Failure propagation in GMPLS optical rings: CTMC model and performance analysis

Network reliability and resilience has become a key design parameter for network operators and Internet service providers. These often seek ways to have their networks fully operational for at least 99.999% of the time, regardless of the number and type of failures that may occur in their networks. This article presents a continuous-time Markov chain model to characterise the propagation of failures in optical GMPLS rings. Two types of failures are considered depending on whether they affect only the control plane, or both the control and data planes of the node. Additionally, it is assumed that control failures propagate along the ring infecting neighbouring nodes, as stated by the Susceptible-Infected-Disabled (SID) propagation model taken from epidemic-based propagation models. A few numerical examples are performed to demonstrate that the CTMC model provides a set of guidelines for selecting the appropriate repair rates in order to attain specific availability requirements, both in the control plane and the data plane.This work is partially supported by the Spanish Ministry of Science and Innovation project TEC 2009-10724 and by the Generalitat de Catalunya research support programme (SGR-1202). Additionally, the authors would like to thank the support of the T2C2 Spanish project (under code TIN2008-06739-C04-01) and the CAM-UC3M Greencom research grant (under code CCG10-UC3M/TIC-5624) in the development of this work.Publicad

Networking - A Statistical Physics Perspective

Efficient networking has a substantial economic and societal impact in a broad range of areas including transportation systems, wired and wireless communications and a range of Internet applications. As transportation and communication networks become increasingly more complex, the ever increasing demand for congestion control, higher traffic capacity, quality of service, robustness and reduced energy consumption require new tools and methods to meet these conflicting requirements. The new methodology should serve for gaining better understanding of the properties of networking systems at the macroscopic level, as well as for the development of new principled optimization and management algorithms at the microscopic level. Methods of statistical physics seem best placed to provide new approaches as they have been developed specifically to deal with non-linear large scale systems. This paper aims at presenting an overview of tools and methods that have been developed within the statistical physics community and that can be readily applied to address the emerging problems in networking. These include diffusion processes, methods from disordered systems and polymer physics, probabilistic inference, which have direct relevance to network routing, file and frequency distribution, the exploration of network structures and vulnerability, and various other practical networking applications.Comment: (Review article) 71 pages, 14 figure

Fiber Channel Vs. Internet Scsi On Storage Area Networks For Disaster Recovery Operations

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2006Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2006Bu tez çalışmasında iSCSI tabanlı veri depolama ağlarının performansının iyileştirilmesi için iSCSI ve TCP katmalarının birbiriyle etkileşimi incelenmektedir. Bu inceleme neticesinde en uygun iSCSI ve TCP parametre değerleri belirlenmeye çalışılmıştır. Uygun parametre değerleri kullanılarak optimize edilmiş bir iSCSI veri depolama çözümünün Fiber Kanal tabanlı veri depolama çözümlerine alternatif olabileceği gösterilmeye çalışılmıştır.This thesis examines the interactions between the iSCSI and TCP layer in order to improve the performance of iSCSI-based storage system. As a result of this study, the most proper iSCSI and TCP parameter values were supposed to be determined. By using these proper parameter values, it was tried to be shown that an optimized iSCSI-based storage solution with suitable parameters can be an alternative to FC-based storage solutions.Yüksek LisansM.Sc