Fttp & power

Just wondering what parts of the Openreach fttp kit actually need power, I realise most of it is passive obviously but what bits likely to be in the street, Chambers or up poles needs power?

The head end in the exchange. The ONT in the property.
The stuff in between does not require power.

The exception to the rule being so called subtended headend (OLT) in street cabs.

But those suckers are relatively few and far between (literally) - or as someone here called it, in “ultra rural” locations (beyond the typical 20km-ish GPON distance limit)

Thanks guys we've finally got Openreach & their contractors nipping around finishing off the stalled BDUK FTTP install that went out of scope due to blocked ducts 2 years ago. Our cfp hit 100% in Nov so work has resumed.

Just wondered as we've got several road closures coming up to put new power installs in, they're in the street so not houses & there's no street lighting so not that & wondered if the 2 were related.

I believe the exchange the fttp is using us about 6 miles away (by road) so I'm guessing it's just a coincidence then.

Thank you for the info

GPON FTTP is almost always unpowered. I believe it can do spans of up to 20km.

(My head-end exchange is about 7km away as the crow flies).

Whenever you have to do things like media conversion power is needed. It's the same for Virgin Media's RFoG which has powered virtual hubs and ONTs.

Edited by deleted (Thu 11-Mar-21 15:30:04)

That's why I was wondering about fttp as typically there isn't much that needs power away from cabs/exchanges. I've been lead to believe that our fttp instead of going to the nearest local exchange is going back to the nearest town exchange, 6 miles by road I didn't know if that meant a slightly different roll out to urban fttp iykwim.

Anyway UKPN will be doing work for new install nearby on 16th so guess we'll figure it out then.

In the meantime I've walked the village following the phone lines some via poles then underground then poles then underground & every pole near abouts has a CBT on it with fibre coiled up still. This us an improvement as previously our road had CBT's fitted & then abandoned & OR are still about putting more up so hopefully in the next few weeks they'll all get hooked up

In reply to a post by Rich44:

That's why I was wondering about fttp as typically there isn't much that needs power away from cabs/exchanges. I've been lead to believe that our fttp instead of going to the nearest local exchange is going back to the nearest town exchange, 6 miles by road I didn't know if that meant a slightly different roll out to urban fttp iykwim.

That's standard across the UK, and is where the current FTTC cabinets in your area already run back to.

The OpenReach network is made up parent and child exchanges.
Each parent exchange (also called a Head-End/Handover exchange) has a number of (usually) smaller child exchanges.

All the fibre services (FTTC(VDSL,G.Fast) and FTTP) come from a parent exchange.

If you are on FTTC then your line runs from your home to the cabinet. The copper line continues to your local exchange for voice services. The fibre runs from the cabinet to your Handover exchange.
This means your voice and broadband although on a single phone line, come from 2 separate exchanges.

My local exchange also happens to be the local Handover exchange so all services come from there.
It makes zero difference to your service if your local exchange is a parent or child exchange.

The intention is to close the child exchanges when everyone is on fibre.

As mentioned above by others the only point where power is needed for FTTP is in the parent exchange and your home. It's passive inbetween.

In very rural areas where the parent exchange is too far away for the FTTP signal to travel they can effectively start the FTTP signal from a subtended head-end, but the power for this is shared with an existing FTTC cabinet.

Any local power work is almost certainly unrelated to OpenReach's FTTP rollout.

The span depends on the number of splits. It's nominally 20km but that is for 32 splits. If you have fewer splits you get longer distances. If you have no splits the reach is about 70km, though at that point you are probably better off using some Ethernet BiDi SFP's than messing about with OLT's which are a lot more expensive per port than an ethernet switch.

I don’t think the “split-less” distance is as long as 70km for GPON. Huawei maintain the maximum physical reach is 40km for class B+ and 60 km for class C+ optics. I believe Openreach optics are class B+ (at least my ONT is). Of course these distances are maximum theoretical; splits, splices and connectors all take their toll on the budget.

There is also a maximum differential distance between ONT/Us of 20km.

https://info.support.huawei.com/AccessInfoTool/PON_B...

Edited by Pheasant (Fri 12-Mar-21 17:24:00)

In reply to a post by jabuzzard:

... though at that point you are probably better off using some Ethernet BiDi SFP's than messing about with OLT's which are a lot more expensive per port than an ethernet switch.

