FTTC Cab Connections

A while ago I asked here how many connections are there in the new Fibre DSLAM, A lot of kind Gents on here told me that it was 288, which I also found this number on various website's.
I've just been outside as an OpenReach Engineer was working on the new DSLAM Cab (he installed my last week), So got talking to him about this and that and noticed some paper work he had and on it, it said 200 Conections, so I asked him about it and he told me that the new cabs now have only 200 and not 288 as before, so just thought people might be interested with this new number.
He also told me that since the cab went live he was on his 86 install and had 1 more to go today and 6 to do tomorrow and I know a lot of people have only just ordered, so the cab may be full before long.
Now I've read somewhere but can't remember where that the more connections being used will affect everybody's speed, not sure if this is correct and forgot to ask him (dull me).
I can say that with the number already using my cab that my speed from last week has not dropped and the only shift's in speed for me has been around 0.5Mb.
iechyd da

The largest full size cabinets can have a maximum of 288 lines. There are smaller variants appearing, I believe one supports a maximum of 128 lines and I think there is a 96 line option available, so its no surprisie to hear that there are a number of sizes being utilised.

Edited by deleted (Mon 11-Apr-11 16:10:21)

In reply to a post by paul1360:

Now I've read somewhere but can't remember where that the more connections being used will affect everybody's speed, not sure if this is correct and forgot to ask him (dull me).

Several have commented on that, more connections = more crosstalk = lower SNR = lower speeds.

When I had mine installed (last August) I was the 3rd one in the cab, and sync'd at 40,000 with a profile of 38717. It's gradually slowed down- had to have an engineer out this morning (no sync) and his box showed a sync around 35,000-odd on a 6db SNRM, profile 34799 and ~20 connections in the cab

Hi, Yes the small cabinets hold 96 connections as advised by an engineer last week. I asked the question re too many requests and not enough slots in the cab. His response was put a second cab beside it. I queried why the small cab which he was unable to answer however it now transpires that the standard 288 sized cab should have been put in place and not the half sized one. So I now have to wait for that to be installed (Only waiting since august 2010)
The engineer also stated that there are new cabs which are being made in Isreal which will be installed in the future ( These may already be in use). These are slightly smaller that the current ones but apparently hold more connections.

I believe ECI equipment is also going to be used in addition to the existing Huawei
http://www.eurocomms.com/features/7112-7112

Edited by deleted (Mon 11-Apr-11 16:35:03)

That seems odd that your speed dropped when more people went live on your cab and yet my speed has stayed constant. Wondering if the equipment in the new cabs are different from yours????????????

iechyd da

It could very well be to do with the condition of the old cabinet and the connections from there to the premises. In fact, thinking while typing, it almost certainly is.

In reply to a post by paul1360:

That seems odd that your speed dropped when more people went live on your cab and yet my speed has stayed constant. Wondering if the equipment in the new cabs are different from yours????????????

It might be, but I doubt it would matter much. Like Bob said, cable condition would matter (mine has been in the ground for ~25 years), also distance to the cab.

Can't remember how far away you are, I'm at least 450 metres (cable length) and suspect I didn't get the initial 40Mbps sync by much of a margin

Mine appears to have suffered a speed drop due to cross-talk.

Initially with just 4 others connected to the cabinet, my sync was the full 40 (38717 profile), however after a couple of weeks during which I had several sightings of an openreach engineer working on the cabinet, I'm down to 32xxx profile. It also interleaved me adding 10ms to my 9ms ping times.

At 600m from the cabinet, I guess I was marginal for 40, and at least 32 is better than the 4 I had previously

jayteedc

A couple of others, like you, have implied the installation engineer worked on the fibre cabinet.

My engineer confirmed they don't go anywhere near it, (unless it is near the PCP of course - ours is 20 metres or so the other side of a main road). The cabling from the FTTC cab to the PCP is already connected at the new cab end, and just needs to jumpered onto the user line at the PCP.

I wonder if different areas are doing things a different way?

The installation engineer you see only goes into the copper cab and is not allowed into the fibre cab. Higher grade engineers who commission the cards and the guys who do the initial copper install are the only ones who actually touch the fibre cab.

In reply to a post by Anonymous:

The installation engineer you see only goes into the copper cab and is not allowed into the fibre cab. Higher grade engineers who commission the cards and the guys who do the initial copper install are the only ones who actually touch the fibre cab.

Exactly . That was my point. Thanks for confirming it, I was beginning to doubt my own belief. Some posters infer that the engineer did something in the FTTC cab, and they are mistaken.

An Openreach friend of mine tells me that all but a very select few are "restricted" from opening the FTTC cabinets due to, in no small part, "health and safety" reasons. I.E the sheer amount of voltage and current going through them.

I suspect it's a mix of that and of course the expensive hardware inside that's the reason.

