Kitz Forum
Broadband Related => Broadband Technology => Topic started by: William Grimsley on February 05, 2016, 08:37:09 AM
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Hi guys,
I was just wondering if anyone could help me with regards to my history of ADSL speeds? When I first moved in to this house in Newton Poppleford in November 2006, we had a download speed of 1 Mbps and an upload speed of 0.2 Mbps. This was our download and upload speed right up until 2012 when it suddenly increased to a download speed of 5 Mbps and an upload speed of 0.4 Mbps. Shortly after this the upload speed increased to 0.8 Mbps and it stayed like this until we had BT Infinity 1 activated on 27/04/2015. So, what were all of these types of ADSL? When we moved in, were we on a fixed line rate or something different? Note, our line was 3.5 km long when we had ADSL.
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Is "infinity" FTTC?
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Hi weaver
Yes, Infiniti 1 is 40/10 and Infiniti 2 is 80/20
That's always been my understanding
I would hazard s guess in 2006, you would be on ADSL, then upgraded to ADSL2, then ADSL2+ and/or your speed caps were raised by ISP
Many thanks
John
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2006 is when ADSL Max came in (variable downstream best-efforts sync). I remember being delighted when I went from 0.5 Mbps to 1.5 Mbps overnight.
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Thanks for the input, guys.
I'm pretty sure I was on ADSL Max in 2006 but saying that I could of been on WBC Fixed Rate then?
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Not sure whether it was WBC in those days, but yes, I'd say you were on fixed rate (nominally 1024/256).
I was on the same at the time, at my previous house, and I eventually persuaded my then ISP, Claranet, to change it to 2048/256.
That was the best I could get, due to a significant proportion of the line being aluminium.
The joints were causing shedloads of faults upstream of the ali, so BT eventually provided copper, and Deep Joy! - I then got around 4.5Mbps on ADSL1, and 5Mbps when ADSL2 came along.
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Ah, cool. In 2006, I was too young (only 8 at the time) to persuade my parents to see if they could ask BT to upgrade the speed, too young to be affected by the slow speed and I didn't know how broadband worked back then.
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So do you think it's fair to say that back then you were on ADSL2 capped rate? That gives us a choice of different capped rates, then suddenly we perhaps go to ADSL2 variable-speed rate. You mentioned 5 Mbps (?), sounds consistent with the 3.5 km you mentioned, a fairly good line though, plus a decent modem which is always important.
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So do you think it's fair to say that back then you were on ADSL2 capped rate? That gives us a choice of different capped rates, then suddenly we perhaps go to ADSL2 variable-speed rate. You mentioned 5 Mbps (?), sounds consistent with the 3.5 km you mentioned, a fairly good line though, plus a decent modem which is always important.
My exchange Colaton Raleigh was ADSL Max enabled on 31/03/2006 so I think we were on ADSL max when we moved in but SamKnows doesn't show the date 21CN WBC (ADSL2) was enabled so I'm not sure whether we had ADSL Max or ADSL2 when we moved in. However, when our download speed increased to 5 Mbps, I think we were given the BT Home Hub 3 which wasn't a "top of the range" router but it did the job.
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I'm pretty sure I was on ADSL Max in 2006 but saying that I could of been on WBC Fixed Rate then?
From memory, before Max the residential service sold was 2meg fixed rate, delivered as 1meg or 512K if the line didn't comply with the 2meg requirements (at the same price). Someone will no doubt remember the attenuation limits. Prior to that the residential service was 512K with 50:1 contention, business services were 512K, 1meg or 2meg with different prices for the different speeds, all at 20:1. (Also 5:1 contention and 1:1 options, although I only remember seeing these offered for private DSL connections, not for Internet access)
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From memory, before Max the residential service sold was 2meg fixed rate, delivered as 1meg or 512K if the line didn't comply with the 2meg requirements (at the same price). Someone will no doubt remember the attenuation limits. Prior to that the residential service was 512K with 50:1 contention, business services were 512K, 1meg or 2meg with different prices for the different speeds, all at 20:1. (Also 5:1 contention and 1:1 options, although I only remember seeing these offered for private DSL connections, not for Internet access)
ADSL was offered at 512K, 1MB or 2MB (at differing price points) - but the line had to me at or under a certain attenuation limit as you mention - 43dB (my line only just made it!) - before an BT engineer would install/sign off on it
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The 0.2Mbps upload speed probably matches with the 288kBps upstream sync of the 3 fixed speed packages.
