When listening to the arguments brandished against 25G PON, one could get the impression they accidentally ended up in the 1986 movie Highlander. In that movie, immortal warriors battle each other through the ages, until only one is left – leading to the movie’s tagline “there can be only one.”
Similarly, 25G passive optical network (PON) opponents make the argument that there’s only room for one technology and that it should be 50GPON.
This line of thinking is fundamentally flawed because it misses two key points.
No two operators are the same
First, different operators have different requirements. Everyone is deploying fiber – telcos, municipalities, alt nets, cable operators, governments, neutral hosts– butthey face different competitive environments, different business cases and different legacies.
For one operator, being able to disrupt the market today with a 20G service might be the key to success or being able to address 10G enterprise connectivity. For another, longer-term evolution to 50G or 100G might be the right strategy.
The key is that operators need to be able to choose the right tool for the job – whatever meets their requirements and their business case. It’s the role of the vendor community to provide those operators with a toolbox of technology options, not to enforce a single option on everyone.
The business-case matters
Second, it’s all about the business case. The technology industry enjoys pushing the boundaries of physics and solving complex technical challenges. But most of the time, “simple and cost-effective” tends to win. 25G PON is basically 10G technology running 2.5x faster. That seems obvious, but it means that operators can implement 25G on 10G chips and products.
If operators deploy 10G today with XGS-PON, chances are that their equipment is already 25G PON ready, and they can just activate it. Today. That’s an incredibly easy evolution path. 50G PON will offer more bandwidth but will require new equipment, and it’s going to be a few years before it’s available for largescale deployments.
Does that mean 50G isn’t going to happen? Of course not: 50G will absolutely be part of the PON evolution. But 25G is a simple and cost-efficient step, enabling operators to address today’s opportunities.
It allows operators to embrace the “Fiber for Everything” concept – where the residential PON/fiber to the home (FTTH) network can be used not just to connect homes but to connect businesses, university/hospital campuses, Industry 4.0 infrastructure, Smart Cities and anything else. It also allows operators to differentiate with multi-gig residential offers.
Making a long-term investment
Whatever evolution path is chosen, rest assured that the investment in the outside plant is safe.
New PON technologies like 25G PON are designed to coexist with existing technologies (GPON, 10G XGS-PON) and with future technologies like 50GPON. 25G also has the same optical budget as GPON and XGS-PON – this means operators don’t have to change the outside plant at all: split factors and loop lengths can all remain as they are.
In the end, this is the whole point of PON evolution: to make sure can operators smoothly evolve their network by running multiple generations of PON technology on the same fiber at the same time.
When introducing 25G, one can keep existing subscribers on GPON or XGS-PON – no forced migrations, no lost investments and no unnecessary OPEX. So if you add 25G PON today, you can also add 50G PON tomorrow. There are no hard decisions to be made; no need to choose only one.
The good news is that the need for 10G(+) capacity is already here: business services, mobile backhaul, high-density Gigabit residential and wholesale, to name a few. With 25G, 50G, 100G and beyond, operators can rest assured that their PON network and investment will be able to meet any demand and will survive –just like the Highlander– for generations to come.
