In reply to a post by ultraproblems:

Hi I agree with your comment, policing it at present is a bit of a nightmare, the ISPs are very shy at revealing the configuration and usage of the PON circuits the fibre circuit providers also have this problem.
What else do purchase that you don’t know what you are getting.

On my TT contract it states what product I have, and what is the minimum acceptable speed, does your contract state that?

Splitters are passive devices hence the name PON, fibre especially single mode 9/125 has very little skew, it’s principle down to launch power, I don’t know if the splitters have any monitoring like some of the old sugar cubes.

Synchronous systems recover the clock to synchronise local system either dedicated space in headers or combined with the data, as opposed to the old asynchronous system which had start indicator and hope for the best, it usually worked I.e. UART chips etc.

Your upstream data is controlled by the BWMap and TDM (Time Domain Multiplex) the time window is 125 microseconds how many of these you get in a second must be down to the number of customers.

In reply to a post by Iniltous:

a GPON splitter with a few customers on it is less likely to ‘congested’ than a XGSPON splitter that has dozens more customers …

Thanks, as always the complexity is in the detail.

I'm a bit confused as to the difference between an optical gpon spliter and a xgs-pon splitter?

There isn’t really a difference between a splitter on a GPON system and a splitter on an XGSPON system, in fact GPON/XGSPON can coexist on the same fibre/splitter network…but XGSPON has the option to go upto a 256 to 1 split , and has an operating range ( distance ) of around 100km, compared to GPON max split of 128 (typically 32/1 is used ) and around 60km….this in essence allows a single fibre to reach further from the headend and have more users hanging of it , OR use 1/32 split so around a quarter of a GPON theoretical capacity, AFAIK , XGSPON operators don’t publish their split ratio but it’s possible they have many more users per PON as well as the PON covering a much larger geographic area, so less headend kit , and although the faster 10g speeds and symmetrical service are undoubtedly beneficial to customers , it also makes it cheaper for the network provider, more customers per ‘PON’ , ( possibly 64 , 128 users or whatever ) , so although the total bandwidth 10Gb is 4 times that of a GPON you may be ‘sharing’ with many more users.

XGSPON somewhat counterintuitively while offering longer range is also more power efficient so more customers and cheaper to run , XGSPON benefits the network operator as much as the customers benefiting from faster symmetrical speeds.

Edited by Iniltous (Sat 14-Jun-25 22:55:39)

In reply to a post by ultraproblems:

Hi I agree with your comment, policing it at present is a bit of a nightmare, the ISPs are very shy at revealing the configuration and usage of the PON circuits the fibre circuit providers also have this problem.
What else do purchase that you don’t know what you are getting.

Every service tells you the guaranteed rate when you sign up. There is no mis-selling occurring.

If you have requirements around contention and are put off by a shared access network then uncontended products are available.

Going back to your original post, if you are only getting 500Mbps up on a 1Gbps symmetric service then you'd be better served by posting a new thread asking for help with a fault than getting into the weeds on PON contention.

Edited by jpm (Sat 14-Jun-25 22:54:24)

I was tempted to write a diatribe, but to be fair been sitting here with the metaphorical popcorn reading all the replies to get the OP on the page so to speak has been far more entertaining.

This thread is like a collective “expectation reset” for the OP. I did wonder if the OP was some random AI / bot but they appear to be genuinely human.

Anyway I’ve polished off the remains of the vermentino (Cotes du Brian, 2020 from Domaine Anne Gros & Jean-Paul Tollot - very good btw) and look forward to the next update…

Crack on crew 😂 🍿

In reply to a post by Iniltous:

There isn’t really a difference between a splitter on a GPON system and a splitter on an XGSPON system, in fact GPON/XGSPON can coexist on the same fibre/splitter network…but XGSPON has the option to go upto a 256 to 1 split , and has an operating range ( distance ) of around 100km, compared to GPON max split of 128 (typically 32/1 is used ) and around 60km…speeds.

For Openreach there isn't a xgs or 25g pon or gpon splitter. As you correctly said, XGSpon can do 256 way compared to 128 for gpon. You can of course add a splitter further back up the path, so that you can split it into 2 or 4 (64 or 128) but of course you reduce the length that light will travel.

That aside, I dobut many would 64 or 128 user splits on gpon. City fibre is going from gpon to xgs pon, so i suspect the contention will stay the same