Sorry I didn't mean to imply that. The van is always parked by the green cabinet (not the fibre one) which is just over the road.

I do know that the engineer who visited was FTTP trained and had undertaken installs of FTTP already, which take many hours to complete by all accounts.

jayteedc

Thinking about it when they started to run the fibre cables something happened to my old Cab (Think it was so rusty it fell apart) and a new 1 was fitted, So maybe with a new cab and new DSLAM has something to do with it???????

iechyd da

I've found a VDSL2 document by Ericsson, with a Speed vs Distance graph that included measurements with crosstalk present. Its on page 8 (though page is marked #43).

The graph is titled "VDSL2 bit rates of different profiles. Real measurement in the presence of crosstalk from 20 VDSL2 systems."

That suggests 40Mbps out to around 200m, 33Mbps at 500m, and 22Mbps at 1km. The limiting point seems to be for UPstream at 1.5km.

That's a pretty good fit to what I'm seeing here, thanks for that

Just had a chat with OR Eng who was installing Infinity across the road from me, It was his 100th Connections, so half of my cab used up, still no change in speed average for the last 13 days 37.49Mb 8.50Mb. He then told me that that's it for now, so asked why and he told me that they only run 1 cable at first from the Dslam to the Cab for 100 connections, There are another 20 or so now waiting for the OR to run another cable so they can be connected up, That seems a bit silly to me??????

iechyd da

Magically, the FTTC checker now states that it's available (again). Two weeks ago it said it was, then vanished, now it says it's available again.

This is essentially for business premises, and I've got my own new line being installed on the 6th of May (via XLN), I'm wondering if I could place my order for FTTC immediately so that they could come and install it either on the same day or within a few days, as it's urgent and I can't wait any longer. Is this possible?

In reply to a post by Saltank:

Magically, the FTTC checker now states that it's available (again). Two weeks ago it said it was, then vanished, now it says it's available again.

This is essentially for business premises, and I've got my own new line being installed on the 6th of May (via XLN), I'm wondering if I could place my order for FTTC immediately so that they could come and install it either on the same day or within a few days, as it's urgent and I can't wait any longer. Is this possible?

It's possible to get a "Simultaneous Provide" of a line and ADSLx, so it may be possible with FTTC. It depends how well developed the new ordering system is, assuming it is new. I don't know.

However, even if it is possible, you have almost certainly missed the boat. On line + ADSLx you have to specify you want a SIM Provide at the time you order the line, and you are then given a LORN, Linked Order Reference Number. You then order your broadband with the LORN associated with it, if your chosen ISP has ever heard of them and their system can handle it.

It is impossible to get a LORN after the line is ordered . You have to wait until it is installed so that you have the phone number to order against.

The cable is already there but they only commission 1 x 1Gb link when the cabinet is 1st installed. So it seems that once they hit 100 connections they will then comission another 1Gb link

Ah ok maybe I misunderstood him then and he was on about commission of the cable and not installing it then, To me that sounds more like it.
LOL after all the messing around BT did with the dates I bet they wished they had done this sooner as they've missed out on a lot of money from use LOL

iechyd da

100th on a particular cab or 100 installs in total.?

Significant difference.

In reply to a post by Ribble:

The cable is already there but they only commission 1 x 1Gb link when the cabinet is 1st installed. So it seems that once they hit 100 connections they will then comission another 1Gb link

That's not completely true.

Because ISP's rent VLANs in the new FTTC cabinets, BT have to keep up with the demand on the fibre capacity back to the exchange where the data is handed over to each ISP. So if there are

So if there are 25 people syncing at 40,000kbps, BT can leave it with the 1Gbps fibre to the exchange as there would not be more than 1Gbps needed.

However, if there are 26 people syncing at 40,000kbps, BT would have to install an additional 1Gbps fibre back to the exchange.

Think of it like this: If a fibre backhaul is set to 1Gbps in this situation (Supplied over TWO fibres & the exchange has a pair of fibres spare, owned by BT Wholesale) and there are 10,000 lines connected to it as BT Broadband packages that is fine (as long as that is what is required by BT Broadband - that's another story).

IF an LLU ISP (Like Sky) comes along and purchases 100Mbps backhaul from BT Wholesale, BT Wholesale would HAVE to provide it to the exchange (In this case, there are fibres spare, so it would be possible) as that is what Sky is paying for.

Likewise, if a cabinet's link to the exchange is full and is congested at all, BT have to make more capacity available as it has other non BT Wholesale ISPs traffic on it.

I hope that explains it

Edited by chris6273 (Tue 19-Apr-11 06:19:33)

orly
There are now 100 people connected to my DSLAM cab using Fibre BB and as I said before there are only 200 slots in this cab. The next Dslam cab down the road only has 23 using it, The others around here he showed me have 20-30 connections. Ours seem to be the Cab in demand.

chris6273
There are no other ISP's offering FTTC around here yet, Talk Talk are from May and Plusnet after Easter.

iechyd da

You are getting Fibre connections and Copper connections muddled up.

