Industrial networks have a mix of devices with different security properties. If a mix of devices with various degrees of security features and capabilities communicate, the overall network dynamics with respect to device trust and security of message exchange will be complex. Therefore, there is a need to understand the trust and risk probabilities of devices in a heterogeneous network. This is required for heterogeneous network where the network configuration has to be made based on how trustworthy they are. In this work we focus on assessing security risks for devices and message exchanges. We define the term assurance value to denote the resilience of a device to security attacks. We study the behavior of a communication network when devices with various degrees of security features exchange messages. We aim to identify the network security properties based on the network architecture. From the study, we propose a model to estimate and predict network security properties in a heterogeneous communication network.