Broadband players agree that they want to get to 50G PON, the next-gen optical standard – they're just not yet sure how to get there.

Many telcos are still grappling with the early stages of 10G PON, also known as XGS PON, which can deliver multi-gigabit services.

But this stage in the cycle is also the time when they need to consider what comes next. Do they go straight to 50G PON, or do they migrate through 25G PON first? And if so, what are the decision points?

Kurt Rodgers, network strategy manager at New Zealand's Chorus, doesn't doubt the future demand for high capacity broadband.

He said that the average monthly consumption per customer at the broadband wholesaler had grown from 10GB a decade ago to 578GB today.

"Bandwidth growth is consistent. It is constantly growing," he said in a discussion at Light Reading's Next-Gen Broadband APAC 2022 forum.

Figure 1: The ability of huge fiber pipes to cope with volatile traffic patterns drives operators to continually upgrade.
(Source: the lightwriter/Alamy Stock Photo)

As well as that, the ability of huge fiber pipes to cope with volatile traffic patterns drives operators to upgrade continually.

Rodgers cited the example of the blockbuster game Fortnite. Because of New Zealand's time zone, updates typically land at 8 p.m. local time, generating a traffic spike 25% above the regular peak.

"These huge surges when events outside our control happen really bring home to the market that fiber and faster speeds are necessary," Rodgers said.

With 69% of customers connected to its GPON fiber and just under a quarter already on premium 1Gbit/s services, Chorus began pushing out 10G PON last year, offering 2Gbit/s to 8Gbit/s.

Proof-of-concept trial

Rodgers said the operator would begin a 25G PON proof-of-concept trial next month.

"It's the start of the process – we're not wedded to any particular direction yet."

Hong Kong Broadband CTO Danny Li had a similar view. 50G PON was the goal, but the challenge would be building the business case, he said.

If the cost of 25G or 50G cannot deliver lower unit costs and prices, then why go down that path, he asked. "This is always the dilemma about which way we go."

Notably, however, China Mobile and its major vendor Huawei are advocates of going straight to 50G PON.

Li Junwei of the China Mobile Research Institute said that the big operator is embracing XGS PON now to build end-to-end broadband networks and then expects to transition to 50G, which it believes will be the mainstream next-gen technology.

Huawei's Liu Dekun said that 50G PON would likely be available by 2025; until then 10G PON would be capable of meeting demand.

He said that with no Tier 1 operators embracing 25G, it lacked the volume cost advantage of 50G.

This was one of the reasons cited by Amirkhanian Prashanthan, a project engineer at Sri Lanka Telecom, for its plan to go directly to 50G PON.

Big players

Big players like Telefonica and China Mobile are backing 50G PON, and the cost of ownership is low, he believes.

"The 50G can co-exist with XGS on the ODN network without compromising anything," he added.

"My suggestion is to currently focus on GPON and XGS-PON and in the future 50G PON will be the only option."

Omdia chief analyst Julie Kunstler said that she saw several operators trial 25G PON, but very few were going to early commercial deployment.

The early adopters were focused on either offering 10Gbit/s or 15Gbit/s symmetrical services to businesses, or xhaul transport for mobile networks.

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A small number of these used 25G PON to exclusively provide business services, ignoring the residential market.

She added: "Every PON vendor that I know has 50G PON ready or in their roadmap. A few vendors who have 25G PON see an opportunity to sell it today."

Additionally, operator strategies in the access network have greatly diversified in recent years.

"It's a very different situation today from 15 to 20 years ago when PON was considered FTTB or FTTH. Now we're seeing operators with a wide variety of strategies on what they want out of their access network."

"Certainly we're seeing a lot of multi-gig bandwidth services being offered by a wide variety of operators around the world. The uptake in my opinion will happen as bandwidth demand continues to grow and as operators continue to push out those services," she said.

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— Robert Clark, contributing editor, special to Light Reading