This paper presents the architecture of a router designed to efficiently support traffic generated by multimedia applications. The router is targeted for use in clusters and LANs rather than in WANs, the latter being served by communication substrates such as ATM. The distinguishing features of the proposed router architecture are the use of small fixed-size buffers, a large number of virtual channels, link-level virtual channel flow control, support for dynamic modification of connection bandwidth and priorities, and coordinated scheduling of connections across all output channels. The paper begins with a discussion of the design choices and architectural trade-offs made in the current MultiMedia Router (MMR) project. The performance evaluation section presents some preliminary results of the coordinated scheduling of constant bit rate (CBR) traffic streams.

Nowadays, the fog computing paradigm is being consolidated as a solution for processing the explosion of data generated by lots of common IoT devices connected to the Internet. In contrast to cloud computing, fog computing achieves efficient data processing without incurring large latencies or data transfers to/from the cloud. The distributed nature of fog computing makes the resource orchestration a challenge. Commonly used centralized solutions are of limited utility in this context. Moreover, fog nodes are usually resource constrained, so the implementation of the management modules should be carefully designed in order not to cause excessive overheads. On the other hand, blockchain has proven its utility beyond cryptocurrencies, to support distributed and reliable information storage. When combined with smart contracts it can provide a distributed computer where all the nodes independently and equally contribute to a common global system state, which must be agreed by consensus. This also provides inherent desirable features, such as immutability and transparency. In this work, a novel architecture called HIDRA is presented, aimed at resource orchestration in fog computing environments based on a Ethereum blockchain implementation. A prototype implementation on a testbed composed of single-board computers has been carried out. Results show the low overhead introduced into the system and its ability to perform a coordinated action among fog nodes without the intervention of any central authority.

Internet of Things (IoT) has posed new requirements to the underlying processing architecture, specially for real-time applications, such as event-detection services. Complex Event Processing (CEP) engines provide a powerful tool to implement these services. Fog computing has raised as a solution to support IoT real-time applications, in contrast to the Cloud-based approach. This work is aimed at analysing a CEP-based Fog architecture for real-time IoT applications that uses a publish-subscribe protocol. A testbed has been developed with low-cost and local resources to verify the suitability of CEP-engines to low-cost computing resources. To assess performance we have analysed the effectiveness and cost of the proposal in terms of latency and resource usage, respectively. Results show that the fog computing architecture reduces event-detection latencies up to 35%, while the available computing resources are being used more efficiently, when compared to a Cloud deployment. Performance evaluation also identifies the communication between the CEP-engine and the final users as the most time consuming component of latency. Moreover, the latency analysis concludes that the time required by CEP-engine is related to the compute resources, but is nonlinear dependent of the number of things connected.