OIF moves to raise coherent transmission baud rate

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Gazettabyte – Roy Rubenstein

May 21, 2015

The Optical Internetworking Forum (OIF) has started modulator and receiver specification work to enhance coherent optical transmission performance. The OIF initiative aims to optimise modulator and receiver photonics operating at a higher baud rate than the current 32 Gigabaud (Gbaud).”We want the two projects to look at those trade-offs and look at how we could build the particular components that could support higher individual channel rates,” says Karl Gass of Qorvo and the OIF physical and link layer working group vice chair, optical.

Karl Gass

The OIF members, which include operators, internet content providers, equipment makers, and optical component and chip players, want components that work over a wide bandwidth, says Gass. This will allow the modulator and receiver to be optimised for the new higher baud rate.

“Perhaps I tune it [the modulator] for 40 Gbaud and it works very linearly there, but because of the trade-off I make, it doesn’t work very well anywhere else,” says Gass. “But I’m willing to make the trade-off to get to that speed.” Gass uses 40 Gbaud as an example only, stressing that much work is required before the OIF members choose the next baud rate.

“We want the two projects to look at those trade-offs and look at how we could build the particular components that could support higher individual channel rates”

The modulator and receiver optimisations will also be chosen independent of technology since lithium niobate, indium phosphide and silicon photonics are all used for coherent modulation.

The OIF has not detailed timescales but Gass says projects usually take 18 months to two years.

Meanwhile, the OIF has completed two projects, the specification outputs of which are referred to as implementation agreements (IAs).

One is for integrated dual polarisation micro-intradyne coherent receivers (micro-ICR) for the CFP2. At OFC 2015, several companies detailed first designs for coherent line side optics using the CFP2 module.

The micro-ICR IA also defines a low-speed SPI bus interface to control the trans-impedence amplifiers in the coherent receiver. The digital bus interface enables circuit settings to be changed with operating temperature. With the first generation coherent receiver design, analogue signalling was used for their control, says Gass. The smaller micro-ICR has a reduced pin count and so uses a narrower digital bus to control the circuits.The second completed IA is the 4×5-inch second-generation 100 Gig long-haul DWDM transmission module.

“This [module] is considered an intermediate step with the almost immediate goal being to go to a CFP module,” says Gass.

 

OIF Publishes Transport SDN Framework Document

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Key Findings from 2014 Demo Inspires Framework Architecture

Fremont, Calif. – May 19, 2015 –Following a 2014 prototype demonstration event, the Optical Internetworking Forum (OIF) has approved an SDN Framework whitepaper that paves the way for implementation of SDN in Carrier Networks. The whitepaper, titled “Framework for Transport SDN:  Components and APIs”, documents the SDN framework for multi-domain carrier networks.  It identifies critical open APIs for Transport SDN based on synthesis of the SDN layered architecture and the ITU-T ASON functional element model for optical network control.

SDN identifies interfaces separating infrastructure and control layers, and control layer from application layer.  The interface between infrastructure and control layers is termed the SouthBound Interface or SBI, the interface between control and application layers is termed the NorthBound Interface or NBI, and provides APIs to the application.

“In 2014, the prototype demonstration brought together multiple vendors and carriers to test cloud-bursting services, utilizing SDN principles and interfaces,” said Lyndon Ong of Ciena and co-chair of the OIF Market Awareness & Education Committee.  “The demonstration results factored into the development of a framework that allows SDN to be deployed over a carrier’s network with multiple, diverse domains.”

One of the key findings from the demonstration was that the separation introduced by the NBI and SBI enables SDN to be applied over greenfield (i.e., OpenFlow) and brownfield environments, allowing integration of domains controlled by management systems and domains using existing distributed control planes as well as centralized SDN.  A variety of SBI protocols could coexist in the carrier’s Transport SDN network, including the OpenFlow protocol, with extensions for optical networks.

