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Author Topic: Strange IP Profile compared to throughput speed.  (Read 1363 times)

waltergmw

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Strange IP Profile compared to throughput speed.
« on: April 14, 2017, 09:47:15 AM »

Gentlefolk,

I wonder if anyone has an explanation for the very low IP profile figure, illustrated below, when compared to the BT throughput figure on this G.DMT ADSL service via a HH6.

Heres a corresponding DSL Reports speed test which is probably nearer the truth as yet another statistical calculation.

http://www.dslreports.com/speedtest/13668605

Here's what newcastle.technical.complaints@bt.com say.
They also refuse to initiate a lift and shift as recommended by the eighth BT Openreach engineer.

______________________________________________________________________________

I need to concentrate on this line alone, and no other lines that you may be monitoring. I can’t take into account any other line stats.
 
There is no reason to change the port with no evidence of a fault (currently). I do not agree that the sync rate is fluctuating substantially, but it does fluctuate. Once again, broadband is ‘rate adaptive’, and it will fluctuate.
 
A hub reboot will cause a resync, sometimes at a different rate. But as DLM monitors the connection for errors and noise, gradually we’d expect that sync rate to level out over time. This appears to be what’s happening with this line.
 
I would investigate the IP profile discrepancy if it was causing problems with the throughput. The IP profile has absolutely no bearing on the DSL connection rate, so is not a factor in this case.
 
Swapping to G993.3 is not an obvious step to take here. There is no reason a circuit performing well below 8mbps should be moved to ADSL2+, and I have seen numerous faults in the past which have been resolved by taking the very opposite measure and moving to 8MB WBC.

___________________________________________________________________________________________________________
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burakkucat

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Re: Strange IP Profile compared to throughput speed.
« Reply #1 on: April 14, 2017, 04:49:57 PM »

. . . Swapping to G993.3 is not an obvious step to take here.  . . .

That is either a typo or more nonsense from within BT.

G.992.1 is "G.Dmt".
G.992.3 is "ADSL2"
G.992.5 is "ADSL2+"
G.993.2 is "VDSL2"

If the exchange based equipment is 20CN then only G.992.1 is possible.

If the exchange based equipment is 21CN then, with an appropriate CPE, the circuit can be configured as either G.992.1, G.992.3 or G.992.5 within the settings of the CPE.

Remember --
  • G.992.1 has a maximum of 256 sub-carriers
  • G.992.3 also has a maximum of 256 sub-carriers but uses a more efficient bit-loading than G.992.1
  • G.992.5 has a maximum of 512 sub-carriers and uses the more efficient bit-loading, just like G.992.3
Summing up you are, unfortunately, in communication with one of BT's "Numpty Nigels from Newcastle" who really should attend the appropriate training course before attempting what he is currently failing to do.
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ejs

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Re: Strange IP Profile compared to throughput speed.
« Reply #2 on: April 14, 2017, 04:59:49 PM »

A BTWholesale based ISP only has options of ADSL1 or ADSL2+ though. And some exchange equipment (TSTC) does give slower speeds because it does ADSL2+ badly on long lines. Other exchange equipment automatically switches to ADSL2, or does ADSL2+ at equal performance with ADSL2 on long lines.
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kitz

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Re: Strange IP Profile compared to throughput speed.
« Reply #3 on: April 16, 2017, 09:48:38 PM »

How odd.  In theory it shouldnt be possible to attain those speeds with an IPprofile of 0.34Mbps.   Something is niggling me about IPprofiles which I cant quite remember now.  Who is the ISP, is it by any chance Plusnet?

Is it on a 20CN exchange?   I'm assuming he read meant G993.3 as ADSL2+. 

Long lines do tend to perform worse on ADSL2+.  As far as BTw is concerned they offer G.DMT or ADSL2+ so I can understand why he has said that. 
I believe that we here were the first to start recommending trying G992.3 because it gave the best of both worlds - the benefit of S=1/2 mode without opening up the line to the higher frequencies.  Its not something that BT configure and must be over-ridden by settings in the modem.  I don't think Openreach are fully aware that some EUs do this.
« Last Edit: April 16, 2017, 11:52:35 PM by kitz »
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burakkucat

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Re: Strange IP Profile compared to throughput speed.
« Reply #4 on: April 16, 2017, 09:58:57 PM »

I believe that we here were the first to start recommending trying G993.3 . . .