On a single link basis, yes, but on broadband deployment, no. Remembering a single GPON port is effectively shared / multipoint, the “cost” per user is a fractional basis. Basic chassis cost for OLT is about the same as an decent L3 switch. A 2-slot Huawei MA5800-X2 OLT with management cards, 10G uplinks + dual PS is less than $3K. ONUs are really dirt cheap. Single port Huawei ONT are about £15 wholesale

At the other end of the scale an 8 no. GPON port Ubiquti OLT is around £950. Their own ONUs are something like £25 to £45 each.

Edited by Pheasant (Fri 12-Mar-21 18:36:06)

In reply to a post by Rich44:

Just wondering what parts of the Openreach fttp kit actually need power, I realise most of it is passive obviously but what bits likely to be in the street, Chambers or up poles needs power?

On your end as a customer, the ONT.

Nothing in the street, nothing in chambers, nothing on poles. Hence "PON" - Passive Optical Network.

In reply to a post by Pheasant:

In reply to a post by jabuzzard:

... though at that point you are probably better off using some Ethernet BiDi SFP's than messing about with OLT's which are a lot more expensive per port than an ethernet switch.

On a single link basis, yes, but on broadband deployment, no.

Well a number of broadband fibre providers would disagree with you. For example B4RN is all PtP BiDi, as is Wightfibre. The cost of the PtP solution has come down significantly faster than GPON. It is also an utterly commodity item so if you want to switch vendors well not remotely a problem.

However the context of the post was that in various places Openreach are going to much lower splits (1:4) with subtended OLT's to get better reach in the "deep rural" areas which is probably reserved for the remotest parts of Scotland. My comment is at that point BiDi ethernet where 120km SFP's are a commodity item is IMHO a better solution. SFP ports are as cheap as chips these days, and the significantly greater reach removes all that out in the field powered equipment the subtended OLT's will require.

At the end of the day GPON looked like a good idea even 10 years ago. However as always in IT things change and if you where starting again today from scratch simple point to point BiDi ethernet looks a better bet.

You have zero vendor lock in, much easier migration paths for higher speeds; for example you could offer symmetric 25Gbps speeds today and igher flexibility in the physical network.

Edited by jabuzzard (Tue 16-Mar-21 22:23:29)

In reply to a post by Pheasant:

I don’t think the “split-less” distance is as long as 70km for GPON. Huawei maintain the maximum physical reach is 40km for class B+ and 60 km for class C+ optics. I believe Openreach optics are class B+ (at least my ONT is). Of course these distances are maximum theoretical; splits, splices and connectors all take their toll on the budget.

There is also a maximum differential distance between ONT/Us of 20km.

https://info.support.huawei.com/AccessInfoTool/PON_B...

I was using a Nokia formula for your optical budget based on number of splits and length of fibre. If you run the numbers for class C+ you get to 70km when you have no loss because you have no splits. It's the splits that really introduce the loss. I am assuming in that a PtP link with no splices. So pearing that back to 60km would probably be prudent, as you are going to need some splices outside the 70km of fibre sitting on a drum in a lab.

Given you can change it on a per port basis on the OLT by plugging in a different SFP nobody is going to get a class C unless they need it.

Going beyond discussing bidi vs pon optics for a moment....

I think they’re quite interesting examples that you cite. Both these nets have somewhat unique ‘environments’ in which they have built their networks. B4RN have a relatively small yet devoted user base of largely rural folks that either contribute their own labour and/or wayleave-free in-verge or land to the cause. Wightfibre similarly quite a rural place - therefore I would argue these aren’t your typical mass scale deployments. I would call these “green field” deployments, where cost per metre is generally quite low and there is more opportunity to have significantly higher fibre count in the ground with less penalty.

The design flexibility of PON is one of it’s biggest draws. The fact is that far less fibre and splicing is required for PON. This a critical consideration especially in dense urban or “brown field” deployments, where high fibre count means high ducts requirements. To try and offset this with PtP requires active hardware to be placed deeper into the network, closer to subscribers. Goes without saying that this has consequences not only for higher numbers of active devices, but also ongoing operational costs to maintain and provide power etc.

The design flexibility of PON makes it a good candidate for dovetailing into existing physical infrastructure, like Openreach PIA. Trying to “do” PtP if your wanting to leverage PIA instead of digging your own ducts from scratch bound be far more difficult proposition. I think this is why networks that are deploying in brown field are opting towards PON architectures.

