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FTTP infrastructure design

darthmuppet

Casual Member
I'm trying to find out more about the physical and logical network designs (generic only) for OpenReach's FTTP network. High-level concepts will be fine for most of it, but I'm looking for a terminologically-correct explanation from house to exchange to next-hop from the exchange covering everything (e.g. what they call the underground chambers in the street, how the fibre is physically connected, how it would be physically presented in the exchange, what it plugs into, how different ISPs can send my broadband data along the same fibre as others. One particular thing I'm trying to look into is that I was just told by Sky that there was no space at the exchange for me to move to their service, and it strikes me as odd that, in a pure fibre service, space is an issue (unless it's logical space of course).

To put me in context, I have designed and managed Cisco-based LANs, so I guess I'm trying to map the associated concepts onto OpenReach's service. I'm familiar with things like DWDM too.

TIA

DM
 

Meatball

Regular Member
Actual detail will probably be need to know (security)

Openreach detailed design will be different dependant on the manufacturer, generation and programme. It will also probably differ in approach as OR moves to centralised CP sites.

The basic naming is included in the attached graphic (source Cartesian)
 

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darthmuppet

Casual Member
Actual detail will probably be need to know (security)

Openreach detailed design will be different dependant on the manufacturer, generation and programme. It will also probably differ in approach as OR moves to centralised CP sites.

The basic naming is included in the attached graphic (source Cartesian)
Thanks, that’s the kind of thing I was looking for. Much as detail would be nice, i have a realistic expectation there (I.e. none).

Still curious about the ‘the exchange is full’ piece, the term the Sky contact used was ‘there are no more ports’ and I just don’t get where’s ‘ports’ come into it with a fibre service - it’s not as if they can patch my fibre anywhere.
 

Meatball

Regular Member
Either OR FTTP is available or not
Either Sky has connectivity to that OR FTTP or not
It is unlikely a capacity issue so early in OR FTTP take up.
 

Internetty

Member
Openreach Use PON as a build method sharing fibres, it is very possible in a busy FTTP area they have run out of ports.
They only typically connect 32 properties to a single fibre, additionally they use pre-connectorised terminals in the ground near the house, so that can fill up quite quickly!
 

Meatball

Regular Member
I can understand that for some Altnets (expecting a certain take-up) and on the OR initial installs but my assumption now was that for NewBuild and Fibre First were building the splitter/access for 100% coverage ready for copper changeover.
 

candlerb

Casual Member
Openreach Use PON as a build method sharing fibres, it is very possible in a busy FTTP area they have run out of ports.
No, that's not likely, because they scale each rollout to allow 100% coverage - i.e. each CBT has at least one port for every property which could be served by that CBT, and each splitter connects to no more than 32 CBT ports.

They do sometimes fill right up to the limit, which means if you ask for a *second* fibre you might not be able to get it.

If Sky said "there was no space at the exchange" it might mean that Sky don't have the necessary interconnects in place at your head-end exchange - i.e. they can't pick up FTTP traffic from there - or that their existing interconnects have insufficient capacity to take new customers.
 

darthmuppet

Casual Member
Openreach Use PON as a build method sharing fibres, it is very possible in a busy FTTP area they have run out of ports.
They only typically connect 32 properties to a single fibre, additionally they use pre-connectorised terminals in the ground near the house, so that can fill up quite quickly!
Would that be relevant to my specific scenario, as I already have the fibre? I'm just wanting to switch from BT to Sky.

The document I posted above suggests that the GEA Cablelink product is either Gbit or 10Gbit from the OLT to the CP's equipment - that's the only real reference to a port that I can find in it. if they only have one connection, and only one available physical port on their layer 2 switch, 'no ports' would make sense. However a quick look in my local Facebook group suggests that FTTP is only on two new developments, i.e. about 130 houses. I also know both estates only recently expired the 18-month exclusivity period for BT, and that none of the 80 on my estate have moved. Based on that, Sky can only have less than 50 FTTP customers in the exchange. Sky's response just seems a bit strange, when it's entirely possible that they actually have no FTTP customers in the village at all (nobody has owned up to switching)

Any idea if CP equipment can be shared between copper and optical end users? at that point in the network, the media is irrelevant, and at layer 2/3 I can't think of a technical reason (maybe the VLAN ID limit) why they could not be shared. I have no idea if they actually are.

