Broadband News

How big a problem are capacity delays on Openreach VDSL2 cabinets?

One of the most annoying aspects of the Openreach VDSL2 roll-outs are when people finally spot that VDSL2 is available to order and they are happy with the price and speeds and then get told by a provider that it is not available due to the cabinet being at capacity. This is because when VDSL2 is deployed a projection is made on the expected uptake and capacity is installed to handle that, and as demand increases the extra capacity, be it in more line cards, extra copper link cables, extra line cards in side pod or a whole new fibre cabinet are added. Alas these upgrades vary greatly in the time they take and thus cabinets can be left sitting with a 'waiting list' of orders for a few weeks or months or in thankfully rare cases much longer.

A word of caution on ordering VDSL2, cabinet capacity issues affect all providers equally, so if one provider says there is no capacity available and another claims they can deliver what you will often find is the order fails, or they migrate you to their ADSL2+ service awaiting more VDSL2 capacity. There is an oddity in the way migrations are handled too, in that for some migrations there needs to be a spare port available even when you have VDSL2 on that line.

This flexing in terms of the number of cabinets available where a service can be ordered has often raised the concern of some campaigners, such that it means the coverage figures are nonsense since at any one time the actual coverage where you can order is less.

There need be no doubt anymore, we have analysed those cabinets which are known to be waiting for more capacity to be installed. In the past we have periodically checked and have found the number of cabinets affected ranged from 1,500 to 2,500 out of the installed base of 79,000 VDSL2 cabinet areas, this is the first time we've calculated the impact on the coverage figures, and will periodically revisit this to ensure that Openreach is not allowing a long backlog of capacity upgrades to build up.

Coverage of Superfast Broadband and the impact of cabinets which are at a capacity limit
  Standard Coverage Figures Change Due to Capacity Limits
Region% 'fibre' coverage
VDSL2/FTTP/Cable
% superfast
Over 30 Mbps
% Openreach Superfast
Over 30 Mbps
'fibre' coverageOver 30 MbpsOpenreach
Over 30 Mbps
United Kingdom 95.5 91.7 89.8 -3.0 -2.7 -2.8
East of England 94.5 90.5 88.5 -4.2 -3.9 -3.9
East Midlands 97.5 94.7 93.1 -2.1 -1.9 -2.0
London 96.6 95.3 91.5 -1.9 -1.8 -1.8
North East 96.6 94.9 93.5 -2.5 -2.4 -2.4
Northern Ireland 97.5 79.4 78.5 -3.0 -2.4 -2.4
North West 97 93.7 92.7 -3 -2.9 -2.8
Scotland 92.6 88 85.1 -4.7 -4.4 -4.3
South East 97.6 94.7 93.4 -3.3 -3.1 -3.1
South West 94.6 88.6 86.9 -3.7 -3.3 -3.3
Wales 94.1 88.9 88.4 -2.3 -2 -2.1
West Midlands 96.9 94.2 92.6 -1.6 -1.5 -1.5
Yorkshire and Humber 91.9 88.9 87.0 -2.3 -2.2 -2.1
Percentages reflect the number of premises that are present in the various regions, thus a cabinet serving 450 premises being at capacity will have a greater impact overall than one serving just 180 premises. Coverage figures are taken from our analysis of coverage on 22nd January 2017 and data on the cabinets with at capacity from early January 2017. The number of active VDSL2 lines on each cabinet is not accounted for, so the numbers will be lower in reality, but those people will also encounter issues in migrating so we have not attempted to compensate.

For BDUK areas the capacity upgrades are funded by Openreach, thus in terms of value for money the BDUK projects got a better deal than if they had insisted on installing 100% capacity from day one, as it seems likely Openreach would have insisted on greater levels of gap funding.

We have encountered the odd rare case where someone is waiting for a new fibre twin to be installed but planning permission and/or wayleaves are holding things up, so while a small number may be waiting for a long time as far we know there is no cabinet where Openreach has flatly refused to install extra capacity. So if you have been trying to order VDSL2 and cabinet has been at capacity for more than two years constantly do get in touch.

Comments

Is there any way to estimate the lead time for cabinet upgrades? There's a big difference between a few days and a few months.