The other aspect to consider is the so called “future proof” nature of PtP. I don’t think one could argue for that perspective as it’s pretty hard to deny that a dedicated strand(s) of glass to each subscriber is the gold standard of a fibre network. However I would say that technology moves fast and the familiar GPON standard has already been skipped by several forward looking alt nets who have adopted XGSPON which addresses bandwidth and symmetry.

Feels like a rerun of Betamax versus VHS!

Just a quick summary (not exhaustive) of some network providers currently installing and/or running PON type nets (many XGSPON) in the UK:

- Openreach
- CityFibre (incl. Air Broadband, Giganet, Highnet, TalkTalk, Triangle Networks, Trunk Networks, Vodafone, and Zen Internet)
- Connect Fibre
- Community Fibre
- Exascale
- G.Network
- Glide
- Hey! Fibre
- Hyperoptic
- Swish Fibre
- Telcom
- toob
- Trooli
- Zzoomn

I’m aware Gigaclear (again mainly rural), but what others are running PtP?

Many years ago, I worked for a large ISP with thousands of dialup modems. Originally they had chassis-mounted analogue blades - there was a separate incoming wire for each phone line. Then they changed to E1 trunks, so one cable carried 30 channels. The saving in both rack space and cable spaghetti was enormous.

The same applies to PtP versus PON. Although you can get switches with high density SFP ports, and more dense than PON blades, you would still need around 30 times as many incoming fibres to service the same customer base - and of course, 30 times as many fibre strands running to your fibre aggregation nodes.

Hence for mass-market consumer FTTP, I think PON still makes a huge amount of sense - and clearly most of the providers do too.

Certainly there will be business users for whom this is not suitable, but that's a much smaller problem to get dedicated fibres to those customers.

In reply to a post by Pheasant:

The design flexibility of PON makes it a good candidate for dovetailing into existing physical infrastructure, like Openreach PIA. Trying to “do” PtP if your wanting to leverage PIA instead of digging your own ducts from scratch bound be far more difficult proposition. I think this is why networks that are deploying in brown field are opting towards PON architectures.

If you can draw a single core of fibre to a splitter you can draw 32 cores, and the cost is almost all in the man power. There is indeed less splicing as any splicing in segments before the splitters is reduced. Once you get to the splitter the amount of splicing/termination is actually more with PON. However again most of the cost is in the labour for pulling of the fibre.

The other aspect to consider is the so called “future proof” nature of PtP. I don’t think one could argue for that perspective as it’s pretty hard to deny that a dedicated strand(s) of glass to each subscriber is the gold standard of a fibre network. However I would say that technology moves fast and the familiar GPON standard has already been skipped by several forward looking alt nets who have adopted XGSPON which addresses bandwidth and symmetry.

Feels like a rerun of Betamax versus VHS!

Even XGSPON does not compete with PtP BiDi ethernet. Where is my symmetric 25Gbps connection today?

The use of PON technologies is historical. Things have moved on and the assumptions that favoured PON have mostly evaportated. If you where starting again PtP ethernet has lots going for it. It is a bit more expensive, but it is vastly superior in the long term.

In reply to a post by candlerb:

The same applies to PtP versus PON. Although you can get switches with high density SFP ports, and more dense than PON blades, you would still need around 30 times as many incoming fibres to service the same customer base - and of course, 30 times as many fibre strands running to your fibre aggregation nodes.

It won't be anywhere near 30 times as many fibres. Because Openreach will have run some spares and you need a lot more spares proportionately for PON than PtP Besides it will be a single cable with X numbers of fibres which are about the thickness of a strand of hair individually.

You can get 96 BiDi ethernet terminations in 1U using dual BiDi SFP's. It's one of the things that has in part eroded the advantage of PON networks.

You are not tied into vendors with BiDi ethernet like you are with GPON. Want to move a customer to XGPON from GPON for higher speeds you are going to have downtime for everyone on that splitter as you patch it somewhere else. BiDi ethernet only impacts the customer getting the upgrade. You have the option of higher speeds sooner. Sure there is a 25Gbps version of GPON in the works, but you can already by 25Gbps BiDi optics today.

Another consideration is you only have one fibre estate to manage, you can use the same fibres for leased lines as you do for consumer broadband. Not so easy on a PON network.

