Toggle Main Menu Toggle Search

Open Access padlockePrints

Building responsive TMR-based servers in presence of timing constraints

Lookup NU author(s): Dr Paul EzhilchelvanORCiD


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


This paper is on the construction of a fault-tolerant and responsive server subsystem in an application context where the subsystem is accessed through an asynchronous network by a large number of clients. The server is made fault-tolerant by the Triple Modular Redundancy (TMR) technique: at least two server processes behave correctly, while the third one can behave arbitrarily. An essential requirement for process replication is that the client inputs be delivered to server replicas for processing in an identical order. Moreover, in order to cope with process' memory requirement, a time bound constraint is imposed: no client input can stay in the local memory of a server process more than Σ units of time. Based on known technologies, two assumptions are made: (1) the network delivers a given client input to any two server processes within a known bounded time (D), and (2), there is an Ordered Timed Atomic Broadcast protocol built on top of the TMR system with timeliness Δ. The paper presents two results. The first is a protocol that delivers an ordered stream of client inputs, such that every client input is delivered exactly once to each correct server, thus eliminating redundant verification. It works under the assumption Σ > D + Δ. The second is an impossibility result, namely there can be no ordering protocol when Σ < D + Δ, where Δ is the minimum timeliness of any reliable broadcast protocol that can be implemented on top of the TMR server (Δ ≤ Δ).

Publication metadata

Author(s): Ezhilchelvan P, Helary J-M, Raynal M

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: Proceedings - Eighth IEEE International Symposium on Object-Oriented Real-Time Distributed Computing, ISORC 2005

Year of Conference: 2005

Pages: 267-274

Publisher: IEEE Computer Society


DOI: 10.1109/ISORC.2005.18

Library holdings: Search Newcastle University Library for this item

ISBN: 0769523560