  • TheEulerID
  • 11 months ago

I should add as that as penetration increases (and in some BDUK areas it seems to be 40%+) might we see a big increase in demands for "fibre twins"? It's possible to imagine that there could be a big increase in such instances if the initial planning guides were (say) for cabinets for 50% of local lines.

  • TheEulerID
  • 11 months ago

The analysis already breaks down to local authority, just have not presented that way for brevity. Maybe next time I'll share the areas with the most cabs at capacity.

  • andrew
  • thinkbroadband staff
  • 11 months ago

On lead times, anything of course is possible, but line card upgrades can often fill up so cabinet goes back on waiting list before we'd have even noticed it was being upgraded. Am sure some providers have found ways of getting info for customers if they spend the time asking.

Real aim is just to track that Openreach aren't getting to the position where 20% of premises cannot order

  • andrew
  • thinkbroadband staff
  • 11 months ago

I think we'd hear the howls if it was anything like 20%. Of course, there will be some cabinets that immediately run out of capacity after an upgrade due to backlog, but (I'd hope) relatively few. A statistical breakdown of the % of cabinets by days waiting for capacity would still be interesting although that would require regular polling.

  • TheEulerID
  • 11 months ago

Saying about capacity, i was collared by some girls from Talk Talk in town a few weeks back and i let them have my postcode, but nothing else an d they come back saying that only a few spaces was available, so I should order quickly. would that really make a difference to me if I was going to go with Talk Talk as i am already on VDSL?

  • zyborg47
  • 11 months ago

Zyborg
You have been listening to marketing speak again to encourage you to buy quickly! ( Hurry only a few left).
If true(?) it would make a difference as it appears that they allocate a new port even if you have FTTC already, this has left some people back on ADSL2+ on a migration between FTTC suppliers.

  • jumpmum
  • 11 months ago

If staying with the same wholesaler people get away with it, since the migration is handled by the wholesaler rather than openreach I believe.

Hence why its to and from LLU that is usually the issue.

  • andrew
  • thinkbroadband staff
  • 11 months ago

Good article.
Where a cabinet is at capacity and requests are outstanding, then in my view the remainder of the properties in that area area no longer is served by NGA.
Does your negative percentages account for the whole area or just the unserved properties?

  • themanstan
  • 11 months ago

We account for the whole cabinet area

  • andrew
  • thinkbroadband staff
  • 11 months ago

Hi Broadband Watchers.
As G/fast starts to be used at the Cab level local post Codes spare ports will become available and even short fibre runs from local node will also remove congestion on the Cab instead of providing a new FTTC. On many Cabs in Surrey they are stopping the provision of ADSL and only giving access to 18-2 of the FTTC this was only available in the last two weeks.

  • Blackmamba
  • 11 months ago

Does anyone know what the total current capacity of the existing cabinets is?

If you assume all the line cards are in place 79,000 times say 256 lines per cabinet is about 20 million or two thirds of premises.

  • gerarda
  • 11 months ago

@ blackmailed. What does " even short fibre runs from local node will also remove congestion on the Cab instead of providing a new FTTC"supposed to mean

  • ribble
  • 11 months ago

Should read @ blackmamba, damned auto correct

  • ribble
  • 11 months ago

@ gerarda. Between 96 and 288 ports total capacity

  • ribble
  • 11 months ago

@ Gerarda . I guess you meant the total number of ports in all cabinets. Difficult to calculate off hand

  • ribble
  • 11 months ago

I think what he's trying to say that when G.fast is deployed, there will be free FTTC capacity for every end user that migrates from VDSL to G.fast.

  • AndyCZ
  • 11 months ago

Hi Ribble.
If you have a full FTTC you run from fibre node (spare fibre) to the required DPs which have FTTC access and off load them to either G/Fact or direct fibre.

  • Blackmamba
  • 11 months ago

@ blackmamba. Sounds like wishful thinking.

  • ribble
  • 11 months ago

Hi Broadband Watchers.
I may recall that all/many FTTC were fitted with a 100 tie cable when first installed as BT/openreach did not know what the demand would be from the ISP,s giving an open market on the fitted ports , there was a 14 Day window on ordering to make it fair to all ISPs

  • Blackmamba
  • 11 months ago

@ribble yes I think my 256 average is probably on the high side of average.

