UK What GPON and XGS-PON are
XGS-PON is the 10 Gbps symmetrical successor to GPON, and both are passive optical network (PON) standards from the ITU-T. A PON carries broadband from the operator’s exchange to many homes and businesses over one shared fibre, split by unpowered optical splitters along the way. Nothing between the exchange and the premises needs electricity, which keeps the street network simple and reliable.
GPON (Gigabit PON, ITU-T G.984) shares about 2.5 Gbps downstream and 1.25 Gbps upstream between every premises on a fibre. XGS-PON (10 Gigabit Symmetrical PON, ITU-T G.9807.1) shares about 10 Gbps in each direction. The XGS stands for 10 Gigabit Symmetrical, which separates it from the earlier XG-PON, which ran 10 Gbps down but only 2.5 Gbps up.
For the customer, the difference shows up as the tiers on offer. GPON comfortably carries 1 Gbps services. XGS-PON is what makes 2, 5 and 8 Gbps tiers, and fast uploads, practical.
How a passive optical network works
Every PON has the same three parts, whichever standard it runs.
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OLT at the exchange. The optical line terminal sends downstream traffic to every premises on the fibre and schedules when each one may send upstream.
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Splitters in the street. Passive splitters divide one fibre into 32 or 64 branches, sometimes in two stages. All branches receive the same downstream light; encryption keeps each premises’ data private.
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ONT at the premises. The optical network terminal turns light into Ethernet. Each ONT reads only its own traffic and transmits upstream in its allotted time slots.
GPON vs XGS-PON compared
Both standards use single-mode fibre and reach around 20 km from the OLT. The main differences are speed, wavelength and how many premises one port can serve.
| Feature | GPON | XGS-PON |
|---|---|---|
| ITU-T standard | G.984 (first published 2003) | G.9807.1 (2016) |
| Downstream | 2.488 Gbps | 9.953 Gbps |
| Upstream | 1.244 Gbps | 9.953 Gbps |
| Downstream wavelength | 1490 nm | 1577 nm |
| Upstream wavelength | 1310 nm | 1270 nm |
| Typical split | 1:32 or 1:64 | 1:32 to 1:128 |
| Typical service tiers | Up to about 1 Gbps | 1 to 8 Gbps, often symmetrical |
Because the capacity is shared, the speed any one customer sees depends on how many others are active and how the operator has planned the network. Ten gigabits split 64 ways still averages over 150 Mbps per premises at full load, and most users are rarely all busy at once.
Why operators are moving to XGS-PON
GPON still works well for gigabit broadband, so the move to XGS-PON is driven by what customers and services now ask of the network.
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Multi-gig tiers. A 2 Gbps or faster service cannot be sold on a network whose whole fibre carries 2.5 Gbps. XGS-PON leaves room for several multi-gig customers on one port.
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Upload speed. Video calls, cloud backup, CCTV upload and remote working all push traffic upstream. GPON’s 1.25 Gbps shared upstream fills quickly; XGS-PON’s 10 Gbps does not.
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Business and mobile backhaul. Symmetrical capacity lets the same fibre carry business lines, small cell and 5G backhaul and public Wi-Fi alongside homes, which helps the business case for each route.
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Fewer ports per premises. With more capacity per fibre, operators can use larger splits such as 1:64 or 1:128, so one OLT port serves more customers.
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Mature equipment. XGS-PON optics, line cards and ONTs are now made in high volume by many vendors, so operators can choose from proven equipment rather than first-generation kit.
Running GPON and XGS-PON on the same fibre
Because the two standards use different wavelengths, they can share one fibre and one set of splitters. An operator upgrades by adding XGS-PON line cards, or combo optics that carry both standards, at the exchange, then swaps the ONT only at premises that order a faster tier. Customers who stay on GPON see no change. This is why most full-fibre operators can launch multi-gig tiers without digging new routes. Our FTTP FAQ explains the full-fibre network these standards run on, and our single-mode vs multimode fibre FAQ covers the fibre type PONs use.
Verifying multi-gig services at the network edge
Operators selling XGS-PON tiers have to prove them. A test point with a Gigabit port can never show more than about 940 Mbps, so verification hardware near the customer needs 2.5GbE or 10GbE ports and enough processing to run sustained throughput tests. It also has to survive street cabinets and exchange rooms, often without fans or on-site staff. Remote management matters as much as speed: a test point that can be rebooted, updated and scheduled from the network operations centre saves a truck roll every time something needs checking, and it can run tests at peak times when congestion on a shared PON is most likely to show.
Our fibre verification case study shows a fanless industrial mini PC with 2.5GbE measuring 2 Gbps services from the cabinet and reporting back remotely.
Quick answers on XGS-PON
GPON and XGS-PON: common questions
What is XGS-PON?
A 10 Gbps symmetrical fibre broadband standard. ITU-T G.9807.1 shares about 10 Gbps up and down between the premises on one fibre, and runs alongside GPON.
Is XGS-PON better than GPON?
Faster, yes. It has four times GPON’s downstream and eight times its upstream capacity. GPON is still fine for 1 Gbps services, which is why operators run both.
How fast is XGS-PON for one customer?
Up to the tier sold, often 2 to 8 Gbps. The 10 Gbps is shared, so operators size tiers and splits to keep peak-time speeds close to the advertised figure.
Do I need a new ONT for XGS-PON?
Yes. A GPON ONT cannot receive the XGS-PON wavelengths, so the operator fits an XGS-PON ONT when a customer moves to a faster tier.
What comes after XGS-PON?
25GS-PON and 50G-PON. 50G-PON is standardised by the ITU-T as G.9804, and both use further wavelengths so they can share the same fibre again.
We supply industrial computers with multi-gig ports set up as standard for remote test, monitoring and edge roles in operator networks. Send us your service tiers and cabinet conditions, and we will specify a system to match.