack is detected, and provides remedial corrective actions so as to enable victims of commerce-related attacks to resume conducting business transactions. Some commerce based transaction recovery mechanisms are suggested to recover from lo... View full abstract»

Update anywhere-anytime-anyway transactional replication has unstable behavior as the workload scales up. To reduce this problem, a two-tier replication algorithm is proposed in (Gray et al., 1996) that allows mobile applications to propose tentative transactions that are later applied to a master copy. However it can suffer from heavy reprocessing overhead in many circumstances. We present the me... View full abstract»

With the increasing complexity of large scale distributed (LSD) systems, an efficient monitoring mechanism has become an essential service for improving the performance and reliability of such complex applications. The paper presents a scalable, dynamic, flexible and nonintrusive monitoring architecture for managing large scale distributed (LSD) systems. This architecture, which is referred to as ... View full abstract»

We describe the design and implementation of an integrated architecture for cache systems that scale to hundreds or thousands of caches with thousands to millions of users. Rather than simply try to maximize hit rates, we take an end-to-end approach to improving response time by also considering hit times and miss times. We begin by studying several Internet caches and workloads, and we derive thr... View full abstract»

This work studies the interaction of Web proxy cache coherency and replacement policies using trace-driven simulations. We specifically examine the relative importance of each type of policy in affecting the overall costs, the potential of incorporating coherency issues in cache replacement and the inclusion of additional factors such as frequency of resource use in replacement and coherency polic... View full abstract»

This paper presents principles and algorithms for the management of a network of media servers. Such a server network allows the online delivery of broadband multimedia data, e.g. audio and video streams, to a large number of widely distributed clients. Thus, the implementation of large scale distributed broadband media information services is possible if such networks can be handled efficiently. ... View full abstract»

The CORBA Trading Service is an object service advertiser for heterogeneous distributed computing environments. Current approaches for the design and implementation of such a CORBA service do not deal with some of the major problems of searching for service offers in large-scale distributed systems, namely performance and scalability problems. This paper proposes an appropriate approach for cluste... View full abstract»

This paper presents a case study in the use of reliable multicasting in Web-based multi-party applications. To carry out this study, we have designed and implemented WEBCLASS, a multicast browser tool written in Java. In WEBCLASS, all the actions of a “master” Web browser are mimicked on a set of client browsers. Monitoring of the master browser is performed by a set of threads, which ... View full abstract»