My fundamental fear is that the information Sky has about what they can offer us might be incorrect, and that makes the end user suffer through lack of choice, and loses Sky some income too, so it's in everyone's interest to make sure it is correct. I would prefer Sky as it would be cheaper to bundle it with my TV service. As it is, I have moved to TalkTalk instead - 500/75 for £17 less than the 330/50 I have from BT.
 

darthmuppet

Casual Member
No, that's not likely, because they scale each rollout to allow 100% coverage - i.e. each CBT has at least one port for every property which could be served by that CBT, and each splitter connects to no more than 32 CBT ports.

They do sometimes fill right up to the limit, which means if you ask for a *second* fibre you might not be able to get it.

If Sky said "there was no space at the exchange" it might mean that Sky don't have the necessary interconnects in place at your head-end exchange - i.e. they can't pick up FTTP traffic from there - or that their existing interconnects have insufficient capacity to take new customers.
She was very clear it was no *ports*, but she couldn't tell me what that actually meant on a physical level. I suspect your third paragraph is on the money - lack of OLT interconnects. However I also wonder if they have no FTTP customers at all, as nobody has come forward to say they have switched. That makes me wonder why they offer it. For my property (along with the entirety of the 3 postcodes on the estate) they cannot offer *any* service of any kind, and they know that. The rest of the village does have a decent FTTC presence, and Sky are well thought of by the posts I've seen locally.
 

darthmuppet

Casual Member
I can understand that for some Altnets (expecting a certain take-up) and on the OR initial installs but my assumption now was that for NewBuild and Fibre First were building the splitter/access for 100% coverage ready for copper changeover.
I hope you're right - planning rules ought to require all new developments over a certain size to have FTTP. We have another estate being built opposite ours, with 300 new properties - all will be fibre only, and we've seen them running the fibre recently. I should have asked the Openreach guys whilst they were there.
 

Meatball

Regular Member
There are a number of variables. FTTC may be hosted in the local exchange and FTTP from the main exchange etc. OR FTTP is new for many ISPs, their people and as you state the records need to be correct.

Perhaps you can provide a long term user experience when on Talk Talk.
We are sold products by line settings and theoretical expectations but real life ISP backhaul performance (not speed tests) will be the issue going forward.

I know its history but back in 2016 I had VM but it still stuttered on a Saturday night using any of the streaming services yet the FTTC was fine so it wasn't the content provider. Its no good an ISP selling a x/y service if it is not effective when you actually need it.
 

Meatball

Regular Member
I hope you're right - planning rules ought to require all new developments over a certain size to have FTTP. We have another estate being built opposite ours, with 300 new properties - all will be fibre only, and we've seen them running the fibre recently. I should have asked the Openreach guys whilst they were there.
I think most developers have got the message now. Not much consolation to those of recent vintage where a phone line was considered sufficient.
 

darthmuppet

Casual Member
There are a number of variables. FTTC may be hosted in the local exchange and FTTP from the main exchange etc. OR FTTP is new for many ISPs, their people and as you state the records need to be correct.

Perhaps you can provide a long term user experience when on Talk Talk.
We are sold products by line settings and theoretical expectations but real life ISP backhaul performance (not speed tests) will be the issue going forward.

I know its history but back in 2016 I had VM but it still stuttered on a Saturday night using any of the streaming services yet the FTTC was fine so it wasn't the content provider. Its no good an ISP selling a x/y service if it is not effective when you actually need it.
As long as it works, I see no reason to move. I'm only leaving BT because I have a choice, and my contract is ending and they won't negotiate a better price - all they would do is off-the-web pricing.

Interestingly, TalkTalk are BB only - no voice service currently, and that's fine for me. I got the automated email from BT telling me that as I was only moving BB, they would put me on the default call plan and start charging me line rental. I called to cancel it and I said that one reason I was leaving was the voice service I don't want, need, or use. He said 'you get it free'. I pointed out that it wasn't free, because they just emailed me to tell me what my line rental would be now I didn't have BB any more. He just couldn't understand the concept that if I didn't have a voice service, they could charge me less (which is exactly what TT do)
 

candlerb

Casual Member
He just couldn't understand the concept that if I didn't have a voice service, they could charge me less (which is exactly what TT do)
Very recently, BT started offering FTTP without voice - and the price is the same.

