Re: adsl parameters: ideal readings?

Ato_Zee wrote:
<snipped>
> With one modem my sync was 2.528Mbps,
> tidying up the wiring, and using a 2700HGV it
> is now 5,920Mbps.

I had a similar experience after changing from a Safecom SAMR-4114 trouter
to a 2700HGV, getting an increased sync speed from between 6000 - 6500 kbps
up to a steady 7616 kbps for 7 months with the 2700HGV. Monitoring the
SNR has shown a reasonable steady value between 5 dB and 7 dB throughout
that 7 month period with 6 dB for most of the time. But beware!! Last
Wednesday morning (15/07) there was a disconnection and when it recovered it
was synching at 4928 kbps, despite the SNR still being as steady as before
at 6dB. I have taken this up with my ISP and they and BT have carriesd out
tests. The resulting comment, I presume originating from BT, states:
<quote>
Unfortunately the speed tests you have performed and that have been logged
with BT do confirm that this is not a problem with the service, but is due
to contention at your local exchange.

This can be seen by the tests that were done which all give you results
within BT's limitations for the speed you are on.

Unfortunately BT quote the following with respect to any ADSL connections
made over their lines:

'As this is a contended service there may be periods that maximum speeds
will not be achieved and as such BT may not accept a speed fault if the
speed test does not show results below certain levels.'

What this can mean is that if you are on a particularly busy exchange, that
you will see high levels of contention during the daytime and early evening
which will cause these dramatic drops in speed.

A breakdown of BT's acceptable speeds is as follows:-

For a line speed of 512kbps, a minimum of 100kbps is acceptable.
For a line speed of 1Mb, a minimum of 200kbps is acceptable.
For a line speed of 2Mb to 8MB, a minimum of 400kbps is acceptable.


Also, as your connection is on the MaxDSL service this means that your
connection is rate adaptable.
etc. etc.
<unquote>

And I am now synching at the lowest speed ever, since changing from a fixed
2 Mbps to a Max connection some years ago. A drop of 35% in connection
speed cannot be reasonable aftera period of several years at much higher
levels surely? Also I was of the impression that contention could severely
limit actual measured download speed at times of excessive traffic, but was
not aware that it produced a severe reduction in sync speed 24/7. Unless
of course BT have deliberately adjusted some settings to limit my connection
speed to a maximum of 5000 kbps. If they have, it doesn't seem a very
good marketing strategy, especially in an area where glass fibre cable
access is only 15' feet away from my front door, and I am forever getting
unsolicited mail through the door from Virgin.
Strangely I have just been interrupted in typing this by an unsolicited text
from Orange (not my ISP) offering me a saving of £118 with FREE up to 8 Meg
broadband. You just have to laugh don't you?
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°9 +, Mungo Brandybuck of Buckland

Peter Crosland wrote:
> Contention only happens between the exchange and the ISP. It has no effect
> whatsoever on the sync speed between the user's premises and the exchange.
> Have tried plugging your router directly into the test socket to see if
> that improves things?
>
> Peter Crosland

Just about to do that Peter - easier now that I have wireless netbook, but
that apart, why have I been told specifically that: ?
<quote>
BT do confirm that this is not a problem with the service, but is due
to contention at your local exchange.
<unquote>
Incidentally my IP Profile has just been further reduce to 3500 kbps,
that's down 3000 kbps in a week.
Will post my plugging router into test socket shortly.



--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°9 +, Mungo Brandybuck of Buckland

Flyiñg Ñuñ 2°°9 + on netbook wrote:
> Peter Crosland wrote:
>> Contention only happens between the exchange and the ISP. It has no
>> effect whatsoever on the sync speed between the user's premises and the
>> exchange. Have tried plugging your router directly into the test socket
>> to see if that improves things?
>>
>> Peter Crosland
>
> Just about to do that Peter - easier now that I have wireless netbook, but
> that apart, why have I been told specifically that: ?
> <quote>
> BT do confirm that this is not a problem with the service, but is due
> to contention at your local exchange.
> <unquote>
> Incidentally my IP Profile has just been further reduce to 3500 kbps,
> that's down 3000 kbps in a week.
> Will post my plugging router into test socket shortly.