The 0.4Mbps upload probably matches with the 448kbps upstream of ADSLmax. Plusnet used to leave subscribers capped on this speed when they transferred them onto 21CN, WBC, ADSL2+ service, so you can't be 100% sure.
When you were on 0.8Mbps upload, then you could be sure to be on a WBC 21CN service.
If I remember right, introduction of ADSL Max wasn't automatic. You had to ask.
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If I remember right, introduction of ADSL Max wasn't automatic. You had to ask.
It depended on the ISP, but there were quite a few who kept their customers on a lower speed product unless they specifically asked. Even if they had migrated the line to maxdsl they artificiality capped the line at their end. It sounds like this was the case with William.
The other option is was a 'max capped rate' line, which could have been triggered by the DLM, but reading Williams OP, its unlikely.
This is what Im assuming
November 2006, download speed of 1 Mbps and an upload speed of 0.2 Mbps. - You purchased this product as fixed rate. In Nov 2006 not all ISPs were selling maxdsl yet as it experienced some issues for the early adapters. It wasnt until mid/late 2007 that BTw pricing changes encouraged more ISPs to offer maxdsl.
2012 when it suddenly increased to a download speed of 5 Mbps and an upload speed of 0.4 Mbps. Your ISP ditched any capped products and moved all over to maxdsl.
Shortly after this the upload speed increased to 0.8 Mbps Your exchange got upgraded to adsl2+
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A very interesting thread so far!
I'm just wondering why there isn't much mention of ADSL2+ that Be offered between 2004 to 2014.
When ADSL2+ was in effect it offered upto 24Mbps download and 2.5Mbps upload speed. I think the high upload speed came by requesting Annex M be implemented. This reduced the download speed, I think by 2Mbps.
I used to connect at 12Mbps. I know there was a 24Mbps 'club' on the ISP forum. But I don't think many people got the full 24Mbps. I remember they had to change the advertising to upto 16Mbps.
Be was at the forefront at the time. It's a real shame they stalled at introducing a fibre product. This was a BIG debate towards the end of the ISP. They said they were working on it. Then out of no where they said Sky was going to buy them out.
I think a lot of the Be staff crossed over to pure fibre supplier, Hyperoptic.
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When ADSL2+ was in effect it offered upto 24Mbps download and 2.5Mbps upload speed.
I know there was a 24Mbps 'club' on the ISP forum.
I was in the '24Mbps club'. ;D I also had Annex_M
I just managed to scrape 24 down and 2.6 up when their MSAN was shiny and new in April 2008. A few months later I was 23,861/2688 where I sat for a while. I still qualified though as I could easily get 24Mbps if I turned Annex_M off in my router.
When they added the O2 users though I lost some downstream due to crosstalk, and gradually my downstream got chipped away. (crosstalk isnt exclusive to fttc).
I just looked at one of my sync speeds taken in July 2012 and it was 22095/2667 SNRM 3.0/3.5, before I left I was down to about 21Mbps.
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Is it safe to say that William's family were BT Retail customers all that time though?
BTW I think Kitz nailed it with her historical analysis. We need a BT Retail customer with a long memory though,mad far as the individual ISP artificially capped products are concerned.
I can't help as I have no history of any sort. I was a Demon 20CN customer when ADSL was introduced and I got automatically upgrade to ADSL Max automatically (with no idea it was going to happen, but delighted) in early 2006. Then nothing at all happened for nearly ten years, until December 2015. Following some exchange hardware upgrades in November, which increased speeds quite a bit, I was able to pay £11 per line to be upgraded to 21CN / ADSL 2+. And that's where I am today.
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Hello,
Thanks everyone for the input. Yes, I can confirm that we were with BT from November 2006 till December 2014 then moved to TalkTalk until we moved back to BT when fibre was enabled. A very interesting post by Kitz, there. It sounds right to me.
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I'm just wondering why there isn't much mention of ADSL2+ that Be offered between 2004 to 2014.
Be were the first to launch ADSL2+ in 2005 but in many ways it many ways it was actually Bulldog Broadband who revolutionised the residential market after their launch in 2004 - offering faster and cheaper connections than were available via BTw resellers at the time. They also launched ADSL2+ shortly after Be.
What I never understood is why it took BT until 2008 to start to rollout ADSL2+ on its network..
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Is it safe to say that William's family were BT Retail customers all that time though?
I don't think we need assume that, most if not all would apply if his family's ISP(s) used exclusively BT wholesale products. For example we were with Demon during those changes, but limited to what BTW offered as there was no LLU in the exchange.
