Do leased lines use same physical fibres as for WBC FTTP ?

Someone I know who owns a small business is having both leased line and WBC FTTP broadband installed into their new business premises. There are newly built (unoccupied) residential apartments above the premises. WBC FTTP only recently became available in the area.

There is a white plastic wall mounted Openreach/Prysmian 24? port Fibre Optic Distribution Point box in the services/utilities room serving entire building.

Landlord says there is a new single multicore fibre cable into the above box.

Openreach has supplied an ONT for the WBC FTTP service, but it is not yet connected to the Distribution Point.

The the leased line apparently will cost £2.5k to install, excluding monthly charges. Openreach missed the first install date following survey last month.

Does anyone know whether a new leased line would use the above infrastructure for WBC FTTP, or is it always separate fibre cable?

100% completely separate in all respects. The only thing the two may share are ducts (or poles)

Actually this isn't totally true anymore. We're finding that Openreach are taking 'leased line' circuits back to aggregation nodes for GEA-FTTP/C on long haul routes in particular. The "serving exchange" is no longer the local "copper" exchange for the premises, but the GEA parent exchange. Comes down the same cable as GEA-FTTP.

This is true even in cities with multiple exchanges, we have a circuit going into a DC and there's a T-Node right outside but they're taking it to an aggregation node instead.

Thank you all for your answers.

Edited by bill888 (Thu 09-Dec-21 03:21:26)

In reply to a post by k4a:

Actually this isn't totally true anymore. We're finding that Openreach are taking 'leased line' circuits back to aggregation nodes for GEA-FTTP/C on long haul routes in particular. The "serving exchange" is no longer the local "copper" exchange for the premises, but the GEA parent exchange. Comes down the same cable as GEA-FTTP.

This is true even in cities with multiple exchanges, we have a circuit going into a DC and there's a T-Node right outside but they're taking it to an aggregation node instead.

Thanks for the update there.

That's rather interesting that this is now a standardised deployment method. I had an Openreach EAD leased circuit installed earlier this year, and it all runs via the local T-node (and several other nodes) to the local exchange (rather than GEA headend exchange).

I do now recall a some Openreach video briefings, like this one, where the presenter mentions 'a mix of technologies...including Ethernet...' running via the Aggregation Nodes.

It would make sense to move leased line circuits to linking back to GEA parent exchanges, otherwise closing exchanges is going to be tricky if they are have leased line circuits.

If you are doing that, then it makes total financial sense to use the one fibre bundle from the aggregation node to the GEA exchange. It's all single mode fibre so it's not like there is a distance limitation issue that requires going to the local exchange anymore. There is also a good chance the aggregation node is a lot closer than the local exchange.

If CDWM-GPON ever becomes a widespread thing then you could even use the same fibre all the way to the premises

Indeed. Given OR are running 432-core ‘ribbon’ fibre in an 11mm diameter spine cable, ought to be ample future capacity from the exchange to the Ag Node.

GPON and 1000/1000 EAD currently use the same 1490nm wavelength down for GPON as is used upstream for EAD. So they definitely wouldn’t be using the same fibre core to carry both currently.

Future iterations / generations of GPON like XGS-PON, 25 GPON and 50 GPON neatly segue their various allocated wavelengths to allow concurrent operation over the same fibre core - at least 4 wavelengths before going to any sort of real CWDM - this providing a pretty seamless upgrade path for PON tech.

It always made sense to keep them entirely separate even if only for reliability reasons. Less chance of someone accidentally being disconnected.

But a leased line would still bypass much of the standard FTTP infrastructure that would be closer to the home/business. It would go directly to the aggregation node, and most engineers don’t have access to that so it still should be nice and reliable. It’s a good compromise and will save Openreach a lot of money.

I can understand the exchange consolidation desire, but there's a lot of RO2 out there, so it would be interesting to see how that is handled.

In reply to a post by k4a:

Actually this isn't totally true anymore. We're finding that Openreach are taking 'leased line' circuits back to aggregation nodes for GEA-FTTP/C on long haul routes in particular.

But even then, the FTTP would go to a splitter node (probably via a CBT), whilst the leased line would go directly to the aggregation node.

So I'd say the chances are extremely high that two fibre cables would be pulled into the building.