Infinera targets the metro cloud

Infinera has styled its latest Cloud Xpress product used to connect data centres as a stackable platform, similar to how servers and storage systems are built. The development is another example of how the rise of the data centre is influencing telecoms.

"There is a drive in the industry that is coming from the data centre world that is starting to slam into the telecom world," says Stuart Elby, Infinera's senior vice president of cloud network strategy and technology.

Cloud Xpress is designed to link data centres up to 200km apart, a market Infinera coins the metro cloud. The two-rack-unit-high (2RU) stackable box features Infinera's 500 Gigabit photonic integrated circuit (PIC) for line side transmission and a total of 500 Gigabit of client side links made up of 10, 40 or 100 Gigabit interfaces. Typically, up to 16 units will be stacked in a rack, providing 8 Terabits of transmission capacity over a fibre.

Cloud Xpress has also been designed with the data centre's stringent power and space requirements in mind. The resulting platform has significantly improved power consumption and density metrics compared to traditional metro networking platforms, claims Infinera.

Metro split

Elby describes how the metro network is evolving into two distinct markets: metro aggregation and metro cloud. Metro aggregation, as the name implies, combines lower speed multi-service traffic from consumers' broadband links and from enterprises into a hub where it is switched onto a network backbone. Metro cloud, in contrast, concerns date centre interconnect: point-to-point links that, for the larger data centres, can total several terabits of capacity.   

Cloud Xpress is Infinera's first metro platform that uses its PIC. "We have plans to offer it all the way out to ultra long haul," says Elby. "There are some data centres that need to get tied between continents."

Cloud Xpress is being aimed at several classes of customer: internet content providers companies (or webcos), entreprises, cloud operators and traditional service providers. The primary end users are webcos and enterprises, which is why the platform is designed as a rack-and-stack. "These are not networking companies, they are data centre ones; they think of equipment in the context of the data centre," says Elby.    

But Infinera expects telcos will also adopt Cloud Xpress. They need to connect their data centres and link data centres to points-of-presence, especially when increasing amounts of traffic from end users now goes to the cloud. Equally, a business customer may link to a cloud service provider through a colocation point, operated by companies such as Equinix, Rackspace and Verizon Terremark.

"There will be a bleed-over of the use of this product into all these metro segments," says Elby. "But the design point [of Cloud Xpress] was for those that operate data centres more than those that are network providers."

Google has shared that a single internet search query travels on average 2,400km before being resolved, while Facebook has revealed that a single http request generates some 930 server-to-server interactions. 

The Magnification Effect  

Webcos' services generate significantly more internal traffic than the triggering event, what Elby calls the magnification effect.

Google has shared that a single internet search query travels on average 2,400km before being resolved, while Facebook has revealed that a single http request generates some 930 server-to-server interactions. These servers may be in one data centre or spread across centres.

"It is no longer one byte in, one byte out," says Elby. "The amount of traffic generated inside the network, between data centres, is much greater than the flow of traffic into or out of the data centre." This magnification effect is what is driving the significant bandwidth demand between data centres. "When we talk to the internet content providers, they talk about terabits," says Elby.

Cloud Xpress   

Cloud Xpress is already being evaluated by customers and will be generally available from December.

The stackable platform will have three client-side faceplate options: 10 Gig, 40 Gig and 100 Gig. The 10 Gig SFP+ faceplate is the sweet spot, says Elby, and there is also a 40 Gig one, while the 100 Gig is in development. "In the data centre world, we are hearing that they [webcos] are much more interested in the QSFP28 [optical module]."  

Infinera says that the Ethernet client signals connect to a simple mapping function IC before being placed onto 100 Gig tributaries. Elby says that Infinera has minimised the latency through the box, to achieve 4.4 microseconds. This is an important requirement for certain data centre operators.

The 500 Gig PIC supports Infinera's 'instant bandwidth' feature. Here, all the 500 Gig super-channel capacity is lit but a user can add 100 Gig  increments as required. This avoids having to turn up wavelengths and simplifies adding more capacity when needed.  

The Cloud Xpress rack can accommodate 21 stackable units but Elby says 16 will be used typically. On the line side, the 500 Gigabit super-channels are passively multiplexed onto a fibre to achieve 8 Terabits. The platform density of 500 Gig per rack unit (500 Gig client and 500 Gig line side per 2RU box), exceeds any competitor's metro platform, says Elby, saving important space in the data centre.

The worse-case power consumption is 130W-per-100 Gig, an improvement on the power consumption performance of competitors' platforms. This is despite the fact that coherent detection is always used, even for links as short as between a data centre's buildings. "We have different flavours of the optical engine for different reaches," says Elby. "It [coherent] is just used because it is there."

The reduced power consumption of Cloud Xpress is achieved partly because of Infinera's integrated PIC, and by scrapping Optical Transport Network (OTN) framing and switching which is not required. "There are no extra bells and whistles for things that aren't needed for point-to-point applications," says Elby. The stackable nature of the design, adding units as needed, also helps.

The Cloud Xpress rack can be controlled using either Infinera's management system or software-defined networking (SDN) application programming interfaces (APIs). "It supports the sort of interfaces the SDN community wants: Web 2.0 interfaces, not traditional telco ones."

Infinera is also developing a metro aggregation platform that will support multi-service interfaces and aggregate flows to the hub, a market that it expects to ramp from 2016.