Software-based fast failure recovery in load balanced SDN-based datacenter networks

Load balancing is currently considered as a candidate solution to tackle the emerging problem of increasing bandwidth demand in intra-datacenter networks. Furthermore, because a short disruption of data transfer would corrupt the result of a long procedure of computation, fast failure management mechanisms are considered as integral part of current datacenters. In this paper, we propose a method which uses active probing to detect and manage failures in an OpenFlow based datacenter network exploiting load balancing among equal cost multiple paths. The proposed method is scalable and effective based on the actions it takes without involving the controller in the fast failure recovery procedure

Single-Layer versus Multilayer Preplanned Lightpath Restoration

Special Issue on ”Optical Networks” October 200

Alteration of volcanic deposits in the ANDRILL AND-1B core: Influence of paleodeposition, eruptive style, and magmatic composition

Alteration minerals, assemblages, and textures were studied in a 175-m-thick volcanic sequence found between 759.32 and 584.19 m below seafloor within the 1285-m-long ANDRILL (Antarctic Geological Drilling project) McMurdo Ice Shelf core (MIS AND-1B). Three main alteration zones were identified through the application of different analytical methods (optical and scanning electron microscopy, electron microprobe, and X-ray diffraction). Alteration zoning is guided by the texture of the volcanic deposits, which is in turn determined by the eruptive style, transport mechanisms, and paleodepositional conditions. In particular, alteration reflects the evolution of paleodepositional conditions from submarine or shallow water to subaerial due to the growth of a nearby volcanic edifice. The general alteration trend is also influenced by the contribution of volcanogenic sediments derived from the reworking of silica-rich pyroclasts from earlier volcanic activity