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> What I never understood is why it took BT until 2008 to start to rollout ADSL2+ on its network..
And then it took another seven years after that to reach me.
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What I never understood is why it took BT until 2008 to start to rollout ADSL2+ on its network..
Agreed they were late to the party with adsl2+ and even annex-m. Just prior to this BTw were busy upgrading the core and backhauls.
When adsl first rolled, it used MSiP (http://www.kitz.co.uk/adsl/equip2.htm#cloud) for backhaul transit. MSiP was built in the 1990's and never designed to handle the amount of traffic for broadband to all. They had to build a total new network (21CN (http://www.kitz.co.uk/adsl/21cn_network.htm)) to cope with the volume of users and bandwidth requirements.
Many of the early DSLAMs such as this
(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Fwww.kitz.co.uk%2Fadsl%2Fimages%2Fphotos%2FDSLAM_02.jpg&hash=d1a05e54c714920552561556f93351927c938b7a) (http://www.kitz.co.uk/adsl/telephone_exchange.htm)
were just not capable of adsl2+ and had to be replaced with MSANs. So therefore it needed the investment and upgrade of a heck of a lot of equipment which cost millions.
On the other hand you had the 'innovative' ISPs such as Be and Easynet who built new networks in the early 00's using more modern equipment from scratch and werent using an ageing backhaul and installed NGN equipment right from the start. I dont think NGN MSANs were common place when BT first started rolling out adsl.
So much of the delay could likely have been the need to upgrade to 21CN before they could offer adsl2+
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@Kitz - understood. It's the time after that, seven years, that is surprising. I just assumed it was tied in with politics.
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We're behind you, no sign of the 21st Century Network or even a planned date. We're still on 19CN over here, with equipment suffering from the Y1K bug.
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@AESmith - commiserations.
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:(
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no sign of the 21st Century Network or even a planned date.
Same here; exchange upgraded to ADSL in July 2007; since then nothing....maybe FTTP sometime this/next year.
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I was reading wiki about ADSL2+ last night. Apparently most BT based ISP's these days cap it down and use it under the ADSL Max label.
I wish the ISP's would give people some prices for providing fibre or adsl technology to their house. It seems if nobody gives a price then there can't be any competition.
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I think Kitz hits the issue... BT realised they needed to overhaul their core network in order to support the traffic levels they saw coming. They obviously decided on a converged IP based core, rather than a telco core "bodged" into supporting ATM, though it probably involved some internal battles.
An IP based core changes the way you would backhaul MSANs, possibly even changes the MSANs you buy, so you need to choose carefully.
I suspect BT would have been faster if they didn't attempt to upgrade the voice network simultaneously.
As for the gradual rollout of WBC...
BT obviously completed the biggest exchanges earlier. The ones with space.
BTW forum presentations, relatively recently, were describing the process to upgrade exchanges with little space. This entailed adding 1 21CN MSAN, then forced upgrading off a 20CN DSLAM, then removal of the DSLAM hardware to create space for the next MSAN. And repeat...
Having reached something like 3600 or 3800 exchanges, they've got to the next phase ... the exchanges with no spare space at all.
Last week's ISP forum had BTW describe a new process that they're trialling for these exchanges. This entails the removal of a 20CN DSLAM, addition of a 20CN MSAN, and migration of all users in one overnight slot. While keeping telephony running in the meantime.
That's for 1,900 exchanges.
I suspect these kinds of forced migrations become a hefty overhead on both BT and ISPs.
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My first modem was a 2400 baud in the mid eighty's in those days we used bps like we use Mbps to-day, the max rate I ever seen on the 2400 was 1500 bps or 1.5K
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BTW forum presentations, relatively recently, were describing the process to upgrade exchanges with little space. This entailed adding 1 21CN MSAN, then forced upgrading off a 20CN DSLAM, then removal of the DSLAM hardware to create space for the next MSAN. And repeat...
Having reached something like 3600 or 3800 exchanges, they've got to the next phase ... the exchanges with no spare space at all.
One of the things I noted when in my exchange last week was the lack of floor space since my last visit. Everything was a lot more crowded and there is now hardly any free space. Its not a large exchange but its certainly far from one of the smallest. They have obviously been shuffling things around - the exchange has one heck of a lot more MSANs than I expected, and theyve moved the fibre backhaul trays which were originally near the back up to the front to make more space for all the LLU MSANs at the back.
