Curious Fibre run...

I've been looking at roadworks.org following the progress of Openreach's contractors blow the fibre which started last Thursday (28/05). The FTTC DSLAM is already in place which happened a week before that (22/05).

What i'm finding curious at the moment that they are not starting the fibre from my exchange that i'm about 4 miles a way from (Martock, WWMART) but they seem to have started at closest and last Fibre Cabinet which is part of the Yeovil (WWYEOV) exchange in the other direction and live and from what i can see they are doing a cable run from there through my village to the Martock Exchange and i assume connecting the FTTC's along the way.
The reference numbers for roadworks.org for these cable runs end IBL10HAL1 all the way to IBL10HAL19 which is roughly where the Martock Exchange is.

Currently all the various checkers say "Exploring Solutions" or "under review" and at this stage i'm not so bothered about that progress is better than nothing
I'm not so bothered about why i'm on that exchange or this cab as there's no changing that really but curious perhaps from an infrastructure and logistics side.

My limited understanding of these things is that most exchanges (at least mine and the Yeovil one) are already fibre linked together which i believe is the 21CN status being enabled but maybe that's not the case?

Perhaps my question can't be answered unless BT/Openreach tell me which is highly unlikely even if i did ask. And there's no point in asking the contractors as they are just doing a job from point A to B.

If anyone can shed some light though that would be awesome!

Thanks in advance

Edited by deleted (Sun 31-May-15 07:50:21)

21cn is a bt wholesale asset.

Openreach often runs fibre from a larger exchange to cabs on smaller exchanges, e.g. Falmouth is the gea handover for 8 exchanges

Thanks MrSaffron!

interesting so although my PCP is connected to a different exchange (wwmart) and from the remediation work done after putting in the NGA (Huawei 288) it seems to at least link them together it could still be that at least our NGA could be running from the last NGA on the larger exchange (wwyeov)?

Do you know if there are benefits for doing this? Is it a cost decision or an infrastructure decision?
I suppose in terms of line speed from my house to the cab it won't make much difference as i'm still 850mtrs'ish from the NGA anyway.

I almost started thinking they might be doing FTTP as the cable run will be going right outside my house

You need to think very long term.......as in decades.
Bypassing the smaller local exchanges by running fibre from larger nearby ones has a long term aim.

So:
Eventually you get the cabinets to handle voice calls as well.
Then move everyone over to FTTC regardless and switch off the exchange ADSL(2) equipment.

So you now have a group of regional mega-exchanges feeding umpteen hundred (if not sometime further off thousands+) cabinets.

At this point the local exchange plus all the E-side cabling from them to each local cabinet is redundant and can be closed down. The exchange building or rather the land in many cases is very valuable and can easily be sold off - for housing.

I suggest that the Yeovil Exchange may have sufficient space to accommodate all of the VDSL/Fibre equipment for that larger catchment area, thus reducing the travelling required etc for its maintenance etc.

I also suspect that it does reduce the amount of roadworks etc involved, to cover such areas - back to the Network Analysis programs I wrote many years ago!


So far, I have not seen any reasonable description of what has to be added at an exchange, to accommodate such VDSL/Fibre upgrades, apart from the assumption that the fibre must go "somewhere" and onwards.

Perhaps someone with "inside knowledge" would oblige.

In reply to a post by eckiedoo:

I suggest that the Yeovil Exchange may have sufficient space to accommodate all of the VDSL/Fibre equipment for that larger catchment area, thus reducing the travelling required etc for its maintenance etc.

I also suspect that it does reduce the amount of roadworks etc involved, to cover such areas - back to the Network Analysis programs I wrote many years ago!


So far, I have not seen any reasonable description of what has to be added at an exchange, to accommodate such VDSL/Fibre upgrades, apart from the assumption that the fibre must go "somewhere" and onwards.

Perhaps someone with "inside knowledge" would oblige.

I don't work exactly in that job but obviously from what I've seen the headends get a very tall box that all of the fibre (ultimately from the cabinets) feeds into from the top. Though I've only ever seen the ECI headend equipment, never the Huawei version.

