Trust plays an important role in our daily life, both implicitly and explicitly. Our decisions are based on our estimation of how trustworthy a person is or how reliable a service is. Consequently, there has been a rise in trust systems that model human trust in a virtual or computing environment. These trust systems or trust models help to bridge the gap of human feelings and intuition in an unfamiliar environment. Trust models collect information regarding the participants' activities and give a trust rating based on observed activities. In a network environment, a plethora of network devices are in constant communication as data packets are transported from source to destination. The autonomous nature of network environments and devices make it difficult to monitor the services and devices from a central point. Security mechanisms, such as IPSec, exist in routing protocols to safeguard network packets travelling in a network, however routing devices that act as service providers are not protected by malicious attacks. For example, an attack aimed at the routing architecture of a network involves a routing device advertising itself as another routing device in order to divert network traffic away from its intended destination. This dissertation investigates trust models in network environments as a possible approach to predict and ultimately eliminate at- tacks on routing devices. To accomplish this, the role of routing devices as service providers and requesters must be stated explicitly. Activities on a routing device must be collected and used to determine the trust level of the routing device. This dissertation presents the TSONE - Trust in Service-Oriented Net- work Environment - model. The model incorporates traditional service- oriented architecture (SOA) principles to define a service-oriented network environment. Services in this environment are then defined. Furthermore the characteristics of this environment are adapted from SOA principles. An approach is defined to collect and measure activities on routing devices. This is later used to determine the trust level of the routing device. Finally, a pro- to type illustrates that incorporation of trust models is a possible option in assessing availability and reliability of routing devices. / Dissertation (MSc)--University of Pretoria, 2011. / Computer Science / unrestricted