Now plugged into test socket directly, using the same filter as before (as
recommended by your good self, an ADSL Nation XF-1e). It is now synching at
5248 kbps (it was 5024 kbps in my pooter room immediately before re-siting
the router) with SNR of 6 dB and line attenuation 37.2 dB very little
difference from before. Still nowhere near as good as the 7616 kbps I was
getting a week ago - also at an SNR of 6 dB. I suppose the next thing to
do is to try it with a different filter. But looks like it's not due to a
fault within my home, doesn't it?
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°9 +, Mungo Brandybuck of Buckland

Peter Crosland wrote:
>>>> Contention only happens between the exchange and the ISP. It has no
>>>> effect whatsoever on the sync speed between the user's premises and the
>>>> exchange. Have tried plugging your router directly into the test socket
>>>> to see if that improves things?
>>>>
>>>> Peter Crosland
>>>
>>> Just about to do that Peter - easier now that I have wireless netbook,
>>> but that apart, why have I been told specifically that: ?
>>> <quote>
>>> BT do confirm that this is not a problem with the service, but is due
>>> to contention at your local exchange.
>>> <unquote>
>>> Incidentally my IP Profile has just been further reduce to 3500 kbps,
>>> that's down 3000 kbps in a week.
>>> Will post my plugging router into test socket shortly.
>>
>> Now plugged into test socket directly, using the same filter as before
>> (as recommended by your good self, an ADSL Nation XF-1e). It is now
>> synching at 5248 kbps (it was 5024 kbps in my pooter room immediately
>> before re-siting the router) with SNR of 6 dB and line attenuation 37.2
>> dB very little difference from before. Still nowhere near as good as
>> the 7616 kbps I was getting a week ago - also at an SNR of 6 dB. I
>> suppose the next thing to do is to try it with a different filter. But
>> looks like it's not due to a fault within my home, doesn't it?
>
>
> There are two crucial things to do. First leave it plugged into the test
> socket and secondly don't reboot the router. Then check the statistics
> within the mdc console.
>
> The important things are the Rate, Max1, Mgn1,Mg2 and Attn.
>
> The only way to establish if the fault is with your internal wiring is to
> use the test socket. If you want to contact me direct then please feel
> free to do so.
>
> Peter Crosland

Those figures I quoted were from the mdc console. To be more specific they
are:
Rate - 5248, Max1 - 5252, Max2 - 5076, Mgn1 - 6.0, Mgn2 - 6.0, Attn -
37.2.

Since setting it up 45 minutes ago there has been 1 uncorrectable block and
29 correctable blocks.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°9 +, Mungo Brandybuck of Buckland

Peter Crosland wrote:
>>>>>> Contention only happens between the exchange and the ISP. It has
>>>>>> no effect whatsoever on the sync speed between the user's
>>>>>> premises and the
>>>>>> exchange. Have tried plugging your router directly into the test
>>>>>> socket
>>>>>> to see if that improves things?
>>>>>>
>>>>>> Peter Crosland
>>>>>
>>>>> Just about to do that Peter - easier now that I have wireless
>>>>> netbook, but that apart, why have I been told specifically
>>>>> that: ? <quote>
>>>>> BT do confirm that this is not a problem with the service, but is
>>>>> due to contention at your local exchange.
>>>>> <unquote>
>>>>> Incidentally my IP Profile has just been further reduce to 3500
>>>>> kbps, that's down 3000 kbps in a week.
>>>>> Will post my plugging router into test socket shortly.
>>>>
>>>> Now plugged into test socket directly, using the same filter as
>>>> before (as recommended by your good self, an ADSL Nation XF-1e). It is
>>>> now synching at 5248 kbps (it was 5024 kbps in my pooter
>>>> room immediately before re-siting the router) with SNR of 6 dB and
>>>> line attenuation 37.2 dB very little difference from before. Still
>>>> nowhere near as good as the 7616 kbps I was getting a week
>>>> ago - also at an SNR of 6 dB. I suppose the next thing to do is
>>>> to try it with a different filter. But looks like it's not due to
>>>> a fault within my home, doesn't it?
>>>
>>>
>>> There are two crucial things to do. First leave it plugged into the
>>> test socket and secondly don't reboot the router. Then check the
>>> statistics within the mdc console.
>>>
>>> The important things are the Rate, Max1, Mgn1,Mg2 and Attn.
>>>
>>> The only way to establish if the fault is with your internal wiring
>>> is to use the test socket. If you want to contact me direct then
>>> please feel free to do so.
>>>
>>> Peter Crosland
>>
>> Those figures I quoted were from the mdc console. To be more
>> specific they are:
>> Rate - 5248, Max1 - 5252, Max2 - 5076, Mgn1 - 6.0, Mgn2 - 6.0,
>> Attn - 37.2.
>>
>> Since setting it up 45 minutes ago there has been 1 uncorrectable
>> block and 29 correctable blocks.
>
> Looking at those figures in Kitz they are not far out. I can't really
> understand how you could get a sync rate as high as you did before.

