Statistical analysis of blocking probability and fragmentation based on Markov modeling of elastic spectrum allocation on fiber link

Abstract In Elastic Optical Network (EON), spectrum fragmentation refers to the existence of non-aligned, small-sized blocks of free subcarrier slots in the optical spectrum. Several metrics have been proposed in order to quantify a level of spectrum fragmentation. Approximation methods might be used for estimating average blocking probability and some fragmentation measures, but are so far unable to accurately evaluate the influence of different sizes of connection requests and do not allow in-depth investigation of blocking events and their relation to fragmentation. The analytical study of the effect of fragmentation on requests’ blocking probability is still under-explored. In this work, we introduce new definitions for blocking that differentiate between the reasons for the blocking events. We developed a framework based on Markov modeling to calculate steady-state probabilities for the different blocking events and to analyze fragmentation related problems in elastic optical links under dynamic traffic conditions. This framework can also be used for evaluation of different definitions of fragmentation in terms of their relation to the blocking probability. We investigate how different allocation request sizes contribute to fragmentation and blocking probability. Moreover, we show to which extend blocking events, due to insufficient amount of available resources, become inevitable and, compared to the amount of blocking events due to fragmented spectrum, we draw conclusions on the possible gains one can achieve by system defragmentation. We also show how efficient spectrum allocation policies really are in reducing the part of fragmentation that in particular leads to actual blocking events. Simulation experiments are carried out showing good match with our analytical results for blocking probability in a small scale scenario. Simulated blocking probabilities for the different blocking events are provided for a larger scale elastic optical link.

[1]  Juan P. Fernández Palacios,et al.  Dynamic routing and spectrum (re)allocation in future flexgrid optical networks , 2012, Comput. Networks.

[2]  Ioannis Tomkos,et al.  Routing and Spectrum Allocation in OFDM-Based Optical Networks with Elastic Bandwidth Allocation , 2010, 2010 IEEE Global Telecommunications Conference GLOBECOM 2010.

[3]  Víctor López,et al.  Elastic Spectrum Allocation for Time-Varying Traffic in FlexGrid Optical Networks , 2013, IEEE Journal on Selected Areas in Communications.

[4]  Masahiko Jinno,et al.  Spectrum-efficient and scalable elastic optical path network: architecture, benefits, and enabling technologies , 2009, IEEE Communications Magazine.

[5]  Tiejun J. Xia,et al.  Flexible architectures for optical transport nodes and networks , 2010, IEEE Communications Magazine.

[6]  Ying Wang,et al.  Routing and spectrum assignment by means of ant colony optimization in flexible bandwidth networks , 2012 .

[7]  Francky Catthoor,et al.  Reducing memory fragmentation in network applications with dynamic memory allocators optimized for performance , 2006, Comput. Commun..

[8]  Ting Wang,et al.  Defragmentation of transparent Flexible optical WDM (FWDM) networks , 2011, 2011 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference.

[9]  Nirwan Ansari,et al.  On the Effect of Bandwidth Fragmentation on Blocking Probability in Elastic Optical Networks , 2013, IEEE Transactions on Communications.

[10]  Ioannis Tomkos,et al.  Elastic Bandwidth Allocation in Flexible OFDM-Based Optical Networks (vol 29, pg 1354, 2011) , 2011 .

[11]  Kumar N. Sivarajan,et al.  Routing and wavelength assignment in all-optical networks , 1995, TNET.

[12]  Eric Bernier,et al.  Filterless optical networks : a unique and novel passive WAN network solution , 2007 .

[13]  Yawei Yin,et al.  Dynamic on-demand defragmentation in flexible bandwidth elastic optical networks. , 2012, Optics express.

[14]  Chunming Qiao,et al.  Theoretical Analyses of Lightpath Blocking Performance in CO-OFDM Optical Networks with/without Spectrum Conversion , 2013, IEEE Communications Letters.

[15]  Ioannis Tomkos,et al.  Dynamic cooperative spectrum sharing and defragmentation for elastic optical networks , 2014, IEEE/OSA Journal of Optical Communications and Networking.

[16]  Lena Wosinska,et al.  Spectrum allocation policy modeling for elastic optical networks , 2012, High Capacity Optical Networks and Emerging/Enabling Technologies.

[17]  Masahiko Jinno,et al.  Elastic optical networking: a new dawn for the optical layer? , 2012, IEEE Communications Magazine.

[18]  M. Sekiya,et al.  Utilization entropy for assessing resource fragmentation in optical networks , 2012, OFC/NFOEC.

[19]  S. J. B. Yoo,et al.  Demonstration of Spectral Defragmentation in Flexible Bandwidth Optical Networking by FWM , 2011, IEEE Photonics Technology Letters.

[20]  Francisco-Jose Martínez-Zaldívar,et al.  Book reviews [Three books reviewed] , 2012, IEEE Communications Magazine.

[21]  H. Tanaka,et al.  Optical OFDM, a hype or is it for real? , 2008, 2008 34th European Conference on Optical Communication.

[22]  Michael A. Saunders,et al.  LSQR: An Algorithm for Sparse Linear Equations and Sparse Least Squares , 1982, TOMS.

[23]  Biswanath Mukherjee,et al.  Spectrum management in heterogeneous bandwidth optical networks , 2014, Opt. Switch. Netw..

[24]  Louis A. Hageman,et al.  Iterative Solution of Large Linear Systems. , 1971 .

[25]  Ernesto Ciaramella,et al.  All DFB-Based Coherent UDWDM PON With 6.25 GHz Spacing and a ${>}{\rm 40}~{\rm dB}$ Power Budget , 2014, IEEE Photonics Technology Letters.

[26]  Ioannis Tomkos,et al.  Time-Varying Spectrum Allocation Policies and Blocking Analysis in Flexible Optical Networks , 2013, IEEE Journal on Selected Areas in Communications.

[27]  Jie Zhang,et al.  Spectrum compactness based defragmentation in flexible bandwidth optical networks , 2012 .

[28]  Martin Maier,et al.  An Analytical Framework for the Performance Evaluation of Node- and Network-Wise Operation Scenarios in Elastic Optical Networks , 2014, IEEE Transactions on Communications.

[29]  Masahiko Jinno,et al.  Disruption minimized spectrum defragmentation in elastic optical path networks that adopt distance adaptive modulation , 2011, 2011 37th European Conference and Exhibition on Optical Communication.

[30]  Masahiko Jinno,et al.  Elastic Optical Networking , 2013 .

[31]  H. Tijms.  A First Course in Stochastic Models , 2003 .

[32]  Biswanath Mukherjee,et al.  A Survey on OFDM-Based Elastic Core Optical Networking , 2013, IEEE Communications Surveys & Tutorials.

[33]  Masahiko Jinno,et al.  Distance-adaptive spectrum resource allocation in spectrum-sliced elastic optical path network [Topics in Optical Communications] , 2010, IEEE Communications Magazine.

[34]  Paul R. Wilson,et al.  Dynamic Storage Allocation: A Survey and Critical Review , 1995, IWMM.

[35]  Yuefeng Ji,et al.  Exact performance analytical model for spectrum allocation in flexible grid optical networks , 2014 .

[36]  Biswanath Mukherjee,et al.  Provisioning in Elastic Optical Networks with Non-Disruptive Defragmentation , 2013, Journal of Lightwave Technology.