The ECI version pretty much looks like a double width ADSL2 DSLAM (roughly same height). You can't really see much of the innards.

MrSaffron-didnt't you go on a visit to an exchange with a headend once where you were shown all of this stuff though?

http://www.coolwebhome.co.uk/fibre-cornwall/

Pages 6 and 7 of the pictures show Falmouth headend

It will make no difference to the speeds you get.

Benefits are that in time, some exchange buildings will be abandoned, but that is many years away, but is a reflection that openreach believes their GEA fibre network will have a long life, hence its support for future FTTP expansion even in areas where just VDSL2 is deployed now.

Edited by MrSaffron (Sun 31-May-15 10:37:17)

And the copper recovery - "little gold-mines".


Also, I wonder if the redundant ducts may have a residual value, such as for electricty supplies, whether new or providing a more protected environment thinking of the recent storms and associated damage?

Edited by deleted (Sun 31-May-15 13:16:12)

Thanks, Icaras.

Edited by deleted (Sun 31-May-15 13:16:45)

In reply to a post by eckiedoo:

And the copper recovery - "little gold-mines".


Also, I wonder if the redundant ducts may have a residual value, such as for electricty supplies, whether new or providing a more protected environment thinking of the recent storms and associated damage?

NO. there are in the wrong place and the duct will be the wrong colour and would suggest that comms cables were inside rather than a dangerous multi-kv supply.

Thanks, MHC - I had forgotten about the colour-coding.

The copper must have some value, though.

Well the guys in white vans think so ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

I do love these kinds of threads and especially when you get pictures like what Mr Saffron posted.

Any more info on how exchanges are linked / how it all physically works etc?

Yes, we do wander a bit.

I also wonder what differences there are in the organisation of the management etc of the (fibre) network, particularly in connection with the differences, if any, arising from running the fibre from a different exchange, such as Yeovil in this particular case.

Thanks to all contributing! It's good to know i posed an interesting question

I was curious whether it linked from WWYEOV to WWMART in some sort of loop. I suppose it some respects it adds some redundancy and failover so if one link goes down you aren't totally ruined.
Particularly as others have said BT are aiming to decentralise from the old Exchange model being that i suppose in some respects they are quite dated buildings etc.

Food for thought though!

No loop. Just tree and branch topology

Last calculation I did put it at about £5 billion if you rip it all out.

Needs voice as in VoIP to become as reliable as old PSTN and then the issue of power backup for emergencies i.e. fibre ONT needs power to run

In fact, it tends to reduce redundancy; and when there is a failure at one of those more centralised exchanges, eg Yeovil, then a much greater number of subscribers/users are affected.

The nearest parallels I can think of are Railway Signalling (implying Control), Air Traffic Control, National (Electricity) Grid and similar.

As an example of possible effects of such concentrations of very similar telecommunications -

http://www.globalrailnews.com/2014/09/17/network-rai...
"
In January 2015, York ROC will take over from the current control ... controlling signalling between King�s Cross and the Scottish border.
"

If the York ROC "goes down", note the widespread effects.

With the fibre being run from WWYEOV they are now half way through my village and should be at the NGA by end of the week i'm thinking.
In terms of when the NGA will go live (i'm not asking for dates) but would they have to complete the cable run from WWYEOV to WWMART (the exchange my cabinet is connected to) before i can order or shortly after hitting my NGA could the order be placed?

Depends on the route the fibre takes and where they have placed the aggregation node (s), but I may not be necessary to take the fibre your local exchange at all.

Edited by deleted (Tue 02-Jun-15 10:53:35)

In reply to a post by Ribble:

Depends on the route the fibre takes and where they have placed the aggregation node (s), but I may nit be necessary to take the fibre your local exchange at all.

hmm ok thanks!

One further possibility, beyond the ones already mentioned related to shutting rural exchanges, is using exchange -> exchange spines to add resilience.