If it is then a significant increase in cabinet installations will be needed as take up grows.

  • gerarda
  • 11 months ago

g.fast pods may provide some relief to VDLS2 cabinet congestion in some locations.

  • TheEulerID
  • 11 months ago

@gerarda 256 would be high, as while cab may support 256 ports, it might only have 2 out of 6 line cards installed. In short going into much more detail is very difficult unless you are a regulator and can force the hand of a supplier.

What the numbers tell us so far, is probably no need to do that though.

  • andrew
  • thinkbroadband staff
  • 11 months ago

@Blackmamba Name one cabinet and exchange in Surrey where its not possible to order an ADSL/ADSL2+ service and you will Only be supplied with an 18/2 VDSL2 product? And which providers?

  • andrew
  • thinkbroadband staff
  • 11 months ago

@Blackmamba on the spare fibre node idea of using FTTP to relieve FTTC demand - wishful thinking as never seen evidence of this happening. Would be an expensive thing to do, unless you have a declared aim of moving every to FTTP in a set time frame.

  • andrew
  • thinkbroadband staff
  • 11 months ago

@Andrew I was assuming that adding extra line cards was quick and relatively cheap so the bottlenecks are when an extra cabinets needs to be installed.

On a 256 average capacity, allowing for areas with no FTTC, each cabinet serves 400 or so premises. A 40% take up is 160, almost 2/3 of the average cabinet capacity. Given that cabinet size can vary enormously from those serving double or more they can handle to ones where they manage twice or more the number of lines, a 40% take up is likely to mean a significant number of cabinets are at or close to capacity.

  • gerarda
  • 11 months ago

There's no doubt that FTTC cabinet capacity is an ongoing and increasingly difficult issue to manage as anyone who had been involved will know

  • ribble
  • 11 months ago

Gfast wont be around for a while yep and will only be deployed where it makes commercial sense to

  • fastman
  • 11 months ago

I did mention g.fast will only be in some areas. As far as timetables go, then rollout starts in earnest this year and whilst commercial considerations will lead, one of those might prioritise locations is as a means of forstalling building a fibre twin. It's also more like this is required in densely populated areas with many lines on a PCP.

  • TheEulerID
  • 11 months ago

@ gerarda "On a 256 average capacity, allowing for areas with no FTTC, each cabinet serves 400 or so premises."

How did you come up with this?

  • AndyCZ
  • 11 months ago

What's the capacity of a GFast add-on to a PCP cabinet?

  • Somerset
  • 11 months ago

I believe a g.fast pod is up to 96 lines. The main point is that they are quick to deploy and can slave power from the FTTC cabinet via the ducting.

  • TheEulerID
  • 11 months ago

@gerarda
Old BT figures had 80,000 cabinets. 28m premises makes 350 premises per cabinet. If you leave out an allowance of 2m for EO lines, that would be 325 premises per cab.

How many EO and AIO cabs have been added now? Probably more than 5k. As many as 10k? I'm sure I've seen figures over 90,000 now.

That would take the average down from 350 to 310.

I have some extra figures on average FTTC cab ports from back in 2014, coming up soon...

  • WWWombat
  • 11 months ago

@somerset
I think the talk for the G.Fast pods were for a DSLAM with 2 line cards. At first they'd have a capacity of 24 ports each, but increase in future to 48 ports each.

  • WWWombat
  • 11 months ago

@gerarda
In mid 2014, we got a snapshot of the makeup of 34,362 of BT's cabinets (from power metering report)

At the time they had probably deployed 55k cabinets, so it is a fair-sized sample - just over 60%.

At the time, take-up reached 3m lines, or 15% of the premises covered.

We found out the DSLAM type, and the number of cards deployed, and a partial breakdown of the number of ports in use. Altogether it told us about 65 cabinets (0.2%) were within 16 ports of being fully-used.

Onto the numbers
...

  • WWWombat
  • 11 months ago

Overall figures:
- 34,362 DSLAMs
- 15,267 ECI M41s (256 capacity)
- 14,527 Huawei MA5603 (288 capacity)
- 4,568 Huawei MA5616 (128 capacity)

Card counts:
- 18k cabs had 1 card installed
- 11k had 2 cards installed
- 3k had 3 cards installed
- Only 1k had more cards (4,5 or 6)

Ports in use (my own rough estimation from data):
- Around 1.9m ports in use
- Around 56 ports in use per DSLAM

Ports available with the installed cards:
- 2.8m available ports (both idle and in use)
- 83 ports available, per DSLAM
- So 27 ports free, per DSLAM
...

