In an era characterised by escalating data demands, network providers seek innovative solutions to enhance optical transport without compromising cost or complexity. Coherent optics emerges as a transformative technology that offers enhanced network capacity, reduced power consumption, and improved efficiency.

Recently, during EXFO's Revolutionising Optical Transport Networks webinar, Andrea Guglielmi, Business Development Manager at EXFO, provided insightful perspectives on the evolution of IP over DWDM, interoperability challenges, and the shaping of the future of high-speed networking through standardisation efforts.

For individuals involved in optical networking, carrier networks, or data centre interconnects, this webinar presented invaluable information and this blog post goes over our key takeaways.

The Rise of Coherent Optics in Optical Transport Networks

Coherent optics has rapidly become the cornerstone of Dense Wavelength Division Multiplexing (DWDM) networks, enabling significantly higher transmission rates over extended distances.

A Brief History of Coherent Optics

  • 2008: Ciena introduced the inaugural 400G coherent line card.
  • 2010s: Advancements in miniaturisation, integration, and pluggability propelled accelerated adoption.
  • Present: 400G ZR/ZR+ transceivers have facilitated seamless IP over DWDM integration, with 800G and 1.6T transceivers poised to emerge.

Why This Matters

“High-speed DWDM optical networks are now mostly based on coherent technology,” noted Andrea Guglielmi. “We’ve seen tremendous progress, particularly in lower power, cost savings, and improved port density.”

The evolution of IP over DWDM is particularly noteworthy. Traditionally, optical transport networks and IP networks were distinct entities. However, with the advent of pluggable coherent transceivers, optical functions can now be seamlessly integrated into switches and routers, obviating the necessity for separate transport line cards.

This transformative shift has far-reaching implications, as it not only diminishes both CAPEX (Capital Expenditure) and OPEX (Operational Expenditure) by:

  • Eliminating transponder line cards
  • Reducing the count of network components
  • Decreasing energy consumption

“With IP over DWDM, network complexity is reduced, leading to significant cost savings while improving overall efficiency.” — Andrea Guglielmi

Interoperability Challenges: Multi-Vendor Networks and Standardisation

While IP over DWDM presents a significant opportunity, it also introduces substantial challenges, particularly in the areas of interoperability and network management.

Key Interoperability Issues

  1. Module-to-Host Compatibility: Ensuring that transceivers work harmoniously with diverse switches and routers.
  2. Module-to-Module Interoperability: Cross-vendor transceivers must communicate seamlessly.
  3. Integration with Optical Line Systems: New transceivers must interoperate effectively with existing DWDM infrastructure.

“A major challenge is that the traditional network demarcation point between IP and optical transport doesn’t exist anymore. Operators now need a converged management system that integrates both layers efficiently.” — Andrea Guglielmi

Standardisation Efforts: The Pivotal Role in Multi-Vendor Compatibility

To overcome these challenges, industry organisations such as the Optical Internetworking Forum (OIF), the TIP (Telecommunications Industry Partnership), and the Internet Engineering Task Force (IETF) are diligently engaged in the development of shared standards.

One of the most pivotal standards is the Common Management Interface Specification (CMIS), which facilitates the streamlined management of coherent transceivers.

“CMIS plays a vital role in simplifying transceiver deployment by ensuring consistent power management, wavelength control, and monitoring capabilities.” — Sean Buckley

Organizations are also conducting Plugfest events, where vendors test their products in multi-vendor setups to ensure real-world interoperability.

“Standardization and multi-vendor Plugfests are key to proving and validating interoperability across different transceivers and network equipment.” — Andrea Guglielmi

Supply Chain and Deployment Considerations

Beyond technical challenges, the transition to multi-vendor optical networks introduces supply chain management complexities. Network operators must make the following decisions:

  • Outsource testing to third parties: This option allows for external validation of testing capabilities.
  • Develop in-house testing capabilities: This approach enables operators to conduct testing independently.

Industry surveys indicate that 65% of network operators favour a multi-vendor approach, but this necessitates the implementation of robust testing frameworks.

To optimise deployment and troubleshooting processes, EXFO has developed DCO Burst and EyeOptics, two tools designed to:

  • Validate transceiver performance prior to field deployment.
  • Monitor and diagnose failures promptly.
  • Automate compliance testing.

“Interoperability is only achievable with extensive testing, whether it’s done in-house or through third-party validation.” — Andrea Guglielmi

The Future of Optical Networking: A Glimpse into the Next Frontier

The optical networking industry is poised for significant transformation, driven by the relentless pursuit of enhanced speeds and the adoption of more compact network architectures. Several key trends are poised to shape the industry’s trajectory:

  • Coherent Transceivers: The emergence of 800G and 1.6T coherent transceivers will enable unprecedented data transfer rates and network efficiency.
  • Standardisation: The growing adoption of OpenZR+ and OpenROADM standards will facilitate interoperability and collaboration among network vendors.
  • AI-Driven Automation: Advancements in artificial intelligence will empower network automation, leading to improved operational efficiency and scalability.

These developments herald a promising future for optical networking, with the potential to revolutionise communication and data transfer across various industries.

“Coherent optics is at the forefront of network transformation. While challenges around interoperability and deployment exist, standardization and robust testing frameworks are paving the way for a fully open, multi-vendor optical ecosystem.” — Andrea Guglielmi

For further insights into coherent optics and the future of optical networking, head to EXFO's site to the full webinar replay.

Key Takeaways from the Webinar

  • Coherent optics is revolutionising optical transport networks, enabling enhanced speeds and reduced operational costs.
  • IP over DWDM simplifies network infrastructure, thereby decreasing capital expenditure (CAPEX) and operational expenditure (OPEX).
  • Interoperability challenges persist, but standardisation initiatives (CMIS, OpenZR+) are progressively making multi-vendor networks viable.
  • Operators necessitate robust testing solutions to validate transceivers and effectively manage supply chains.
  • Future innovations such as 800G/1.6T optics and AI-driven network automation will continue to shape high-speed networking.