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Standard User GonePostal
(learned) Tue 03-Nov-15 15:37:51
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FTTC Sync speed vs Download Speed


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We are on FTTC but a good distance from the cabinet. ISP is Origin Broadband who appear to be acting as a re-seller for PlusNet in our part of the world. We have a stable line which last re-sync'd 7 days 13 hours ago. The re-sync before gave an up-time of 15 days and the one before that 35 days. The sync speeds have been gradually rising (16764/19267/23320) over that period.

When the first re-sync occurred average download speed jumped accordingly (from about 16 to 18.5). Following the last re-sync the download speed has not not moved but has remained at about 18.5. Those download speeds are pretty constant throughout the 24 hours.

I suspect that the jump in sync speed is due to G.INP. I haven't got the details recorded but IIRC for the first spell INP (DMT symbol) was in single figures, then jumped to 41.00 and is now showing as 45.00.

Should I expect the download speed to eventually rise towards the current sync speed or am I likely to see download speeds at less than 80% of the sync speed for ever.

Current stats for a system up-time of over 56 days are:

xDSL
Mode VDSL2
Traffic Type PTM
Status Up
Link Power State L0
Downstream Upstream
Line Coding (Trellis) On On
SNR Margin (dB) 6.8 6.4
Attenuation (dB) 29.4 0.0
Output Power (dBm) 11.1 10.5
Attainable Rate (Kbps) 24641 1133
Rate (Kbps) 23320 1133
B (# of bytes in Mux Data Frame) 243 31
M (# of Mux Data Frames in an RS codeword) 1 1
T (# of Mux Data Frames in an OH sub-frame) 0 52
R (# of redundancy bytes in the RS codeword) 10 0
S (# of data symbols over which the RS code word spans) 0.3332 0.8828
L (# of bits transmitted in each data symbol) 6099 290
D (interleaver depth) 8 1
I (interleaver block size in bytes) 254 32
N (RS codeword size) 254 32
Delay (msec) 0 0
INP (DMT symbol) 45.00 0.00
OH Frames 507433009 169451350
OH Frame Errors 23435 4075
RS Words 3498155104 2386926
RS Correctable Errors 3814368 0
RS Uncorrectable Errors 0 0
HEC Errors 338535 0
OCD Errors 0 0
LCD Errors 0 0
Total Cells 3451630761 0
Data Cells 220858334 0
Bit Errors 0 0
Total ES 7207 3958
Total SES 44 0
Total UAS 104 84
Administrator MrSaffron
(staff) Tue 03-Nov-15 15:57:25
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Re: FTTC Sync speed vs Download Speed


[re: GonePostal] [link to this post]
 
If you follow the test at
http://speedtest.btwholesale.com/
until you find out your IP Profile (Configured throughput speed) then that will give you the maximum TCP/IP speed you will see which should be close to 22387 Kbps

PlusNet for their own customers run a mirror copy which sometimes fails to update, so if Origin is a resale of PlusNet this may be the case and Origin should be able to check.

The upload speed looks very unbalanced, generally people with those sorts of connection speeds see an upload of 4 to 7 Mbps, those sync speeds are from the test socket with no telephones plugged in anywhere (test socket so that negative effect of extension wiring does not impact you)

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User GonePostal
(learned) Tue 03-Nov-15 18:56:50
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Re: FTTC Sync speed vs Download Speed


[re: MrSaffron] [link to this post]
 
Andrew

Thanks. IP Profile is shown as 22.55 Mbps and the Upstream IP profile as 10Mbps.

I suspect that it is the Plusnet problem you have identified as we migrated from BT about 3 months ago where I was on the 40/2 Product and it could be that the Plusnet data has just carried over from there. The actual speeds we are currently getting are pretty much as the speeds we got with BT although the sync is now significantly higher.


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Standard User RobertoS
(elder) Tue 03-Nov-15 19:35:42
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Re: FTTC Sync speed vs Download Speed


[re: GonePostal] [link to this post]
 
The IP Profile is also consistent with G.INP being on. I'm not sure your INP number earlier actually tells us that. I'll need to find some pre-G.INP stats of mine to see what is there.

There has always been Impulse Noise Protection. Bearer 0 and Bearer 1 both show it in my stats.
Bearer 0
INP: 48.00 0.00
INPRein: 0.00 0.00
delay: 0 0
PER: 0.00 8.03
OR: 0.01 30.87
AgR: 60058.37 15172.73

Bearer 1
INP: 2.00 0.00
INPRein: 2.00 0.00
delay: 0 0
PER: 16.06 0.01
OR: 63.75 0.01
AgR: 63.75 0.01
Bearer 0 is the main connection. Bearer 1 appears to be a communication channel for G.INP.

