Open Access. Powered by Scholars. Published by Universities.®

Computer Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 7 of 7

Full-Text Articles in Computer Engineering

Byzantine Fault Tolerant Coordination For Web Services Atomic Transactions, Wenbing Zhao Aug 2014

Byzantine Fault Tolerant Coordination For Web Services Atomic Transactions, Wenbing Zhao

Wenbing Zhao

In this paper, we present the mechanisms needed for Byzantine fault tolerant coordination of Web services atomic transactions. The mechanisms have been incorporated into an open-source framework implementing the standard Web services atomic transactions specification. The core services of the framework, namely, the activation service, the registration service, the completion service, and the distributed commit service, are replicated and protected with our Byzantine fault tolerance mechanisms. Such a framework can be useful for many transactional Web services that require high degree of security and dependability.


A Reservation-Based Extended Transaction Protocol, Wenbing Zhao, Louise E. Moser, P. Michale Melliar-Smith Aug 2014

A Reservation-Based Extended Transaction Protocol, Wenbing Zhao, Louise E. Moser, P. Michale Melliar-Smith

Wenbing Zhao

With the advent of the new generation of Internet-based technology, in particular, web services, the automation of business activities that are distributed across multiple enterprises becomes possible. Business activities are different from traditional transactions in that they are typically asynchronous, loosely coupled, and long running. Therefore, extended transaction protocols are needed to coordinate business activities that span multiple enterprises. Existing extended transaction protocols typically rely on compensating transactions to handle exceptional conditions. In this paper, we identify a number of issues with compensation-based extended transaction protocols and describe a reservation-based extended transaction protocol that addresses those issues. Moreover, we define …


Proactive Service Migration For Long-Running Byzantine Fault-Tolerant Systems, Wenbing Zhao, H. Zhang Aug 2014

Proactive Service Migration For Long-Running Byzantine Fault-Tolerant Systems, Wenbing Zhao, H. Zhang

Wenbing Zhao

A proactive recovery scheme based on service migration for long-running Byzantine fault-tolerant systems is described. Proactive recovery is an essential method for ensuring the long-term reliability of fault-tolerant systems that are under continuous threats from malicious adversaries. The primary benefit of our proactive recovery scheme is a reduced vulnerability window under normal operation. This is achieved in two ways. First, the time-consuming reboot step is removed from the critical path of proactive recovery. Second, the response time and the service migration latency are continuously profiled and an optimal service migration interval is dynamically determined during runtime based on the observed …


Design And Implementation Of A Byzantine Fault Tolerance Framework For Web Services, Wenbing Zhao Aug 2014

Design And Implementation Of A Byzantine Fault Tolerance Framework For Web Services, Wenbing Zhao

Wenbing Zhao

Many Web services are expected to run with high degree of security and dependability. To achieve this goal, it is essential to use a Web services compatible framework that tolerates not only crash faults, but Byzantine faults as well, due to the untrusted communication environment in which the Web services operate. In this paper, we describe the design and implementation of such a framework, called BFT-WS. BFT-WS is designed to operate on top of the standard SOAP messaging framework for maximum interoperability. It is implemented as a pluggable module within the Axis2 architecture, as such, it requires minimum changes to …


Design And Implementation Of A Byzantine Fault Tolerance Framework For Non-Deterministic Applications, H. Zhang, Wenbing Zhao, Louise E. Moser, P. Michael Melliar-Smith Aug 2014

Design And Implementation Of A Byzantine Fault Tolerance Framework For Non-Deterministic Applications, H. Zhang, Wenbing Zhao, Louise E. Moser, P. Michael Melliar-Smith

Wenbing Zhao

State-machine-based replication is an effective way to increase the availability and dependability of mission-critical applications. However, all practical applications contain some degree of non-determinism. Consequently, ensuring strong replica consistency in the presence of application non-determinism has been one of the biggest challenges in building dependable distributed systems. In this Study, the authors propose a classification of common types of application non-determinism with respect to the requirement of achieving Byzantine fault tolerance (BFT), and present the design and implementation of a BFT framework that controls these types of non-determinism in a systematic manner.


End-To-End Latency Of A Fault-Tolerant Corba Infrastructure, Wenbing Zhao, Louise E. Moser, P. Michale Melliar-Smith Aug 2014

End-To-End Latency Of A Fault-Tolerant Corba Infrastructure, Wenbing Zhao, Louise E. Moser, P. Michale Melliar-Smith

Wenbing Zhao

This paper presents an evaluation of the end-to-end latency of a fault-tolerant CORBA infrastructure that we have implemented. The fault-tolerant infrastructure replicates the server applications using active, passive and semi-active replication, and maintains strong replica consistency of the server replicas. By analyses and by measurements of the running fault-tolerant infrastructure, we characterize the end-to-end latency under fault-free conditions. The main determining factor of the run-time performance of the fault-tolerant infrastructure is the Totem group communication protocol, which contributes to the end-to-end latency primarily in two ways: the delay in sending messages and the processing cost of the rotating token. To …


Unification Of Transactions And Replication In Three-Tier Architectures Based On Corba, Wenbing Zhao, Louise E. Moser, P. Michael Melliar-Smith Aug 2014

Unification Of Transactions And Replication In Three-Tier Architectures Based On Corba, Wenbing Zhao, Louise E. Moser, P. Michael Melliar-Smith

Wenbing Zhao

In this paper, we describe a software infrastructure that unifies transactions and replication in three-tier architectures and provides data consistency and high availability for enterprise applications. The infrastructure uses transactions based on the CORBA object transaction service to protect the application data in databases on stable storage, using a roll-backward recovery strategy, and replication based on the fault tolerant CORBA standard to protect the middle-tier servers, using a roll-forward recovery strategy. The infrastructure replicates the middle-tier servers to protect the application business logic processing. In addition, it replicates the transaction coordinator, which renders the two-phase commit protocol nonblocking and, thus, …