Nokia, Huawei, and Ciena continue to dominate the carrier optical networking space though their positions at the top have changed.

According to a recent IHS Markit survey and report of 28 service providers – and with excerpts provided by Ciena – Nokia and Huawei were cited as being part of network deployments by 39 percent of respondents, each. Ciena was connected with 32 percent of deployments.

Those numbers were slightly different from a survey conducted in late 2016, which put Ciena on top. Other vendors noted in the latest survey included Infinera, Coriant, Fujitsu, ADVA Optical, and Cisco.

While it may have slipped in total deployments, Ciena remained the top vote getter in terms of its position in the space. Sixty-eight percent of those surveyed said Ciena was one of the market’s top three vendors, followed by 46 percent for Huawei, and 39 percent for Nokia.

However, the future does not look as bright for Huawei. The IHS survey found only 11 percent of respondents said they had the vendor’s products “under evaluation,” which was well below the 25 percent recorded for Nokia, Ciena, and Infinera.

“For Ciena and Nokia, this represents a good bump over 2016, where they were only under consideration by 14 percent of respondents,” explained Heidi Adams, senior director of transport networks at IHS, in the report.

Digging into market specifics, Ciena was deemed the top data center interconnection (DCI) vendor by 39 percent of those surveyed. Cisco, Coriant, and Infinera each garnered 36 percent of the votes.

The IHS report predicts DCI will be a significant driver for the optical equipment market, surging from 19 percent of overall equipment sales at mid-2017 to nearly 30 percent by 2021. Last year Ciena reportedly swiped a DCI deal from rival ADVA Optical, which had an impact on ADVA’s operational results.

Ciena also topped the list of top transport software-defined networking (SDN) vendors, with 46 percent of those surveyed citing the company as a leader in the segment. Adams noted that while this market was still in its early days, Ciena’s continued integration of its Blue Planet software platform with its optical equipment products was driving differentiation in the market.

Cisco attracted the second most votes in terms of transport SDN leadership, followed by Nokia and Infinera.

Ciena topped the field in terms of reported equipment reliability, which was deemed the most important consideration in selecting a vendor by those surveyed. Thirty-seven percent of respondents said they perceived Ciena to have the highest reliability, compared with 30 percent for Infinera, and 16 percent for Fujitsu.

If something does go wrong, 21 percent of those surveyed said Nokia provided the best service and support, followed by Cisco with 19 percent, and Coriant with 18 percent.

Adams did note that “there is some correlation between these two factors as well; higher product quality and reliability should lead to fewer calls to the technical assistance center. It continues to be more important that issues don’t occur in the first place.”