I have just looked at http://www.kitz.co.uk/adsl/max_speed_calc.php and fed
in my line attenuation 37.2 dB which it rounded down to 37 dB and equates
that with a line length of 2.7 km which is about right, but that gives
dslMAX speed of 7328 kbps and IP Profile 6000 kbps.

My current values using the 2700HGV are 5024 kbps with an IP Profile of 3500
kbps.

I've just checked some old Safecom logs and find that on 03/10/2008 the line
attenuation was 40.1 dB and data rate was 6784 kbps


> Has the attenuation changed significantly from when you 7616?

Nope it's always been in the 37 dB to 40 dB range

> One thing I have noticed over the last ten days the level of RF
> interference has been very high here and at another site I look
> after. That would of course drop the speed. Are the any notches
> shown on upper part of the bit-loading chart?
There appear to be 3 at about 210, 240 and 250, but nothing like as
pronounced as the ones at 32, 64 and 96. Nothing of note between those.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°9 +, Mungo Brandybuck of Buckland

Ato_Zee wrote:
>> Still nowhere near as good as the 7616 kbps I was
>> getting a week ago - also at an SNR of 6 dB. I suppose the next thing
>> to do is to try it with a different filter.
>
> Give it time, sync speed can rise in steps over a period of
> around a month.
> You can plug more than one filter into another to get 2
> (or more) stages of filtering, PROVIDED you plug your
> modem into the first one, and you phone side into
> the last one.
> That said I haven't seen any improvement with more
> than two, and three doesn't affect voice quality or caller
> ID units.

Having had it drop from 7616 to 4980 kbps in an instant and not having it
recover at all yet in 6 days, forgive me for being somewhat sceptical.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°9 +, Mungo Brandybuck of Buckland

Peter Crosland wrote:
>>>> Still nowhere near as good as the 7616 kbps I was
>>>> getting a week ago - also at an SNR of 6 dB. I suppose the next thing
>>>> to do is to try it with a different filter.
>>>
>>> Give it time, sync speed can rise in steps over a period of
>>> around a month.
>>> You can plug more than one filter into another to get 2
>>> (or more) stages of filtering, PROVIDED you plug your
>>> modem into the first one, and you phone side into
>>> the last one.
>>> That said I haven't seen any improvement with more
>>> than two, and three doesn't affect voice quality or caller
>>> ID units.
>>
>> Having had it drop from 7616 to 4980 kbps in an instant and not having it
>> recover at all yet in 6 days, forgive me for being somewhat sceptical.
>
>
> Thismis the Kitz link you need
>
> http://www.kitz.co.uk/adsl/max_speed_calc.php
>
> Peter Crosland