I also think that they may have moved the PSTN equipment too. I cant be certain as I dont have photo's which show the old layout, but Im sure last time I was in that they were laid out in an L shape at the very back. Now there is just one wall of them but seemingly on higher racks. May be my bad memory though as BS told me those things weigh a ton and aren't for shifting. Whatever way, last time I was in there, there was quite a lot of free floor space.... now there's hardly any.
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Moving PSTN for the sake of it seems unlikely - the need to stay in service would surely make things "fun".
I'd have thought that were even more true of the fibre backhaul.
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When you mentioned forced upgrading from 20CN, it made me start pondering. Forced upgrading for me would have saved me having to pay £11 per line for upgrades to 21CN, but I was so impatient, I wanted it done for Xmas (which BT OpenReach did manage, by one day), rather than having to wait until some mysterious unspecified date. It's all very weird, what happens is - if my understanding is correct- a mixture of user choice, ISP choice and no choice, if that makes any sense.
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When you mentioned forced upgrading from 20CN, it made me start pondering. Forced upgrading for me would have saved me having to pay £11 per line for upgrades to 21CN, but I was so impatient, I wanted it done for Xmas (which BT OpenReach did manage, by one day), rather than having to wait until some mysterious unspecified date. It's all very weird, what happens is - if my understanding is correct- a mixture of user choice, ISP choice and no choice, if that makes any sense.
For exchanges like yours (the majority), BT Wholesale offer ISPs free bulk migrations to 21CN. Your decision/impatience(!) to order it before then resulted in you paying the £11/line (though you have saved on A&A fees).
Eventually though BT decommission the 20CN equipment and IPStream Connect at migrated exchanges, so if an ISP doesn't opt for a free upgrade they will ultimately need to take action later
Some of the newer exchanges don't have space to run the older DSLAMS along side newer MSANS hence the prospect of 'forced migrations'
As BT Wholesale put it
We would like to convert more to WBC but it’s problematic. These tend to:
•be much smaller exchanges so have limited space for new equipment
•have older equipment
•have more challenging economics
•pre-Undertakings wiring (so Ofcom will need to update the existing exemption)
though I don't think you're going to see this start until the summer - they are still completing the last of the 'easier' exchanges to convert.
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> (though you have saved on A&A fees).
You mean I saved money because of the half-price daytime 21CN GB per unit deal ?
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> (though you have saved on A&A fees).
You mean I saved money because of the half-price daytime 21CN GB per unit deal ?
Yes:) reflecting the fact that 21CN is cheaper for ISPs as well..
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I'd have thought that were even more true of the fibre backhaul.
That definitely appears to have been relocated.
Original position of the fibre trays was at the back near to the LLU MSANs. (Both LLU & BTw)
Where is was, there are now more MSANs and all the fibre trays for the backhaul are at the very front. There's a hell of a lot more fibre trays now and they are in a totally different casing.
I have a photo from last time I was in there, which if you look closely you can see the reflection of an LLU Handover frame, which were (and still are) at the back. BS should be able to confirm that they are now at the front and they look nothing like this:
(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Fwww.kitz.co.uk%2Fadsl%2Fimages%2Fphotos%2Fadsl_backhaul.jpg&hash=1db18e1853aca9aec70c24a413a51781bc3a7115)
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As the lady says above ^^^^. :)
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Guys, what am I seeing in Kitz' excellent photo?
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Fibre trays, Weaver. Exactly what duties these particular trays are performing is anybody's guess ...... the writing on the trays themselves would have to be read and interpreted ?? :)
Kitz took the photo I assume, so maybe she can enlighten us further ...... but I suspect it's as she comments above that they are possibly backhaul ??
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I'd have thought that were even more true of the fibre backhaul.
That definitely appears to have been relocated.
Original position of the fibre trays was at the back near to the LLU MSANs. (Both LLU & BTw)
Where is was, there are now more MSANs and all the fibre trays for the backhaul are at the very front. There's a hell of a lot more fibre trays now and they are in a totally different casing.
By backhaul, I assume you mean backhaul from the exchange back to the nearest WDM/Metro node? Rather than backhaul from FTTC into the exchange?
Perhaps the growth of this fibre, and the pooled nature it can offer, has allowed for easy migration. You just add more fibre at the "front", migrate backhaul sessions off the "back", which then allows you to calmly re-parent the original fibre so that it too arrives into the front space.
Migrating live copper offers something that live fibre doesn't ... it can be connected to two points in the exchange at a time, allowing temporary bypasses to be wired in when a migration is needed.
