Piggbyacking on a FTTC cabinet?

Our community has just had FTTC delivered under the BDUK subsidy programme, but only to ex-EO (directly cabled) customers, for whom a new cabinet has been installed opposite the exchange.

Those who were already connected to the existing cabinet serving the western end of the village now discover that their (smallish - perhaps 50 lines) cabinet is not part of the current subsidy programme (which runs to 2018). And they are trying to examine their options.

The obvious solution would appear to be for those wanting Fast Broadband to have their circuits diverted at the exchange to run the extra 40m to the new FTTC cabinet. Looking at the works done for the new cabinet suggests that existing EO lines have been diverted in exactly that way.

The only difference would appear to be that such circuits would run through two cabinets: the total line distances (at 400-600m) are no longer than the longest-but-one ex-EO line which does get Fast Broadband. And they are a lot shorter than the 1.67km line to a farm which also qualifies for Fast Broadband (albeit at pretty low speeds).

Have I missed some technical subtlety that makes it impossible to route a circuit through two cabinets?

Or are the non-FTTC customers simply the victims of an Openreach policy which conveniently leaves angry people desperate for Fast Broadband, and so builds up political pressure for Openreach to be given a further round of public subsidy for conversion of remaining cabinets?

The conspiracy is simple, if covering 90% of the UK, there will be 10% missing out and with some dense areas already well above 90% the more rural areas will bear the lions share of missing out.

What you suggest is potentially possible but a decision somewhere will have been made to spend the money it would cost helping someone else to get a FTTC solution. Has the local project absolutely confirmed that your cabinet is going to miss out?

The technical subtlety is that you end up with a more custom solution for an area and may not fit in the phase 2 (extension project plans).

When you have ~26,500,000 households in the country, on ~5600 exchanges, and way more cabinets, in order to stand a chance of maintaining it you need a relatively standard architecture.

Meaning that a line goes to 1 cabinet, which goes to the exchange.

BDUK has a budget, iirc, of about £100 per house passed. 50 lines means that if it costs more than £5k to deploy a cabinet to you, it's too expensive. It would cost way more than £5k.

The layout you've just invented would work, but it would be unique in the whole country and won't be done.

In reply to a post by JohnGeddes:

The obvious solution would appear to be for those wanting Fast Broadband to have their circuits diverted at the exchange to run the extra 40m to the new FTTC cabinet. Looking at the works done for the new cabinet suggests that existing EO lines have been diverted in exactly that way.

Just to be clear - when you say "at the exchange" - the EO diversion will be just outside the exchange, rather than within it - the technical regulations (known as the ANFP) don't want the VDSL2 frequencies within the exchange building.

In reply to a post by JohnGeddes:

Have I missed some technical subtlety that makes it impossible to route a circuit through two cabinets?

You might have missed a technical subtlety. Not about routing through 2 cabinets as such (secondary cabinets already exist in the network), but about whether it is feasible to divert your cable at all. Not about copper, but about insulation and protection.

The subtlety stems from the fact that E-side cables are different from D-side cables.

E-side cables, feeding from exchange to cabinet, have lots of pairs, tend to be older, and can even be insulated internally with paper. They are often protected from water incursion using air pressure fed from the exchange. Keeping water out is vital, so there is a great desire to not break into these cables at all. The oldest E-side cables can be lead-covered - so any work requires the services of a skilled lead jointer who can re-seal afterwards. Rare.

Diverting an E-side cable means the portion between the diversion point and the existing cabinet will no longer be protected from water ingress. And may be made of a material that sucks water in.

D-side cables, feeding from cabinet to poles, have fewer pairs, and are more likely to have been replaced - so nowadays tend to be gel-filled for water protection. These are so much easier to break into, as the gel automatically keeps water out.

EO lines are a strange mix, but are much less likely to be large bundles of air-protected cable. That means there is a reduced risk from breaking into an EO bundle, and diverting it to a new cabinet.

So...

If your E-side cable is constructed this way, the last thing BT would want to do is to break into the cable - as this will remove any remaining protection as it runs from (just outside) the exchange to the PCP.

That means they would need to replace the entire length of the E-side cable to the cabinet, using a gel-filled alternative. Definitely not cheap.

Quite how much this applies to tiny village exchanges is another matter.

Or are the non-FTTC customers simply the victims of an Openreach policy which conveniently leaves angry people desperate for Fast Broadband, and so builds up political pressure for Openreach to be given a further round of public subsidy for conversion of remaining cabinets?

Whoever is left out will have a cadre of angry people - it doesn't need a policy from Openreach for this to happen. But there are probably more of them who think the political pressure should be to NOT give the money to Openreach.

Thanks for that detailed description.

Takes me back to the 1950s when lead-covered; and oil-impregnated insulation were the norm.

If I remember correctly, the "cloths" for moulding and dressing the large lead joints, like water plumbing, were moleskins.

The large "soup" ladles for transferring the molten lead to the joint/seal.

The piggybacking that I envisage would not requiring any cable diversion.

As showing in this schematic, non-FTTC customers would have an idenitcal topography as some (or perhaps all) of the ex-EO customers apart from having cables jointed in an extra, inert, street cabinet.

Notes on the schematic:

Ex-EO customers in areas A and B (at least) appear still to be cabled directly to the exchange - there was no reason that their routes would have crossed the road before the advent of the FTTC cabinet, and there are no civil works that suggest that they have been diverted as part of the upgrade. So presumably these lines are still connected to a frame in the exchange, with a new cable then connecting them 40m or so to the FTTC cabinet.

(Ex-EO customers in areas C and D might still have circuits via exchange, but their cables might have been intercepted at the footway box and routed directly to the FTTC cabinet.)

Given that it's OK for ex-EO areas A and B to have be routed home->exchange->FTTC cabinet, why is it so unthinkable for via-cabinet Area E to be routed home->non-FTTC cabinet->exchange->FTTC cabinet?

Are areas A & B actually routed to a FTTC cab via the exchange i.e. can order now or is it your assumption that this will happen.

Have seen exchange grounds gain a few cabinets for EO lines on travels

Nobody is going to be running any grease filled cables out of the exchange for E0 cab cut ins. Grease filled cables only go up to 100prs and pressurised cables go up to 4800prs. You can simply airblock either side of the cabinet and bridge with an air tube.

Nothing technically impossible with what you suggest. But the better solution is to cut a cab in for the E0 area and then fibre tube out to the existing cab and fit a second more effective FTTC cab.

As with all this game, it's about what is the best engineering solution and what is a quick solution that is second best. Second best is labour intensive jointing time that doesn't keep the punters happy for long.

Edited by deleted (Wed 09-Dec-15 21:39:50)

Yes - both areas have FTTC available to order now, and there is only one FTTC cabinet in the village.