Who is responsible for BT's core network?

If Openreach only looks after the local loop and exchanges which division looks after the core? I've come across 'BT Technology' that sounds like they might be the ones.

Indeed.
OR look after the Access network, TSO (that was - there have been several name changes over time) manage core networks which the customer facing divisions (Consumer, Wholesale etc.) provide products and services over.

Openreach also own the backhaul from exchanges too. If you're an ISP that requires backhaul to your own building that is something you purchase from Openreach.

Not quite.

Wholesale manage the backhaul, whether they get Openreach to physically maintain the cables, routers and switches I'm not sure. It could be TSO.

The MD and Chief Architect and his team within BT TSO are the team responsible.

Yes, basically TSO run the head end electronics beyond the OLT cards , switch and transmission equipment, and openreach run the cables and street DSLAM and PON equipment.

Edited by deleted (Fri 21-Oct-16 21:25:40)

In reply to a post by lee111s:

Not quite.

Wholesale manage the backhaul, whether they get Openreach to physically maintain the cables, routers and switches I'm not sure. It could be TSO.

Here's a link:
https://www.openreach.co.uk/orpg/home/products/ether...

I suppose it depends on how you read the initial question. Wholesale ARE responsible for BT Consumer's backhaul, presumably buying the EBD product from Openreach. . However someone like Sky, TalkTalk, Voda, Zen etc who want their own backhaul would used the EBD product from Openreach directly, not via BT Wholesale.

Edited by deleted (Sat 22-Oct-16 08:43:56)

Sky mostly use virgin provided backhaul which uses cable link to their own fibre. I suspect talk talk do similar with their own fibre. BT wholesale mostly likely use SDH systems from TSO for most of their main network

Vodafone own and presumably use the C & W network where available. Which is a lot of places.

Guys you're telling me stuff I already know here. To say Sky "mostly" use Virgin Media backhaul is so, so wrong by the way.

I know Vodafone have their own network but they have to pay Openreach to link into their network. Go to most exchanges and you won't see C&W ducting outside, or Virgin Media. This happens every time we discuss this subject and most of you don't work on the network so....

This is a myth

i don't know who started it

i've heard it a few times now.

I don't think I am. Others perhaps. Re your earlier question as to what the OP means, I would have thought he means the BT Wholesale core.

You seem to be trying to say every provider uses BT core. To me, Vodafone uses ex-C & W to a large extent, and other services which may or may not be BT Group owned where they do not have a close enough POP on their own core.

Linking from the exchange to their own core even using BT cabling belonging to any division is not "BT core network". It is simply dark fibre available to rent.

Rogan8

BT's core network for BB has not been SDH for some years. WDM running ethernet at 10G/40G/100G per wavelength. There is still SDH for the TDM private circuit products and voice ccts but the last (3+) iterations for Data have been Ethernet.

In reply to a post by RobertoS:

I don't think I am. Others perhaps. Re your earlier question as to what the OP means, I would have thought he means the BT Wholesale core.

You seem to be trying to say every provider uses BT core. To me, Vodafone uses ex-C & W to a large extent, and other services which may or may not be BT Group owned where they do not have a close enough POP on their own core.

Linking from the exchange to their own core even using BT cabling belonging to any division is not "BT core network". It is simply dark fibre available to rent.

It isn't! Honestly you're wrong on some aspects and I do this stuff for my job. The dark fibre product launches next year. Dark fibre is NOT available from any part of BT Group right now.

I'm not saying every provider uses the BT core. That just isn't what I'm saying at all.

Re-reading the question I think you're right and he's asking about the BT Wholesale core network actually. So some of what I've written is in retrospect a bit irrelevant. But still, the fact people think Virgin Media run fibre into "most BT" exchanges for Sky is interesting.

Edited by deleted (Sat 22-Oct-16 15:04:00)

Roberto / Icarus
I think people need to define what they mean by Core network.

To me ( & I think Roberto) the following apply

Customer to local exchange is : Access network ( BTOR)
Local exchange to first router (Metro node or CP equivelent) is backhaul. ( BTOR, C&W, Virgin etc)
Between routers and Internet peer sites is Core network. BT TSO & CPs

Messy point is the Backhaul where CPs ( and BT divisions ) can buy products from both OR and BTW depending on whether they are bandwidth or dedicated circuits.

I agree with you quite a few providers have their own core, but only a few have any amount of non BT backhaul ( Virgin & Vodafone [C&W] ) outside the biggest cities.

Yes, the question was vague, and what non-BT Wholesale providers use is a side-issue anyway.

By "dark fibre" I am quite possible using the wrong term. I simply mean anything that is unused capacity - and by unused I mean not attracting rental revenue but just buried somewhere as part of a bundle in a trunk network. Waiting for someone/anyone to rent it and get linked to it.

I don't see trunk networking as such as being the same as core network.

