if theres a FTTC cabinet in 99.9% of cases theres an aggregation point, that goes to a headend exchange. In some cases where properties where directly connected to exchanges OR did put FTTC cabs there but these are likely to have their aggregation point inside the exchange.

OR pons are up to 30 premiss per pon with 2 spare connections.

Thank you. Having read further I understand you to be saying that there is invariably an aggregation node in the vicinity of a FTTC DSLAM cabinet. Except perhaps in the small percentage of cases where a cabinet was built to provide better internet on EO lines (cables running all the way back to the exchange without passing through any jointing cabinet (PCP)).

So I assume that in a rural area with FTTC the decision to deploy FTTP will be strongly influenced by the cost of getting the fibres into the premises locally, rather than the distance from the headend.

For interest, I understand that a fibre would go from the aggregation node to a splitter node and individual fibres from there to the distribution points and premises.

The data from the aggregation node to the splitter would be formatted for a PON (passive optical network). I presume that other fibres from the aggregation node to the DSLAM would be formatted differently - ATM? Ethernet? (how many fibres are there per card or port?).

And I presume that all these different types of data (PON, Ethernet, others?) are merged by the aggregator into yet another format providing security of transmission to the headend where they are all unpacked and forwarded on to the corresponding upstream functions.

Is this all generally correct?

In reply to a post by Thinker27:

Thank you. Having read further I understand you to be saying that there is invariably an aggregation node in the vicinity of a FTTC DSLAM cabinet.

No, not necessarily. The FTTC cabinet is invariably linked back to a fibre aggregation node, but that node might be some distance away.

There has been talk of deploying subtended headends (mini OLTs) inside FTTC cabinets, exactly for the case where the FTTC cabinet has a spare fibre strand back to the FAN, but it would be prohibitively expensive to bring a new cable for FTTP.

That's unusual though. In many cases, when an FTTC cabinet was deployed a FAN was deployed close by at the same time. (If you see a large footway box with three covers, that's quite a good indication).

EDIT: you should also be aware that the FTTP network doesn't necessarily have the same topology as the copper network, since the FTTP connections are headed towards the head-end exchange, whereas the copper network is headed towards the local exchange.

In reply to a post by Thinker27:

Except perhaps in the small percentage of cases where a cabinet was built to provide better internet on EO lines (cables running all the way back to the exchange without passing through any jointing cabinet (PCP)).

If an infill cabinet is added to serve those users, then those lines are no longer EO lines, by definition.

In reply to a post by Thinker27:

So I assume that in a rural area with FTTC the decision to deploy FTTP will be strongly influenced by the cost of getting the fibres into the premises locally, rather than the distance from the headend.

There are lots of things that influence the cost. The OP talked about a cluster of 20 buildings; if so, those could be attractive to connect, since the cost of bringing the fibre to the cluster is divided by 20 for the per-property cost. But that assumes that sticking a single splitter node in a single location will serve them all, and they all have either good underground ducts or are served overhead. If they are geographically dispersed rather than a tight cluster that might not work.

In reply to a post by Thinker27:

For interest, I understand that a fibre would go from the aggregation node to a splitter node and individual fibres from there to the distribution points and premises.

That's correct (for FTTP). Splitter nodes are usually underground.

In reply to a post by Thinker27:

The data from the aggregation node to the splitter would be formatted for a PON (passive optical network). I presume that other fibres from the aggregation node to the DSLAM would be formatted differently - ATM? Ethernet? (how many fibres are there per card or port?).

Have you now changed to talking about FTTC? For FTTC, I'm unclear about the details of exactly how the backhaul from DSLAMs to exchange works (e.g. ethernet or PON), but I don't think it really makes much difference.

For FTTP, the network is completely passive. Each splitter has one dedicated fibre which is spliced all the way back to the head-end exchange where it plugs into its own port on the OLT.

GPON uses two different wavelengths (lambdas), one for receive and one for transmit, and these pass directly through to all the ONTs on that PON. The infrastructure in between doesn't care about framing. Indeed, multiple types of PON can run over the same fibre, on different lambdas (e.g. GPON and XGS-PON).

In reply to a post by Thinker27:

And I presume that all these different types of data (PON, Ethernet, others?) are merged by the aggregator into yet another format providing security of transmission to the headend

No. The fibre aggregation node is completely passive. It's just a place where distribution fibres are spliced into spine fibres; the spine is a thick cable with hundreds of fibre strands going back to the head-end exchange.

Edited by candlerb (Tue 15-Oct-24 12:56:25)

Wow. Thank you to everyone who’s replied so far, I wasn’t expecting quite as much feedback and guidance.