  • WWWombat
  • 11 months ago

Port capability if DSLAMs fully populated:
- 8.7m port capability
- 253 port capability, per DSLAM

Caveats:
- The original data showed DSLAM type.
- The original data did not show cabinet wiring type. M41's and MA5616's in cabinets with wiring for only 128 or 96 lines (respectively) mean my figures are an overestimate ... but it seems the wiring in these cabs can be retro-upgraded.
...

  • WWWombat
  • 11 months ago

Possibilities

- We know that the Huawei 288 cabinets can be retro-fitted with 64-port cards to support 384 lines.

- We know that the DSLAM in the Huawei 128 cabinets has the option of using 48-port cards, keeping open the possibility of an upgrade to 192 ports.

- BDUK projects have considerably more Huawei DSLAMs, and my gut feel is that more 288-line cabs are in the mix.
...

  • WWWombat
  • 11 months ago

Conclusions

Back then, full coverage was 20m premises. It is likely these 34k DSLAMs were meant to cover around 12m premises (60% of 20m), which would be 350 premises per cabinet.

253 ports per DSLAM, but 350 premises per PCP makes for capacity of around 70%.

However, VM takes around 20% of the market, and between 15% and 20% don't take broadband.

On average, capacity looks reasonable. In places, it won't be enough - especially if BT choose to not retro-fit additional wiring into some of the smaller cabs.

  • WWWombat
  • 11 months ago

This worries me a little, my cabinet is about to go live, it's an ECI one, and there are just over 700 houses it serves! I better get in quick!

  • redrum217uk
  • 11 months ago

redrum which cab is yours -- on 700 homes ?

  • fastman
  • 11 months ago

Dunston 29, the estate is a combo of houses and flats. I'm just trying to find out if that's right as that does seem like alot!

  • redrum217uk
  • 11 months ago

@fastman oops 635 properties.

  • redrum217uk
  • 11 months ago

@wwwombat Thanks very much for that exercise.

It does look like overall capacity is OK, but looking at some of the individual numbers it looks like some of the early commercial rollout may run into problems. Cabinets serving 600 or more premises are not uncommon. In Cambridge for example there are 3 serving well over 700 premises. Unless the cabinets are upgradeable they do not have capacity to meet a 40% take up demand.

  • gerarda
  • 11 months ago

@gerarda
Ta.

Yes - they're the kind of locations likely to need a second cabinet. I see on Kitz that they're seeing places where an H-288 is being added to an existing ECI.

I just tried extrapolating takeup to today's numbers. It amounts to, on average, 0.55 of a card on the 4-card DSLAMs and 0.8 of a card on the 6-card models.

That's about 23,000 card upgrades in 30 months, 25 per weekday, in the sampled DSLAMs. Maybe double that for today's installed base?

It also means around 1,100 of those cabinets would have a complete set of cards (3.2%), while about 250 of them would be full (0.7%).

  • WWWombat
  • 11 months ago

@andrew
I see you've assumed that the whole of a cabinet's coverage is discounted when a cab goes full.

I understand why you do that, as there are too many variations to "full" to attempt to account for.

However, one adjustment might be possible in a straightforward way. When a cab goes "full", the one thing we can be sure of is that it has now supported at least 1 linecard's worth of ports. 32, 48 or 64 ports at a minimum, or 53 ports on average.

You can automatically subtract one of these numbers from cab coverage, as you know they are the minimum covered.

  • WWWombat
  • 11 months ago

Seeing cabinets with loose wires being upgraded to strips to make capacity for G.fast.

  • Somerset
  • 11 months ago

Its not just line card multiples to subtract, you can have a full 288 cabinet that's full.

So I can subtract one, but which one?

  • andrew
  • thinkbroadband staff
  • 11 months ago

Hi Broadband Watchers.
Most of the FTTC that I saw fitted were with full capacity cards and some were bespoke and would cover approx 50% of the D side premises all had a fibre node that was close so GFast could be used or direct fibre or a new FTTC. I would think the final provision of CAbs would be 100k covering 22 million customers.