The use of PON is a decision of it's time, that is harder to justify today than it was when it was made. It happens all the time in IT and something you have to be careful of so you don't keep doing something even when it doesn't make sense anymore. Of course Openreach are locked intousing PON now.

In reply to a post by jabuzzard:

If you can draw a single core of fibre to a splitter you can draw 32 cores, and the cost is almost all in the man power. There is indeed less splicing as any splicing in segments before the splitters is reduced. Once you get to the splitter the amount of splicing/termination is actually more with PON. However again most of the cost is in the labour for pulling of the fibre.

The other aspect to consider is the so called “future proof” nature of PtP. I don’t think one could argue for that perspective as it’s pretty hard to deny that a dedicated strand(s) of glass to each subscriber is the gold standard of a fibre network. However I would say that technology moves fast and the familiar GPON standard has already been skipped by several forward looking alt nets who have adopted XGSPON which addresses bandwidth and symmetry.

Feels like a rerun of Betamax versus VHS!

Even XGSPON does not compete with PtP BiDi ethernet. Where is my symmetric 25Gbps connection today?

The use of PON technologies is historical. Things have moved on and the assumptions that favoured PON have mostly evaportated. If you where starting again PtP ethernet has lots going for it. It is a bit more expensive, but it is vastly superior in the long term.

Are there really only three networks (all rural) in the UK that are building PtP nets (Gigaclear, Wightfibre & BB4RN)?

Surely there must be more than 3 nets here, if PtP total superiority over PON is as assured as you would have us believe?

You say that "things have moved on", but have they really? You speak as if PON is yesterdays technology, but as I said in my post above, it's not just Openreach that have decided to use PON but subsequently at least a dozen other large and small alt nets are either building and/or running PON fibre nets. Some, like CF are already selling 3Gbps symmetric consumer packages and 10 Gbps business packages. Surely they can't all be so wrong.

Will 25 Gbps PON ever see the light of day...dunno, news out last month that single wavelength 100 Gbps symmetric PON has been tested in the lab with Nokia and Vodafone:

https://www.lightwaveonline.com/fttx/pon-systems/art...

"“Once this DSP is adopted,” in the words of a joint press release, 50G and 100G PON development would become relatively straightforward, leading to commercial availability in the second half of this decade, the companies assert."

Is PON a dead end? I think you'd be foolish to think so.

In reply to a post by Pheasant:

Are there really only three networks (all rural) in the UK that are building PtP nets (Gigaclear, Wightfibre & BB4RN)?

There is also B4SH (Broadband for Surrey Hills), who have been installing their PtP network since 2018.

Looks to me like a small rural alt net very much in “help us dig it and we will come” mould of B4RN (I think they even say as much in their website)

Yes, correct.

This is the list of UK PtP fibre broadband networks I’ve got. Any more?

- Grain Connect
- Gigaclear
- B4RN and B4SH
- VXFIBER/LilaConnect
- Wightfibre

I think I’m right in saying that with the exception of VXFIBER who are building in Stoke-on-Trent and Colchester, the rest are by and large building in rural settings.

There's a good description of Wightfibre's urban/rural mix, as well as their technology, here: https://www.ispreview.co.uk/index.php/2020/04/wightf...

👍 Sounds like a 35/65 rural to urban mix then, with 10% of extra-rural "uneconomic" for FTTP.

What I found most telling was that they would have probably upgraded to DOCSIS 3.1 rather than full fibre if they had to make the decision again today 😝 Good heavens is there no accounting for taste. hahaha 🤷‍♀️

Edited by Pheasant (Thu 18-Mar-21 09:57:35)

Yes I know about that hence why I said street. We've got FTTP being installed slowly lol & UKPN now installing a new supply across right where the phone lines go so was curious given the fibre is going back to the next nearest exchange 6 miles away (by road)

In reply to a post by burakkucat:

In reply to a post by Pheasant:

Are there really only three networks (all rural) in the UK that are building PtP nets (Gigaclear, Wightfibre & BB4RN)?

There is also B4SH (Broadband for Surrey Hills), who have been installing their PtP network since 2018.

I've just been connected today with FTTP by Quantum Air Fibre. funded via the Gigabit rural scheme. They are installing FTTP in seven villages around here. Speedtest. I did think about the 1Gb connection but found the cost hard to justify so went for the 500Mb. Installation was a total breeze - 30mins from arrival;. There is just a small box on the wall (smaller than the BT master socket above it with a fibre connector (I presume) that goes direct to the supplied WiFi router.

