Optical Line Interoperability Illusion

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Although Microsoft and others have been discussing the notion of an Open Line System (OLS) to provide standardization with long-haul and metro equipment, there is little precedent for such grand notions ever coming close to being real with any technologies in the past. Naturally, large service providers are always inclined to ask for everything under the sun, including compatibility between vendors to potentially reduce their operational costs. (In responding to an RFI or RFP from the three largest incumbent carriers in the US, if a supplier does not at least say it has a plan to accommodate absolutely every request, it will immediately be eliminated from consideration.). However, despite countless successful interoperability tests that have been performed over the years, optical vendors, especially the biggest ones, at the end of the day, usually have absolutely no desire to enable their competitors to succeed.

In fact, historically, it has been hard enough at times to get the same supplier’s hardware to work with its other gear that may be in a particular network, let alone with the offerings from a different company. So, fibeReality finds it hard to comprehend why there would be much optimism about present efforts being more than pipe dreams.

Clearly, certain smaller vendors, some of which could be in a distressed situation, may be legitimately advocating open transport with the hope that it will facilitate business for them. They will contend that it would substantially lower the cost per bit. Yet, with margins squeezed to such a high degree already, the major providers of gear will become even more adamant (perhaps only behind closed doors) to avoid OLS.

All in all, the larger suppliers have no incentive to become less differentiated, and despite any hype to the contrary, they have never been in a hurry to remove proprietary aspects of their solutions and become more interoperable with their competitors. The most extreme example happened with the SONET/SDH standards in which the system manufacturers were given so much latitude in constructing the message sets incorporated in the data communications channel that it even made mid-span meets a problem.

Carriers have surely been able to bookend distinct long-haul links by matching up DSPs on the transmit and receive sides, and while there has been 10G GFEC heterogeneity in the metro, we are unaware of any actual line side interoperability involving the OTN standard. In general, from the perspective of the operators, performance will always ultimately trump even mandatory interoperability imposed by them.

We do not find other arguments of proponents totally convincing, some of whom will state that the metro will become so intricate that the need for solutions to talk to each other will become even more acute. We also are not necessarily swayed by any assertions resulting from the recent European Court of Justice ruling, which invalidated “Safe Harbour,” and could lead to US-based companies being forced to store data in various countries on the continent – which could at least theoretically, result in implications for a greater amount of interoperability — as more colocation space gets leased. (Certainly, the expected build-out of a greater number of data centers in Europe is the first positive aberration for the optical industry in a long time after seemingly only negative anomalies, such as the rise in cyber-hacking, the US federal government’s takeover of the Internet, and the apparent movement by large enterprises to build fewer data centers.) Of course, it would be all based on the assumption that the European Union can remain intact, which appears to become less likely with each passing day.

[written by Mark Lutkowitz]



  1. Funny reading. I stumbled upon a recent White Paper from GEANT (Pan-European research network)and it seemed the pipe dream just happened (see p.31). Conclusion was: “The test result was better than expected. Configuration of the routers and DWDM was done in accordance with the procedure and without any obstacles. Even if the DWDM system had an OSNR value close to the limit of HG-FEC operation, there was no pre-FEC bit error and packet loss.”

  2. We have written since that time that OLS has actually been deployed in data center networks. We have also discussed our shock that large vendors are willing to sell piece-parts.

    The focus of this article was on public network operators. Please give me a holler back when Verizon, which probably has the most advanced optical capability of any incumbent service provider decides to move in this direction.

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