Speed, simplicity and agility. These needs are all top of mind as service providers look for ways to maximize their existing optical network while building enough bandwidth overhead to support the massive increase in data driven by today’s digital world.

In the past, network growth and transitions were delivered with new generations of hardware technology. Today, some of the most challenging transitions are operational and are now driven by network software enhancements. In the optical area, we are continuously striving for new enhancements, especially software enhancements. By using a new, flexible control plane, the software-driven network lets service and content providers adjust their bandwidth automatically and take a proactive approach to maximizing the tradeoffs that exist between capacity and distance in the optical network.

Cisco’s Flexible Light Orchestration of Wavelengths (FLOW) is a new software control plane that supports flex spectrum by extending the Generalized Multiprotocol Label Switching (GMPLS) control plane. It is compliant with the Spectrum Switched Optical Networks (SSON) standard and allows operators to provision, protect and restore new bandwidth by simply dismounting the fixed grid network, and replacing it with a flexible grid (aka Flex Spectrum). FLOW incorporates enhanced optical calculation algorithms to manage the new higher bit rate wavelengths and is flexible because it is software configurable and not constrained by a fixed wavelength grid. With the availability of enhanced algorithms integrated into this solution, bandwidth congestion can be easily adjusted on a dynamic basis. This is an important new benefit for optical networking.

The FLOW control plane includes a new optical signal hierarchy called the media channel in order to support flex spectrum capability. This media channel acts as the continuous spectrum portion from the initial source to the final destination. The set of carriers inside the media channel is called a “superchannel.” The media channel includes information about the allocated optical bandwidth as well as the path within the network. It is possible to aggregate several media channels into a Media Channel Group (MCG).

The primary use case is where multiple or many 100G wavelengths have already been deployed in a network. These can now be grouped together, but if one fails, the other waves are not affected. The FLOW control plane is alerted that these wavelengths have been put into a media channel group. The key use case for FLOW is to transport higher bit rate wavelengths that have not been created before, such as 250G, and eventually up to 600G. The FLOW control plane will also use this information to squeeze the media channels into the smallest portion of spectrum required for the end-to-end distance. The media channel group is also defined by the source to destination of the path.

Existing optical networks can benefit substantially from the new Cisco FLOW control plane. Fiber carrying capacity is increased on the existing infrastructure, along with support for next-generation data rates such as 600G, 1 Terabit and higher. With FLOW, the number of bits per fiber is increased dramatically, which in turn decreases the cost per bit by leveraging the advances in silicon. In addition, advances in automation will reduce operational costs and provide more flexibility.

With the agility of a configurable solution, bandwidth congestion can be easily adjusted on a dynamic and automated basis. The capital and operational advantages of FLOW and massive spectral efficiency are obvious: bandwidth on existing platforms can be increased by up to 50 percent while optimizing larger wavelengths within the same spectrum, resulting in significant CapEx and OpEx savings for all network operators.

Learn more about Cisco’s Flexible Light Orchestration of Wavelengths here.

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Bill Gartner

Senior Vice President/GM

Optical Systems & Optics Group