I have 14days to decide if I'm happy! And to think just 6 yrs ago I was lucky to get 1.2Mb/s - we won't mention the upload speed. Progress in the rurals.

Sounds good 👍. Hope they work out well for you. It’s hard to tell exactly but I think they may be a PtP network, rather than PoN. But there’s scant info out there. What sort of box (make/model) is on the wall.

Their peering arrangements look quite minimal. As far as I can see it’s just a single 1 Gbps connection on LONAP. That will have to change as they bring more subscribers on board

What about Truespeed? All their packages offer the same speed up and down and up to 900Mbps.

In reply to a post by Michael_Chare:

What about Truespeed? All their packages offer the same speed up and down and up to 900Mbps.

So does Vodafone on the Cityfibre network, but that's GPON.

They look PtP - read something dated 2019-ish on ISPreview about them connecting folks via 10Gbps SFP+ using DKT gear.

Edit: links below from DKT Comega...

https://dktcomega.com/wp-content/uploads/2019/06/Tru...

Edited by Pheasant (Sat 20-Mar-21 12:51:23)

Indeed. There's several other providers offering symmetric 1 Gbps (and higher) symmetric services on XGS-PON based nets.

In reply to a post by Pheasant:

They look PtP - read something dated 2019-ish on ISPreview about them connecting folks via 10Gbps SFP+ using DKT gear.

Edit: links below from DKT Comega...

https://dktcomega.com/wp-content/uploads/2019/06/Tru...

Some variants of the "DKT Gateway" are GPON, and some not:
https://dktcomega.com/wp-content/uploads/2020/08/DKT...

In reply to a post by Pheasant:

Sounds good 👍. Hope they work out well for you. It’s hard to tell exactly but I think they may be a PtP network, rather than PoN. But there’s scant info out there. What sort of box (make/model) is on the wall.

Make and model....there isn't anything apart from a surface mounted white box - normal single gang size but very shallow. From the bottom of that box a length of very thin cable (fibre?) goes across to the supplied WiFi HALNy router which, given the length of cable (currently coiled up), presumably could be sited within about a 3 meter distance of the box. Apart from the power supply, that is it.

I do know Quantum are involved with Fixed Wireless internet tech around these parts already - bit like another local company - Quickline. As such I'd imagine their network would be fairly robust already. Certainly yesterday and today the connection has sailed along. The only info I've seen was here As you say hopefully things work out well.

The box on the wall could just contain a splice or fibre connector from external to internal. Doesn’t sound like it’s active (has power running to it).

Is this the HALNy WiFi router you have?

https://halny.com/portfolio/gpon-ont-with-4x4-5ghz-a...

(That’s an all in one GPON ONT and WiFi router)

That's it There is no power running to the box on the wall, only the WiFi router has the usual power adapter.

👍 you’ll have to update the BQM in your sig! Enjoy

Lol I said that a few years back on here & was criticised that the fttp fibre wouldn't come via the fttc cab etc. I was always fairly sure it'd come from the cab direction myself

In reply to a post by Rich44:

Lol I said that a few years back on here & was criticised that the fttp fibre wouldn't come via the fttc cab etc. I was always fairly sure it'd come from the cab direction myself

They were actually correct in pointing that out.

That's because it won't come from the FTTC cabinet.
Coming from the cabinet direction is very different to coming from the cabinet itself.

The fibre for the FTTC cabinet and the fibre for FTTP both originate from the same exchange, both from an OLT (also known as a Head-End).
They both run to the exact same fibre Aggregation Node, which may or may not be near your cabinet.

There's already ducting and/or poles between the Aggregation Node and your cabinet, and between your home and your cabinet. So they will often use the same route as the current copper feed.
The fibre for FTTP won't touch or use the cabinet though. It will only share the ducting to/from the cabinet.

Sometimes they feed FTTP in more of a straight line from the Aggregation Node and don't go "via" the cabinet at all.

It's always been correct to say the fibre for FTTP won't come from the cabinet, though it could pass through the ducting at the front of the cabinet.

*Subtended Head-Ends are a very recent exception to all of the above.
They are basically mini versions of the FTTP OLT's (usually based in the exchange) that they bolt on to the PCP to boost the range of FTTP.
They utilise spare fibres from the FTTC cabinet.
They aren't very common and are usually used in very rural areas.