Deterministic ethernet in a safety critical environment

This thesis explores the concept of creating safety critical networks with low congestion and latency (known as critical networking) for real time critical communication (safety critical environment). Critical networking refers to the dynamic management of all the application demands in a network within all available network bandwidth, in order to avoid congestion. Critical networking removes traffic congestion and delay to provide quicker response times. A Deterministic Ethernet communication system in a Safety Critical environment addresses the disorderly Ethernet traffic condition inherent in all Ethernet networks. Safety Critical environment means both time critical (delay sensitive) and content critical (error free). Ethernet networks however do not operate in a deterministic fashion, giving rise to congestion. To discover the common traffic patterns that cause congestion a detailed analysis was carried out using neural network techniques. This analysis has investigated the issues associated with delay and congestion and identified their root cause, namely unknown transmission conditions. The congestion delay, and its removal, was explored in a simulated control environment in a small star network using the Air-field communication standard. A Deterministic Ethernet was created and implemented using a Network Traffic Oscillator (NTO). NTO uses Critical Networking principles to transform random burst application transmission impulses into deterministic sinusoid transmissions. It is proved that the NTO has the potential to remove congestion and minimise latency. Based on its potential, it is concluded that the proposed Deterministic Ethernet can be used to improve network security as well as control long haul communication

Erlang B as a performance model for IP flows

Flow-based networking has gained momentum in the research community in recent years. It allows improved performance guarantees and dynamic, load-aware routing. Flowbased networking takes the nature of traffic into account and considers the fact that multiple packets are a part of the same transaction. Blocking probability has been used as a performance parameter in circuit switched networks for a long time; however, it has not been used in IP networks, since traffic is not admission controlled. This paper investigates blocking as a generic performance parameter aiding performance modelling of flowbased networks. Simulation results are presented, underlining the observation that there is a relationship between traditional IP performance parameters and flow blocking. Furthermore, it outlines how blocking can be used in a practical context to asses performance and define thresholds for network actions