Abstract

Elastic optical networks (EONs) have emerged to provide higher spectrum efficiency than traditional Dense Wavelength-Division-Multiplexing (DWDM) by utilizing enabling technologies such as flexible spectrum grid, Orthogonal Frequency Division Multiplexing (OFDM), and distance adaptive rate and modulation. The choice of the control-plane is an important consideration when deploying any new technology, especially in optical networks. This paper considers generic distributed and centralized spectrum assignment policies in conjunction with the accompanying connection set-up signaling protocols in EONs. A network simulator for Generalized Multiprotocol Label Switching (GMPLS) was developed with Forward Reservation Protocol and Backward Reservation Protocol signaling methods. These signaling techniques are used with the First Fit (FF) and Random Fit (RF) Routing and Spectrum Allocation (RSA) algorithms. The paper discusses control elements (central and distributed architectures) decisions under busy hour and normal network conditions and presents a comprehensive performance analysis of key performance metrics such as connection success rate, connection establishment time, and capacity requirement.

Highlights

  • Today’s DATA communication networks are growing at a rapid pace (Figure 1)

  • Elastic optical networks (EONs) have been extensively studied over the past decade [22, 24,25,26,27,28,29,30,31,32] from various perspectives [24], from early architectural assessments establishing the potential advantages of EONs over fixed-grid Wavelength Division Multiplexed (WDM) [25] to specific resource allocation studies that aim to provide efficient routing and spectrum allocation algorithms [24, 26, 27] or solutions to the spectrum fragmentation problem in EONs [29]

  • Realistic case studies [33] have been simulated for a network’s busy hour, with a lesser number of connection requests, in a near parallel mode to differentiate between the efficiency of Centralized Network Operation Mode (CNOM) and a Distributed Network Operation Mode (DNOM)

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Summary

Introduction

Today’s DATA communication networks are growing at a rapid pace (Figure 1). Of late, the Internet caters to end users with different applications, such as high-definition IP videos (Netflix, Hulu, YouTube), file sharing tools (Google Drive, Dropbox), Voice over IP, and fully immersive video technologies such as Virtual Reality. To sustain the growth of bandwidth capacity, it is essential to have flexible data-rates, multicarrier modulation techniques, and resource efficient spectrum allocation methodologies, as compared to traditional WDM networks. It is noted that despite the recent interest in applying a Software Defined Networking (SDN) paradigm (e.g., OpenFLow protocols) in optical networks [21, 22] some researchers envision that a traditional embedded control-plane based on GMPLS will continue to be in place even in optical networks that utilize SDN due to factors and performance requirements specific to optical networks [23] These factors include vendor proprietary frame formats, different granularity of grooming functions, proprietary modulation/encoding and Forward Error Correcting (FEC) schemes, and stringent recovery time constraints [23].

Related Work
EON and GMPLS Background
RESV 3
Problem of Routing and Spectrum Allocation
Simulation Environment
Forward Reservation Protocol
Backward Reservation Protocol
Comparison between FRP and BRP
Findings
Conclusion
Full Text
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