25G PON

Just found out that Openreach is testing out a newer PON system 25G PON that can operate along side GPON XG-PON. Most info so far I can find really is marketing info from Nokia.

Youtube: 25G PON is a game changer
Youtube: GB The future of fiber - 25G PON
https://www.techradar.com/uk/news/openreach-trials-n...
https://www.nokia.com/networks/solutions/25gpon/

There is an article on ispreview.co.uk with some pictures. They are running 1G, 10G and 25G simultaneously on the same fibre. The 25G ONT appears to be a 1U rackmount unit, so a long way from being a consumer product

In reply to a post by amiga_dude:

that can operate along side GPON XG-PON.

Isn't it the job of the existing wavelength division multiplexer (WDM) at the head end exchange that allows this to happen.

Not looked at the wavelengths of 25G PON but the wavelengths of GPON and XGS-PON are already complimentary, allowing simultaneous operation with nothing more than a passive FWDM to combine them.

Nokia and Vodafone announced in February that they were trialling 100G PON over a single wavelength here.

The ispreview article shows a screenshot of a spectrum analyzer, and you can see all three wavelengths.

Indeed. Looks like 25G will be a subset of the new 50G-PON standard currently in ratification with ITU.

See last months article on ISPreview and external article from IEEE last year on progress.

Looks like there’ll be plenty of upgrade scope in the old pipe for years to come 🤣

Looks like the ONT is actually a switch / router with SFP28 ports.

I wouldn't be surprised if the early ONTs are 25G at the front and 10G out the back much as early GPON ONTs were 2.5G on the optical side and 1G on the LAN.

My guess is that the early ONT's are being delivered as SFP28's so basically your only option is to stick it in a switch.

Though to be fair give the ~32 split that Openreach are using this could be used to deliver a lightly contended 1Gbps symmetric service. At which point a standard 1000Base-T connection would be more than adequate. Anything more than 10GBaseT or an SFP+ is over the top in any scenario.

I would note that your basic GPON is 2.5Gbps down 1.25Gbps up but next to nothing exposes more than a 1Gbps connection consumer side.

In reply to a post by candlerb:

The ispreview article shows a screenshot of a spectrum analyzer, and you can see all three wavelengths.

Makes sense now - the wavelength shown for 25G PON downstream @ 1358 nm is actually 25G-EPON (802.3ca) - so its from a completely different PON standard (family) to what is deployed here now in GPON and XGS-PON which are all ITU-T standard rather than IEEE 802.3ca EPON standard.

There are basically two global competing PON standards families for folks that are unaware; the ITU-T G.984/G.9807 standards and the IEEE EPON (802.3ca) standards. The next generation of ITU-T based PON standard is 50G-PON.

I guess we'll be reading about that marketing exercise in 6 months time once the 50G-PON ITU-T PON standard is ratified and Nokia want to test some silicon for it....