8 meg, why is this?

I recently got a regrade from 2 to 8 meg. If the modem/router syncs at about
6.5 meg, then the bt speedtest returns a speed of about 5mbps.
If I get a higher sync, then the speed seems to go down. Is this
explainable?

Here's the modem numbers (currently):
u/s rate 448 kbps
d/s rate 7072 kbps
u/s margin 23
d/s margin 2
d/s attenuation 33
u/s attenuation 38

The bt speedtest returns about 2000 kbps for this.
If the sync gets to 7500 kbps, then the speed can be reported at less than
1000.

In an earlier contribution to this discussion,
Grumps <(E-Mail Removed)> wrote:

> I recently got a regrade from 2 to 8 meg. If the modem/router syncs
> at about 6.5 meg, then the bt speedtest returns a speed of about 5mbps.
> If I get a higher sync, then the speed seems to go down. Is this
> explainable?
>
> Here's the modem numbers (currently):
> u/s rate 448 kbps
> d/s rate 7072 kbps
> u/s margin 23
> d/s margin 2
> d/s attenuation 33
> u/s attenuation 38
>
> The bt speedtest returns about 2000 kbps for this.
> If the sync gets to 7500 kbps, then the speed can be reported at less
> than 1000.

I think your answer is in the line which says:
> d/s margin 2

This is a very low margin and suggests that your line cannot sustain this
speed reliably. The faster it synchs, the more discrete levels it needs, and
the more it eats into the margin - to the extent that there's more noise
than signal, causing a very high error rate - coupled with a catastrophic
effect on throughput. Is your modem able to display error rate stats? If so,
they will probably make 'interesting' reading!
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

That's about right..if you've only just been upgraded then it'll be varying
to find the best speed your line can support and should settle down..


--
Colin
*Drop DEAD from the email address to reply*

"Grumps" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>I recently got a regrade from 2 to 8 meg. If the modem/router syncs at
>about 6.5 meg, then the bt speedtest returns a speed of about 5mbps.
> If I get a higher sync, then the speed seems to go down. Is this
> explainable?
>
> Here's the modem numbers (currently):
> u/s rate 448 kbps
> d/s rate 7072 kbps
> u/s margin 23
> d/s margin 2
> d/s attenuation 33
> u/s attenuation 38
>
> The bt speedtest returns about 2000 kbps for this.
> If the sync gets to 7500 kbps, then the speed can be reported at less than
> 1000.

Can you remeber what your d/s margin was before you got upgraded to 8Mb?

Dan
>
>

Roger Mills wrote:
> In an earlier contribution to this discussion,
> Grumps <(E-Mail Removed)> wrote:
>
>> I recently got a regrade from 2 to 8 meg. If the modem/router syncs
>> at about 6.5 meg, then the bt speedtest returns a speed of about
>> 5mbps. If I get a higher sync, then the speed seems to go down. Is
>> this explainable?
>>
>> Here's the modem numbers (currently):
>> u/s rate 448 kbps
>> d/s rate 7072 kbps
>> u/s margin 23
>> d/s margin 2
>> d/s attenuation 33
>> u/s attenuation 38
>>
>> The bt speedtest returns about 2000 kbps for this.
>> If the sync gets to 7500 kbps, then the speed can be reported at less
>> than 1000.
>
> I think your answer is in the line which says:
>> d/s margin 2
>
> This is a very low margin and suggests that your line cannot sustain
> this speed reliably. The faster it synchs, the more discrete levels
> it needs, and the more it eats into the margin - to the extent that
> there's more noise than signal, causing a very high error rate -
> coupled with a catastrophic effect on throughput. Is your modem able
> to display error rate stats? If so, they will probably make
> 'interesting' reading!

From my modem's network stats;
Rx PDUs 366,796
Rx total bytes 257,792,873 (up time 8 hours 57 mins)
Rx Total Error Counts 47

So, is there any way to reduce the rate at which it syncs?

Daniel wrote:
> "Grumps" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> I recently got a regrade from 2 to 8 meg. If the modem/router syncs
>> at about 6.5 meg, then the bt speedtest returns a speed of about
>> 5mbps. If I get a higher sync, then the speed seems to go down. Is this
>> explainable?
>>
>> Here's the modem numbers (currently):
>> u/s rate 448 kbps
>> d/s rate 7072 kbps
>> u/s margin 23
>> d/s margin 2
>> d/s attenuation 33
>> u/s attenuation 38
>>
>> The bt speedtest returns about 2000 kbps for this.
>> If the sync gets to 7500 kbps, then the speed can be reported at
>> less than 1000.
>
> Can you remeber what your d/s margin was before you got upgraded to
> 8Mb?

From my (bad) memory, I think it was 6.
I really should've paid more attention to these figures. But, before the
upgrade, it was rock solid 2 meg with no blips.

