Very long ping times and slow downloads on 1MB ADSL

A customer is experiencing very slow downloads (web pages, email) over his
newly-installed ADSL line with BT Yahoo. At various times between about 10
AM and 5 PM I never saw anything higher than 10 KB/sec when downloading exe
files from various sources (Microsoft, Skype, Netgear).

The router (Netgear DG834PN, though the fault was also seen with his old
DG834) syncs at around 1.2 to 1.7 Mbps. Typical ADSL parameters are:

(down/up)
line speed 1408 448
attenuation 63.0 31.5
noise margin 6.3 16.0

While the downstream attenuation is rather high and the noise margin is
rather low, the router is successfully syncing at over 1 Mbps - presumably
this means that it is happy to work at that speed with those line
parameters: if they had been too bad, it would have synced at a lower speed.

The ping times (ping -t news.bbc.co.uk) are about 30-40 msec with the router
totally idle, but they shoot up to 1000-3000 msec as soon as a PC (either
the same PC that's doing the ping or a different PC) starts to access web
pages or read from a POP mailbox, returning to 30 msec afterwards.

Do these symptoms suggest what the problem and solution might be?

Martin Underwood wrote:
> A customer is experiencing very slow downloads (web pages, email) over his
> newly-installed ADSL line with BT Yahoo. At various times between about 10
> AM and 5 PM I never saw anything higher than 10 KB/sec when downloading
> exe
> files from various sources (Microsoft, Skype, Netgear).
>
> The router (Netgear DG834PN, though the fault was also seen with his old
> DG834) syncs at around 1.2 to 1.7 Mbps. Typical ADSL parameters are:
>
> (down/up)
> line speed 1408 448
> attenuation 63.0 31.5
> noise margin 6.3 16.0
>

It is syncing at to fast a rate, you need a less aggressive profile,
hopefully they will understand when you ask for it at bt....

Gaz

Gaz wrote in message
(E-Mail Removed):

> Martin Underwood wrote:
>> A customer is experiencing very slow downloads (web pages, email)
>> over his newly-installed ADSL line with BT Yahoo. At various times
>> between about 10 AM and 5 PM I never saw anything higher than 10
>> KB/sec when downloading exe
>> files from various sources (Microsoft, Skype, Netgear).
>>
>> The router (Netgear DG834PN, though the fault was also seen with his
>> old DG834) syncs at around 1.2 to 1.7 Mbps. Typical ADSL parameters
>> are: (down/up)
>> line speed 1408 448
>> attenuation 63.0 31.5
>> noise margin 6.3 16.0
>>
>
> It is syncing at to fast a rate, you need a less aggressive profile,
> hopefully they will understand when you ask for it at bt....

So it needs the customer to contact her ISP? I wasn't sure whether it was
because the exchange equipment was still learning the characteristics of the
newly-enabled line and would sort itself out in due course.

But if that's not that case, I'll get the customer to describe the symptom
and ask for a lower profile.

I presume the ping times are long and the data rate is low because there are
a lot retries. Someone posted a referecne to a site which analysed the
number of retries, but I forgot to bookmark the URL. Can anyone remind me
what it was.

Martin Underwood wrote:
> Gaz wrote in message
> (E-Mail Removed):
>
>> Martin Underwood wrote:
>>> A customer is experiencing very slow downloads (web pages, email)
>>> over his newly-installed ADSL line with BT Yahoo. At various times
>>> between about 10 AM and 5 PM I never saw anything higher than 10
>>> KB/sec when downloading exe
>>> files from various sources (Microsoft, Skype, Netgear).
>>>
>>> The router (Netgear DG834PN, though the fault was also seen with his
>>> old DG834) syncs at around 1.2 to 1.7 Mbps. Typical ADSL parameters
>>> are: (down/up)
>>> line speed 1408 448
>>> attenuation 63.0 31.5
>>> noise margin 6.3 16.0
>>>
>>
>> It is syncing at to fast a rate, you need a less aggressive profile,
>> hopefully they will understand when you ask for it at bt....
>
> So it needs the customer to contact her ISP? I wasn't sure whether it was
> because the exchange equipment was still learning the characteristics of
> the
> newly-enabled line and would sort itself out in due course.
>
> But if that's not that case, I'll get the customer to describe the symptom
> and ask for a lower profile.
>
> I presume the ping times are long and the data rate is low because there
> are
> a lot retries. Someone posted a referecne to a site which analysed the
> number of retries, but I forgot to bookmark the URL. Can anyone remind me
> what it was.

When shitheap eclipse put me on llu, it was a max style service, and i got
throughput of below a regular 56k modem, despite connecting at 1.5mbps The
problem was only solved by me leaving eclipse....

This kind of problem seems to be a regular thing on long lines...

Gaz

Gaz wrote in message
(E-Mail Removed):

> Martin Underwood wrote:
>> Gaz wrote in message
>> (E-Mail Removed):
>>
>>> It is syncing at to fast a rate, you need a less aggressive profile,
>>> hopefully they will understand when you ask for it at bt....
>>
>> So it needs the customer to contact her ISP? I wasn't sure whether
>> it was because the exchange equipment was still learning the
>> characteristics of the
>> newly-enabled line and would sort itself out in due course.
>>
>> But if that's not that case, I'll get the customer to describe the
>> symptom and ask for a lower profile.
>>
>> I presume the ping times are long and the data rate is low because
>> there are
>> a lot retries. Someone posted a referecne to a site which analysed
>> the number of retries, but I forgot to bookmark the URL. Can anyone
>> remind me what it was.
>
> When shitheap eclipse put me on llu, it was a max style service, and
> i got throughput of below a regular 56k modem, despite connecting at
> 1.5mbps The problem was only solved by me leaving eclipse....
>
> This kind of problem seems to be a regular thing on long lines...

This is a BT line, so LLU isn't involved in this particular case. I've asked
the customer to run http://speedtester.bt.com/ and to let me know the
results, so it will be interesting to see just how bad it really is: I'll
report back. Also, armed with the results and my evidence of long ping
times, she's going to contact BT (as the ISP) to request that they
investigate and fix, maybe by reducing the profile.