So I can image that backhaul fibre can be migrated by soft switching of sessions - unless there are no strands left available - but access network fibre would be somewhat harder.
I can't imagine that, once one of these is full, you would ever want to move it much...
(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Fwww.coolwebhome.co.uk%2Ffibre-cornwall%2Fimages%2Fimage%2F21-handover-fibre-management.JPG&hash=1e540d4e80623148a6fbe00c12f7b42ee4be952f) (http://www.coolwebhome.co.uk/fibre-cornwall/images/fullsize/21-handover-fibre-management.JPG.JPG)
Click for full-size image
I think the yellow cables coming in top-left are the fibres coming in from the aggregation nodes; 576 fibres when full.
The cables exiting top-right are the hydra cables that take those fibres into the handover layer 2 switch.
I think this is, essentially, the MDF of the optical world.
That photo was from MrSaffron's Cornish visit, and the hydra cables fed into layer 2 switches like this:
(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Fwww.coolwebhome.co.uk%2Ffibre-cornwall%2Fimages%2Fimage%2F22-handover-populated.JPG&hash=18f460d9d2d3c1ccbbed18b519a800e9176a1232)
Migrating these fibres over to a different physical location, either for the rack or the switch, would surely be hellish!
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Guys, what am I seeing in Kitz' excellent photo?
Fibre trays, Weaver. Exactly what duties these particular trays are performing is anybody's guess ...... the writing on the trays themselves would have to be read and interpreted ?? :)
Kitz took the photo I assume, so maybe she can enlighten us further ...... but I suspect it's as she comments above that they are possibly backhaul ??
That was the ODF / Optical Fibre Distribution Fame Cabinet which is kind of a convergence point for all the DSLAMs and MSANs in the exchange.
Kind of like a large version of the FTTP spitters in the field. The difference being those in the field split bandwith from the exchange into fibre to the premises. Those in effect do the reverse, by merging the MSAN traffic to the backhaul... or perhaps easier to understand.. split traffic coming from the exchange backhaul into lots of smaller fibre cables to the correct MSANs.
The top rack was for the LLU MSANs - From top to bottom BE, Tiscali, Opal, Easynet.
The bottom rack was BTw owned DSLAMS and MSANs.
The (thinner orange) optical fiber you see in each tray on the RH side of the picture connect to each of the MSANs (or NIM modules on say the Fujitsu hubs) and the thicker fibre cable on the left was the backhaul out of the exchange to the bRAS (BTw) or PoP (LLU).
At that particular time, the exchange only had 5 LLU MSANs and in the larger image hi res image I have, you can see that the Opal Tray fed both what was the AOL and TalkTalk MSAN.
[Moderator edited to correct a minor typo; nothing factual.]
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By backhaul, I assume you mean backhaul from the exchange back to the nearest WDM/Metro node? Rather than backhaul from FTTC into the exchange?
Yes the exchange ATM backhaul on to what used to be known as MSiP. That exchange was still 20CN when the above photo was taken.
Migrating live copper offers something that live fibre doesn't ... it can be connected to two points in the exchange at a time, allowing temporary bypasses to be wired in when a migration is needed.
No idea how they did it, perhaps during the migration to 21CN? I certainly recall there being several outages in the wee small hours usually at around 1am - despite me being on BE at the time. During that period there was lots of night work going on and I'd see lights on when coming home at night.
Ive been trying to rack my brains what was at the front where the new ODF now is. I think it was where or at least very near to where the DACs units and LDU's (http://www.kitz.co.uk/adsl/images/photos/dacs.jpg) used to be.
BS may also be able to help me out here, but I think just to the left of that photo there may also some old fashioned black dial like meters which iirc were explained to me as pressure guages/monitors for something or other which was in the basement? Really cant recall anything much about what was downstairs as we were only allowed a quick peek around the door. The excuse at the time was something about a build up of gasses and it wasn't very nice down there without masks. [Thinking again - could it have been flooded at some time and stunk? Im sure they said something about H&S]. Im not certain on my facts here... long time ago.
What used to be at the front in the row where the fibre trays now are (such as the LDU's, DACs and those pressure gauge thingies)- I cant recall seeing any of that now there. That said the other day was a flying visit and I was more looking at the fibre trays than what was around it, so may have missed it.
In fact just looking through some of the photos I didn't publish and on this photo of the geostream_hub (http://www.kitz.co.uk/adsl/images/photos/geostream_hub.jpg), if you look to the left it shows what would now more or less now where the new ODF is located.