The Two Cabs (New and Old) are connected by 100 pair cables, one from Old to new to get to the VDSL and Splitter, One from new to old to get the voice back to the copper back to the exchange.

These are all provided up front and cabled to the VDSL cards.

Engineer now only has to work on the old cab, 1st customer gets jumpered from house to Pair one (Old to new) and pair 1 (New-old) to the exchange. Therefore no work on the VDSL cab so lowwer fault liability as the electronics are not open to the elements.

When 100 customers are used two new 100 pair coppers are required to connect the two cabs for the next 100 customers. This is what is now required.

Fibre Connectivity goes in 1GE per 66 customers to keep within the 15Mb guarranteed backhaul speed. So every 66 customers a new GE is required but the fibres are alll installed as aprt of the original build. The GE cards would be supplied as required as they are an added cost.

Kitkat

In reply to a post by paul1360:

chris6273
There are no other ISP's offering FTTC around here yet, Talk Talk are from May and Plusnet after Easter.

iechyd da

I am aware of that but I was talking about when LLU providers start offering FTTC products, that is the way it will be handled.

Edited by chris6273 (Tue 19-Apr-11 14:15:36)

http://www.thinkbroadband.com/guide/fibre-broadband....

Urm lots are selling the BT Wholesale WBC FTTC products.

TalkTalk will be more different since they have their own LLU, but Plusnet is simply just another addition to that list as they sell what BT Wholesale offer.

Hang on what am I getting mixed up over??????
All I've said is that the new Fibre Cab has 200 slots for people, that has a fibre cable going from there back to the Exchange, it also has 2 x 100 pair cables going from it to the old Cab and that cable is connected up for FTTC for people like me. Now the OR Eng told me that he did the 100th fibre connection yesterday, so the cab has used 1/2 it's capacity.

iechyd da

In reply to a post by paul1360:

Hang on what am I getting mixed up over??????
All I've said is that the new Fibre Cab has 200 slots for people, that has a fibre cable going from there back to the Exchange, it also has 2 x 100 pair cables going from it to the old Cab and that cable is connected up for FTTC for people like me. Now the OR Eng told me that he did the 100th fibre connection yesterday, so the cab has used 1/2 it's capacity.

iechyd da

It's at half its capacity because at more than 200 lines (probably a smaller cabinet than typical ones) there will physically not be any more frame space in the FTTC cabinet.

Edited by chris6273 (Tue 19-Apr-11 17:34:15)

I'm getting confused here. The FTTC DSLAM has room for 200 people to have Infinity. The old green cab that's been there for years with the phone lines for however many there is

iechyd da

In reply to a post by paul1360:

I'm getting confused here. The FTTC DSLAM has room for 200 people to have Infinity. The old green cab that's been there for years with the phone lines for however many there is

iechyd da

Customers only get their lines transferred over to the FTTC Cabinet if they purchase an FTTC package.

People who are not on FTTC packages go through the old Green cabinets and through the E-line as they used to (nothing is changed).

That would assume 1:1 contention on the FTTC backhaul which I dont believe is guaranteed

Me neither.

It also assumes everyone syncs/connects at the full 40Mbit, which is essentially impossible in the real world.

In reply to a post by Ribble:

That would assume 1:1 contention on the FTTC backhaul which I dont believe is guaranteed

If LLU Providers are present at a particular FTTC exchange, I think BTo have to make the capacity available to the cabinet provided the ISPs pay for it (Obviously not everyone will sync at 40Mbps).

Everyone around by me are getting 37Mb to 38Mb and 8Mb - 9Mb.
I popped down to a mates house who is a lot further away from the cab than use and he's got the same. Yes there are still people off my cable using Sky,Talk Talk et al (my son is 1)

iechyd da

In reply to a post by RobertoS:

In reply to a post by Saltank:

Magically, the FTTC checker now states that it's available (again). Two weeks ago it said it was, then vanished, now it says it's available again.

This is essentially for business premises, and I've got my own new line being installed on the 6th of May (via XLN), I'm wondering if I could place my order for FTTC immediately so that they could come and install it either on the same day or within a few days, as it's urgent and I can't wait any longer. Is this possible?

It's possible to get a "Simultaneous Provide" of a line and ADSLx, so it may be possible with FTTC. It depends how well developed the new ordering system is, assuming it is new. I don't know.

However, even if it is possible, you have almost certainly missed the boat. On line + ADSLx you have to specify you want a SIM Provide at the time you order the line, and you are then given a LORN, Linked Order Reference Number. You then order your broadband with the LORN associated with it, if your chosen ISP has ever heard of them and their system can handle it.

