Ciena's stackable platform for data centre interconnect

Ciena is the latest system vendor to unveil its optical transport platform for the burgeoning data centre interconnect market. Data centre operators require scalable platforms that can carry significant amounts of traffic to link sites over metro and long-haul distances, and are power efficient. 

The Waveserver stackable interconnect system delivers 800 Gig traffic throughput in a 1 rack unit (1RU) form factor. The throughput comprises 400 Gigabit of client-side interfaces and 400 Gigabit coherent dense WDM transport. 

For the Waveserver’s client-side interfaces, a mix of 10, 40 and 100 Gigabit interfaces can be used, with the platform supporting the latest 100 Gig QSFP28 optical module form factor. One prominent theme at the recent OFC 2015 show was the number of interface types now supported in a QSFP28.

On the line side, Ciena uses two of its latest WaveLogic 3 Extreme coherent DSP-ASICs. Each DSP-ASIC supports polarisation multiplexing, 16 quadrature amplitude modulation (PM–16-QAM), equating to 200 Gigabit transmission capacity.

The Extreme was chosen rather than Ciena’s more power-efficient WaveLogic 3 Nano DSP-ASIC to maximise capacity over a fibre. “The amount of fibre the internet content providers have tends to be limited so getting high capacity is key,” says Michael Adams, vice president of product and technical marketing at Ciena. The Nano DSP-ASIC does not support 16-QAM. 

A rack can accommodate up to 44 Waveserver stackable units to deliver 88 wavelengths, each 50GHz wide, or 17.6 Terabit-per-second (Tbps) of capacity. And up to 96 wavelengths, or 19.2Tbps, is supported on a fibre pair. 

"We are going down the path of opening the platform to automation"

“We could add flexible grid and probably get closer to 24 or 25 Tbps,” says Adams. Flexible grid refers to moving off the C-band's set ITU grid by using digital signal processing at the transmitter. By shaping the signal before it is sent, each carrier can be squeezed from a 50GHz channel into a 37.5GHz wide one, boosting overall capacity carried over the fibre. 

Adams says that it is not straightforward to compare the power consumption of different vendors’ data centre interconnect platforms but Ciena believes its platform is competitive. He estimates that the Waveserver consumes between 1W and 1.5W per Gigabit line side.

Ciena has stated that between five and 10 percent of its revenues come from web-scale customers, and accounts for a third of its total 100 Gig line-side port shipments. 

Web-scale companies include Internet content providers, providers of data centre co-location and interconnect, and enterprises. Web-scale companies also drive the traditional telecom optical networking market as they also use large amounts of the telcos' network capacity to link their sites. 

The global data centre interconnect market grew 16 percent in 2014 to reach $US 2.5 billion, according to market research firm, Ovum. Almost half of the spending was by the communications service providers whereas the Internet content providers spending grew 64 percent last year.   

Open software

Ciena also announced an open application development environment, dubbed emulation cloud, that allows applications to be developed without needing Waveserver hardware. 

One obvious application is the moving server virtual machines between data centres. But more novel applications can be developed by the data centre operators and third-party developers. Ciena cites what it calls an augmented reality application that allows a mobile phone to be pointed at a Waveserver to inform the of user the status of the machine: which ports are active and what type of bandwidth each port is consuming. “It can also show power and specific optical parameters of each line port,” says Adams. “Right there, you have all the data you need to know.”   

The Waveserver platform also comes with software that allows data centre managers to engineer, plan, provision and operate links via a browser. More sophisticated users can benefit from Ciena’s OPn architecture and a set of open application programming interfaces (APIs).

“We are going down the path of opening the platform to automation,” says Adams. “We can foresee for the most sophisticated users, plugging into APIs and going to some very specific optical parameters and playing with them.” 

Waveserver Status

Ciena is demonstrating its Waveserver platform to over 100 customers, as part of an annual event at the company’s Ottawa site.

“We are well engaged with a variety of Internet content providers,” says Adams. “We will be in trials with many of those folks this summer.” General availability is expected at the end of the third quarter.

In May, Ciena announced it had entered a definitive agreement to acquire Cyan. Cyan announced its own N-Series data centre interconnect platform earlier this year. Ciena says it is premature to comment on the future of the N-Series platform.