Component and equipment vendors outlined the investments they are making in anticipation of some service providers adopting open line systems or fully dis-aggregated optical systems. This is a contentious technology trend in the industry; one which ignites opinions and whose conclusion is far from clear.

After silicon photonics, this was the area of the most interesting activity during OFC 2016. It is a complex trend requires equipment & component vendors to pivot both their hardware architectures and business models to address new potential opportunities. And it is far from clear whether this market will extend beyond the webco.

We review vendor activity and our observations of this market.

Technology Definitions

It is important to share what we feel are the formal definitions for two different use cases surrounding this concept:

Open line systems

Open line systems are the use of a single vendor’s common equipment (Amps, ROADMs, etc) mixed with line equipment from other vendors. This technique was first pioneered in undersea systems when existing cables and line equipment supplied by an integrated vendor were upgraded with new, faster line equipment from other vendors. For example, equipment from Ciena or Infinera would be connected to cables originally designed by Alcatel-Lucent or NEC intended to work only with their own equipment.

Some operators now use the same strategy with terrestrial networks – building or recycling a common equipment infrastructure and operating wavelengths from multiple optical line systems. These line systems are typically operated with existing, legacy network management systems – one running the common equipment and another the line systems.

Open line systems have been a quiet trend for several years now as equipment companies added the capability for their equipment to support wavelengths from other companies line systems – also known as ‘alien wavelengths’. Most major vendors are either supplying systems used in this way today, or have seen this as a requirement in customer requirements. The advent of LCOS based WSS ROADMs further enhanced this capability, allowing line systems to actively carve out optical spectrum, tune performance for different vendors using the same line, and even block or prevent interference from misbehaving optical sources.

Dis-aggregated optical systems (Optical Whitebox)

Dis-aggregated optical systems are open line systems but built with a heterogeneous mix of different vendors, linked via software defined networking. Open line systems have a single vendor supplying the common equipment and managing the optical layer. By contrast, dis-aggregated systems are built with individual components sourced from multiple vendors, all controlled by another 3rd party set of software. This is the same concept embraced by large webcos inside the data center – picking components best suited for compute, storage, and networking and then designing, integrating and managing the systems themselves.

Building fully dis-aggregated optical systems is a much larger challenge as operators must integrate hardware and software from a multitude of vendors and make it all work. There is no ‘one throat to choke’ and for most operators, we believe the complexity of this approach outweighs the benefits. While cost is sometimes a reason, the key reason some operators would embrace this complexity is because of the control and flexibility it gives them in constructing and operating their network.

Vendor Activity

ADVA

ADVA has supported open line systems for some time as its customers tend to be dark fiber providers or large enterprises building their own networks. ADVA’s latest success is providing the common equipment for Microsoft’s 80km DCI solution with Inphi. This solution requires special low-noise amplifiers that ADVA has designed. As other webco’s evaluate Inphi’s solution ADVA is well positioned to provide thsee amplifiers and other equipment required for the implementation of this complex technology. More importantly, the company can provide the integration expertise required to make this novel direct-detect solution work. Given the proposed scale of Microsoft’s deployment this should be a material business for ADVA.

While ADVA has not invested as heavily in the software side for control of dis-aggregated systems, the company has embraced open interfaces to its equipment allowing external control via SDN by supporting REST based interfaces such as NETCONF/YANG. It has also worked closely with a number of operators such as Telefonica to trial these solutions.

Fujitsu

Fujitsu Network Communications (USA based FNC) is leading the charge towards dis-aggregation with the introduction of its 1FINITY. This includes a transport system that looks much like other DCI systems, but expands the concept further with a broader set of functions including an L2 switch and GPON OLTs. AT&T is clearly the target customer since FNC has a long and strong relationship with them, and the hope is that other service providers (Cable companies are ripe targets) will adopt these same dis-aggregated transport architectures that previously were the domain of more exotic service providers. FNC pairs this hardware development with SDN control software developed in house.

Altogether, FNCs efforts to pursue optical dis-aggregation outstrip those of other vendors. In short they are all-in on this concept, and considering their roots as a staid provider of equipment to tier-1 vendors it is a rather radical departure.

Coriant

Coriant is also committed to the same model with its new Groove platform. The modular sled architecture provides the best pay-as-you-grow approach of all the DCI platforms. Each chassis has four small discrete slots that can contain coherent transponders. Later versions of this platform will incorporate new sleds; this includes amplifiers, 1×2 ROADMs, and other functions to address applications of opportunity. While all sleds are initially provided by Coriant, one can see a future where other vendors can design to the sled specifications. Like Fujitsu, Coriant’s ultimate goal is to supply both the lower margin hardware as well as the higher margin software interfacing and controlling these aggregated systems.

Others

Lumentum has a long history of supplying optical subsystems like ROADM blades and amplifiers, and is now applying this experience to dis-aggregated applications, announcing a ROADM subsystem just for this application at OFC.

Ciena continues to invest in the software side of dis-aggregated systems via Blue Planet (Cyan acquisition) though the company has not pursued the marketing of hardware as aggressively as Fujitsu and Coriant. One operator privately mentioned an unwillingness of Ciena to participate in this type of approach.

Summary

Two vendors privately expressed surprise that AT&T was pursuing a dis-aggregated optical strategy so aggressively, and felt the company would return to more traditional approaches after a not-so-positive conclusion of the current strategy. One vendor colorfully noted that AT&T was trying so hard to be ‘disruptive’ that ultimately they would be successful – by breaking their network. We’re not taking sides yet on whether this works out for AT&T – but its efforts certainly have provided tremendous leverage on the supply chain regardless of whether they are fully implemented or not.

These dis-aggregated hardware models suit the straightforward network designs of the webco world and are potentially well suited to the wildcat architectures of cable companies. It is not clear if more traditional service providers around the world will successfully embrace this model. So far, most of the activity by Telefonica, NTT, Deutsche Telekom and others is mostly experimental and not at the same level of commitment at AT&T.