The general understanding has been that fibre spines ran out from an exchange, taking in a number of PCPs en route. However, I saw a suggestion today that spines run exchange to exchange.

Quite a while ago, I saw a proposal from within BT suggesting that fibre could run from exchange to exchange, offering the possibility for cabinets to be dual-parented, improving resilience.
http://www.ecoc2010.org/contents/attached/c20/WS_5_R...

This concept extended backwards, as suggested by others, allowing those small exchanges to close - ultimately leaving the spines running between core nodes instead.

I wonder if BT have been putting into place exactly this kind of resilient architecture.

It could, of course, mean that they're putting in additional exchanges exchange backhaul.

Perhaps that's what they are doing.
Connecting Devon & Somerset said that the Yeovil Exchange is the headend for our area.
I just thought it was quite strange they were running the fibre from the last cabinet in Yeovil nearest to us and on to Martock as I would have assumed they would have already been linked by fibre in the first place if that topology is in use.

It's killing me not knowing how this works

oh and i spoke to TalkTalk (my provider) who said it wasn't available yet however there were some fibre lines already in use at the exchange.

The plot thickens!

Edited by deleted (Thu 04-Jun-15 06:11:15)

In reply to a post by WWWombat:

One further possibility, beyond the ones already mentioned related to shutting rural exchanges, is using exchange -> exchange spines to add resilience.

The general understanding has been that fibre spines ran out from an exchange, taking in a number of PCPs en route. However, I saw a suggestion today that spines run exchange to exchange.

Quite a while ago, I saw a proposal from within BT suggesting that fibre could run from exchange to exchange, offering the possibility for cabinets to be dual-parented, improving resilience.
http://www.ecoc2010.org/contents/attached/c20/WS_5_R...

This concept extended backwards, as suggested by others, allowing those small exchanges to close - ultimately leaving the spines running between core nodes instead.

I wonder if BT have been putting into place exactly this kind of resilient architecture.

It could, of course, mean that they're putting in additional exchanges exchange backhaul.

Thanks for linking this it made interesting reading, has this been done anywhere that anyone knows of? I live in a village next to the OP (bewA) but on the same exchange, we have both watched as this fibre cable runs from yeovil, through their village, now through mine Stoke Sub Hamdon and then onto the village with the exchange (Martock), along the way has run next to all the new fibre cabinets and yet it appears albeit it early days nothing has been activated.

*

, has this been done anywhere that anyone knows of?

No. Generally the fibre spine goes from the head end exchange out to the local exchange area, maybe via an existing route or via a new route if none exists, to the aggression node (s). Outlying cabs maybe fed from a node in the adjacent exchange area to avoid having to double back The spine rarely if ever goes through the local exchange unless it is also the headend, but may go to a node ( manhole) outside to feed the local cabinets

In reply to a post by Ribble:

Outlying cabs maybe fed from a node in the adjacent exchange area to avoid having to double back The spine rarely if ever goes through the local exchange unless it is also the headend, but may go to a node ( manhole) outside to feed the local cabinets

On this last point, the text on page 14 shows the same idea - "When Intermediate exchanges are no longer required can be bypassed", with the diagram showing: In one local exchange, the thicker spine line is implied to go into the exchange, but in two cases it goes into a "junction access point" in front of the exchange.

Spines might not exist entirely in this resilient mode, but the ability to drop intermediate exchanges, and connect only to "enduring" exchanges seems to be thoroughly employed.

Well everything has gone quiet now. Looks like the initial load of NGA's are in with some planning for a couple of others late August/September.
BT/contractors had to put in new ducting between the next village and the exchange home village (Martock). Not sure if they put the fibre in yet where they had to replace the ducting. It was about 0.5km of new ducting anyways.
the PCP serving my village has been reshelled as of a couple of weeks a go.
I suppose now the waiting game between now and commissioning the NGA.
Nothing new about speeds for FTTC on BT's Wholesale checker.

The only date i've got is from CDS' website saying Jan 2016 for PCP5 on WWMART but after emailing CDS direct they are suggesting October at the moment!