ADSL Max training - repeated disconnects

I upgraded to ADSL Max yesterday (Zen Active 8000, as it happens). In
the 36 hours or so since the upgrade, I've had about 350 retrains. I was
expecting some instability, but the damn thing can't stay up for more
than 15 minutes. It's obvious to me that it can't sustain the 6-7Mbps
line rate it's connecting at, but it seems BT's automagic systems
haven't noticed yet or still need convincing. It doesn't appear to be
trying any lower speeds, at least not significantly lower.

Is this level of instability is considered normal in the initial phase?
How long will I have to wait for BT to twig that hundreds of retrains
per day might and bucketloads of CRC errors might, just perhaps, mean
it's trying to go too fast? I just can't believe it should be this bad
for this long without it trying to lower the line rate.


Tim

On Mar 21, 6:20 pm, Tim Auton <tim.au...@uton.borg.invalid> wrote:
> I upgraded to ADSL Max yesterday (Zen Active 8000, as it happens). In
> the 36 hours or so since the upgrade, I've had about 350 retrains.

10 per hour is supposedly the threshold for BT to step up the SNR
margin and turn interleaving on, but as you don't quote any stats we
don't know what's happening.

Can you get it in the test socket behind the master faceplate to see
if it's better there ?

Sometimes one type of modem or router crashes about like this and
another is rock solid - depends on th echipsets used at both ends.

Phil

PhilT <(E-Mail Removed)> wrote:
> On Mar 21, 6:20 pm, Tim Auton <tim.au...@uton.borg.invalid> wrote:
>> I upgraded to ADSL Max yesterday (Zen Active 8000, as it happens). In
>> the 36 hours or so since the upgrade, I've had about 350 retrains.
>
> 10 per hour is supposedly the threshold for BT to step up the SNR
> margin and turn interleaving on, but as you don't quote any stats we
> don't know what's happening.

Wow, 10 per hour is much higher than I expected, but it's also less than
I've been experiencing for the best part of two days with no change in
speed, SNR margin or interleaving status. A threshold of 10 per hour
implies that BT think 9 per hour would be acceptable, which is a long,
long, long way from what I'd either expect or accept. In the 8 hours
since I last restarted the router I've averaged 15 retrains per hour.

I'm about 1.8km (as the crow flies) from the Beauchief, Sheffield
exchange and my router is currently reporting:

Downtream Upstream
Data rate 6048 448
Latency FAST FAST
SNR Margin 5.9 28.0
Attenuation 41.4 24.0

SNR margin varies fairly rapidly by +/- 0.5dB or so, data rate peaked
about 7000kbps during the day, the lowest I've seen is about 5600kbps
late last night.

> Can you get it in the test socket behind the master faceplate to see
> if it's better there ?

I tried, but couldn't get the screws off - there's a huge bookcase 4" in
front of it, which makes it a bit tricky. There are no extensions and
it's a fairly new installation (~18 months). I'm using a decent ADSL
Nation filter and short cables. Disconnecting the phone and moving the
router and cabling away from the PC and other gubbins it's next to
hasn't helped and there's no audible noise on the line.

> Sometimes one type of modem or router crashes about like this and
> another is rock solid - depends on th echipsets used at both ends.

It's a PTI PAE-CE84, which is a pretty generic (and cheap) 4-port based
on a Conexant chipset. It worked flawlessly for years on 512kbps (which
obviously isn't so difficult, but at least shows it's not totally
broken).


Tim

On Mar 22, 12:22 am, Tim Auton <tim.au...@uton.borg.invalid> wrote:

> It's a PTI PAE-CE84, which is a pretty generic (and cheap) 4-port based
> on a Conexant chipset. It worked flawlessly for years on 512kbps (which
> obviously isn't so difficult, but at least shows it's not totally
> broken).

beg steal or borrow something that uses a TI AR7 chipset - Netgear
834, various Zyxels etc, may well resolve it. Some kit just isn't
happy with a 6 dB margin.

Phil

Tim Auton wrote:
> PhilT <(E-Mail Removed)> wrote:
>> On Mar 21, 6:20 pm, Tim Auton <tim.au...@uton.borg.invalid> wrote:
>>> I upgraded to ADSL Max yesterday (Zen Active 8000, as it happens). In
>>> the 36 hours or so since the upgrade, I've had about 350 retrains.
>> 10 per hour is supposedly the threshold for BT to step up the SNR
>> margin and turn interleaving on, but as you don't quote any stats we
>> don't know what's happening.
>
> Wow, 10 per hour is much higher than I expected, but it's also less than
> I've been experiencing for the best part of two days with no change in
> speed, SNR margin or interleaving status. A threshold of 10 per hour
> implies that BT think 9 per hour would be acceptable, which is a long,
> long, long way from what I'd either expect or accept. In the 8 hours
> since I last restarted the router I've averaged 15 retrains per hour.

