Bijoy Chand Chatterjee

Knapsack based multicast traffic grooming for optical networks

Abstract This paper proposes a light-tree based heuristic algorithm, called 0/1 knapsack based multicast traffic grooming, in order to minimize the network cost by reducing the number of higher layer electronic and optical devices, such as transmitters, receivers, and splitters, and used wavelengths in the network. The proposed algorithm constructs light-trees or sub light-trees, which satisfy sub bandwidth demands of all multicast requests. We present a light-tree based integer linear programming (ILP) formulation to minimize the network cost. We solve the ILP problem for sample four-node and six-node networks and compare the ILP results with the proposed heuristic algorithm. We observe that the performance of the proposed algorithm is comparable to the ILP in terms of cost. When the introduced ILP is not tractable for large network, the proposed algorithm still able to find the results. Furthermore, we compare the proposed heuristic algorithm to existing heuristic algorithms for different backbone networks. Numerical results indicate that the proposed heuristic algorithm outperforms the conventional algorithms in terms of cost and resource utilization.

Designing a Hadoop system based on computational resources and network delay for wide area networks

This paper proposes a Hadoop system that considers both slave server’s processing capacity and network delay for wide area networks to reduce the job processing time. The task allocation scheme in the proposed Hadoop system divides each individual job into multiple tasks using suitable splitting ratios and then allocates the tasks to different slaves according to the computational capability of each server and the availability of network resources. We incorporate software-defined networking to the proposed Hadoop system to manage path computation elements and network resources. The performance of proposed Hadoop system is experimentally evaluated with fourteen machines located in the different parts of the globe using a scale-out approach. A scale-out experiment using the proposed and conventional Hadoop systems is conducted by executing both single job and multiple jobs. The practical testbed and simulation results indicate that the proposed Hadoop system is effective compared to the conventional Hadoop system in terms of processing time.

Recent research progress on spectrum management approaches in software-defined elastic optical networks

Abstract The flex-grid technology or elastic optical network (EON) is accepted to be a propitious solution for the future transport network due to its unique properties, which are bandwidth aggregation that creates super wavelength channels, different data rate accommodation, bandwidth segmentation that creates sub-wavelength channels, and elastic variation of assigned bandwidth. The software-defined network (SDN) is incorporated with the emerging technology of EON for enhancing its performance by enabling dynamic provisioning and releasing of optical lightpaths. This reduces the required time for lightpath control, which leads to improve the network performances. This paper exploits the software-defined elastic optical network (SD-EON) by identifying its architectures, existing literature, resource management approaches, and future challenges. In addition, the performance of EONs related to the SDN technology is compared in terms of blocking probability. Numerical results indicate that the SD-EON accommodates 25% more admissible traffic than the EON without considering SDN, when the acceptable blocking probability is considered 0.01.

Performance of elastic optical network with allowable spectrum conversion at intermediate switches

This paper evaluates the performances of elastic optical networks (EONs) in terms of request blocking probability with and without incorporation of spectrum conversions at intermediate switches. In EONs, dynamically setting up and tearing down of lightpath connections generate spectrum fragmentation problems. The spectrum fragmentation problem occurs when the available spectrum slots are isolated from each other as neither they are aligned along the routing path nor they are contiguous in the spectrum domain. The spectrum conversion at intermediate switches is performed for blocked requests without triggering any defragmentation process. Simulation results indicate that the incorporation of spectrum conversions significantly suppresses the request blocking probability and increases the traffic admissibility when the traffic load is low. In a congested network under heavy traffic load, the performance is comparable with and without incorporation of spectrum conversion.

Performance evaluation of first-last-exact fit spectrum allocation policy for elastic optical networks

This paper evaluates the performance of the first-last-exact fit spectrum allocation policy for elastic optical networks. The first-last-exact fit spectrum allocation policy is intended to increase the number of aligned available slots and avoid small contiguous available slots, and hence suppresses the blocking probability. This policy separates the allocation of disjoint and non-disjoint connections. Connections with disjoint paths are allocated using the first-exact fit allocation policy, whereas connections with non-disjoint paths are allocated using the last-exact fit allocation policy. The separation of the disjoint and non-disjoint connections provides a higher number of aligned available slots. Simulation results show that the first-last-exact fit spectrum allocation policy improves the traffic admissibility compared to the conventional first fit and first-last fit policies.