Yep tyhat's the one I found overnight. Putting in my attenuation 37.2 dB,
gives an approx line length of 2.7 km with estimated max speed on dslMAX of
7328 kbps and IP Profile of 6000 kbps, which isn't that far different from
the 7616 kbps and IP Profile of 6000 kbps I was enjoying before last
Wednesday morning's crash to 4928 kbps and IP Profile of 4000 kbps.
Currently the 2700HGV has been running plugged into the test socket
overnight (that's for 11 hours) and connection speed is still 5024 kbps, IP
Profile 3500 kbps, SNR 6-0 dB, line attn 37.2 dB with a total of 14
uncorrectable errors in that period. That certainly doesn't seem right
does it? Looks like something somewhere is deliberately limiting my
connection speed. Just over a week ago I was measuring d/l speeds of 5900
kbps (6111 kbps on July 7th) and today it's only 3470 kbps and still no
amendment to my ticket at support help since Friday when I made an
additional comment/request.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°9 +, Mungo Brandybuck of Buckland

On Wed, 22 Jul 2009 10:30:38 +0100, Flyi g �u 2 9 + on netbook wrote:

> Currently the 2700HGV has been running plugged into the test socket
>overnight (that's for 11 hours) and connection speed is still 5024 kbps, IP
>Profile 3500 kbps, SNR 6-0 dB, line attn 37.2 dB with a total of 14
>uncorrectable errors in that period. That certainly doesn't seem right
>does it? Looks like something somewhere is deliberately limiting my
>connection speed. Just over a week ago I was measuring d/l speeds of 5900
>kbps (6111 kbps on July 7th) and today it's only 3470 kbps and still no
>amendment to my ticket at support help since Friday when I made an
>additional comment/request.

Sounds more like the line has degraded, possibly due to water or a poor
contact somewhere. What does the voice side of things sound like? Any
crackling or hissing or an unusually quiet dial tone and you need to
report a voice fault to your provider and, if so, once that's fixed
your sync speed should rise again and eventually your download rate.

--
Regards - Rodney Pont
The from address exists but is mostly dumped,
please send any emails to the address below
e-mail ngpsm4 (at) infohitsystems (dot) ltd (dot) uk

Rodney Pont wrote:
> On Wed, 22 Jul 2009 10:30:38 +0100, Flyi g �u 2 9 + on netbook
> wrote:
>
>> Currently the 2700HGV has been running plugged into the test
>> socket overnight (that's for 11 hours) and connection speed is still
>> 5024 kbps, IP Profile 3500 kbps, SNR 6-0 dB, line attn 37.2 dB
>> with a total of 14 uncorrectable errors in that period. That
>> certainly doesn't seem right does it? Looks like something
>> somewhere is deliberately limiting my connection speed. Just over
>> a week ago I was measuring d/l speeds of 5900 kbps (6111 kbps on
>> July 7th) and today it's only 3470 kbps and still no amendment to my
>> ticket at support help since Friday when I made an additional
>> comment/request.
>
> Sounds more like the line has degraded, possibly due to water or a
> poor contact somewhere. What does the voice side of things sound
> like? Any crackling or hissing or an unusually quiet dial tone and
> you need to report a voice fault to your provider and, if so, once
> that's fixed your sync speed should rise again and eventually your
> download rate.

No crackling or hissing, and SNR seems pretty good and constant at 6 dB.
And very few crc errors. No, I'm certain that some other change has
occurred, most likely at the exchange.

Similar events have happened in the past a couple of times some years ago.
On one after 4 engineer's visits to my home in as many weeks, where they
renewed all the original outside wiring (circa 1950s) and rewired my main
socket - both giving no measurable improvement, a 5th engineer located a
fault at the exchange and fixed it immediately. He then phoned me from the
exchanged and checked all my readings to make sure the fault was rectified
my end.

On another separate occasion a BT enginner 'phoned and described the
connection speed and other readings which he was monitoring on my line.
The ones he was quoting were fine, but my router as I was talking to him
was showing only 256 kbps both upstream and downstream. So off he went to
investigate further. Can't remember the SNR and line attenuation values
then - it was a few years ago. But strangely enough after 2 weeks at
those unbelievably low BB speeds it suddenly recovered. No explanation was
ever offered.