To call out a few:
candlerb - you’ve really helped a lot of this click for me. thank you so much for your answers and explinations.

tdw42
Thank you for pointing out that the A in ADSL wasn’t analogue [FacePalm] !!

Many of my questions were skewed by my expectation that analogue switch off would also turn of ADSL and that needed a replacement IP based solution.

Whilst I asked my questions with reference to analogue and talked about cell signal. It’s actually the robustness and performance of internet links that I’m most keen to understand the future for.

My take away so far is that OR are working to get 96% of homes able to order FTTP by 2027.
So there is actually a better chance than I thought that FTTP might be available in the not too distant future.

The ability to order will be dictated by how far/difficult the last mile is.
the D-Side copper could be sticking around for years to come in very rural areas and will be dictated by how expensive those D-side links are to replace.

I’m still not entirely clear on this exchange vs a head exchange.

The Turville Health (THTV) exchange that the cabinet sits below, isn’t yet on the upgrade plans but presumably will be 2027.
I think this may be a fairly small (number of premises served) exchange.

Does it seem possible/likely that this could be replaced as part of the FTTP roll out?
perhaps OR could cable the FTTC cabs back to a larger close-by exchange instead of upgrading THTV to be FTTP ready?

My Wife was keen to walk away from the property and I was rather included to agree.
(We don’t expect FTTP day 1 in a country village but in the next 5 years would be desirable)

In terms of peoples best guesses, is there anything about the following setup that would be a red flag to upgrading to FTTP?

In terms of geographic layout of the potential house to cabinet ..
It’s a pretty short run. 50 to 75m meter and ducted into the property (I’m not sure where from - cab or nearest pole?))
Two houses closer to the cabinet are on over head cables.

Given the cabinet has been upgraded to FTTC and the house gets very good speed to the premises does this mean that a FTTC cabinet can be upgraded to be FTTP after exchange is upgraded fairly easily and without too much expense to OR?

my fear was that with under 50 houses on the cabinet they might leave it as a FTTC cab with copper last mile indefinitely and this is what scares us off the property.

(Cell coverage is bad as it’s in a valley)
4G on EE is possible at the property by only gets 1 bar outside so it’s not a suitable backup.
three shows on their map has having signal but it’s very patchy 1 bar at best.
I will be buying and testing an LTE booster with roof mounted antenna but I can’t rely upon this for work from home - hence wanting to understand peoples expectations on FTTP at a location like this.

thank you again for all of the insight and suggestions and guidance.

In reply to a post by kommando:

So by 2027 4% of homes will still have no access to FTTP.

No by 2028 (Openreach are talking about the 31st of December 2027 in there roadmap) 4% of homes won't have access to Openreach based FTTP. A significant proportion of the remainder will have access to FTTP from another provider.

In reply to a post by tonyj2:

I’m still not entirely clear on this exchange vs a head exchange.

Because fibre optic links can be very long without degradation not all exchanges will be needed in the future. Typically on the 1:32 split ratio that Openreach uses, you can reach out 20km from the exchange to the premises. Consequently, only a fraction of the exchanges have FTTP equipment installed. These are called headend exchanges. From memory, it's about 1500 out of the 5600 that Openreach has. Note that the FTTC cabinets are fed from the headend exchanges so once the analogue switch off occurs (assuming there is no one on ADSL) Openreach will be looking to close those ~4000 exchanges.

I had the notion that along side the analogue switch off, people on ADSL that had a VDSL option were going to be forced to migrate to VDSL. Basically you can only keep an ADSL connection if that is your only option. Even then I am sure I have seen talk of putting ADSL cards in the cabinets for people not on a headend exchange.

Basically Openreach really want to be shot the non headend exchanges as they sold them all off and leased them back and thus it costs to have them.

Theoretically, if there is a splitter next to the cabinet and you have ducting to your property then FTTP on demand might not be too expensive where it will still be several thousand but people move into a property and spend £10k on a new kitchen or spend >£50k on new car etc. So all depends on your priorities

In reply to a post by tonyj2:

So there is actually a better chance than I thought that FTTP might be available in the not too distant future.

The ability to order will be dictated by how far/difficult the last mile is.
the D-Side copper could be sticking around for years to come in very rural areas and will be dictated by how expensive those D-side links are to replace.

The bottom line is that Openreach is a business and they want to make as much profit as they can for the shareholders so their planners will continually be re-evaluating areas - the largest groups of premises which can be upgraded at the lowest cost per premises passed will be at the top of the list, they may prioritise areas where altnets are planning to build to get their foot in the door first, and they may actually push small clusters of premises with high costs per premises past down the list if there is a chance of winning a bid for BDUK / Project Gigagbit funding.

I’m still not entirely clear on this exchange vs a head exchange.

