In this paper, we address the problem of routing and wavelength assignment of multicast sessions with subwavelength traffic demands. We consider this problem in the scenario of WDM ring networks. In order to support multicasting, individual nodes need to have the capability to duplicate traffic. We consider two different node architectures which perform the duplication in optical and electronic domain, respectively. As traffic duplication at the electronic level is much more expensive than the optical alternative, we study the problem of assigning routes and wavelengths to the multicast sessions so as to minimize electronic copying. The solution to this problem can be divided into three phases -1 . routing of multicast sessions, 2. construction of circles by grouping non-overlapping arcs and 3. grouping these circles onto wavelengths. We propose a heuristic algorithm which implements the routing as well as circle construction phases simultaneously and then groups the circles. We present extensive simulation results to show that our approach leads to much lesser equipment cost than that obtained by routing each multicast session along its minimum spanning tree and then using the best known heuristic for circle construction.'
The Internet of Things (IoT) extends the Internet wherein real world things are part of a computing network. The IoT has seen exponential growth and according to Cisco prediction about 50 billion devices will be connected by 2020. Handling this massive scale is challenging research issue. In this paper, we use cloud-fog-edge based IoT middleware for distributed IoT service provisioning. We model IoT middleware using queueing network, perform analytical analysis of IoT middleware components. Followed by dynamic scaling algorithm which considers contention and coherency as limiting factors for scalability. It is used for quantitative analysis of IoT middleware with the increasing workload. The scalability function was evaluated using the simulation for important performance and scalability parameters namely throughput, CPU utilization and response time. It is observed that because of contention and coherency overhead, the proposed approach is able to scale sub-linearly which is practical compared ideal scalability of multi-server queueing network and not very restrictive as given universal scalability law(USL) applied for tightly coupled systems.
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