Nooo.  :no:  Not G.993.3 . . . but G.992.3

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kitz

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Re: Strange IP Profile compared to throughput speed.
« Reply #5 on: April 16, 2017, 10:10:20 PM »

lol see easy done.  Already edited it. :D  :paperbag:
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burakkucat

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Re: Strange IP Profile compared to throughput speed.
« Reply #6 on: April 16, 2017, 10:21:08 PM »

. . . I'm assuming he read G993.3 as ADSL2+.

But what about the above? There is no such ITU-T Recommendation!  ;D

G.993.1 is Very high speed digital subscriber line transceivers (VDSL)
G.993.2 is Very high speed digital subscriber line transceivers 2 (VDSL2)
G.993.5 is Self-FEXT cancellation (vectoring) for use with VDSL2 transceivers

There are (currently) just three recommendations in the G.993.n range.  :angel:
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kitz

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Re: Strange IP Profile compared to throughput speed.
« Reply #7 on: April 16, 2017, 11:56:28 PM »

We don't know the exact question sent to him but Im assuming he read a request from Walter for 992.3 as putting the line on ADSL2+ .   As already stated, BTw dont provision 992.3.

The 3 in 993.3 is an obvious typo - I doubt he was in any way referring to VDSL because he says ADSL2+
The fact that he types G993.3, then says ADSL2+ in the same paragraph infers to me that he should have typed G.992.5.

Who knows because we havent seen the full convo, but I wouldnt be surprised if the conversation went something like

WW:  Can we put this line on G922.3
BT:  Thinks we dont provision G922.3 Perhaps WW means ADSL2+
BT:  Means to type G992.5 but it comes out as G993.3

I myself accidentally typed a 3 several times in this post but I have a valid excuse. As you know it takes me a long time to type anythign these days and why I no longer post much.   
Grr it sounds like Im defending BT when it wasnt my intention, other than to say I think it was a typo.  Ive edited my post does that make it clearer?  :)
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burakkucat

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Re: Strange IP Profile compared to throughput speed.
« Reply #8 on: April 17, 2017, 12:28:11 AM »

Pesky kitteh offers Kitz  :hug:  :flower:
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waltergmw

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Re: Strange IP Profile compared to throughput speed.
« Reply #9 on: April 19, 2017, 04:43:00 PM »

Gentlefolk,

I'll return to the semantics discussions later but in the meantime the exchange details according to SamKnows are:-

Exchange name:   Cheriton Fitzpaine
Exchange code:   WWCFIT
Location:   Devon   South West
Postcode:   EX17 4HU
Serves (approx):   646 residential premises
58 non-residential premises.
Broadband availability overview
ADSL:   
Yes
SDSL:   
No
LLU services:   
No
Cable:   
No
Wireless:   
No
BT Wholesale information
ADSL status:   
Enabled as of 06/10/2004
ADSL Max status:   
Enabled as of 31/03/2006
SDSL status:   
Not available
21CN WBC status:   
Not available
FTTC status:   
Available in some areas
FTTP status:   
Available in some areas

BUT there are at least four services in close proximity all with sync speeds of around 2 mbps with the best AAISP service:-

BT 21CN ADSL2+
Copper pair for broadband service
Standard care on DSL service
Standard stability line setting
Automatic interleaving
Transfer requests are allowed. Request anti-slamming
Line rate:   Down: 2.26M (FTTC forecast: No - checked 2017-04-01)

BUT Newcastle won't consider them as the norm for the longish distance lines.

This battle has been ongoing for over a year during which BT retail (I assume) has provided three different HH6s.
The EIGHTH engineer visiting recommended doing a "Lift and Shift" but Newcastle insist that line is stable above the minimum contracted offering of 1 Mbps so won't lift a finger even though that process would remove a significant area of uncertainty.

I can only guess that there is a DSLAM port problem or there is some provisioning error / inconsistency with BT's "Operate" empire.
We can power - reset the line which causes an immediate sync rate increase often to just over 2 mbps but usually within 24 Hours that drops back often in two stages to a sync speed of 1.664 Mbps with a (ridiculous ?) IP Profile / bRAS figure of 0.34 Mbps.

