Reliable Broadcast

... atomic broadcast protocol that is suitable for building highly available and intrusion-tolerantservices in the ... system that the adversary can exploit, for example, through denial-of-service attacks. ... polynomial-time feasibility of randomized agreement [5,6,7] and atomic broadcast [8 ...

The purpose of a reliable broadcast protocol is to allow groups of nodes on unreliable broadcast networks to reliably broadcast messages. A reliable broadcast protocol must guarantee two properties: (1) all of the receivers in a group receive the broadcast messages, and (2) each of the receivers orders the messages in the same sequence. In an optimistic approach to reliable broadcast protocol, a batch acknowledgement is employed for a sequence of broadcast messages, instead of one or more acknowledgements per broadcast message used in the pessimistic approach. In this paper, based on the optimistic approach, we have proposed a counter-based reliable broadcast protocol. In this protocol, the unique token ownership is circulated among all the nodes in an order specified by a token-passing-list. The system state which records related information about messages broadcast by each node is included in the token message. By appropriately updating the counter information recorded in the system state included in the token message, instead of using explicit acknowledgement messages, the proposed protocol needs fewer control messages to commit a broadcast message than other protocols, no matter whether the rate of transmission errors is high or low. Moreover, we show how to handle the flow control problem and describe the token update technique.

A reliable broadcast is communication primitive used to develop fault tolerant distributed applications. It in due course delivers messages to all participating sites irrespective of their ordering. Total order broadcast impose restriction on message ordering and satisfies total order requirement.

A clear specifications, rigorous validation and verification is key to obtain better design of dependable services in such applications. With the help of formal methods one can specify and verify systems in systematic rather than ad hoc manner. It reveals ambiguities, incompleteness, and inconsistencies in a
system by facilitating clear specification, rigorous validation and verification.

In this paper, we present a formal development of total order broadcast. The model have been developed and checked by using event-B techniques supported by the RODIN tool. Event-B is a formal technique that supports the incremental design of a distributed applications using notion of refinements.

We consider the broadcasting problem in sensor networks where the nodes have no prior knowledge of their neighborhood. That is, to preserve power and bandwidth, no beacons or ’hello’ messages are sent. We describe several Area based Beaconless Broadcasting Algorithms (ABBAs). In 2D, upon receiving the packet, each node calculates the ratio P of its perimeter, along the circle of transmission radius, that is not covered by this and previous transmissions of the same packet. The node then sets or updates its timeout to be inversely proportional to P. We also consider an alternative random timeout function. If the perimeter becomes fully covered, the node cancels retransmissions. The protocol is reliable, assuming an ideal MAC layer. We also describe three 3D ABBAs, one of them being reliable, each with two choices of timeouts.These three protocols are based on covering three projections, covering particular points on intersection circles, and covering intersection points of three spheres. Our protocols are the first reliable broadcasting protocols, other than blind flooding. We compare 2D ABBAs with two other existing beaconless protocols, BPS and Geoflood, showing its superiority. We also consider a MAC layer with collisions and show that all of our methods still remain very robust, showing high delivery ratio during the broadcast.

Considerations of the real-time self-organization of neural networks for speech recog- nition and production have lead to a new understanding of several key issues in such networks, most notably a definition of new processing units and functions of hierarchical levels in the auditory system. An important function of a particular neural level in the auditory system is to provide a

Abstract This paper proposes a novel protocol for reliable broadcasting of life safety messages in Vehicular Ad-hoc Networks (VANETs) simulating reactions of car drivers. In case of any dramatic change of speed or moving direction, the vehicle is considered ...

This paper proposes a novel protocol for reliable broadcasting of life safety messages in Vehicular Ad-hoc Networks (VANETs) simulating reactions of car drivers. In case of any dramatic change of speed or moving direction, the vehicle is considered abnormal and hence it transmits an emergency warning message over the control channel of the Dedicated Short-Range Communication Protocol (DSRC). The proposed protocol gives the vehicle in the most dangerous situation the highest priority to transmit the acknowledgement signal. The choice of that vehicle is done locally based on the location, direction, and speed of the receiving vehicle. The superiority of the proposed protocol over existing protocols is highlighted conceptually and with simulations.

This letter proposes a busy-tone based scheme for reliable and efficient broadcasting in mobile ad hoc networks. Control packets such as RTS, CTS and ACK are ignored in the broadcast scheme, and two busy tones are used, one for channel reservation and the other for negative acknowledgement. Unlike traditional schemes for reliable broadcasting, the proposed scheme is highly efficient as

Abstract-Orca is a language for implementing parallel ap- plications on loosely coupled distributed systems. Unlike most languages for distributed programming, it allows processes on different machines to share data. Such data are encapsulated in data-objects, which are instances ...

In the recent past composability has emerged as a key requirement for various distributed protocols. It is not enough for a protocol to be robust when it runs in isolation or in a “stand-alone” setting but it should be robust even in an environment where several copies of the same protocol or other protocol(s) are running simultaneously. In this work, we investigate the composability for protocols that tolerate a bounded adversary modeled as a probabilistic polynomial time Turing machine. We examine composability of protocols for two fundamental problems in distributed computing - reliable unicast and reliable broadcast. We show that any composable protocol – for reliable unicast tolerating an adversary, that corrupts up to any t nodes, requires 2t + 1 connectivity and for reliable broadcast tolerating an adversary, that corrupts up to any t nodes, requires n > 3t and 2t + 1 connectivity.

Many distributed and parallel applications can make good use of broadcast communication. In this paper we present a (software) protocol that simulates reliable broadcast, even on an unreliable network. Using this protocol, application programs need not worry about lost messages. Recovery of communication failures is handled automatically and transparently by the protocol. In normal operation, our protocol is more efficient than previously published reliable broadcast protocols. An initial implementation of the protocol on 10 MC68020 CPUs connected by a 10 Mbit/sec Ethernet performs a reliable broadcast in 1.5 msec.

A reliable broadcast is communication primitive used to develop fault tolerant distributed applications. It in due course delivers messages to all participating sites irrespective of their ordering. Total order broadcast impose restriction on message ordering and satisfies total order requirement. A clear specifications, rigorous validation and verification is key to obtain better design of dependable services in such applications. With the help of formal methods one can specify and verify systems in systematic rather than ad hoc manner. It reveals ambiguities, incompleteness, and inconsistencies in a system by facilitating clear specification, rigorous validation and verification. In this paper, we present a formal development of total order broadcast. The model have been developed and checked by using event-B techniques supported by the RODIN tool. Event-B is a formal technique that supports the incremental design of a distributed applications using notion of refinements.