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FTTC - a few questions

jafreer
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Registered: 13-10-2012

FTTC - a few questions

I had FTTC installed in the last few days, having been on the PN ADSL product for some time.
Liking the difference in speed so far, but had a few questions that I am hoping some of the forum experts can answer.
1) Mk3 Master socket installed and fortunately the OpenReach contractor used the CAT6 cable I installed to the computer room as running a dedicated extension to that room on the surface (along skirting boards etc) would have been a nightmare. The CAT6 cable is kroned in to the VDSL connector on the master socket. So all neat and tidy there. At the other end of the CAT6 cable, I assumed the installer would just fit a surface box with RJ11 socket on it (as per the 'OpenReach VDSL extension kit' I see advertised). However the installer put another MK3 socket in the computer room. So it has the RJ11 socket for the BT modem (currently being used), and also a standard telephone socket (presumably filtered) which I don't use.
Long winded explanation, but my question is this... Will there be any negative impact by hanging another MK3 socket off of the master and using that as a VDSL extension? If so, I assume I would just replace it with a RJ11 only box?

2) I know I am still in the 10 day 'training' period, but I have been monitoring speed each day. Unfortunately I can't get access to any line stats as the BT modem is locked. Forgetting wireless (the Technicolor router I find is not that great for wi-fi coverage) and using a direct connection to the Technicolor router, I am getting a very good and very solid 37.5 Mbps download speed. This is very much in line with PN estimates. I am on the 40/20 product.
I am assuming the download speed is capped by the PN profile (which is 40 Mbps) because the BT speedtester reports an IP Profile of 50.3 Mbps?
(I understand why PN would cap it to 40 since I am only paying for the 40 service, but because PN offer 40/20, the BT side is the 80/20 service, so PN cap it to 40? - at least that's what I think I found out from digging).
So far so good on the download side.
3) On the upload side, I consistently achieve 7 Mbps, yet the BT Speedtester reports an upstream profile of 20 mbps.
I thought I would realise a higher speed on upload given that the BT profile is 20 Mbps.
So the question I have, is the upload profile also set at the PN side, and if so, what is it set to?
I sometimes see requests on the forum asking for upload to be uncapped. Is this something that applies here?
Thanks in advance for any input/comments regarding the above.
Best regards

11 REPLIES
Community Veteran
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Registered: 24-10-2013

Re: FTTC - a few questions

there is no 10 day training period for FTTC, that is just for ADSL.
taras
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Registered: 22-08-2008

Re: FTTC - a few questions

1) vdsl isn't filtered its the voice side to make sure the phones do not cause noise on the dsl frequencies.
2) PN do two fibre products 40/20 and 80/20 both are actually a capped service in terms of download/upload as some who are very close to the cabs can exceed 100mbits. so you have really answered your own Q
3) upload speed is firstly (like your download speed) is dictated by the line length to cabinet, this with your line is 7mbit, the 20mbit cap on the service is infact bt's rather than PN's.
PeeGee
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Re: FTTC - a few questions

Quote from: jafreer
I am assuming the download speed is capped by the PN profile (which is 40 Mbps) because the BT speedtester reports an IP Profile of 50.3 Mbps?

You assume correctly - however, the Plusnet profile is designed to reduce problems caused by sending data to the exchange faster than it can pass it on Shocked
Quote from: jafreer
3) On the upload side, I consistently achieve 7 Mbps, yet the BT Speedtester reports an upstream profile of 20 Mbps.

The 20Mb "cap" on upload would operate the same way by queueing packets at your end (not that you can currently send data that fast anyway) Roll eyes
Plusnet Fibre (Sep 2014), Essentials (Feb 2013); ADSL (Apr 2009); Customer since Jan 2004 (on 28kb dial-up)
Using a TP-Link TD-W9980 modem-router.
jafreer
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Registered: 13-10-2012

Re: FTTC - a few questions

Thanks for the replies so far.
I understand that it is the voice side that is filtered with VDSL/ADSL, however with VDSL (FTTC) there is usually a single filter, at the master socket (as opposed to multiple individual filters like with ADSL). I have that filter at the master socket, but I also have another filter at the end of my VDSL extension (because BT fitted another MK3 socket). So whilst no filters are used for the VDSL side of the signal, will having another filter hanging at the end of the VDSL extension cause an issue? It kind of goes against the principle of having one filter on the line.
Regarding upload, I understand that it is determined by your distance from the cabinet, but BT have an IP profile of 20 Mbps on the upload. I assumed that IP profile was selected based on what the line can support and takes into account the distance from the cabinet. So if 7 Mbps was as fast as my line could support on the upload, wouldn't that be reflected in a lower BT upload IP profile? The fact that the BT upload profile is 20 Mbps, would make me wonder if PN has a cap on the speed?
Is there any way to find out what the PN upload IP profile is?
Community Veteran
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Re: FTTC - a few questions