NBI is an area of particular importance; by providing access to ASON functional elements, the NBI opens up access to the network control plane and provides greater programmability of services, improving the speed of service deployment and overall manageability of the network.  Functional elements accessible via NBI in this framework include Call Control, Connection Control, Topology and Path Computation.

The document assesses where existing protocols may be used to support NBI access.  In addition to existing protocols, there are benefits from defining new REST-based interfaces such as were prototyped in the demo, based on a common information model.

For a copy of the SDN framework document http://www.oiforum.com/documents/technical-white-papers/

About the OIF
The OIF facilitates the development and deployment of interoperable networking solutions and services. Members collaborate to drive Implementation Agreements (IAs) and interoperability demonstrations to accelerate and maximize market adoption of advanced internetworking technologies. OIF work applies to optical and electrical interconnects, optical component and network processing technologies, and to network control and operations including software defined networks and network function virtualization. The OIF actively supports and extends the work of national and international standards bodies. Launched in 1998, the OIF is the only industry group uniting representatives from across the spectrum of networking, including many of the world’s leading service providers, system vendors, component manufacturers, software and testing vendors. Information on the OIF can be found at http://www.oiforum.com

The OIF Launches New Integrated Photonics Projects

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Two Implementation Agreements Published for Industry Use

Fremont, Calif. – May 7, 2015– In the wake of the Optical Internetworking Forum’s April quarterly meeting in Lisbon, Portugal, the organization announced that initial work has begun on technical specifications for high bandwidth optical modulators and receivers for coherent applications. Members also approved implementation agreements for 100G applications. The Q2 meeting also saw several OIF technical committees meet to continue the Forum’s work on the FlexEthernet and Common Electrical Interface (CEI) projects begun in 2014. Finally, based on the success of technical demonstrations in 2014, Forum members held initial discussions regarding an SDN-focused demo for 2016.

“Our members are working at full capacity right now,” said Karl Gass, of Qorvo and the OIF Physical and Link Layer Working Group vice chair, Optical. “With as many as 19 documents going to ballot this quarter alone we are completing technical work at an extremely fast pace. These two new electro-optical component projects will fill a gap in the line side component space, providing systems engineers more tools to increase channel capacity beyond 100Gb/s.”

The utilized coherent ASIC Baud Rate is no longer sufficient information to define the frequency response requirements for coherent electro-optical (EO) components now that the industry has embraced the use of preconditioning. The High Bandwidth Polarization Multiplexed Quadrature Optical Modulator project enables coherent electro-optical modulation of a wider optical spectrum per optical carrier defined in terms of frequency response. The Intradyne Coherent Receiver project proposes an improved RF high frequency response that enables coherent electro-optic demodulation of a wider optical spectrum per optical carrier.

Implementation Agreements Approved for Public

The IA for Integrated Dual Polarization Micro-Intradyne Coherent Receivers targets coherent 100G PM-QPSK applications with nominal symbol rates up to 32 GBaud in a CFP2 form factor. This IA also defines a low speed electrical interface incorporating an SPI bus for control of the TIAs in the coherent receiver.

The IA for Generation 2.0 100G Long-Haul DWDM Transmission Module-Electromechanical applies to optical line interface applications. The IA reduces the size and power consumption requirements by defining a 4×5 module that can be used for 100G long-haul DWDM transmission applications.

For more information go to http://www.oiforum.com/documents/implementation-agreements/

About the OIF
The OIF facilitates the development and deployment of interoperable networking solutions and services. Members collaborate to drive Implementation Agreements (IAs) and interoperability demonstrations to accelerate and maximize market adoption of advanced internetworking technologies. OIF work applies to optical and electrical interconnects, optical component and network processing technologies, and to network control and operations including software defined networks and network function virtualization. The OIF actively supports and extends the work of national and international standards bodies. Launched in 1998, the OIF is the only industry group uniting representatives from across the spectrum of networking, including many of the world’s leading service providers, system vendors, component manufacturers, software and testing vendors. Information on the OIF can be found at http://www.oiforum.com.