A question about upload speed.

Technically speaking, why would an upload speed drop from 17-7 Mbps, yet my download speed only from 60-55 Mbps.

This is related to this thread but I thought I should ask as new thread.

Line fault or a lot of power cuts banding the DLM.

Thanks - that's what I thought also.

I've seen my upload drop from around 11 to 5, but my download actually increased, after a few days it returned to normal.

Perhaps it is related to the teed line...

I was trying to figure out why that would have any effect at all, and the best answer I could come up with was multipath fading... which is usually a mobile problem.

Perhaps, having 2 copper paths of slightly different length, the signal is following both, and getting a tiny delay in one leg, enough to cause cancellation issues at certain frequencies.

Perhaps, then, the upstream frequencies are more susceptible, or perhaps there's a difference in power that helps cause it.

Have you got before/after graphs of SNR, Hlog, QLN, Bitloading etc?

I was trying to figure out why that would have any effect at all,

Bridge tap possibly, and the general fannying around with all the stuff in the cabs is surely bound to have an effect on the signal itself

Bridge tap possibly, and the general fannying around with all the stuff in the cabs is surely bound to have an effect on the signal itself

Does that mean my upload speed 'may' return to normal levels when the work is finished on the cab?

At a guess, and it is just a guess, yes. Given some good lengthy of stability.

In reply to a post by shalom2005:

Technically speaking, why would an upload speed drop from 17-7 Mbps, yet my download speed only from 60-55 Mbps.

This is related to this thread but I thought I should ask as new thread.

Have you just installed an ad-blocker or similar application that monitors network traffic? One that I used to use did exactly what you said.

In reply to a post by Andrue:

In reply to a post by shalom2005:

Technically speaking, why would an upload speed drop from 17-7 Mbps, yet my download speed only from 60-55 Mbps.

This is related to this thread but I thought I should ask as new thread.

Have you just installed an ad-blocker or similar application that monitors network traffic? One that I used to use did exactly what you said.

No. The only program I have used is called DuMeter - used it for years! However just uninstalled it & still only 7 Mbps upload - now installed it back

How are you measuring upload speed?

I have found that some testers seriously underestimate under certain circumstances. The old now defunct BT retail test was the worst, the new one and BY Wholesale test fairly bad. The most reliable for me recently is this site's own: http://www.thinkbroadband.com/speedtest.html
That consistent matches what I get from FileZilla upload to good upload sites (SquirrelSave for example)

When I had server download speed problems because of some bad wiring (down to 12Mbps, briefly 3Mbps), my upload stayed at 17Mbps. However, most testers reported well under 10Mbps.

Some BT users have found that one (or more) resets of the HomeHub can dramatically improve upload speed. Not sure if that is because of establishing a different IP with different routing, or something internal in the HomeHub.

aside: If you unlock an HG612 modem and remove QoS, you may find upload increase from around 17 to around 18.5.

Well I tested with thinkbroad! Originally 17.4 now 7.4.

You need to get an HG612 and unlock it, to give a better idea of what's going on, or just wait patiently until the works on your cabinet are completed.

And it's always nice to have higher figures, but do you actually use 17 upload?

I use cloud back up, but I've never seen the upload speed go above 3, and I have 10 on tap.

Well I mainly upload photos onto Flickr - the upload 2 weeks ago was really fast, but now
the much lower upload speed slows down the process quite a lot. Having said that, all the photos have been uploaded now (33 gig) - only new ones to be taken in the future will suffer.

As for getting an unlocked HG12 - good idea, but I'll be patient & wait.

Ironic really... Having the unlocked modem is almost perfect for situations like this.

The thing that makes it fully perfect is that you have to have it unlocked, and baseline conditions recorded, before things go bad.

When you get really motivated to unlock the modem, it is usually 2 or 3 days too late.

Well I have the stat's already of what my speeds are historically with the Sam Knows box, plus I keep a spreadsheet of my speeds (!).

Anyway even if I have the numbers can I convince OR or Plusnet to do anything about it?

Speeds are an all-or-nothing thing. They prove how fast something can go when everything is working. But when they slow down, they don't help point to *where* they've slowed.

Getting action from the stats depends, as there are a few levels. They certainly can help in getting PN on your side (BaldEagle can attest to that). An Openreach engineer won't make much use of them though - he'll just see the line as it is presented to him at the time of appointment.

If the stats only show you've had FEC/interleaving turned on, then you're not likely to get much joy out of anyone (especially Openreach). However, there's quite a lot of support staff who don't understand the technical details behind this, nor the reason that it is happening more as take-up increases.

In reply to a post by shalom2005:

Well I have the stat's already of what my speeds are historically with the Sam Knows box, plus I keep a spreadsheet of my speeds (!).

Anyway even if I have the numbers can I convince OR or Plusnet to do anything about it?

If it's line related your chances are probably quite high. Where there seems to be a problem is getting someone to look at network issues. Last time IDNet raised my problem with BT they specifically asked for a network investigation and told them the line was fine. The chap who came out knew nothing about network issues and had no information other than a request to fix my line.

