Next-generation PON is Here

At some point during the last year, practically every ISP I know that uses PON technology has quietly upgraded to next-generation PON. For now, that mostly means XGS-PON, which can deliver 10 gigabits of bandwidth to a neighborhood. We’re on the verge of seeing even faster PON cards that will be able to deliver 40 gigabits and probably beyond to 100 gigabits.

This is a big upgrade over GPON which delivers 2.5 Gbps download speed to a neighborhood node. In recent years ISPs have been able to use GPON technology to sell reliable gigabit speeds to homes or businesses that share the network in a neighborhood.

We saw a similar upgrade a dozen years ago when the industry upgraded from BPON, which delivered 622 Mbps to a neighborhood – the upgrade to GPON was a 4-fold increase in available bandwidth. Upgrading to XGS-PON is another 4-fold increase. 40-gigabit PON will be another 4-fold increase.

The best thing about the current upgrade to faster PON is that the vendors got smarter this time. I still have clients who were angry that the upgrade from BPON to GPON meant a total replacement of all electronics – even though the vendors had declared that there would be an easy upgrade path from BPON. Many ISPs decided to change vendors for the upgrade to GPON, and I think vendors got the message.

The PON architecture for most vendors allows upgrading some customers to XGS-PON by adding a faster card to an existing GPON platform. This smart kind of upgrade means that ISPs don’t need to make a flash-cut to faster PON but can move customers one at a time or neighborhood by neighborhood. Upgrades to even faster generations of PON are supposed to work in the same way.

The impact of going to GPON was the widespread introduction of gigabit-speed broadband. A decade ago, gigabit broadband was declared by cable companies to be a gimmick – likely because they couldn’t touch gigabit speeds that fast at the time. But now, all large cable companies are successfully selling gigabit products. According to the latest report from OpenVault, a quarter of homes now subscribe to gigabit or faster broadband products and almost 20% of homes regularly use more than a terabyte of data in a month.

We’ve already seen changes in the market due to next-generation PON. I know a number of ISPs that are now selling 2 Gbps and 5 Gbps broadband products using the new technology. A few are now offering 10 Gbps connections.

One of the biggest decisions faced by an ISP is how many customers to load onto a single PON card at the chassis. GPON allowed for putting up to 128 customers on a PON card, but most ISPs I know only loaded 32 customers. While this was a conservative decision, it meant there was a lot of safety so that customers almost always get the bandwidth they subscribe to.

It’s possible to load a lot more customers onto an XGS-PON card. Most of my clients are still configuring with 32 customers per card, although I’m now seeing a few ISP load 48 or 64 customers per card. There is enough bandwidth on a 10-gigabit card to give everybody a gigabit product, even with a higher customer counts, except perhaps in business districts where there might be some customers using a lot of bandwidth all of the time. The main consideration for loading extra customers on a card is the consequence of a bad card knocking out a greater number of customers.

While you never hear them talking about it, the widespread introduction of XGS-PON is one of the driving factors behind cable companies scrambling to upgrade to faster bandwidth. While the cable companies initially scoffed at gigabit speeds on GPON, I think they’ve learned that claims of faster speeds by fiber ISPs have convinced the public that fiber is superior, even when a cable company can match fiber speeds.

The race for faster technologies is clearly on. Many industry skeptics still scoff that people don’t need faster speeds – but ISPs have learned that people will buy it. That’s a fact that is hard to argue with.