They definitely have done some major shifting around and upgrading in there. There used to be a lot of floor space, now there is hardly any and the LLU MSANs take up quite a fair chunk of it.
I think the yellow cables coming in top-left are the fibres coming in from the aggregation nodes; 576 fibres when full.
The cables exiting top-right are the hydra cables that take those fibres into the handover layer 2 switch.
I think this is, essentially, the MDF of the optical world.
Calling it an optical equivalent of the MDF is quite a good comparison.
I think the photos you posted, the top one is an FTTx OLT and the bottom one is possibly what is classed as Element Manager (http://www.kitz.co.uk/adsl/DLM_system.htm#element_manager) for ECI cabs when we talk about DLM. They come under differing names depending on manufacturer, but its kind of the FTTC equivalent of the Fujitsu geostream hub for the adsl MSANs. These are the master switches/hubs and convergence of the 'xbrand' dslams or msans. Could be very wrong here though as Im assuming from descriptions, so please dont take it as gospel.
One of the things I'd like to do is visit an exchange that has FTTC/FTTH head end equipment but something Ive not got around to doing or even asking. It would be even better if like last time they designated someone from BTw to guide me round and explain what everything was. On that occasion most of the visit was at a larger exchange.
The second (1/2) day was my own exchange with an Openreach guy... that was also quite interesting because they'd taken my phone no and plotted its route my traffic would take.. eg your copper terminates here. This is your line on the MDF, from here it goes to this MSAN, then it goes over here (waving hands in air at the overhead cables) to this ODF.
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PS note
Its a shame I have to do the justification and explanation post, but of late I'm a bit tired of the false accusations.
Let me state I am not a BT employee, Im not paid by BT, I have no official links with BT and don't receive remuneration in any shape or form from BT. The whole idea of the site was to make information public about BT about how they work for those who were interested. Its a hobbyist, help and information site. BT are aware of the site and its contents but dont have any say over what I write.
Re the photo's and reasons why Ive been allowed several exchange visits.
I was lucky it was all authorised at the top by Ben Verwaayen just prior to him leaving.. and before anyone thinks its to do with 'being in bed or paid by BT' no its not. I was one of the very first adsl campaigners to bring broadband to the Blackpool area. We worked hard and I have fought many a battle with BTw in the past when we did eventually get adsl for and on behalf of others. Ben was actually very supportive of the campaigners - broadband was his baby. When DSL was eventually rolled out to most exchanges in the UK, we were all invited to BTtowers (iirc there were about 50 of us dotted around the UK). Unfortunately I couldn't go due to work commitments on that day, and although most campaigners had already been around their own exchanges... this was something I requested for missing out on the BT Tower visit before he left.
In my time Ive fought many bloody battles to get things sorted by BT and Plusnet. I earned respect because I presented facts and fought for EU's. I didnt go around saying BT are p00 I would take research facts and present them as a counter augment. Around here at one point they jokingly called me Kitz the Krusader because of the battles I fought with BT on behalf of the community. I earned my respect with BT the hard way and through that came previously undisclosed knowledge. Its surprising how much more info you could get if you say things like "why cant you do this?" if you have spend time doing your research properly... rather than "BT are spawn of the devil because they wont do that" without understanding that they may have some constraints too.
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BS may also be able to help me out here, but I think just to the left of that photo there may also some old fashioned black dial like meters which iirc were explained to me as pressure gauges/monitors for something or other which was in the basement?
Indeed, Kitz ......... the old-style ECP (Equipment Cable Pressure) Rack was just to the side of that, as you say. This has now been replaced for a more modern looking unit. I haven't time to go looking for a photo of one, but shall endeavour to do so later if I remember ??
Both old and new style had the same function, to keep water ingress out of the E-side cables (Exchange to Cab cables). The rack was upstairs, but the flow-meters were connected to each cables pressured joint down in the cable-chamber. This chamber can sometimes see gasses get in through the ducts that lead from here into the outside world, and I'm guessing this is why you weren't allowed access ??
TBH ....... there's not much to see at all in there and they're dank places at the best of times. :)
[Moderator edited to correct a minor typo, nothing factual.]
