Termite inspired algorithm for traffic engineering in hybrid software defined networks

In the era of Internet of Things and 5G networks, handling real time network traffic with the required Quality of Services and optimal utilization of network resources is a challenging task. Traffic Engineering provides mechanisms to guide network traffic to improve utilization of network resources and meet requirements of the network Quality of Service (QoS). Traditional networks use IP based and Multi-Protocol Label Switching (MPLS) based Traffic Engineering mechanisms. Software Defined Networking (SDN) have characteristics useful for solving traffic scheduling and management. Currently the traditional networks are not going to be replaced fully by SDN enabled resources and hence traffic engineering solutions for Hybrid IP/SDN setups have to be explored. In this paper we propose a new Termite Inspired Optimization algorithm for dynamic path allocation and better utilization of network links using hybrid SDN setup. The proposed bioinspired algorithm based on Termite behaviour implemented in the SDN Controller supports elastic bandwidth demands from applications, by avoiding congestion, handling traffic priority and link availability. Testing in both simulated and physical test bed demonstrate the performance of the algorithm with the support of SDN. In cases of link failures, the algorithm in the SDN Controller performs failure recovery gracefully. The algorithm also performs very well in congestion avoidance. The SDN based algorithm can be implemented in the existing traditional WAN as a hybrid setup and is a less complex, better alternative to the traditional MPLS Traffic Engineering setup. Document type: Articl

Photoisomerization of bridgehead monosubstituted dibenzobarrelenes and interesting thermal isomerization of their photoproducts

Phototransformations of a few bridgehead monosubstituted dibenzobarrelenes, 4a-d, and thermal isomerizations of their primary photoproducts, 7a and 11a-c, are described. Irradiation of 4a in benzene gave a mixture of regioisomeric products, 7a (8b-isomer) and 11a (4b-isomer), in 20 and 70% yields, respectively. In contrast, irradiation of 4b, under identical conditions, yielded only the corresponding 4b-substituted dibenzosemibullvalene, 11b, in 95% yield. Similarly, irradiation of the nitro- (4c) and chloro- (4d) substituted dibenzobarrelenes gave exclusively the corresponding dibenzosemibullvalenes, 11c (81%) and 11d (81%), respectively. The formation of regioselective products in these systems has been attributed to the relative stabilities of the diradical intermediates involved in these transformations. Interestingly, the dibenzosemibullvalene 7a, on refluxing in xylene, gave the corresponding dibenzopentalenofuran 9a (94%). Thermolysis of 11a and 11c in o-dichlorobenzene and, likewise, of 11b in xylene, yielded 94-97% of the corresponding dibenzopentalenofurans 12a, 12c, and 12b, respectively. Activation energies for the thermal isomerizations of 7a to 9a, 11a to 12a, and 11b to 12b have been found to be 21.57, 25.97, and 17.93 kcal/mol, respectively. The structures of 11a, 11c, 11b, and 12b were established unambiguously through X-ray crystallographic analysis, whereas the structures of the different photoproducts, 7a, 11a-d, 12a-c and 9a, have been arrived at on the basis of spectral data and analytical results

Regioselectivity in dibenzobarrelene photorearrangements: photoproducts derived from 9-substituted-dibenzobarrelenes

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