Thankfully I wasn't charged even though he found no fault. Dunno if IDNet picked up that tab but I read somewhere that at the moment there is no charge for FTTC call-outs. Anyway the problem is due to strike again in 9 days so I'll give IDNet one more chance then I think I'll switch to AAISP. It really should be possible for someone to resolve this. It strikes every 60 days starting at 1500utc and is clearly network related (fixed by establishing a new PPP session four or five days after it starts).

Edited by Andrue (Mon 10-Jun-13 11:18:04)

Off the subject slightly but:

I noticed a lot of the neighbors have had fibre installed recently and so wanted to check how crosstalk was affecting my line.. I know I was the first one on the cabinet (BT engineer told me I was the only one connected) and I was achieving a full 79999 sync and a achievable of about 97Mb... Now achievable is down to 87Mb and 79889 sync or something weird like that.

The cabinet is ECI and I usually use the supplied ECI modem but swapped to my unlocked Huawei for the stats. Interestingly the attenuation was rock solid at 8.9db instead of 6db. I've swapped back now hoping that it'll return to full sync.

So for me having the unlocked stats allows me conclude that I should try to dissuade my neighbors from ordering/using FTTC because I'm probably suffering from crosstalk.

In reply to a post by timl:

Interestingly the attenuation was rock solid at 8.9db instead of 6db.

I think you mean SNR margin. You should have left the unlocked modem on until it did go back to 6dB imo.

Yes I did mean SNR margin.. Sorry.

I'd assumed that the DLM had decided my line was better syncing with a higher margin - fewer errors. I hadn't thought to leave it on... Perhaps I should see where it takes me. I'm frightened of the DLM though

There were some errors on the line - about 8 CRC errors in 12 hours. And very oddly for a non interleaved line... FEC and HEC errors - but still no more than about 20.

In reply to a post by timl:

I'd assumed that the DLM had decided my line was better syncing with a higher margin - fewer errors.

No - your line is good enough that it reaches 80Mbps without requiring too much signal - so you have extra SNR margin to spare. It is all related to the sync, and nothing to do with DLM.

If "DLM decided" your line needed to sync with higher margin in order to cause fewer errors, it would have chosen to band you, limiting you to a lower speed.

That wouldn't be DLM's first choice though.

DLM would make a different choice first, where it would turn on FEC and interleaving. In your case, those would use more of that "max attainable" speed to carry the extra overhead for FEC, so your SNRM would lower first. If the extra capacity in the "attainable" wasn't quite enough for FEC, then you'd lose a bit of your sync speed too, and still have a 6dB SNRM.

Edited by deleted (Mon 10-Jun-13 13:00:08)

In reply to a post by timl:

There were some errors on the line - about 8 CRC errors in 12 hours. And very oddly for a non interleaved line... FEC and HEC errors - but still no more than about 20.

I take it you are looking at the GUI, rather than the output from the "xdslcmd" on the comand line.

The GUI uses figures from the wrong place for some of those error counts, so isn't to be trusted. It is the FEC figure that it gets wrong, IIRC.

And I'm not sure what the HEC figure really represents. HEC applies to ATM (and PPPoA), which isn't used in FTTC.

I'm not sure if I was looking at the gui or the output from the stats program by BaldEagle1.

So do you also think I should put the HG612 back and see if it recovers to 6db in a week or so? I suppose it would be an interesting experiment.

There are two ways that your SNRM will reduce to 6dB...

1. If the current noise levels stay the same, and your speed increases.

2. If your speed stays the same, and the noise increases.


As you are at 80Mbps (that 110kbps is insignificant here, even if inexplicable), #1 can't happen. There's no "recovery" to happen here.

#2 will mean more noise, more crosstalk, and more interference is happening. I'm not sure I'd class that as "recovery".

Personally, I'd be perfectly happy to keep the 80Mbps sync and the 8.9 dB SNRM.

Even if there is no recovery to expect, I'd still leave the HG612 in place, and collect regular stats from it.

In reply to a post by timl:

I was achieving a full 79999 sync and a achievable of about 97Mb... Now achievable is down to 87Mb and 79889 sync or something weird like that.

Mine was 79999 at first as well, but after 14 months it was down to 65Mb/s with interleaving although this morning it seems interleaving has been removed.

Swapped them back. You're right about stats being more important.

Attainable rate (kbit/s) 88128 34202
SNR margin (dB) 8.2 15.4

Line rate (kbit/s) 79987 20000

An update to my original question

Today I was visited by an SFI engineer who spent six hours on trying to resolve the issue with my upload speed! Ports were swapped over on the cabinet, the wires from the cabinet to outside my house were swapped and after all that my Download speed has now increased (which I was not complaining about) from 55.57 to 65.93, but my Upload speed is still low - was 6.97 now 5.71!.

Various phone calls were made around the Open Reach circuit and it was concluded that

a) They have never had one complaint (locally I presume) of a low upload speed, most people complain about download speed

b) As the original estimate was 13 Upload speed and they have it as 7, as it it more than 50% of that speed they will close the job

c) Work is still going on at the cabinet, 'line tethered', which in this thread has been noted that this could cause my issue. The OR engineers said this also possible, but was unsure as my Download speed has not changed (although got it higher). They said once the work has finished at the end of this week to monitor the line speed for the next 10 days & see what happens.