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BS may also be able to help me out here, but I think just to the left of that photo there may also some old fashioned black dial like meters which iirc were explained to me as pressure guages/monitors for something or other which was in the basement? Really cant recall anything much about what was downstairs as we were only allowed a quick peek around the door. The excuse at the time was something about a build up of gasses and it wasn't very nice down there without masks. [Thinking again - could it have been flooded at some time and stunk? Im sure they said something about H&S]. Im not certain on my facts here... long time ago.
Does this page (http://www.britishtelephones.com/gpo/jointbox2.htm) help explain what you might have seen, and how it links to the basement?
The E-side cables (and the junction/trunk cables to other exchanges, when copper) will have been pressurised by air to keep water out, so there's a good chance you saw something related to that.
I think the photos you posted, the top one is an FTTx OLT and the bottom one is possibly what is classed as Element Manager (http://www.kitz.co.uk/adsl/DLM_system.htm#element_manager) for ECI cabs when we talk about DLM. They come under differing names depending on manufacturer, but its kind of the FTTC equivalent of the Fujitsu geostream hub for the adsl MSANs. These are the master switches/hubs and convergence of the 'xbrand' dslams or msans. Could be very wrong here though as Im assuming from descriptions, so please dont take it as gospel.
I thought the top picture was an OCR - Optical Consolidation Rack, as seen near the bottom of this page (http://www.prysmiangroup.com/en/business_markets/markets/telecom-solutions/products/optical-connectivity/racks-and-rack-mounted/racks/). (The same manufacturer as the pole-mounted FTTP splitters and DP's, recently discussed). Also pictured here (https://www.flickr.com/photos/107803477@N08/14626513882), but named confusingly. Don't spend ages following the rest of that photostream ;)
And I'm very sure the bottom picture was an Openreach layer 2 switch - this one specifically an ECI F152-HB OLT (http://www2.ecitele.com/OurOffering/Products/Pages/F152-HB.aspx) (more visible in the pdf on that page). The cards on the right terminate the GPON fibres; one nearer the centre terminates the fibres to FTTC cabinets, the one to the left terminates the cablelinks.
The combination of an OLT and an OCR feature in almost all of the FTTC architecture pictures (http://www.trefor.net/wp-content/uploads/2010/07/fttc.jpg) and the FTTP architecture pictures (http://www.ispreview.co.uk/ispnews/data/upimages/subfolders/2012%20Misc/bt_fttp_on_demand_diagram.gif) we've come to know and love from BT, described as the handover node.
(While looking for links, I've come across one (http://www.optservices.eu/FTTP%20-%202%20Level%20of%20Split%2032%20Way%20Overhead%20Distribution%20(Brownfield%20&%20FoD)%20V3%20-%20No%20title.png) or two (http://www.optservices.eu/FTTP%20-%20NEW%20SITES%20(GEA)%20V3.1%20-%20No%20Title.png) interesting FTTP alternatives.)
One of the things I'd like to do is visit an exchange that has FTTC/FTTH head end equipment but something Ive not got around to doing or even asking.
Something like this (http://connectingshropshire.co.uk/2015/01/fibre-fact-finding-expedition-2/)?
The second (1/2) day was my own exchange with an Openreach guy... that was also quite interesting because they'd taken my phone no and plotted its route my traffic would take.. eg your copper terminates here. This is your line on the MDF, from here it goes to this MSAN, then it goes over here (waving hands in air at the overhead cables) to this ODF.
That's quite neat. A personalised cable tracer ;)
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Nice link regarding the ECP equipment ..... that is indeed the old-style rack with compressor. :)
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Does this page (http://www.britishtelephones.com/gpo/jointbox2.htm) help explain what you might have seen, and how it links to the basement?
The E-side cables (and the junction/trunk cables to other exchanges, when copper) will have been pressurised by air to keep water out, so there's a good chance you saw something related to that.
Ohh.. yes, something like the Exchange Pressure Rack... dont think it was quite the same, but near as damnit from what I can recall.
The E-side cables (and the junction/trunk cables to other exchanges, when copper) will have been pressurised by air to keep water out,
Yep that was it.
That's quite neat. A personalised cable tracer
The 2nd day was interesting in a very different way than the first because it did make things personal. They could call up all my details and track my line right through the system. Im not sure if OR can do that these days as I know things have clamped down a bit since LLU on what info is readily available. I think they also tried to make that day a bit historical too by showing some old cards which is how they used to keep records of the phone lines and mentioned that the exchange was the first in the UK to go fully automated blah blah. :)
Something like this?
