Search

Safety-critical networks often have stringent real-time requirements; they must also be resilient to failures. In this paper, we propose the RealFlow framework that uses commodity software-defined networks (SDNs) to realize networks with end-to-end timing guarantees, while also: (a) increasing resiliency against link/switch failures and (b) increasing network utilization. The use of SDNs in this space also improves the management capabilities of the system due to the global visibility into the network. RealFlow is implemented as a northbound SDN controller application compatible with standard OpenFlow protocols with little to no runtime overheads. We demonstrate feasibility on a real hardware testbed (Pica8 SDN switches+Raspberry Pi endhosts) and a practical avionics case study. Our evaluations show that RealFlow can accommodate 63% more network flows with safety-critical guarantees when compared to current designs and up to 18% when link resiliency (via backup paths) is also considered.

Compute platforms for wireless sensor networks and Vehicle-to-Vehicle (V2V) communications employ random channel access for message transmission and typically suffer from limited processing capability and on-board memory on a per-application basis because of the multiple processes going on in parallel. Appending digital signatures to transmitted messages in such systems increases information reliability, but requires an intemperate use of scarce resources, more so with an increased security requirement.It thus appears imperative to tradeoff security for network performance to conserve scarce resources for a given resource constrained platform. This requires a good understanding of the communication performance of these systems. We observe that resource constraints in these systems induce complex interaction between the security and MAC layers at a node, obviating the possibility of layer specific optimizations to improve system performance for broadcast applications. For example, reducing the channel access probability at the MAC layer reduces collision probabilities, in turn increasing the verification load on the security layer. There is hence a need to take a holistic approach to dimension such systems to improve performance. In achieving this objective, we provide:• an analytical framework to model these systems with or without an impersonation attacker. This analysis also takes into consideration the possibility of multiple digital signatures being attached to a message, so that the receiver has a choice of verifying one of these.• a characterization of the stability region of the system.• an information-theoretic approach towards reliable communication of application data over these systems. We view the combination of security-MAC-security layers as an erasure channel and provide attainable rates, jointly optimizing on sampling rate and channel transmission rate.

Application of sensor networks in different fields is an interesting area to work with and has already drawn widespread attention. Since sensors have limited supply of on-board energy, efficient management of network is a compulsion in extending life of the sensor. At the same time, frequent damage to sensors and link failure occur because of the adverse environment in which they are deployed. A sensor network has to tolerate and recover from these failures themselves with no external help. In this respect, we have designed a self-stabilizing energy-aware routing protocol in a sensor network. Our protocol ensures the sensor network, starting from an arbitrary state, eventually set up reliable communication in network with minimum energy consumption and in a finite number of steps.