Operators are currently transforming their optical transmissions and upgrading equipment to higher-speed wavelengths (such as 40G and 100G), using wavelength-division multiplexing (WDM) to transport SONET/SDH, OTN and Ethernet network traffic.
Their eagerness to deploy higher-speed 40G/100G optical transport technologies and equipment is motivated by numerous factors, such as lowering the cost per bit for new wavelengths and reducing incremental and common costs for equipment thanks to increased spectral efficiency.
The superior dispersion performance of coherent optics is another key consideration. Indeed, many operators are in the process of moving the majority of their installations to 100G now that the connectivity and related products are ready for widespread availability.
When adopting a deployment strategy, operators need to take many factors into consideration, including strategies for deploying 40G and 100G in optical systems, and how to deploy the new wavelengths, i.e., over the existing network using existing traffic (brownfield deployments), or over new fiber with new equipment installations (greenfield deployments). In addition, vendor selection criteria is another important factor in the decision-making process.
When it comes to whether to deploy brownfield or greenfield technologies, there is no easy answer, because both have their pros and cons, challenges and trade-offs. As such, the right decision will depend on the actual context, the type of network involved, growing capacity requirements and other important considerations.