Standards as an afterthought

Most of us involved in optical communications know the value of standards. A well-defined standard establishes a set of specifications that enables compatible approaches ...

by Stephen Hardy

Most of us involved in optical communications know the value of standards. A well-defined standard establishes a set of specifications that enables compatible approaches in support of a given requirement, streamlines R&D, and promotes interoperability. Generally, lower prices result.

So standards are seen as a good thing – unless you're in a hurry. A new standard often takes years to develop, which often isn't soon enough if you have a hot new technology you're racing to get to market. In that case, standards become more of an afterthought.

We're seeing this phenomenon in optical communications on several fronts. Take, for example, software-defined networks (SDN). It's true that the Open Networking Foundation has laid the groundwork for SDN in the data center based on OpenFlow. But the group is just getting started on figuring out how to apply SDN to the carrier environment. That hasn't stopped a variety of vendors from unveiling their own versions of SDN for service-provider networks, including SDN-based control of optical communications resources. SDN, of course, aims to create an open multivendor approach to service flexibility – which is rather difficult to achieve if there isn't a standard way to do that in the optical domain.

Meanwhile, several vendors are hot on the trail of 400-Gbps coherent technology, where there are even fewer standards in place than there are for SDN. But here, I don't think the lack of standards will prove harmful. The first generation of 100-Gbps development progressed just fine without standards. It wasn't until the second generation, built around coherent transponders, that standards – or, more precisely, implementation agreements from the Optical Internetworking Forum (OIF) – became a requirement. The same scenario will take place here. There will of course be standards for 400 Gigabit Ethernet (and there may not be a huge demand for coherent 400G until the IEEE finishes that work), but the OIF won't have to step in until developers require transponders once again.

A new set of specifications for Optical Transport Network (OTN) also will be necessary – but that probably won't hold up early adopters, either.

And speaking of early adopters, some carriers appear to have interest in 200 Gbps for metro/regional applications. Talk about a lack of standards. Here, the service provider would take advantage of the fact that some of the first 400G systems will use a pair of 200-Gbps subcarriers. If your requirements take you beyond 100G, but you don't need a full 400 Gbps, why not take the halfway step, these carriers figure. If there are no standards for 400G transmission, you're certainly on your own when using half of the technology's capabilities.

But, again, it shouldn't matter. One company likely will supply the systems at each end of the transmission, so interoperability won't be a requirement. As long as it works, it works.

In the case of SDN, it seems likely that standards of some sort – at least de facto standards – will be necessary before more than a handful of carriers adopt the technology. In the case of 400G and 200G, standards won't be the major hurdle. Need will be. If the need is great enough, standards can wait.

stephenh@pennwell.com

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