For instance, Colossus (IIRC) was BT Wholesales "core network" from exchanges to ISP's Centrals. It still presumably wasn't physically theirs.

I think the OP is savvy enough that if he meant wider than the replacement for that, i.e. an Openreach core, he wouldn't have said BT. I also think if referring to BT Consumer or Business he would have said so. Which leaves BTW.

In turn leaving us with the question does he mean the capacity they have, or the physical installation and maintenance of it? What about the kit at the ends of the fibres?

There isn't anything available that reflects what you're describing there. Dark fibre is just unlit fibre. It's explained on that page I linked to pretty well and at present is not available.

You basically cannot bring your own fibre into a BT building at the moment and terminate it on your own equipment. You have to rent the last bit of the fibre (at a minimum) and it must link on to a bit of Openreach (ADVA) equipment where it can be tested if need be etc. In other words it is always "lit".

Where things will change next year is that providers can rent actual unlit dark fibre which no part of BT Group will have any dealings with other than if it is physically damaged and needs repairing.

I agree with you quite a few providers have their own core, but only a few have any amount of non BT backhaul ( Virgin & Vodafone [C&W] ) outside the biggest cities.

Yeah this bit is crucial, you only have to have a walk around a BT exchange in many large towns and you'll be surprised to find you'll only see BT jointbox (manhole) covers.

Edited by deleted (Sat 22-Oct-16 16:00:34)

Roberto

BT TSO are responsible for ALL the Core electronics including the WDM and Optics that runs over the fibres on CORE fibres. This includes all the Core Routers and other boxes that comprise a core network. BT TSO deal with all capacity issues in this space.

( DNS, BRAs and other boxes can be owned by other divisions as they relate to their customers but all BT ones will be located within the same Core nodes as the rest of the network.)

Access fibres and electronics are ALL BT OR.

Backhaul between exchanges is also BT OR responsibility BUT BT TSO usually look after the electronics on their behalf. ( Yes this can be in the same cables as the Core!). This was all setup in the original (2005) undertakings that split BT OR from the rest of BT and can be very confusing! ( Instide BT asd well as outside BT).

BT Wholesale's core run over logical bearers within the overall TSO Core. These can be VLANs or whole wavelengths making up a logically seperate network . BT Retail, BT Business and CPs and managed customers can also rent capacity on the core network to make up parts or all of their own core.

CPs handover points are (usually) in Manholes outside major exchanges (ISI: in span interconnect)) where each operator splices their fibres to BT fibres to enter the exchange, the Electronics are mutually agreed ( Identical) on both ends each owned and run by BT and the CP. Where there is LLU equipment within the exchange this still applies! But many operators rent capacity back to a larger ( ISI) exchange rather than pay to build fibre to that many exchanges.

Sometime in the next year BT will have to offer to supply dark fibre to other operators.
The terms are still unclear to me as this may involve just splicing fibres to make sections from CP site A to CP site B available and they will supply all electronics. Otherwise the CP will have to rent space, power & vent in BT exchanges to fit their own equipment and pay charges for this.

Where the equipment is LLU this already exists at one end but at some point the fibre will still need to be spliced to the CPs fibre.

Faulting then becomes a nightmare for BT as they have no vision of the service but I would lay money the CPs will always report a fault to BT first before looking at their own equipment. ( Always have done as it is easy to blame BT). All BT's electronics are connected to a managment network for reporting that allows faulting from both ends and remote management access, this allows 'guesses' at how far the break is in a 'cut fibre' incident, this ability is unlikely for many CPs.

That looks quite comprehensive, and thanks. Too much to take in all at one go while salivating at the smells emanating from the kitchen on a Saturday night .

Working out how that answers the OP's question is for another day, but your detail even more shows we need to know what was meant it.

I still don't think it answers the Vodafone point. A link from inside the exchange to any non-BT supplier with fibre arriving in a manhole outside that exchange is not BT core. I accepted a while ago that my understanding of what dark fibre is was incorrect.

It remains the case that what I said before is true - that non-BT fibre owned by Vodafone and linked from the exchange in a manhole outside the exchange, going all the way from there to their own routers/services, is not running over BT core. "However someone like Sky, TalkTalk, Voda, Zen etc who want their own backhaul would used the EBD product from Openreach directly" is not true about Vodafone other than if the link from the exchange to outside is an EBD product. If it is, it still isn't "core".

If every BT fibre is core, then none are.

In reply to a post by RobertoS:

"However someone like Sky, TalkTalk, Voda, Zen etc who want their own backhaul would used the EBD product from Openreach directly" is not true about Vodafone other than if the link from the exchange to outside is an EBD product. If it is, it still isn't "core".

If every BT fibre is core, then none are.

Well we are both right. If you think about it the likes of Vodafone and Sky won't have their own fibre networks running to a manhole right outside the BT exchange in MOST places. Larger towns and cities, maybe. But most places, no.

