Knowledge of a network’s entities and the physical connections between them, a network’s physical topology, can be useful in a variety of network scenarios and applications. Administrators can use topology information for fault- finding, inventorying and network planning. Topology information can also be used during protocol and routing algorithm development, for performance prediction and as a basis for accurate network simulations. Specifically, from a network security perspective, threat detection, network monitoring, network access control and forensic investigations can benefit from accurate network topology information. The dynamic nature of large networks has led to the development of various automatic topology discovery techniques, but these techniques have mainly focused on cooperative network environments where network elements can be queried for topology related information. The primary objective of this study is to develop techniques for discovering the physical topology of an Ethernet network without the assistance of the network’s elements. This dissertation describes the experiments performed and the techniques developed in order to identify network nodes and the connections between these nodes. The product of the investigation was the formulation of an algorithm and heuristic that, in combination with measurement techniques, can be used for inferring the physical topology of a target network. / Dissertation (MSc)--University of Pretoria, 2008. / Computer Science / unrestricted

Modern heterogeneous networks present a great challenge for network operators and engineers from a management and configuration perspective. The Tail-f Systems’ Network Control System (NCS) is a network management framework that addresses these challenges. NCS offers centralized network configuration management functionality, along with providing options for extending the framework with additional features. The devices managed by NCS are stored in its Configuration Database (CDB). However, currently there is no mechanism for automatically adding network devices to the configuration of NCS, thus each device’s management parameters have to be entered manually. The goal of this master’s thesis project is to develop a software module for NCS that simplifies the process of initial NCS configuration by allowing NCS to automatically add network devices to the NCS CDB. Apart from developing the software module for discovery, this project aims to summarize existing methods and to develop new methods for automated discovery of network devices with the main focus on differentiating between different types of devices. A credential-based device discovery method was developed and utilized to make advantage of known credentials to access devices, which allows for more precise discovery compared to some other existing methods. The selected methods were implemented as a component of NCS to provide device discovery functionality. Another focus of this master’s thesis project was the development of an approach to network topology discovery and its representation. The aim is to provide both a logical Internet Protocol (IP) network topology and a physical topology of device interconnections. The result is that we are able to automatically discover and store the topology representation as a data structure, and subsequently generate a visualization of the network topology. / Moderna heterogena nätverk utgör en stor utmaning för operatörer och ingenjörer att hantera och konfigurera. Tail-f Systems NCS produkt är ett ramverk för nätverks konfiguration som addresserar dessa utmaningar. NCS är ett centraliserat nätverks konfigurations verktyg. NCS är användbart som det är, men kan också byggas ut av användaren med ytterligare funktioner. De enheter som hanteras med NCS lagras i konfigurationsdatabasen (CDB). För närvarande finns det ingen automatiserad mekanism för att addera nätverksenheter till NCS, och varje enhets parametrar måste fyllas i manuellt. Detta examensarbetes mål är att utveckla en mjukvarumodul för NCS som förenklar NCS konfiguration genom att automatiskt lägga nätverksenheter till NCS CDB. Förutom att utveckla programvara för enhetsidentifiering, syftar detta projekt till att sammanfatta befintliga metoder och utveckla nya metoder för automatiserad nätverksenhetsidentifiering med huvudfokus på att skilja mellan olika typer av enheter. En metod baserad på förkonfigurerade autenticeringsuppgifter har utvecklats och den används för att precist kunna identifiera olika typer av nätverkselement. De valda metoderna har implementerats som en optionell modul till NCS som erbjuder enhetsidentifieringsfunktionalitet. Ytterligare ett fokus för detta examensarbete har varit att utveckla metoder för identifieraing av nätverkstopologin, och modeller för hur topologin ska representeras.  Vi har syftat till att identifiera både den logiska IP nätverkstopologin (L3) och den fysiska topologin av sammankopplade enheter (L2). Den viktigaste uppgiften har varit att identifiera och lagra topologi representation som en datastruktur, och dessutom generera en visualisering av nätverkstopologin.