So, for me, a long day with a 10 meg download increase but a upload speed gone a further 1 meg

I'd be interested to hear your comments.

Are the line stats available from an unlocked modem?

No, but we ran stats over & over with the electronic box they brought with them, everything checks out fine - except the upload speed!

So do you know the sync speed, snr, attenuation, band plans, etc?

In reply to a post by shalom2005:

Well I have the stat's already of what my speeds are historically with the Sam Knows box

But not the router stats/sync speeds. That box is only aware of and records throughputs.

In reply to a post by BatBoy:

So do you know the sync speed, snr, attenuation, band plans, etc?

I know the SNR is 6 db, I saw it on the OR engineer's box. The other stat's I did not note myself.

SamBox Stats shows the upload speeds in the last few months:

2013-06-17 7.87
2013-06-16 7.82
2013-06-15 7.81
2013-06-14 7.71
2013-06-13 7.14
2013-06-12 7.20
2013-06-11 7.20
2013-06-10 7.11
2013-06-09 7.18
2013-06-08 7.19
2013-06-07 7.26
2013-06-06 7.17
2013-06-05 6.64
2013-06-04 6.70
2013-06-03 7.34
2013-05-31 10.33 AFTER THIS MY LINE WAS DEAD FOR 3 DAYS
2013-05-30 9.76
2013-05-29 17.22
2013-05-28 16.94
2013-05-27 17.07
2013-05-26 17.13
2013-05-25 17.08
2013-05-24 17.18
2013-05-23 17.16
2013-05-22 17.23
2013-05-21 17.13
2013-05-20 17.11
2013-05-19 17.16
2013-05-18 17.14
2013-05-17 17.16
2013-05-16 17.06
2013-05-15 17.14
2013-05-14 17.13
2013-05-13 15.39
2013-05-12 16.86
2013-05-11 17.15
2013-05-10 17.10
2013-05-09 17.15

SNR 6 is meaningless without the sync speed, but it looks like your speed is slowly rising.

Well it was slowly rising, until today when, as I said my download has increased by 10.3 but my upload decreased by 2.3!

Once the work on the cab is finished (at the end of the week I'll update this thread with my new readings (maybe this time next week).

The best thing would be to use a hacked modem to find out the actual line stats.

Well even if I knew the stats, all this would do, is, I guess give me evidence to argue my case for a fault to be raised, but as Plusnet have been more than obliging I don't see any reason to get a 'hacked modem' (yet!).

RESOLVED

I'm delighted to report that my Upload speed has now returned to normal speeds, after three weeks. Looks like the work on the cabinet is complete.

http://www.thinkbroadband.com/speedtest/results.html...

That's good news and with the added bonus of a quicker download speed.

Yes! Thanks. The engineer who came yesterday was here for six hours and really tried everything he could - even changed the twisted wires to the cabinet. I think the tethering at the cabinet was the issue - so maybe now I'll have stability again

Speedtest result today

http://www.thinkbroadband.com/speedtest/button/13715...

Edited by shalom2005 (Tue 18-Jun-13 19:40:02)

You did far better than I did, when I was pursuing my speed problem he was here for about 30 minutes and was not allowed near the PCP cabinet! My speed has improved recently but I'm still 10 meg below my download estimate of 57Mbps, was getting just under 40 at one point.

Edited by R0NSKI (Tue 18-Jun-13 20:36:00)

In reply to a post by R0NSKI:

You did far better than I did, when I was pursuing my speed problem he was here for about 30 minutes and was not allowed near the PCP cabinet! My speed has improved recently but I'm still 10 meg below my download estimate of 57Mbps, was getting just under 40 at one point.

Well at least you did not get a 'Kelly Comms' engineer...or did you

Speed increased even more today, delighted with a BT IP Profile of 70.4 the highest I've had

In reply to a post by shalom2005:

at least you did not get a 'Kelly Comms' engineer...or did you

No, both the install and the fault check were done by a BT engineer.

You may gain more speed yet, if you have interleaving on, if it's reduced further you will gain speed.

he was here for about 30 minutes and was not allowed near the PCP cabinet!

That is utter twaddle !

Yes, he can't access the DSLAM cabinet, but doesn't need to, just check on the end of the ties in the copper cabinet. There is no skill set for Openreach engineers which does not allow for work in PCP.

You were shined on, I'm afraid.

Yes, I guessed as much, he was going to swap ports and pairs but said he was told not to. After the engineer left he phoned me about half an hour later and said he'd driven past the pcp and there was another engineer working on the FTTC cab, as there had been reports of disconnections from other users. Apparently down to loose wires. This was last September / October IIRC.

I had been having many resyncs which greatly reduced after this. I was first on the cab last August, but I think the fastest I ever synced at was just over 50, which reduced to around 40 over a few days/weeks after connection . Up until about a month ago I was syncing at 42, but I'm now syncing on fast path at 47 Mbps , which is 10 below my estimate of 57, at least my connection seems to be increasing in speed