The indispensable man or woman passes from the scene, and what happens next is more or less the same thing as was happening before.
My broadband basic info/help site - www.robertos.me.uk. Domains, site and mail hosting - Tsohost.
Connection - AAISP Home::1 80/20. Sync 59997/15142kbps @ 600m. - BQM
Standard User GonePostal
(learned) Wed 04-Nov-15 09:31:25
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Re: FTTC Sync speed vs Download Speed


[re: MrSaffron] [link to this post]
 
Further updates. BTW still showing profile as 22.55 downstream and 10 upstream. I have had the following responses in a chain of e-mails from Origin Broadband support:

1. I can see that your profile is set appropriately for your lines capability and the throughput speed of 18.5Mbps/1Mbps is within your estimated range so a profile reset likely wont increase the speeds if it was to get actioned.

2. In relation to your connection you are currently in sync at 23.3/1.1Mbps. I can see you did a speed test this afternoon, in which you achieved the throughput of 17.6/0.9Mbps which when taking into consideration overheads and loss over line length the speed falls within the appropriate range. As you are in sync at 23.3 a reset of your profile which is set at 22.4 will not increase your speeds.

3. With regards to your upload speed your range is 0.6Mbps - 1.7Mbps because of this your upload speeds will never be between 4 - 7 because the line simply isn't capable of those speeds.

Are these reasonable responses or am I being bathed in ungulate ordure?
Administrator MrSaffron
(staff) Wed 04-Nov-15 09:50:37
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Re: FTTC Sync speed vs Download Speed


[re: GonePostal] [link to this post]
 
1. A profile reset would achieve nothing, as you are asking why the difference between low speed tests and IP profile, ableit not massively low

2. Loss over length was waffle as the sync speed has already taken that into account. The issue of why throughput is so much lower than the IP Profile has not been addressed.

3. The modem does support this statement, hence asking if you have tried to use the test socket to remove any influence from the wiring in your property.

So a bit of waffle, but in the right ball park if you are someone whose line is over 1km long to the green cabinet

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User RobertoS
(elder) Wed 04-Nov-15 09:58:56
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Re: FTTC Sync speed vs Download Speed


[re: GonePostal] [link to this post]
 
You need to tell them that you believe they are reselling Plusnet, and that Plusnet automatically receive a copy of the BT IP Profile. They call the copy the Plusnet Line Speed.

That copy update can fail, and seems to have done so. It needs Origin to contact their Account Manager or Support Executive at Plusnet and get it manually updated to equal the IP Profile. This is an internal setting in the Plusnet system, not a profile reset.

The indispensable man or woman passes from the scene, and what happens next is more or less the same thing as was happening before.
My broadband basic info/help site - www.robertos.me.uk. Domains, site and mail hosting - Tsohost.
Connection - AAISP Home::1 80/20. Sync 59997/15142kbps @ 600m. - BQM
Standard User GonePostal
(learned) Wed 04-Nov-15 10:13:24
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Re: FTTC Sync speed vs Download Speed


[re: MrSaffron] [link to this post]
 
Andrew

Thanks again for taking the time to follow through on this. Line length to the cabinet is probably nearer a mile than a kilometre so it looks like we are stuck with the upload speed (which would be borne out by BT only offering a 40/2 service and not Infinity).

Given the responses so far, I don't expect to get any further on a rational basis with Origin. However, my inquisitiveness is still bothered by the gap between sync and download speeds. The download speed on FTTC has been consistently running at between 95% and 99% of sync until this last re-sync since when we are showing about 80%. Could it just be a max rate the line can handle or should the download speed always react proportionately to the sync speed?
Administrator MrSaffron
(staff) Wed 04-Nov-15 10:17:54
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Re: FTTC Sync speed vs Download Speed


[re: GonePostal] [link to this post]
 
The gap is down to what RobertoS says, i.e. a stall copy of the IP profile stored by Plusnet

The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User GonePostal
(learned) Fri 06-Nov-15 09:48:26
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Re: FTTC Sync speed vs Download Speed


[re: MrSaffron] [link to this post]
 
Thanks to both RobertoS and Mr. Saffron for their advice.

Trying to get Origin to talk to Plusnet about the stalled IP profile has been like wading through treacle and I am still waiting to hear whether anything has been actioned.

However, in the meantime, I've re-booted the router. The INP (DMT Symbol) value has dropped back to 42.00 and the sync to 19233. Download speed is 18Mbps+.

Maybe the 23Mbps sync was an aberration and not attainable in actual use. If the INP value goes back to 45.00 and the sync takes a jump again, I'll report back but otherwise it looks like the end of the road. Thanks again, chaps.
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