When I substitute an unlocked HG612 without authentication I get the following sync figures:-

Max:   Upstream rate = 972 Kbps, Downstream rate = 5816 Kbps
Bearer:   0, Upstream rate = 963 Kbps, Downstream rate = 5120 Kbps

Link Power State:   L0
Mode:         ADSL2 Annex A
TPS-TC:         ATM Mode(0x0)
Trellis:      U:ON /D:ON
Line Status:      No Defect
Training Status:   Showtime
      Down      Up
SNR (dB):    6.6       6.1
Attn(dB):    45.5       28.6
Pwr(dBm):    0.0       12.8

I guess that DLM or other logic would adjust the figures if the HG612 was left connected.

(More data are available if anybody wishes it.)

I would be VERY grateful for:-
a) any ideas what might be wrong
b) any "instruction" I could give Newcastle to at least try to resolve this most unsatisfactory situation.

Kind regards,
Walter

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waltergmw

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Re: Strange IP Profile compared to throughput speed.
« Reply #10 on: April 19, 2017, 04:55:19 PM »

The following words are Newcastle's "explanation"


The IP profile on a 21cn line is not as significant as the IP profile on a 20cn circuit, which will not allow the throughput to exceed the BRAS profile.
 
I can see that the profile is listed as 0.1 – 0.5mbps, but clearly this is not causing problems given that the throughput you’ve reported was 1.4mbps.
I can see that the sync rate is still 1.6mbps today. I would not pay too much attention to the IP profile, which I believe is not being correctly reported on BTW systems.
 
The upload profile will be 0.45mbps which is correct, because Mr Xxxxxx is on an emulated 20cn (up to 8mbps) profile which caps the upload at 448kbps.
 
You’ve mentioned that the fundamental problem of instability has not been addressed, but in recent days/ weeks, I can see no evidence of an unstable connection. The sync rate has been above the minimum guaranteed 1mbps since the engineer visit on the 28th March.
 
As mentioned, broadband is a rate adaptive service and we do not offer a fixed rate profile.
 
I don’t feel that we need to take any further action at the moment given that the last two weeks have shown a stable connection.


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ejs

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Re: Strange IP Profile compared to throughput speed.
« Reply #11 on: April 19, 2017, 04:59:29 PM »

WWCFIT has a WBC availability date of 15/11/2016. So apparently the exchange was upgraded with ADSL2+ available at some point in the middle of the problem. The SamKnows data is out of date.

Considering the dramatic improvement seen with the HG612, I would recommend using something other than a HH6 for a few days.
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gouledw

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Re: Strange IP Profile compared to throughput speed.
« Reply #12 on: April 20, 2017, 01:18:41 AM »

Ditch the HH6 in its entirety. What you want is a HH4/5 Type B hard to get hold of. Broadcom based chipset and as good as any billion router. If your line is on a 21CN exchange then your BRAS profile should work the same way as if your connection was set to 24M WBC. The sync speed is perfect for attenuation. Something seems a miss here. I agree that a lift and shift is not needed. However something is wrong with this bras profile. It's hard to say without having all the facts of your connection. However the HLC in Newcastle in my opinion should be asking BT wholesale to do some further investigations in the ether that is wholesale broadband connect to see exactly what's going on. The fact that you can achieve 5mb sync then them saying 1mb is acceptable is just pure ignorance. 20% speed of what's physicalslly possible on your line is disgraceful. Cheriton exchange area is locally referred to as Cheriton [something rude]stain because of its difficult dynamics. I wish you luck.
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waltergmw

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Re: Strange IP Profile compared to throughput speed.
« Reply #13 on: April 20, 2017, 08:44:32 AM »

Thanks very much ejs and Gouledw,

I'm about to send a PM to Gouledw.

My reasoning for a Lift and Shift was firstly to eliminate one of the variables and secondly to hope that the process just MIGHT get somebody to look at the provisioning data.

If anybody else would like to suggest other ADSL2+ modems I'd be pleased to hear from you.

Kind regards,
Walter
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tickmike

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Re: Strange IP Profile compared to throughput speed.
« Reply #14 on: April 20, 2017, 12:06:51 PM »


If anybody else would like to suggest other ADSL2+ modems I'd be pleased to hear from you.

Kind regards,
Walter
Hello Walter.
I have been trying my old Netgear DG834GT (set only for ADSL2)  for a time on my long ADSL2+ line 4.3kl and it worked very well.
I also did some tests with modem forced on ADSL only setting on my ADSL2+ line with good results.
Gone back to a HG612 Modem  (set only for ADSL2)  which also works well.
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