ABSTRACT

Broadcasting and gossiping are fundamental tasks in network communication. In broadcasting, or onetoall communication, information originally held in one node of the network called the source must be transmitted to all other nodes. In gossiping, or alltoall communication, every node holds a message which has to be transmitted to all other nodes. As communication networks grow in size, they become increasingly vulnerable to component failures. Thus, capabilities for faulttolerant broadcasting and gossiping gain importance. The present paper is a survey of the fastgrowing area of research investigating these capabilities. We focus on two most important efficiency measures of broadcasting and gossiping algorithms: running time and number of elementary transmissions required by the communication process. We emphasize the unifying thread in most results from the research in faulttolerant communication: the tradeoffs between efficiency of communication schemes and their faulttolerance.

CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND OF THE RESEARCH

This research is mostly concerned with two fundamental tasks in network communication: broadcasting and gossiping. They both aim at disseminating information among nodes. In broadcasting, also called onetoall communication, information originally held in one node of the network called the source has to be transmitted to all other nodes. In gossiping, or alltoall communication, every node holds a message value which must be transmitted to all other nodes. These types of network communication often occur in distributed computing, e.g., in global processor synchronization and updating distributed databases. Moreover, such communication tasks are implicit in many parallel computation problems, where data and results are distributed among processors. This happens, e.g., in matrix multiplication, parallel solving of linear systems, parallel computing of Discrete Fourier Transform, or parallel sorting

As communication networks grow in size, they become increasingly vulnerable to component failures. Some links and/or nodes of the network may fail. It becomes important to design communication algorithms in such a way that the desired communication task be accomplished efficiently in spite of these faults, usually without knowing their location ahead of time.

1.2STATEMENT OF RESEARCH PROBLEM

Reliability of message transmission is a critical issue in communication networks. As communication networks grow in size, they become increasingly vulnerable to component faults, such as link or node failures. Broadcasting and gossiping are fundamental tasks in network communication, and it becomes important to design reliable broadcasting and gossiping schemes that work for networks as sparse as possible.

Even though a component in a communication network may not fail completely, nevertheless a message may be corrupted when passing through this component. One way to verify the correctness of a given message is to arrange for nodes in the network to receive the message multiple times. For example, in broadcasting onetoall communication from a given source node u, if a message sent by u is received by all other nodes at least k1 times, then each node can perform k checks against the original message to verify that it has not been corrupted in transmission. Similar behavior would be useful for gossiping alltoall communication where information originally held in each node is to be communicated to all other nodes. In gossiping, in a communication step, all information held by each end node in the link is exchanged. For an nnode network, we consider the problem of determining the minimum number of network links required to support this kfold verifiability for broadcasting and gossiping.

1.3 OBJECTIVES OF THE STUDY

A faulttolerant broadcast protocol is a distributed program that ensures delivery of a message to the functioning processors in a computer network, despite the fact that processors may fail at any time. Faulttolerant broadcast protocols have application in a wide variety of distributed programming problems.

Based on the issues discussed as the research problem the researcher now seeks to address the problem by solving them

A network where the buffer memory will have enough space to manage all message it received by the interface unit,

A network interface unit that will be monitoring the network at the time the message is delivered

Thus, while current broadcast networks allow messages to be broadcast, they do not directly support faulttolerant broadcasts so this research work will be design to have such.

1.4 SIGNIFICANCE OF THE STUDY

i. Academicians and students of accounting and other allied courses in tertiary institutions in Nigeria will benefit from this study. This is because this study will enable them at least to some extent to know the gap between fault tolerant in communication network and gossiping in broadcasting.

ii. The research will also be beneficial to the researcher. This is because the study will expose the researcher to so many related areas in the course of carrying out his research. This will enhance the researchers experience, knowledge and understanding of fault tolerant broadcasting and gossiping in communication network.

iii. Finally, the research will contribute to knowledge and serve as a secondary document for any other researcher in a related area.

1.5DEFINITION OF TERMS

Fault tolerance: is the property that enables a system to continue operating properly in the event of the failure of or one or more faults within some of its components.

Gossip protocol: A gossip protocol is a style of computertocomputer communication protocol inspired by the form of gossip seen in social networks. Modern distributed systems often use gossip protocols to solve problems that might be difficult to solve in other ways, either because the underlying network has an inconvenient structure, is extremely large, or because gossip solutions are the most efficient ones available.

Networks: A network is a group of two or more computer systems linked together. There are many types of computer networks, including the following: localarea networks LANs: The computers are geographically close together that is, in the same building.