Transport SDN's Time Has Come
The optical systems market has been shaken up in the past couple of years by the emergence of programmable optical modules using digital signal processors (DSPs) capable of utilising multiple modulation schemes to deliver flexible combinations of reach and capacity.
These DSPs are being adopted because they enable the more expensive optical modules and radio frequency (RF) components to be reused more cost-effectively -- the DSP is a relatively cheaper component of the complete line card.
While the approach has largely been used for shorter spans in the metro market, the principles of programmability of optical line cards apply more widely, and the industry is looking ahead to a time -- not long away -- when programmability is a basic feature of coherent systems across most applications. As operators converge their fixed and mobile access networks, and cloudify their radio access networks (RANs), such programmability will be a useful way to support multiple services flexibly and dynamically, and there is no reason why the programmable DSPs cannot be deployed in systems for long-haul applications too -- as the speed of the electronics increases, FEC algorithms improve and systems become more capable of delivering capacity over longer distances.
But there is an issue to be dealt with before this can happen: It's all very well having flexibility and programmability at the level of the line card, and it's quite another thing to match this in the management of traditionally static optical networks to enable the most efficient use of optical assets. It requires the orchestration and software-defined networking (SDN) approaches that have been making an impact in other areas of carriers' network operations to extend to the optical transport network -- both in terms of processes and management systems.
Some vendors are responding to this with the introduction of new management systems that provide the greater visibility into what is happening in the optical network that will be needed to enable more dynamic and automated management. Ciena's Liquid Spectrum approach, introduced in March 2017, encompasses a management system (Blue Planet MCP) and software applications that promise real-time visibility into network performance, easier wavelength provisioning and greater automation -- for instance, for path restoration. It also has open application programming interfaces (APIs) and standard data models.
In a similar vein, Coriant's Aware system, demonstrated in March 2017, pulls optical performance data from the network -- including from coherent receivers -- and analyses it in real time with its Margin Processing Engine to assess the residual margin (a signal quality parameter) per channel, enabling faster and simpler wavelength provisioning. I expect to see other vendors revamping their management systems along similar lines over the next few months.
The Heavy Reading report Telco Optical Systems Beyond 100G, looks at how demand for optical transport has changed, how coherent optics is evolving and what the future holds for this established but dynamic technology. It examines advances in electronics that are pushing speeds faster, as well as the consequences for the standard optical grid spacing.
Further, it looks at standardisation efforts, including those led from the demand-side of the market, and compares the approaches and portfolios of 11 vendors of telco-focused optical systems.
— Danny Dicks, Contributing Analyst, Heavy Reading