It is impossible to get a LORN after the line is ordered . You have to wait until it is installed so that you have the phone number to order against.

You were right about that. I told off the guys at XLN for not knowing about this, even though I explicitly told them I need to order broadband really fast. So now I'm stuck with waiting until 6th of May to make an order. UGH! Horrendous!

Just an update there are 130 people now getting Infinity from my cab and still no drop in speed

iechyd da

Hi Paul, how are you able to find that out, or is it just a case of door-stepping the OR engineer when he's there?

That sounds impressive. Were you originally estimated at full speed?

IIRC crosstalk is rejected by the use of twists in the copper pairs, and even more so with tighter twist rates, and when the twist rate differs for different pairs within the same core.

I imagine that the new cables that connect the old & new cabinets are designed to be very resistant to crosstalk at VDSL frequencies, as these cables are guaranteed to be carrying a dense fill of such subscribers.

However, I guess the existing D-side cables are probably not quite so high spec, and open to more crosstalk. However, the D-side cables are likely to be less densely crowded with VDSL2, so statistically, you get a little less affected. In this case, the 130 subscribers are now diluted across the total number served by the original cabinet (maybe 300-400???)

More than anything, it is going to be the spec (and age) of the D-side, and the luck of the draw in whether your line routes down the same core as other VDSL customers, and how many there are.

How many pairs are there in the "normal" case of D-side distribution cable?

This may come out wrong but I don't mean anything by it.
When th OP Eng came to install my Infinity I gave him a cup of coffee, he said hey this is great coffee so I asked him did he want another 1 (I make my own with different beans) and he said yes, any way Infinity all installed and up and running, we were chatting about this and that and he kept looking at my coffee pot so I asked him want another 1, yes please he said, on his way out I told him if he was installing any more around in and he wants a coffee call in, not thinking he would but he did and does (Hence above) and we chat about Infinity et all and thats how I know. lol.
My estimated speed I think was 35Mb/s down and 7Mb/s up and as I've said on here when they started to lay the cables my main green cab fell to bits and they had to install a new, so maybe thats the reason things are good around here.
By all accounts there are another 8 people waiting to swap to infinity.

iechyd da

LOL - good tip there!

Your estimate suggests your line is a little shorter than the most-borderline cases around here. I think people of around 500 meters, with estimates of 30-31mbps have managed to get 40Mbps. From the look of the VDSL speed-distance graphs, they are within limits (ignoring crosstalk), but outside the limits when crosstalk is applied.

I suspect your estimate of 35 gives you a little more margin.

All the same, having that main customers on there is a good test of the crosstalk, and probably a good sign for BT's profit margin!

I've just received my monthly report card from my SamsKnows BB Performance Testing.

Downstream throughput 38.83Mbps (Average) Min 13.35Mbps Max 40.27Mbps
Upstream throughput 8.96Mbps (Average) Min 7.50Mbps Max 10.15Mbps
Latency 13.60ms (Average) Min 12.17ms Max 79.78ms
Packet loss 0.35% (Average) Min 0% Max 1.66%

Looks very good to me and any happy with my Infinity.

iechyd da

In reply to a post by paul1360:

Looks very good to me and any happy with my Infinity.

Those are good numbers, thanks for posting. It shows the wide range, but even on the low point was was similar to my BE 16meg ADSL2+.

Here's mine:
Downstream throughput 14.86Mbps (Average) Min 13.68Mbps Max 15.68Mbps
Upstream throughput 1.12Mbps (Average) Min 0.57Mbps Max 1.47Mbps
Latency 9.2ms (Average) Min 7.27ms Max 111.50ms
Packet loss 0.70% (Average) Min 0.00ms Max 19.69%

I'm still waiting for an FTTC cabinet

Seems odd that both of our Latency MAX are very high???
I just been looking at my Dashboard and I've got some very speeds results at 23:00 every other night, my Downstream throughput drops but my Upstream throughput goes up, are your's the same?????????

iechyd da

In reply to a post by paul1360:

Seems odd that both of our Latency MAX are very high???

In a month of testing, I'm not that surprised. It might have been only one ICMP test packet that was high.

I just been looking at my Dashboard and I've got some very speeds results at 23:00 every other night, my Downstream throughput drops but my Upstream throughput goes up, are your's the same?????????

Nope - I get pretty much flat lines for download and upload on a 24hr basis.

Just an off-topic question - is your BQM spikes normal?

Been unable to get it to work just get it all coloured in red, so gave up on it.
Maybe it's something to do with Infinity jchamier for got your on ADSL.
iechyd da

In reply to a post by paul1360:

Been unable to get it to work just get it all coloured in red

That usually means you haven't enabled ICMP pings from the WAN (internet) side in your router.

But the BQM is also only really useful if you have a static IP, and I think Infinity uses dynamic.