If you are in the 10 day training period virtually anything is
acceptable. Your ISP will not raise the issue with BT until after the
training period is over.

--
Eps

Tim Auton wrote:

>
> It's a PTI PAE-CE84, which is a pretty generic (and cheap) 4-port based
> on a Conexant chipset. It worked flawlessly for years on 512kbps (which
> obviously isn't so difficult, but at least shows it's not totally
> broken).

Since you have that router I would highly recommend trying to test
with a combination of router cable and filter which is known to be
working on a max line. I installed a lot of these Connexant routers on
512 and 1Mb lines but no longer use them on max lines since they don't
make best use of the speed available and/or are unstable.
You can also pick up second user routers from www.dsldepot.co.uk -
the Draytek 2600 and Netgear ones I have had from there have been
faultless and they have a 30 day warranty.

It is still possible your problem is a line fault of course but trying
another router would help pin it down.

JP

PhilT <(E-Mail Removed)> wrote:
> On Mar 22, 12:22 am, Tim Auton <tim.au...@uton.borg.invalid> wrote:
>
>> It's a PTI PAE-CE84, which is a pretty generic (and cheap) 4-port based
>> on a Conexant chipset. It worked flawlessly for years on 512kbps (which
>> obviously isn't so difficult, but at least shows it's not totally
>> broken).
>
> beg steal or borrow something that uses a TI AR7 chipset - Netgear
> 834, various Zyxels etc, may well resolve it. Some kit just isn't
> happy with a 6 dB margin.

It seems mine isn't, which is why I would have expected BT to try a
higher margin by now!

Evidently BT are either not competent at determining an acceptable line
rate or have very different priorities to me. Can anybody suggest a
router which supports Zen's routed IP blocks, has a resaonable firewall
(stateful, works with routed IP blocks, configurable per-host) and let
you set the maximum line rate yourself? Wired with 4+ ports ideally, but
I can add a switch or make use of wireless. I'll look myself, but it's
slow work with an unreliable connection...


Tim

Tim Auton wrote:
> Evidently BT are either not competent at determining an acceptable line
> rate or have very different priorities to me. Can anybody suggest a
> router which supports Zen's routed IP blocks, has a resaonable firewall
> (stateful, works with routed IP blocks, configurable per-host) and let
> you set the maximum line rate yourself? Wired with 4+ ports ideally, but
> I can add a switch or make use of wireless. I'll look myself, but it's
> slow work with an unreliable connection...


If you dont want to spend on a new Router and can put up with a
slightler lower speed (plus higher SNR), could you not make it up to 10
resynch an hour by removing Telephone lead etc as necessary?

Great Eastern <(E-Mail Removed)> wrote:
> Tim Auton wrote:
>> Evidently BT are either not competent at determining an acceptable line
>> rate or have very different priorities to me. Can anybody suggest a
>> router which supports Zen's routed IP blocks, has a resaonable firewall
>> (stateful, works with routed IP blocks, configurable per-host) and let
>> you set the maximum line rate yourself? Wired with 4+ ports ideally, but
>> I can add a switch or make use of wireless. I'll look myself, but it's
>> slow work with an unreliable connection...
>
> If you dont want to spend on a new Router and can put up with a
> slightler lower speed (plus higher SNR), could you not make it up to 10
> resynch an hour by removing Telephone lead etc as necessary?

I've been at 15 resynchs per hour for the past 24 hours and something
similar for the 36 hours before that with no change, which is what made
me think BT's systems weren't working and post in the first place
(although I didn't know the threshold was 10 at the time). If the
threshold is 10/hour, it's either 10/hour for several days or it's not
working properly on my line.


Tim

On 22 Mar 2007, John P <(E-Mail Removed)> wrote:

>I installed a lot of these Connexant routers on 512 and 1Mb lines
>but no longer use them on max lines since they don't make best
>use of the speed available and/or are unstable.

My experience agrees with this view. While I've had good sync speeds
(eg 8096/448 on an "Origo" - web menu says Safecom!) the speed of data
through the unit, and general stability, is lower on Conexant than on
(for example) a Zyxel router. I'm going to buy a Prestige 660R-661
(1-port model, connected into my LAN) soon... they're under 30 quid
including the delivery.

For example, in the last 48 hours, I've had 14 disconnections. That
hasn't actually been a problem, this week, because I've been busy on
another project and my traffic has only been ~ 4 GB in that time but
I know the older blue+black PTI/DabsValue 4 and 1 port units were all
the more unstable - I guaranteed at least 5 disconnections each day,
from 1800 to 0400 I knew to expect quite a number (affecting enjoyment
of streaming audio/video services, and a pain when using Total Recorder
or RadioGrabber to collect streamed audio onto disk).