Having decided to pull out of the GPON market, Nokia Siemens Networks (NSN) is now taking very public pot shots at the passive optical access technology, claiming that it's uneconomic to deploy and will be redundant by the time residential fiber access is widely deployed.

Outlining the company's fixed broadband access strategy in Brussels this week, NSN's chief technical officer Stephan Scholz told journalists and analysts that VDSL2 technology is mature enough to rival GPON in terms of bandwidth capabilities, and that GPON will be an outdated technology by the time fiber-to-the-home (FTTH) becomes a mass market in four or five years' time.

By that time, carriers will be able to migrate straight to next-generation PON technology, namely wavelength division multiplexing-passive optical network (WDM-PON), making GPON redundant, believes NSN.

That's why NSN is focusing on developing what it calls next-generation optical access (NGOA) technology, and has ditched its previous GPON approach. "We don't believe we would have been able to get our investments back on GPON because we see there is a delay in GPON rollout... The current turmoil in the financial markets could further delay GPON," stated Scholz.

Instead, NSN says "technology tricks" enable VDSL2 to deliver downstream bandwidth of up to 100 Mbit/s over 1 kilometer, which, believes NSN, is more than enough bandwidth to cope with any service mix likely to be offered in the near future.

When asked about the "tricks," Scholz said that didn't mean NSN was looking to introduce proprietary enhancements to VDSL2. Instead, he said NSN is working with chip vendors to introduce ways to reduce crosstalk on copper access lines, using technology such as dynamic spectrum management (DSM).

Scholz also claimed, using statistics gleaned from a recent report published by the Broadband Stakeholder Group (BSG) in the U.K., that deploying a fiber-to-the-curb/VDSL2 access network in Europe costs, on average about 20 percent of a GPON deployment covering the same market, while point-to-point active Ethernet access costs even more to deploy than GPON. (See Report: UK FTTH Would Cost $50B.)

However, the BSG's report was focused on potential U.K. costs, and while NSN is happy to use that as representative of any European market, an analyst who contributed work to the BSG report told Light Reading he was uncomfortable with the way the report's findings had been used in NSN's presentation.

So is NSN's position credible?

Well, it's "not ridiculous," says Heavy Reading chief analyst Graham Finnie. "GPON has made little progress outside the U.S., even though it is supposed to be a global technology. EPON has dominated in Asia/Pacific, and in Europe much of the fiber access is point-to-point."
 
Adds Finnie, "some European incumbents have committed to GPON, but it's going slowly, and it's possible that in a few years the industry might move on to another technology."

However, ongoing GPON developments have to be considered, especially 10-Gig GPON, notes Finnie. If that development becomes viable then "that will get GPON through a few more years." 

Overall, NSN "has a point, but there is a strong argument to say that GPON will be widely deployed globally, including in Europe, the Middle East, and in emerging markets, particularly China, which will be the big one," adds the analyst.

Finnie also questions NSN's claims that VDSL2 is capable of 100 Mbit/s downstream in commercial deployments. "There is no evidence that VDSL2 can achieve that sort of bandwidth," says the Heavy Reading man.

Not surprisingly, the GPON camp is dismissive of NSN's claims. "There are so many ways in which they [NSN] are wrong," says Marcus Weldon, CTO of Alcatel-Lucent (NYSE: ALU - message board)'s Fixed Access Division.

"Carriers need to find the services to justify the investment in GPON, sure, but Verizon Communications Inc. (NYSE: VZ - message board) has found this with its triple-play offer, with quite straightforward video services," continues Weldon. "And GPON always makes sense in greenfield deployments -- even the MSOs agree on that," he adds.

Source:lightreading