Collisions free scheduling in the NEPHELE hybrid electrical/optical datacenter interconnect

Kostas Christodoulopoulos, Konstantinos Kontodimas, Apostolos Siokis, Konstantinos Yiannopoulos, E. Varvarigos

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearch


The NEPHELE datacenter network is divided into pods/clusters of racks and relies on hybrid electro-optical top-of rack switches that access an all-optical network consisting of WDM rings. To enable dynamic and efficient sharing of the optical resources and a collision-free network operation, the NEPHELE network is designed to operate in a slotted manner with a software-defined-network (SDN) based control plane. We describe the NEPHELE resource allocation problem, consider the wavelength conflicts on the shared WDM rings, translate them into resource allocation constraints and investigate the effect of these constraints on network performance. To do so, we define the worst-case traffic pattern and perform simulations to evaluate performance for the average traffic. Finally, we propose a variation to the NEPHELE architecture that reduces the effects of these wavelength conflict constraints on performance.

Original languageEnglish
Title of host publication2016 IEEE International Conference on Electronics, Circuits and Systems (ICECS 2016)
EditorsSandro Carrara, Patricia Desgreys, Domenico Zito
Place of PublicationPiscataway NJ USA
PublisherIEEE, Institute of Electrical and Electronics Engineers
Number of pages4
ISBN (Electronic)9781509061136, 9781509061129
ISBN (Print)9781509061143
Publication statusPublished - 2016
Externally publishedYes
EventIEEE International Conference on Electronics, Circuits and Systems 2016 - Monte Carlo, Monaco
Duration: 11 Dec 201614 Dec 2016
Conference number: 23rd


ConferenceIEEE International Conference on Electronics, Circuits and Systems 2016
Abbreviated titleICECS 2016
CityMonte Carlo


  • resource allocation
  • rings
  • scheduling
  • slotted operation
  • time division multiplexing (TDM)
  • wavelenght collsions
  • wavelength division multiplexing (WDM)

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