Yes, but I also have another idea ;)
I thought the top picture was an OCR -
You are likely correct. I trust your judgement... In fact when I look again, I am certain that you are correct.
this one specifically an ECI F152-HB OLT (more visible in the pdf on that page)
Having seen the pdf, it does seem that as well as being the OLT, this is what BTw referred to as the element manager in DLM. I knew it would be something similar to what the Fujitsu switch hubs/master control shelves do as explained by the BTw guy in the larger exchange I visited.
It would kind of be the fttc equivalent of this? Which is a Fujitsu master shelf to OR... and on here you can see the orange STM4 which connected up to the ODF > Backhaul.
(https://forum.kitz.co.uk/proxy.php?request=http%3A%2F%2Fwww.kitz.co.uk%2Fadsl%2Fimages%2Fphotos%2FDSLAM_03.jpg&hash=5f3419ff05360b5743d2a41ed1766da015217f69)
Where I think I got muxed up [pun], is I was thinking that with
ASDL you go
MDF > Handover > DSLAM > Master Hub/Switch > ODF > Backhaul or
MDF > Handover > MSAN > ODF > Backhaul
Looking at the Openreach diagram again, I can see for FTTC it goes
DSLAM > Handover > OCR > OLT > Backhaul
Not having seen an OLT and FTTC headend exchange, my mistaken impression was thinking that there may be something like the ODFs before the backhaul. :-[ Thank you I think its much clearer now. I just need to find time to sit and digest all those new links.. most informative.
I really must get my arse in gear and request that visit but I really dont know when :(
It is frustrating that when it came to adsl I knew a a fair bit, but I have large gaps when it comes to Fibre. I dont seem to find the time these days to do the massive amounts of research. I think DLM was the last time I did anything meaty. :/
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Strange ... while I wrote that last post, the website didn't show me that BS had replied with details of the ECP, nor Kitz' PS. Sorry I missed those.
@Kitz: I can understand both your sentiment and reasoning, and find it a shame that there are those who choose to spend their time flinging wrath and accusation, but can't find a positive channel for their energy. Your way is much better - but it probably came with more appreciation in the past than currently.
@BS:
I was surprised when looking at the photos of the OCR that the incoming fibre was in a yellow jacket. Then some of the photos visible on that Flickr Photostream (like this one (https://www.flickr.com/photos/107803477@N08/14624872954/in/photostream/)) show a number of joints in the cable chamber that perhaps convert the external black cable into internal yellow. Is that likely to be the case? The photos then have lots of orange cables mixed into the same splice joints, so I'm wondering about those. However, I assume H&S raises its head even inside exchanges, so you'd expect a swap from external-grade plastics into low-smoke internal-grade.
Those pictures probably answer another question. All those architecture pictures show the route from head-end to aggregation node to include "CCJ" and "TJ". I wondered about what a CCJ was, but I now guess it is a "cable chamber joint". The "Connecting Shropshire" page reckoned TJ=Track Joint.
Looking at the Openreach diagram again, I can see for FTTC it goes
DSLAM > Handover > OCR > OLT > Backhaul
Not having seen an OLT and FTTC headend exchange, my mistaken impression was thinking that there may be something like the ODFs before the backhaul.
The output from the OLT is the Openreach cablelink product, which I guess goes off to CP equipment for different CP's - BTW, Sky, TT being most likely - and quite possibly combined with other cablelinks (multiple OLT's?) to then be distributed onto backhaul fibre. If I had to guess, I'd say that each CP would have still have some kind of ODF (optical distribution frame) where there is a handover between the in-building backhaul fibre, and the backhaul fibre leading back out of the building.
Having seen the pdf, it does seem that as well as being the OLT, this is what BTw referred to as the element manager in DLM. I knew it would be something similar to what the Fujitsu switch hubs/master control shelves do as explained by the BTw guy in the larger exchange I visited.
It would kind of be the fttc equivalent of this? Which is a Fujitsu master shelf to OR... and on here you can see the orange STM4 which connected up to the ODF > Backhaul.
An element manager? Related to DLM?
Hmmm ... that name rings a bell, but in a totally different context, all to do with O&M. Nothing to do with the flow of traffic.
I'll have to investigate more... Is there anything else on your site that shows the element manager, or the master/hub, in relationship to other things?
It is frustrating that when it came to adsl I knew a a fair bit, but I have large gaps when it comes to Fibre.
Its safe to say that what I've learnt about fibre has come in dribs and drabs. And whenever I learn something new, it usually manages to show that my previous understanding was wrong in some fashion. But I expect not campaigning so much takes away a little of the priority too...