The Turville Health (THTV) exchange that the cabinet sits below, isn’t yet on the upgrade plans but presumably will be 2027.
I think this may be a fairly small (number of premises served) exchange.

Does it seem possible/likely that this could be replaced as part of the FTTP roll out?
perhaps OR could cable the FTTC cabs back to a larger close-by exchange instead of upgrading THTV to be FTTP ready?

Nettlebed (THNB), Rotherfield Greys (THRO) and Turville Heath (THTV) have Henley-On-Thames (THHT) as their head-end exchange. Fibre from all of the DSLAMs makes its way back to THHT via aggregation nodes.

Openreach intend to close around 4600 satellite exchanges leaving around 1000 head-end exchanges. There are pilot programmes running with plans to close 100 by the end of 2030 and the remaining 4500 in the early 2030s, many Openreach premises were sold and leased back so they will want to complete closures before leases expire rather than having to renegotiate them.

Once the PSTN voice services are shut down only ADSL will be served from the satellite exchanges (not completely true, there are various B2B products but those wouldn't affect normal residential and most business premises) so Openreach could actually deploy more infill cabinets moving customers to SOGEA if they desparately need to close down the exchange and FTTP is too expensive or delayed in that area.

If the fibre connections from the DSLAMs do run through the satellite exchange they would reroute these into inspection chambers near those exchanges, e.g. the footway immediately outside it, as part of the decomissioning process.

At the end of the day if you have good rate SOGEA, e.g. somewhere between 60/15 and 80/20, and FTTP build is expensive (e.g. having to build new spine crossing rivers, railways, motoways or other major roads) that may be all you get until the 2030s.

In reply to a post by jabuzzard:

Theoretically, if there is a splitter next to the cabinet and you have ducting to your property then FTTP on demand might not be too expensive where it will still be several thousand but people move into a property and spend £10k on a new kitchen or spend >£50k on new car etc. So all depends on your priorities

Is FTTP on demand still a thing through OR in 2024?

Last time I looked at that I was put off by the high monthly subscription fees more than the one-off install fee. From memory, the fees were over £150 a month after the FTTP-OD install.

Where I to pay for FTTP-OD would that install/upgrade on my cabinet and enable FTTP for all my neighbours too? (wondering about splitting the install costs if it did)

Would I be able to buy Internet through any ISP that supports normal O.R. FTTP wholesale pricing?

thanks again, everyone.
Feeling a little more comfortable about a rural house now

Nettlebed (THNB), Rotherfield Greys (THRO) and Turville Heath (THTV)

All of them very rural exchange areas. Wasted MANY an hour chasing faults down monstrous D sides there.

I wonder if the OP has actually found Turville Heath exchange yet ?

(it appears out of the mist like Brigadoon every hundred years or so)

In reply to a post by tonyj2:

In reply to a post by jabuzzard:

Theoretically, if there is a splitter next to the cabinet and you have ducting to your property then FTTP on demand might not be too expensive where it will still be several thousand but people move into a property and spend £10k on a new kitchen or spend >£50k on new car etc. So all depends on your priorities

Is FTTP on demand still a thing through OR in 2024?

Last time I looked at that I was put off by the high monthly subscription fees more than the one-off install fee. From memory, the fees were over £150 a month after the FTTP-OD install.

Where I to pay for FTTP-OD would that install/upgrade on my cabinet and enable FTTP for all my neighbours too? (wondering about splitting the install costs if it did)

Would I be able to buy Internet through any ISP that supports normal O.R. FTTP wholesale pricing?

thanks again, everyone.
Feeling a little more comfortable about a rural house now

AFAIK , FTTPod is still available, ( it was paused , but has been made available again ) it’s always been a niche product and available from a small number of providers ( mass market ISP’s generally are not interested in offering this Openreach product ) , the higher monthly cost ( after paying the construction costs ) is only until the end of the minimum term at which point you can negotiate with the supplying ISP to move onto their regular pricing, or change provider and get native FTTP pricing from them .

There is no cabinet upgrade, ( FTTP doesn’t originate from a ‘cabinet’ ) anyone who does pay for an FTTPod provide basically provides the network to the CBT that they are served from , and any neighbours that can also be served from that CBT will have access to native FTTP ( its available as a consequence of the FTTPod build ) , obviously the number of neighbours that benefit will vary depending on the situation, if someone lives pretty remotely ( no neighbours served from the same copper DP ) then no one else would benefit, but if someone was ( for example ) served from a telegraph pole , that 10 others were served from , then those 10 would have access to FTTP , from any ISP’s that offers OR FTTP , at that ISP’s ‘regular’ prices .

Edited by Iniltous (Tue 15-Oct-24 22:13:12)