  • Blackmamba
  • 11 months ago

@Blackmamba the existing footprint already exceeds 22 million premises by some margin.

  • andrew
  • thinkbroadband staff
  • 11 months ago

@Blackmamba G.fast pods will be served by PON or WDM via a multiplexer in the FTTC cabinet. proximity to a node isn't an issue.

I am not sure what you mean by most FTTC being fitted with 'full capacity cards'. This seems very unusual if you mean all service board slots loaded; during commercial and BDUK deployments that I've seen the DSLAMs start off with one or two line cards and more are added as and when required.

  • CarlThomas
  • 11 months ago

Hi Andrew staff.
What ever the total coverage is there is a high % that are not interested to be involved with better broadband service so this figure is irreverent. Hi Carl all the FTTC cabs I witnessed transferred from transport were unboxed with full cards for that D side coverage. I agree with you the first cabs were missing Line cards plus short of tie pairs. The multiplexer is just a bolt on item.

  • Blackmamba
  • 11 months ago

@somerset
Are those upgrades use the older krone-style strips? Or the new-fangled tool-less stuff?

  • WWWombat
  • 11 months ago

I agree - you cannot know if the cabinet has become totally full, or if it needs a 6th, 5th, 4th, 3rd or second card. Or tie-pairs, for that matter.

But you can be sure that it isn't waiting for the first card ... so you can be sure those ports are full.

How many to allow for?

If you can distinguish DSLAM types, choose the 32/48/64 as appropriate.
...

  • WWWombat
  • 11 months ago

If you can't distinguish, or you are doing a nationwide count, why not just allow 53 ports per DSLAM? We know that is a valid average port count for 1 card from that sample of 34k DSLAMs.

Of course, the balance of ECI DSLAMs has since reduced - so there will be far more 48-port cards in place of 64-port ones. You could reduce to 50 to account for this.

If all DSLAMs since mid-2014 have been Huawei, and split 50:50 between the 128:288, then the overall average would drop to 48.

Anything between 48 and 53 is better than zero.

  • WWWombat
  • 11 months ago

If you want to err on the absolute side of caution, then just use 32, which is the smallest linecard.

  • WWWombat
  • 11 months ago

@WWW - new-fangled.

  • Somerset
  • 11 months ago

@WWWombat the aim is not to tell precisely how many lines are affected, but to help release at least some data, so those campaigning have something reasonably concrete. Where as its often the case of people extrapolating the 3/4 cabinets full in their village as a national picture.

  • andrew
  • thinkbroadband staff
  • 11 months ago

@Blackmamba As far as I am aware the DSLAMs come off the truck with no service boards at all installed, just blanking plates. They are installed as part of the commissioning process.

This is how cabinets are being installed to this day for financial and operational reasons.

Colour me confused.

  • CarlThomas
  • 11 months ago

Hi Carl.
I targeted this Cab as a project I was there when the EL ducting was provided road crossing fibre ducting run and the base. By chance the contractor was there when he unloaded the unit and fixed it to the base so I saw the 4 Cards. I returned a few days later and the the site was cleared and tidy and open for senvice. I did maintain this exchange when I worked for BT on this Cab had an old concetrator 24/4 24=customers 4= E sides.

  • Blackmamba
  • 11 months ago

@andrew
If you said that in the first place, I wouldn't have bothered doing the calculations for you ;)

It'd likely drop your coverage percentages by about one-sixth (eg 3.0 to 2.5%)%

  • WWWombat
  • 11 months ago

@Blackmamba
When I look at the DSLAM opposite me, it is hard to tell the difference between a real linecard and a blanking plate that is mostly hidden by the connector that sits in front anyway.

Hopefully you were counting cards, and not connectors.

  • WWWombat
  • 11 months ago

Hi Wombat.
I may have been been mistaken over the later Cabs but I do no on various other cabs extra cards were fitted in two weeks example Cab or Elstead exchange when they had a mass change over on the first card. I would think that a cab would have a deterred /prompt alarm % on ports working.

  • Blackmamba
  • 11 months ago

Haha. Used to live in Elstead. I wonder if the Thai at the Fleece is still excruciatingly hot.