The 20Mbps IP profile is only the maximum speed the product is capable of providing for any user regardless of distance from the cab
Plusnet don't have an upstream IP profile as it would be meaningless given that you can't push data down the line from your router faster than the upstream sync rate and in any case the profile could only be applied once your data reaches the Plusnet servers and that is subject to the line speed restriction already
jafreer
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Re: FTTC - a few questions

Thanks for the explanation Jim - so my assumption that the BT upload IP profile was linked to the performance of the specific line was incorrect. So whilst the download BT IP profile is set based on the capability of the line, the upload is not and everyone (who is on the 20 product) gets a BT upload profile of 20 Mbps, irrespective of what their line is capable of?
It is a little counter intuitive because I am so used to thinking of IP profile as something that is set for each line based on the performance that line can achieve, and that is true of download, but not, apparently upload - how odd.
Did you have any thoughts on the additional filter at the end of the VDSL extension (albeit the filter is not used with a phone, it is still connected to the line)?
Thanks again
MJN
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Re: FTTC - a few questions

Quote from: jafreer
I understand that it is the voice side that is filtered with VDSL/ADSL, however with VDSL (FTTC) there is usually a single filter, at the master socket (as opposed to multiple individual filters like with ADSL). I have that filter at the master socket, but I also have another filter at the end of my VDSL extension (because BT fitted another MK3 socket). So whilst no filters are used for the VDSL side of the signal, will having another filter hanging at the end of the VDSL extension cause an issue? It kind of goes against the principle of having one filter on the line.

For what it's worth my setup is similar in that the BT engineer fitted a MK 3 faceplate at the master socket and was happy to use my existing CAT5e extension to allow the modem to be placed elsewhere. However, at the other end of this extension was an ADSL Nation XTF filtered faceplate which he removed and replaced with a single RJ11 socket. He did this on the grounds that having a second filter on the line can 'sometimes cause issues'. He wasn't any more explicit than that and I didn't question it because it wasn't an issue for me i.e. I wasn't ever going to use a phone in that location.
If I were you I'd be tempted to replace the second MK3 faceplate/socket with a completely unfiltered RJ11 socket, even if only as a 'why not?' and to allay any concerns that any issues might be down to the current setup.
On the subject of throughput, if you are able to get 37.5Mbps down I would expect you to achieve more than 7Mbps up. What do the figures at BT's checker predict?
sjptd
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Re: FTTC - a few questions

The point about the upload profile being irrelevant was important.
Upload speeds can suffer in curious ways and get misrepresented by speedtests, which often give figures significantly lower than real speeds to good real sites.  At one point I was getting BT speedtests below 10Mbps and real upload speeds of 17Mbps.  The difference was due to some minor issue in my internal network, I forget exactly what it was I am afraid.
I find http://www.thinkbroadband.com/speedtest.html the most reliable for upload at the moment.
jafreer
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Registered: 13-10-2012

Re: FTTC - a few questions

Thanks for the replies.
MJN, I think I may order the RJ11 socket and do the replacement. The crazy thing is, there is already a phone extension in that location, that is connected to the MK3 filter at the master socket, so even if I wanted a phone at that location (which I don't), I could use that. I wonder if the installer simply didn't have an RJ11 socket and used a MK3 instead. He didn't seem overly clued up and initially wanted to run my VDSL extension over the existing extension cable (flat cable). I persuaded him to use the CAT6 at least.
You asked about BT's checker. It predicts as shown in the attachment. Basically downstream 45.3 to 64.4 (clean), 30.6 to 54.8 (impacted). Upstream 11.9 to 18.5 (clean), 7.9 to 18 (impacted).
Like you, I would have expected a little more than 7 Mbps.
sjptd, it is the thinkbroadband speed checker I have been using (wired connection) and I consistently get from 7.3 Mbps to 8 Mbps.
Dezz
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Registered: 21-12-2014

Re: FTTC - a few questions

I too had a pre-laid CAT5 cable and the engineer advised me that using the data connector in the Mk 3 socket would provide an extension for data only and not voice. I did however connect it to my existing wiring for the modem and extensions in the loft and the phone extensions all still worked surprisingly. I have since split the voice (extension) and data into 2 pairs in the same CAT5 cable from the master socket, just to avoid any future issues,  and it all works fine. Smiley
MJN
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Re: FTTC - a few questions

Yes, the data connector is completely unfiltered. It is only the voice extension that is filtered (using a low pass filter to stop the high frequency DSL signal from reaching the phones and any high frequency interference from the phones from affecting the DSL signal).  It would perhaps have been more accurate for him to say that you shouldn't use the data connector for voice extensions rather than imply you can't. It does however keep things simple to make things appear black and white.