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Mar 15 2015

CDC-F optical networks propel us forward

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CDC-F optical network solutions, now realizable, provide a level of scalability and operational efficiency the industry has never seen. Along with software-defined networking (SDN), CDC-F optical networks -- colorless, directionless, contentionless, with FlexGrid channel support -- will propel networks forward to support services that we’re only beginning to envision.

What is a CDC-F optical network?

The optical networking industry has defined the concept of CDC-F as a way of cost-effectively routing routing high capacity wavelengths throughout an optical network.

The physical realization of CDC-F results in extremely agile optical networks.  On-site visits to change or route wavelength connectivity are no longer required. And a whole new set of capabilities reduce network total cost of ownership while maximizing fiber and optical network capacity.

Optical networks today

Today’s era of ultra broadband connectivity allows us to do things that were science fiction only a decade ago. New lifestyle-changing ultra broadband connected devices let us work and play any time or place that we want.

Supporting all this ultra broadband data communications is a fiber optic network that we’ve come to take for granted.

Decades ago, we heard that a fiber strand as thin as a human hair could carry 2.5 Gbps of data traffic. Since this revolutionary step, our foundational optical communication networks have silently evolved to the point where we can support 17.6 terabits-per-second (Tbps) over a single fiber strand – enough to transmit the contents of 88 Blu-ray discs in a single second. Hard to believe! We’ve come a long way!

The software that controls our networks has also come a long way. It’s given service providers the network scale and ability to offer new types of IP/MPLS services. However, software-defined networks introduce a new option for the way we control and leverage our networks for the creation of new revenue generating services. Which in turn will require more scale, agility and efficiency from the underlying optical network.

We scale fiber optic cable capacity by using different colors, or frequencies, of light that we refer to as wavelengths or DWDM. As we scale individual wavelength capacities from 100G, 200Gbps, and 400 Gbps, we’re reaching the point where it’s getting increasingly difficult to scale individual wavelength capacity.

So in addition to scaling individual wavelength capacities, we have to start routing increasing numbers of high capacity wavelengths throughout a maze of fiber optic cables with more agility and efficiency to scale and maximize the capacity of optical networks. And we need to stay in the light/photonic domain as long as possible in order to reduce the cost associated with repeatedly converting wavelength photonic signals to electrical.

A related issue is: How do we accurately and reliably monitor photonic wavelength performance throughout an optical network? We don’t want a situation where we have high capacity wavelengths dropping our data traffic -- with no way to diagnose what is causing the problem, or to know where to look to fix it.

Benefits of CDC-F optical networks

The implementation of CDC-F optical network technology allows us to:

  • Dynamically optimize/reroute wavelength connections to recover network capacity, thus extending optical network lifespan and avoiding premature fiber exhaustion.
  • Reduce, and in some cases eliminate altogether, the cost and scale required to network wavelengths in the electrical domain (OEO in optical parlance). This can lead to significant CAPEX and power savings, making networks more efficient and environmentally friendly.
  • Use more efficient wavelength protection options to conserve network wavelength counts.
  • Efficiently reroute wavelengths onto newly installed fiber routes to rapidly utilize the network more efficiently.
  • Increase wavelength capacities (e.g., from 100G to 200G) without changing the network equipment that routes wavelengths, thus extending the life of optical network well into the future.

This new wavelength agility also enables agile optical networking that can more rapidly respond to new SDN related service innovation.

Although the optical networking industry has been talking about the benefits that CDC-F technology can bring to optical networking for several years now, very few solutions can actually be deployed at scale. One of the reasons for this has been the lack of suitable operations, administration, and maintenance (OAM) tools to diagnose wavelength connectivity issues -- issues that are increasingly likely to arise given the wavelength scale and agility that CDC-F optical networks can support

Alcatel-Lucent has as a commercially available CDC-F wavelength routing solution that can be deployed at scale, a solution that will be supporting a North America Tier 1 service provider’s national optical core network.  A key component of this solution is the support for in-band per wavelength OAM. It can be used to isolate with surgical precision wavelength issues throughout the network, including between the modules that comprise a wavelength routing node.

This feature, together with the ability efficiently and optimally route wavelengths, are critical to bringing the operational efficiency required to deploy CDC-F optical networks at scale.

Together, CDC-F and SDN technologies are set to propel our networks forward -- and make what’s science fiction today, a reality in the not too distant future.

Related Material

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To contact the author or request additional information, please send an email to networks.nokia_news@nokia.com.

About Scott Larrigan
Scott is responsible for marketing the company's ION portfolio including optical networks, microwave, and mobile backhaul. For years, Scott has been supporting an IP packet over optics network evolution and the optimization of mobile networks to support 2G, 3G, 4G/LTE and 5G over a common packet optical network. Scott has over 20 years experience in the telecom industry with roles ranging from marketing, business development, product management, and R&D. He holds a Bachelor of Science (BSc) degree, specializing in computer science, from the University of Manitoba in Canada. He also is a co-author of 4 patents related to IP networking technologies
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