Grumps wrote:
> Roger Mills wrote:
>> In an earlier contribution to this discussion,
>> Grumps <(E-Mail Removed)> wrote:
>>
>>> I recently got a regrade from 2 to 8 meg. If the modem/router syncs
>>> at about 6.5 meg, then the bt speedtest returns a speed of about
>>> 5mbps. If I get a higher sync, then the speed seems to go down. Is
>>> this explainable?
>>>
>>> Here's the modem numbers (currently):
>>> u/s rate 448 kbps
>>> d/s rate 7072 kbps
>>> u/s margin 23
>>> d/s margin 2
>>> d/s attenuation 33
>>> u/s attenuation 38
>>>
>>> The bt speedtest returns about 2000 kbps for this.
>>> If the sync gets to 7500 kbps, then the speed can be reported at
>>> less than 1000.
>>
>> I think your answer is in the line which says:
>>> d/s margin 2
>>
>> This is a very low margin and suggests that your line cannot sustain
>> this speed reliably. The faster it synchs, the more discrete levels
>> it needs, and the more it eats into the margin - to the extent that
>> there's more noise than signal, causing a very high error rate -
>> coupled with a catastrophic effect on throughput. Is your modem able
>> to display error rate stats? If so, they will probably make
>> 'interesting' reading!
>
> From my modem's network stats;
> Rx PDUs 366,796
> Rx total bytes 257,792,873 (up time 8 hours 57 mins)
> Rx Total Error Counts 47
>
> So, is there any way to reduce the rate at which it syncs?

More info; I have a d/s margin of 6 this morning (7:48am), and it's all
running nicely with sustained downloads of 680kbytes/s.

In article <(E-Mail Removed)>, Grumps says...
> I recently got a regrade from 2 to 8 meg. If the modem/router syncs at about
> 6.5 meg, then the bt speedtest returns a speed of about 5mbps.
> If I get a higher sync, then the speed seems to go down. Is this
> explainable?
>
> Here's the modem numbers (currently):
> u/s rate 448 kbps
> d/s rate 7072 kbps
> u/s margin 23
> d/s margin 2
> d/s attenuation 33
> u/s attenuation 38
>
> The bt speedtest returns about 2000 kbps for this.
> If the sync gets to 7500 kbps, then the speed can be reported at less than
> 1000.
>
>
>
Your BRAS rate hasn't stabilised yet.

http://www.zensupport.co.uk/knowledg....aspx?id=10537

Takes a while for the line to 'train' and your data rate to settle. Read
that page then power down for 30 minutes. That should trigger the
process again

FR

In article <(E-Mail Removed)>,
Flying Rat <(E-Mail Removed)> writes:
> In article <(E-Mail Removed)>, Grumps says...
> > I recently got a regrade from 2 to 8 meg. If the modem/router syncs at
> > about 6.5 meg, then the bt speedtest returns a speed of about 5mbps.
> > If I get a higher sync, then the speed seems to go down. Is this
> > explainable?
>
> Your BRAS rate hasn't stabilised yet.
>
> http://www.zensupport.co.uk/knowledg....aspx?id=10537
>
> Takes a while for the line to 'train' and your data rate to settle. Read
> that page then power down for 30 minutes. That should trigger the
> process again

So the implication is that the router at the customer's end of the line
needs to be always-on in these circumstances?
--
SAm.

Flying Rat wrote:
> In article <(E-Mail Removed)>, Grumps says...
>> I recently got a regrade from 2 to 8 meg. If the modem/router syncs
>> at about
>> 6.5 meg, then the bt speedtest returns a speed of about 5mbps.
>> If I get a higher sync, then the speed seems to go down. Is this
>> explainable?
>>
>> Here's the modem numbers (currently):
>> u/s rate 448 kbps
>> d/s rate 7072 kbps
>> u/s margin 23
>> d/s margin 2
>> d/s attenuation 33
>> u/s attenuation 38
>>
>> The bt speedtest returns about 2000 kbps for this.
>> If the sync gets to 7500 kbps, then the speed can be reported at
>> less than 1000.
>>
>>
>>
> Your BRAS rate hasn't stabilised yet.
>
> http://www.zensupport.co.uk/knowledg....aspx?id=10537
>
> Takes a while for the line to 'train' and your data rate to settle.
> Read that page then power down for 30 minutes. That should trigger the
> process again

Thanks for the info. I wish my ISP told me this.
It's got a sync of 7000+, a d/s margin of 6, and is currently sustaining
(long) downloads of 680kbytes/s.
Do you think that the d/s margin is playing any part in the line speed? It
was reading 2 yesterday, and magically shot up to 7 early this morning

Does this also mean that everytime you power your modem off (for > 30 mins),
then the system will take another 10 days to retrain the line?