This is because there is very fixed little cost associated with dial tone (*) - the cost is in providing the line. Arguably the voice service subsidises the line a little, because people sometimes pick up the handset and place a call at extortionate cost, or else pay a flat rate for inclusive "minutes".

(*) Except when BT decide to provide the voice service on a parallel copper cable. The FVA port on the ONT is no longer used, but BT now have the option of "Digital Voice" via a port on the router they provide.

If you order FTTP with voice, then it's up to BT whether they deliver a copper line or Digital Voice, and there don't seem to be hard-and-fast rules as to when they choose one over the other.
 

Meatball

Regular Member
I think BT just quickly saw that some customers (not just business) do not necessarily want a BT phone service and it would be enough to make them consider another ISP for their BB. That's BT's main problem that existing customers will review their options on any significant change.

However in the same way VM offer BB with telephone cheaper than just BB, BT will do the same. It costs nothing if left dormant and BT does not need to send out a DECT handset if not. Many BT consumers will be tempted with the new free cordless phone and the benefits of consistency, therefore subscribing to DV.

The reality is that both BT and VM only make a profit if people actively use their line for outgoing calls and buy a call package.

BT Digital Voice will now increasingly be the default for residential (unless there is a short term number porting issue) and BT Cloud Phone for SME if telephony is requested.
 

darthmuppet

Casual Member
Very recently, BT started offering FTTP without voice - and the price is the same.
*Openreach* now offer that service, but the two BT staff I spoke with yesterday both hadn't heard of it, told me that BT doesn't offer anything like it and they were not aware of any plan to. If they did, and dropped the price accordingly, I'd have stayed. Interesting if they did though - surely they would drive away those that don't want a landline, as others offer the same for much less. In my case, TT's price for 500/75 is £17 cheaper than the closest BT offering ( 330/50 @ £56.95 / month for an existing customer)
This is because there is very fixed little cost associated with dial tone (*) - the cost is in providing the line.
Yes, but (I assume OfCom ensure that) the cost of the line is fixed for all CPs so BT charges me an extra £17 for (literally) nothing. That's pure profit. I don't begrudge them a profit, but when you do nothing for it *and* give me no alternative, and I can avoid that cost somewhere else, I'll go somewhere else.
Arguably the voice service subsidises the line a little, because people sometimes pick up the handset and place a call at extortionate cost, or else pay a flat rate for inclusive "minutes".
Agreed - I imagine there is very little money in any voice service these days, and I've not made a single call from mine. I did plug a handset in though, just to see how may robodiallers called it - 4 in a day was the most, but usually about one a week. They should be illegal.
(*) Except when BT decide to provide the voice service on a parallel copper cable. The FVA port on the ONT is no longer used, but BT now have the option of "Digital Voice" via a port on the router they provide.
My voice service is delivered to the FVA port on the ONT. TT don't actually offer any voice on FTTP currently but they are trialling a digital service that would be offered through their router, presumably in the same way. I would have to change how I do things to use that, as I have a commercial-grade firewall facing the ONT, not the BT / TT router. We have 3 unlimited-minutes mobiles on two separate networks, which is why a fixed line offers me no value.
If you order FTTP with voice, then it's up to BT whether they deliver a copper line or Digital Voice, and there don't seem to be hard-and-fast rules as to when they choose one over the other.
Yes, I came across that too. Weird. I'm sure there's a reason.
 

Meatball

Regular Member
As you were on FVA their processes may default to FVA for now or as
BT DV is only available if you have the BT Smart Hub 2 that also can be the reason. Retrofit of BT FVA with BT DV will be later.
 

ManOfMeans

ULTIMATE Member
Its a cable link capacity I think, also I'm sure I read some where Sky are not offering the 500 and 1 gig speeds yet on FTTP, I could be wrong and that's outdated info.

Openreach only supply these cable links in fibre AFAIK Ive not come across one which is copper.
 
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