I'm stood outside/inside an exchange right now. It has LLU services from most providers. Certainly Voda, TalkTalk and Sky. But none of them have a core network nearby that they could extend to the exchange. So ALL of them will be renting backhaul.

Hopefully I'm being a little bit clearer, the explanation given by the poster above is fantastic and should answer most of your questions though.

Just to clarify the question comes from here:

http://forums.theregister.co.uk/forum/1/2016/10/21/h...

"If Openreach looks after the trunk network as well as "local" circuits (which the Wikipedia article suggests they don't) then splitting off Openreach as it currently exists could have unintended consequences. And if Openreach doesn't look after trunk routes then who does?"

Andre

We can now see the context of your enquiry.

This gets messy!!

Due to the complexities of trying to do what was required back in 2005 by the BT undertakings All BT fibre Cables and ducts are taken to be OR responsibility. Thus regardless or which BT divisions utilise each fibre within them OR maintain them.

(Asset wise they are accounted to the division that uses them, thus Access fibres are OR, Trunk fibres are TSO. Internal trading covers Retail Business and Wholesale.)

IF OR is split off in theory nothing changes, in practice all BTs services are provided by OR and the accounting and communications chains get messier, ( This also happens with Dark Fibre and Duct leasing) as there will be more players shouting at OR all wanting to pay less. Depending on the Dark fibre prices BT divisions may well be better off and OR worse off than at present!

BT would have to split all its Fibre ( and Duct space) assets into sub products internally so that TSO would pay real rent to OR for the assets it uses in each class. This must all be happening under the radar to meet the non discriminartory requirements for Dark fibre and Duct sharing.

The real messy part is the OSS ( computer systems) which would all have to be changed and cost tens of £m each time you redesign a system. eg; Incident management is pan BT at present so that all CPs ( internal and external) get a total view of what service is down in any incident ( What they do with the info is a different matter!) This allows OR to prioritise the recovery of fibres/Cu circuits depending on SLA AND government requirements.( Emergency users over paying customers!)

This all costs and is part of the regulatory cost BT has to pay to meet OFCOMs wants. BUT doesn't make it cheaper for you and I and takes a long time to change when it is a live system. ( BTs computer people regularly do the equivalent of changing the engines on a jet whilst in flight without a major failure.) This is where the real difficulty splitting OR from BT will arise. along with the pension deficit and debt ( It will be like bad divorce and will make everybody poorer except the accountants).

Same goes for buildings!!

I don't want to think about the mess when Network rail break a duct with duct sharing in, engineers may fight to be first/last in the hole!

For those wondering how it takes up to a week to fix. ( practically all lines affected would be Access lines)

Approx time order
The emergency lines affected will be restored first, Hospitals / Police/ Fire.
and critical Residential lines ( Kidney dialysis etc)

At the same time, if they can get at them together, the fibres will be rejointed in priority order. ( Trunk ones will usualy be rerouted where capacity exists by electronic switching) .

Where customers paid for resilience they should not be affected (but may if the resilience was not route based but duct or fibre based)

Then it is a case of working through the rest of the access circuits with 30k+ joints to be remade.

All the above depend on whether the contractors just cut or completely destroyed the ducts and cables and in the latter where they have to cut back to to replace the section. The closness to the railway may make this further than optimum!

I've also noticed that 'bml utilities' have been installing cable in underground distribution points, and also at the cabinets in my area?

What are their responsibilities?

Contractor working on behalf of Openreach.

In reference to www.bizdb.co.uk/company/bml-utility-contractors-ltd-06579615/:

On Monday 15th December 2014, it started searching for new employees for a Telecom Jointers E & D side for PCP/DSLAM work.

In reply to a post by Andrue:

Just to clarify the question comes from here:

http://forums.theregister.co.uk/forum/1/2016/10/21/h...

"If Openreach looks after the trunk network as well as "local" circuits (which the Wikipedia article suggests they don't) then splitting off Openreach as it currently exists could have unintended consequences. And if Openreach doesn't look after trunk routes then who does?"

It's interesting isn't it? As you say it's not just the local loop they look after. It would be so much more officially to split off OR than many people (and maybe even Ofcom) realise. Even down to establishing things like ownership of the actual buildings. Absolute nightmare!

Kitcat, thank you for that and to others for their in-depth explanations. I think that addresses the gist of my question. Until I saw that comment on Wikipedia I assumed that openreach 'owned' all the physical cabling and switches (in effect that openreach was the 'real' BT I suppose) and that the other divisions just attached their own routers and paid rental to them. Clearly it's a lot more complicated than that (not a great surprise to me). And would certainly be yet another problem if OR were to be separated off.

BT wholesale.

Openreach do own fibre outside of the local loop which is even rented out by companies like sky to get traffic from exchanges to their own network.