Facebook TIP’s latest target for disruption and huge scale is fiber transport

Facebook’s Telecom Infra Project (TIP) is just one aspect of a general, if slow, process of disintegration in the traditional mobile network equipment market. But it is certainly the most impactful, thanks to the high profile and deep funds of its initiator, which aims to remake this closed market in the image of the webscale sector; and the growing support of operators.

There are other open source hardware and, of course, software projects in the mobile network world, other attempts to commoditize base stations and make them as easy to deploy as WiFi routers. But TIP is the one to which mobile operators are moving, however reluctantly – because they know they will just be swapping the lock-in of Ericsson, Huawei and Nokia for an ecosystem dominated by Facebook and the web giants; and that the price they pay for affordable networks will be even less control than they have in their existing value chains.

Some are trying to drive a different outcome, in which they embrace the new open source approach so whole-heartedly that they secure significant influence in future. AT&T is doing this with its ECOMP open orchestration software on the SDN/NFV side, and Telia looks set to be the vanguard of turning the TIP talk into commercial reality.

Telia’s wholesale division, Telia Carrier, has been working with Facebook and Coriant to trial Voyager, one of the flagships of the TIP initiative. Voyager is a DWDM (Dense Wavelength Division Multiplexin) transponder for fiber providers and Telia has completed a trial of 100G and 200G using the Facebook-designed open source equipment on its 1,089-kilometer fiber route from Stockholm to Hamburg. Technology developed by Coriant was used to demonstrate that 16QAM signalling works effectively over long distances.

Facebook unveiled Voyager in November, hailing it as the “first white box transponder and routing solution” and promising that it would open up packet DWDM transport networks just as the firm hopes the TIP base stations, OpenCellular and Terragraph, and its Project Aries Massive MIMO array, will open up the wireless access network. It is the basis of the Open DWDM platform, itself part of the Open Packet Transport project, which is designed to drive down costs in the same way as Facebook’s Wedge 100 white box switch did in the data center. Voyager uses the same Broadcom Tomahawk switch ASIC chip as Wedge 100.

Facebook has opened up the design to the TIP community via the Backhaul Open Optical Packet Transport project group and has been working with partners to test the solution. Orange also says it plans to trial the hardware.

Last fall, Facebook said that other partners in developing Voyager were Acacia Communications, Lumentum Holdings, Celestica and Snaproute. The first triallists, leaping in before Telia and Orange, were Equinix and MTN in South Africa. Equinix said preliminary trial results “showed zero packet loss and significant overall cost savings due to this disaggregated hardware and software networking model”.

The first vendor to support the Open Packet Transport platform was ADVA Optical Networking, which plans to sell Voyager and provide network management, operations support and maintenance. ADVA CTO and COO Christoph Glingener called Voyager: “A game changer that will open up networks to a whole new range of customers”.

The importance of Voyager and OpenCellular is not that they are unique – there is a significant rise in open and white box designs for fiber units and even base stations. The significance is Facebook’s market weight – its ability to convince MNOs that they must embrace open hardware or lose out to emerging service providers with these webscale economics; its power to bring together many stakeholders and force them to adopt standard components and interfaces, to make the long-held dream of multivendor, interoperable telco network gear a reality.

The optical space is ripe for change in backhaul and data centers. The optical transport network is one of the areas where telcos are moving most rapidly towards software-defined networking (SDN), which is a major spur to migrate from proprietary equipment to off-the-shelf boxes.

This not just about cost, but about keeping up the rate of evolution in important technologies such as DWDM, which enabled a step increase in fiber network capacity when it was first commercialized.

In a blog post in November, three Facebook engineers, Ilya Lyubomirsky, Brian Taylor and Hans-Juergen Schmidtke, wrote: “The pace of innovation has slowed over the past 10 years as we approach the limits of spectral efficiency”. They argue in the post that an open approach drives greater efficiencies into DWDM transport. “By unbundling the hardware and software in existing ‘black box’ systems, which include transponders, filters, line systems, and control and management software, we can advance each component independently and deliver even more bandwidth with greater cost efficiency,” they wrote.

So, Voyager is actually similar to many other small form-factor WDM units available in the competitive metro area fiber market. It is an open one-rack unit DWDM device with eight 100Gbps quad small form-factor clients and four 200Gbps 16QAM on the line side. It can support longhaul transport and metro area data center links. Now, it will have to live up to its promises of low costs to make an impact, beyond Facebook’s own deployments, and to drive adoption of the open platform. Support from multiple operators is a good start on that road.

Facebook’s overall goal is to encourage the rapid expansion of high speed internet to every corner of the globe, carrying its services with it. This requires, the company argues – as does Google – that the open, highly efficient  and easily deployable platforms which have revolutionized the cloud data center market, and enabled the webscale firms to reach such massive scale, need to be replicated in telco networks.

“Telia Carrier is committed to innovation, and being a flexible option for content and service providers looking to meet the demands of today and tomorrow,” said Mattias Fridström, chief evangelist at Telia Carrier. “Telia Carrier is a long time partner of Facebook, having built and managed the multi-terabit optical network connecting their data center in Sweden to multiple exchange points throughout Europe. Like TIP and Facebook, we stand for openness and transparency for everyone looking to connect to the wider world around them.”

The TIP approach decouples hardware and software to commoditize the former, creating low power, easily deployable boxes on which network functions are virtualized and fully programmable. “The emergence of packet switching/routing white boxes like Voyager opens up the potential for more open, more programmable, and more cost-disruptive network architectures,” said JC Fahmy, VP of product management and business development for Coriant data center solutions. “We are excited to be teaming with TIP to extend our LightIP networking software to Voyager.”

Orange is also working with Facebook to evaluate Voyager under the auspices of the TIP Open Optical Packet Transport project group community. Orange will define the use case over its production optical transport network and share the trial results with the TIP community as soon as possible.

Meanwhile, Facebook’s efforts to get fast Internet access to every person are getting increasingly serious, diverse and expensive. Last week, it announced a project with Nokia’s Bell Labs R&D arm, which has broken the spectral efficiency record for a submarine cable. The field trial used a new optical digital signal processing (DSP) technology developed in Bell Labs, called probabilistic constellation shaping (PCS), over a cable between Ireland and New York, a distance of 5,500 kilometers. This boosted the stated capacity of the system by almost 2.5 times, said the partners.
This may seem tangential to Facebook’s usual network activities, but there is a strong common thread. It is all about scaling up telecoms infrastructure to address massive coverage and bandwidth demands, cost-effectively. For subsea cable backbone routes, it is clearly cheaper to enhance the efficiency of existing cables than to lay new fiber.

This is the aim of the Bell Labs technology. The PCS technique which it implements uses ‘shaped’ QAM formats to adjust transmission capacity flexibly to close to the physical limits of a given optical fiber link. Facebook was interested in this lab-based technology and so initiated and supported the trial to see whether PCS would be effective on long submarine routes. The spectral efficiency achieved was based on 64QAM digital non-linearity compensation and low-linewidth lasers. The result was a record spectral efficiency of 7.46bps/Hz, which means there is potential to upgrade the cable to 32Tbps per fiber in future.

“Facebook wants to increase the pace of innovation and adoption of next generation optical technologies,” said Stephen Grubb, global optical network architect at Facebook. “This field trial with Nokia demonstrates that the scalable optical technology of PCS together with narrow linewidth laser sources can achieve capacities extremely close to the Shannon limit. This ensures that we are both maximizing our investment in submarine cable systems, as well as continuing to drive the cost per bit of submarine transport lower.”