I've seen that Openreach say they will add a card when they reach 75% ultilisation (presumably, they mean 75% of the last card they fitted).

  • WWWombat
  • 11 months ago

Hi Wombat.
If you lived in Elstead you may have know that Cab1 was located in the back garden of the Old Post Office this has been moved due to the building been sold to fit the new FTTC this served the Fleece. The Openreach crew who fibred the area I have access to plus their line managers only to ask. You may know R T who was line manager for transmission Guildford area.

  • Blackmamba
  • 11 months ago

@BM
I moved out of Elstead before even ADSL became known. There was no reason to have to understand BT infrastructure back then ... it "just worked".

We did live there when I first signed up with Demon for internet access, though, so the phone certainly got some use.

Our old house was on cab1, & has bad speeds for being 450m from the post office cottage. I assume the wiring is "strange".

I've looked on streetview before, but failed to find cabs 1 and 5. I see new images from 2016 puts a new PCP onto the corner of Upper Springfield, which is probably one of them.

  • WWWombat
  • 11 months ago

Hi Wombat.
Yes Cab 5 is in the direction of Peper Harrow towards the industrial estate served by a bespoke Cab the Same as Peper Harrow all this area provided transport for the Normandy landing under the control of Monty which was residing at Hindhead. The area was cabled using DON 8 and the main junction route London-Portsmouth 150 Lb CC on 50 -60 poles I was on the gang when we removed some of them.

  • Blackmamba
  • 11 months ago

"There is an oddity in the way migrations are handled too, in that for some migrations there needs to be a spare port available even when you have VDSL2 on that line."

I have been wondering about tis aspect.

Originally on ADSL from EE, when VDSL became available, I upgraded to 40/10, acombination that it was only £1 per month increase basically, as opposed to £10 for 80/20, all EE.

I don't really need 80/20; but have been wondering what "technicalities" would be involved, as at first sight, it looked as though it should be simply change a contracted parameter.

Anyone done such an upgrade?

  • alexdow
  • 11 months ago

@alex
An upgrade without changing ISP? Yes- that is a simple regrade, which can happen even if the cabinet is already full.

  • WWWombat
  • 11 months ago

@bm
Cable laying WWII-style!
https://www.awm.gov.au/collection/F05224/

  • WWWombat
  • 11 months ago

I'm geting fed up at reading all these stats etc. How can I actually find out if the Cabinet to which I'm connected with ADSL2 will ever get any better than 0.87MB upload and 11Mb download? I'm less than 100m from Cabimnet 7 in Romsey, Hants. Chasing my MP last year hasn't done much!

  • jonesjh99
  • 11 months ago

No obvious evidence that cabinet 7 is on any plans for upgrading. Looking at area seems to have Virgin Media and that is likely reason, i.e. if a superfast provider present public money should not be used.

So do you have Virgin available as an option?

  • andrew
  • thinkbroadband staff
  • 11 months ago

Yes, Virgin cable runs up my street. However, I am, untypically, quite happy with TalkTalk which means Openreach. Apart from a better upload speed I can cope and I don't want to go through the hassle of changing from my f2s.com email addresses just to change to virgin. I don't want all Virgin's bells and whistles either. I'm in the middle of town so I agree that public money should help elsewhere. What I can't understand is why Openreach have not enabled Cab 7. And Virgin is all over (most of) Romsey. Or, what it takes to get them to consider it.

  • jonesjh99
  • 11 months ago

What was even more aggrevating was staying with family in Harwell Village over Christmas and finding that Openreach was supplying them with 30Mbps download and 9Mbps upload!

  • jonesjh99
  • 11 months ago

@jonesjh99
Likely one of two reasons: too small, or already more than 90% covered by VM.

Note: Every fibre cab on Romsey has needed subsidising. One privately, by builder of a new estate. The rest (33, 9 of which are in-build) by state aid.

State aid can be used on a cab if VM only get to less than 90% of the premises, no more. You could be caught out by this limitation.

Your cab has a similar number of postcodes to the one next to it - cab 34. That was done 6 months ago as part of phase 2, but only covers 85 properties ... which is relatively low.

  • WWWombat
  • 11 months ago

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