On a third occasion I lost both BB and voice 'phone. Having the local
exchange number - from when the engineer had 'phoned me previously - I was
able to phone them immediately on my mobile. The guy who answered was the
engineer who had just disconnected me. He said he had a job docket to do
so since I was changing ISPs. That was news to both me and my ISP.
Unfortunately he could nit reconnect my BB until he had a docket from his
manager instructing him so to do. My ISP set up a free dial up connection
for the two week period it took BT to reconnect my BB. The normal audio
had been reconnected immediately I had contacted them. No-one ever
disclosed who had authorised the wrong disconnection in the first place.

Now BT are saying that my drop in connection speed is due to contention at
the exchange, and basically there is nothing that can be done. But
contention shouldn't affect connection speed 24/7, only actual d/l speed
when there is excessive traffic, or so I've been led to believe. It looks
like there is some way in which they are limiting my connection speed
deliberately. Up till a week ago I have been synching at well over 6000
kbps and for the last 7 months (after changing to a 2wire 2700HGV business
hub) at a pretty constant 7616 kbps

So you can understand why I have very little faith in that side of things.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°9 +, Mungo Brandybuck of Buckland

Peter Crosland wrote:
>>>>>> Still nowhere near as good as the 7616 kbps I was
>>>>>> getting a week ago - also at an SNR of 6 dB. I suppose the next
>>>>>> thing
>>>>>> to do is to try it with a different filter.
>>>>>
>>>>> Give it time, sync speed can rise in steps over a period of
>>>>> around a month.
>>>>> You can plug more than one filter into another to get 2
>>>>> (or more) stages of filtering, PROVIDED you plug your
>>>>> modem into the first one, and you phone side into
>>>>> the last one.
>>>>> That said I haven't seen any improvement with more
>>>>> than two, and three doesn't affect voice quality or caller
>>>>> ID units.
>>>>
>>>> Having had it drop from 7616 to 4980 kbps in an instant and not
>>>> having it
>>>> recover at all yet in 6 days, forgive me for being somewhat
>>>> sceptical.
>>>
>>>
>>> Thismis the Kitz link you need
>>>
>>> http://www.kitz.co.uk/adsl/max_speed_calc.php
>>>
>>> Peter Crosland
>>
>> Yep tyhat's the one I found overnight. Putting in my attenuation
>> 37.2 dB, gives an approx line length of 2.7 km with estimated max
>> speed on dslMAX of 7328 kbps and IP Profile of 6000 kbps, which
>> isn't that far different from the 7616 kbps and IP Profile of 6000
>> kbps I was enjoying before last Wednesday morning's crash to 4928
>> kbps and IP Profile of 4000 kbps. Currently the 2700HGV has been
>> running plugged into the test socket overnight (that's for 11 hours)
>> and connection speed is still 5024 kbps, IP Profile 3500 kbps, SNR
>> 6-0 dB, line attn 37.2 dB with a total of 14 uncorrectable errors
>> in that period. That certainly doesn't seem right does it? Looks
>> like something somewhere is deliberately limiting my
>> connection speed. Just over a week ago I was measuring d/l speeds
>> of 5900 kbps (6111 kbps on July 7th) and today it's only 3470 kbps
>> and still no amendment to my ticket at support help since Friday
>> when I made an additional comment/request.
>
>
> If you have disconnected the router or rebooted several times then
> that may well cause the BT (BRAS) profile to drop. Unless, and until,
> you leave it alone for several days you will achieve nothing. I
> really can't emphasise that enough! The actual download speed is
> another matter and could be due to all sorts of things the main one
> of which is contention which you just have to live with.
>
> Peter Crosland

The IP Profile had dropped to 3500 kbps before I disconnected the router I
disconeected it to resite it downstairs at the main test socket yesterday
evening.
--
Heard melodies are sweet, but those Unheard are sweeter
(E-Mail Removed) FN 2°°9 +, Mungo Brandybuck of Buckland