With GPON set to become the dominant fibre-to-the-premises (FTTP) architecture by 2016, network operators are starting to show some concern over equipment interoperability.

According to an industry survey carried out by Informa Telecoms & Media on behalf of the Broadband Forum, interoperability is second only to price in terms of operators' ONU (optical network unit) selection criteria.

"Interoperability seems to be a major problem," Rob Gallagher, principal analyst at Informa told a press conference at Broadband World Forum in Amsterdam on Tuesday. He explained that the lack of interoperability is in some cases compelling operators to use the same vendor for their ONU and optical line terminal (OLT) equipment.

Using equipment from different vendors has increased the internal testing burden for 53.1% of the 64 operators that took part in the survey, while 43.8% reported having concerns over network performance issues and 40.6% feared greater management overheads.

Informa also conducted face-to-face interviews on the subject with four operators and four vendors, Gallagher said. "Orange thinks [interoperability] can lower capex," he said, while Chunghwa Telecom "really wants to avoid [vendor] lock-in."

Interestingly, there was also vendor support for greater interoperability, despite the fact that to a certain extent "it implies commoditisation," Gallagher said.

Huawei said it will speed up deployment time, Alcatel-Lucent believes it will engender greater confidence in GPON in general, while Calix said interoperability will help it to expand out of its core North American market into new areas.

The findings of the survey back up the Broadband Forum's BBF.247 certification programme and TR-255 ONU/OLT interoperability text plan, noted Robin Mersh, Broadband Forum CEO.

To date 10 companies have publicly announced products that are BBF.247 certified, the most recent being Genexis, Mersh said. "The list is getting longer all the time."