What is IP to DWDM and why is it important

What is IP-to-DWDM and why is it important?

Are IPoWDM solutions also efficient for carriers' infrastructure?

The Optical Internetworking Forum (OIF) published the 400ZR implementation agreement in 2020. Since then, we've seen a rapid ramp-up of 400Gbit/s IP over DWDM (IPoWDM) solutions, which feature direct integration of 400Gbit/s coherent pluggable optics into routers and switches in point-to-point data center interconnects (DCI) stretching up to 120km. Now, with a broader range of ZR coherent interfaces, carriers and service providers are looking for ways to adopt IPoWDM in their optical networks to take advantage of the promised lower cost, space and power consumption compared to classical transponder-based DWDM solutions. But do these promises also hold true for this type of infrastructure?

Power and space advantages are not disputable. ZR coherent pluggable optics use a very small form factor and consume little power. Moreover, they slot directly into end-application devices, leading to additional power and space savings.

Lower cost? It depends on the cost components and the time frames being considered.

Classical transponder-based DWDM solutions may have higher upfront costs, but they tend to be more straightforward to manage and maintain over time. On the other hand, IPoWDM uses a simplified architecture without DWDM transponders, significantly reducing capex, space and power consumption, but users may experience some operational challenges in the short and long term. For example, achieving IP and optical layer management integration requires tremendous effort, and there is no clear consensus yet on the best approach, as highlighted in one of the panel discussions at the last OFC event in San Diego. Scalability is also something to be considered. Since there is no separation between IP and optical layers, upgrades to higher speeds are tied to switches and routers' capabilities. Also, without a clear demarcation, fault isolation is more difficult and troubleshooting more time-consuming. These limitations can increase the cost of IPoWDM solutions.

No silver bullet

These are just a few examples. While these challenges might not be critical for short point-to-point DCI applications, they can be significant for carriers and service providers with more complex networks that include ROADMs and longer transmission links. Additionally, organizations with separate teams managing IP and optical transport might find these challenges particularly daunting.
There is no silver bullet. Each carrier and service provider must carefully evaluate their specific requirements, organization and resources, and consider the trade-offs when choosing between IPoDWDM and traditional transponder-based DWDM solutions.

Until now …

New IP-to-DWDM approach

What if there was a way to take advantage of both ZR/ZR+ coherent optics and a cost-efficient DWDM demarcation and muxponding solution?

In response to this question, Adtran recently announced the release of the FSP 3000 M-Flex800™, an innovative optical terminal that offers a new approach called "IP-to-DWDM" that bridges the gap between classical transponder-based DWDM and the latest IPoWDM solutions.

The FSP 3000 M-Flex800™ leverages ZR/ZR+ pluggable coherent optics, creating a thin layer between the end application devices and the open optical line system (OLS). It supports a wide range of coherent pluggable optics from 100Gbit/s up to 800Gbit/s, including the latest ZR and ZR+ optics with QSFP28 and QSFP-DD form factors, and provides additional features compared to IPoWDM solutions, such as client service multiplexing into 400Gbit/s and 800Gbit/s line speeds and open APIs for seamless integration into SDN environments. And all of this comes in a compact, single-slot card that can be flexibly equipped in multiple chassis sizes in new or existing deployments, indoor and outdoor. And at much lower cost and power levels than traditional transponder-based solutions.

The M-Flex800™ uses a more straightforward client service multiplexing technique than traditional OTN-based muxponders, significantly reducing cost and power.How does it work?

The M-Flex800™ uses a more straightforward client service multiplexing technique than traditional OTN-based muxponders, significantly reducing cost and power. Moreover, it offers a triple 100Gbit/s transponder, a dual 400Gbit/s trans-/muxponder and an 800Gbit/s trans-/muxponder in a single-slot card, enabling high-density solutions that can scale. It also facilitates other use cases, such as ZR-to-ZR metro/core interconnects and coherent fanout solutions that further reduce overall cost and optimize the use of switches and router ports.

That's great, but that's not all.

With its flexibility and versatility, the FSP 3000 M-Flex800™ offers high operational simplicity now and in the long term. Besides the multiple operating modes mentioned before, it supports client and line speeds from 100Gbit/s up to 800Gbit/s and a wide array of coherent pluggable optical interfaces, such as ZR, ZR+ and OpenROADM, which might grow with new coherent optics innovation. This facilitates fast and smooth upgrades to 400Gbit/s and 800Gbit/s independent from switches or router renewals. This also means IP-to-DWDM solutions with M-Flex800™ can be used from the edge to the network's core, in the central office, data center or street cabinet, depending on the pluggable optics and chassis.

The FSP 3000 M-Flex800™ provides a clear demarcation between the optical and IP layers, and it gives users the choice to manage it via integrated open, standardized APIs, which are not directly available in the ZR/ZR+ coherent plugs or traditional management options. These include the Adtran end-to-end network and service management suite. It also offers equipment and path protection options, along with comprehensive monitoring capabilities, ensuring the highest reliability.

Finally, yet importantly, while the FSP 3000 M-Flex800™ can work with any OLS, using the FSP 3000 M-Flex800™ with an FSP 3000 OLS configuration offers additional benefits in end-to-end optimization to maximize optical transmission performance along each optical path. This can translate to increases in the transmission distance, minimizing the need for regeneration and reducing associated capital costs.

Get the best of both worlds

With all these features, the FSP 3000 M-Flex800™ facilitates a broad range of cost-efficient IP-to-DWDM applications from the edge to the core, in carriers and DCI networks, leveraging ZR/ZR+ coherent optics without giving up significant capabilities. Contact Adtran to learn more about the FSP 3000 M-Flex800™ and the new IP-to-WDM solutions it enables.