Tad Hofmeister
Tad Hofmeister is a Network Architect at Google with a focus on scalable, cost-effective DWDM technologies and software management innovations. He manages the Optical Architecture and Transport Engineering teams in Google’s Cloud Networking group and is Vice President and member of the board of the OIF. Prior to working at Google, Tad was an architect, system engineer, and hardware designer for several optical transport and packet processing companies including: Ciena, Matisse Networks, OpVista, and Applied Signal Technology. Dr. Hofmeister earned MS and Ph.D. degrees in EE from Stanford University and BS degrees from Columbia University and Bates College.
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Open Optical Communication Systems at a Hyperscale Operator
Matt Newland
Rene Marcel Schmogrow
Vijay Vusirikala
Journal of Optical Communications (2020)
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Open optical networks present a variety of benefits such as single vendor independence and the opportunity to select best in class devices for each individual role. In this paper we review two degrees of open optical networks, namely ones with transponder-line system and line system-line system interoperability. In this context we discuss Google's experiences with respect to optical link design, software, and controls, deployment, and operation.
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Data Models for Optical Devices in Data Center Operator Networks
Nancy El-Sakkary
Vijay Vusirikala
OSA Technical Digest, OSA Publishing (2019)
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Standardized, vendor agnostic data models deliver major operational benefits. OpenConfig has been implemented on multiple platforms and is an ideal data model to take advantage of these benefits. This document provides an overview.
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Optical Network Control & Management Plane Evolution-A Large Datacenter Operator Perspective
Nancy El-Sakkary
Vijay Vusirikala
OSA Technical Digest, OSA Publishing (2019)
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Legacy management technologies and concepts are a major blocker to efficiently building and operating a large scale optical network. We provide an overview of new, modern device management technologies and discuss deployment and operational efficiencies that they enable.
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Opportunities and Challenges of C+L Transmission Systems
Rene Marcel Schmogrow
Matt Newland
Vijay Vusirikala
IEEE/OSA Journal of Lightwave Technology (2019)
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C+L open line systems represent a cost-effective way to scale backbone network capacity. In this article, we review challenges and opportunities for C+L line systems stemming from Google's experience in designing, deploying, and operating a global C+L open optical network. We discuss business, operational, and technical aspects of C+L systems, and describe best practices for designing C+L links. Finally, we compare C and C+L systems, showing how the latter not only conceal capacity penalties but can even increase, depending on the deployed fiber types, the total system capacity with respect to two parallel C-band only systems.
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Optical Zero Touch Networking - A Large Operator Perspective
Nancy El-Sakkary
Vijay Vusirikala
OSA Technical Digest, OSA Publishing (2019)
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A key area of innovation in optical networking has been enabling modern, vendoragnostic APIs on devices. We provide specifics of how these new capabilities enable deployment and operational efficiencies.
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Vendor-neutral Network Representations for Transport SDN
Vinayak Dangui
Vijay Vusirikala
Proc. of Optical Fiber Communication Conference (2016)
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We describe a model-based approach for building a transport SDN platform that uses operator-defined data models to build common APIs for managing multi-vendor optical networks consisting of terminal devices and line systems.
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The Prospect of Inter-Data-Center Optical Networks
Xiaoxue Zhao
Vijay Vusirikala
Valey Kamalov
IEEE Communication Magazine, 51 (2013), pp. 32-38
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Mega data centers and their interconnection
networks have drawn great attention in recent
years because of the rapid public adoption of
cloud-based services. The unprecedented
amount of data that needs to be communicated
between data centers imposes new requirements
and challenges to inter-data-center optical networks.
In this article, we discuss the traffic
growth trends and capacity demands of Google’s
inter-data-center network, and how they
drive the network architectures and technologies
to scale capacities and operational ease on existing
fiber plants. We extensively review recent
research findings and emerging technologies,
such as digital coherent detection and the flexgrid
dense wavelength-division multiplexed channel
plan, and propose practical implementations,
such as C+L-band transmission, packet and
optical layer integration, and a software-defined
networking enabled network architecture for
both capacity and operational scaling. In addition,
we point out a few critical areas that require
more attention and research to improve efficiency
and flexibility of an inter-data-center optical
network: optical regeneration, data rate mismatch
between Ethernet and optical transport,
and real-time optical performance monitoring.
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