Is there a router where you can specify min sync speed?

Hi,

My line is capable of syncing day and night at around 7Mb/s with about 8db noise margin. This is good. I am happy with this.

The problem I have is that during working day hours I get random short periods of noise of the order of a few minutes from some unknown appliance between me and the exchange that cause disconnects and if the router reconnects during the noisy period then the sync speed can be very low <1Mb/s. This shoots my IP profile to hell for days at a time.

I would much rather that my router refuse to resync below a set speed of my choice because I'd take the extra few minutes of outage over the multiple days of BT's punitive IP profile capping.

Does such a router exist where I can say "don't sync below xMb/s"?

Regards,
- Andy

With certain routers you can specify the target noise margin, however this may break BT's profiling system and leave you on a permanently high margin and low speed.

I don't think there is.

As BatBoy says, some routers can be made to play with things, but they wouldn't achieve what you need.

Approaching it from another side - do you have to be on a BT IP Profile based ISP? If you have LLU suppliers at your exchange then you avoid the problem. That's one of the main advantages of LLU.

Please post the link to what samknows says about your exchange.

IIRC the draytek 2800 (NOT 2820) allows targeting of sync speed in some form.. A search will no doubt bring something up - don't just take my word for it.

No there is no real way to stop it happening, each isp configure their Dslams ect to force a re sync when a connection reaches the set threshold for things such as the error rate within a given time and several other factors, that is on top of any DLM if active on the connection, so setting the downstream noise margin higher won't stop it re syncing , if your isp did not use DLM you would not get a reduction in sync speed at all,
This interference /noise could well be so strong that it degrades the ADSL signal so much it looses sync, only way to stop that is by the source of it being traced and dealt with from there a job for your isp and bt openreach

That would be good, as long as it refuses to sync. The tweaking methods involve sync'ing, then re-sync'ing, which almost certainly wouldn't stop the IP Profile falling.

In reply to a post by Anonymous:

No there is no real way to stop it happening, each isp configure their Dslams ect to force a re sync when a connection reaches the set threshold for things such as the error rate within a given time and several other factors, that is on top of any DLM if active on the connection, so setting the downstream noise margin higher won't stop it re syncing , if your isp did not use DLM you would not get a reduction in sync speed at all,
This interference /noise could well be so strong that it degrades the ADSL signal so much it looses sync, only way to stop that is by the source of it being traced and dealt with from there a job for your isp and bt openreach

Are you the OP, or another Anon? If the OP, please can we have the samknows link .

I wish there were LLU suppliers at my exchange (Kelvedon). There's only BT wholesale and no cable.

The noisy periods are quite extreme and very clearly defined. Monitoring the state with routerstats shows a nice steady SNR, then suddenly bam! some guy down the road starts playing with his tesla coil and off goes my connection followed by some pretty bad noise (audible on the phone line too) for about 10 mins until stability returns.

Do you reckon BT would investigate this kind of problem? It's clearly outside my house where it's happening but I know what these companies are like with intermittent problems: "it was fine when we tested it thank you and your ticket is closed, goodbye."

In reply to a post by Anonymous:

Do you reckon BT would investigate this kind of problem? It's clearly outside my house where it's happening but I know what these companies are like with intermittent problems: "it was fine when we tested it thank you and your ticket is closed, goodbye."

Openreach and many ISPs will wash their hands of problems with REIN/interference on the line if the physical copper tests ok, as they regard that as the limit of their remit. If downtime occurs whilst the engineer is present then you stand a chance of it being investigated, otherwise no. Worse still, if the copper tests ok to the exchange, you could be handed a bill of around £130 for the visit.

That's rotten. Not a lot can be done.

There is one trick that worked nearly every time for me on a dodgy line, on the occasions when I got landed with a low profile.

The way the DLM works is that the larger the percentage jump in sync following, the faster the IP Profile rises.

So given a poor profile, I used to force a resync with the noise margin set as high as possible, preferably as late as possible without running into the normal evening noise increases. This gave the lowest possible sync and within minutes the IP profile to go with it. Then resync again with the noise margin set as high as possible without risking over-night reconnection.

The result was that the profile rise would happen over-night.

Yeah, the Vigor 2800 has the maxdnrate command. But, this is what it says - it is the maximum sync speed that the router will attempt to sync at, not the minimum. From what I understand of the OP, they want a router where you can set the minimum, and if it doesn't manage that, it just refuses to sync. On top of that, I think maxdnrate only works for plain ADSL max lines (ADSL1), not ADSL2(+).

My only suggestion is to try and find a router which allows you set the target SNR of the sync, as if this is high enough (and interleaving is also on), that will probably stop the re-syncs happening. I know SpeedTouch modems on an older (v6) firmware allow that, but I'm sure there is newer kit available now - maybe someone can advise on that.

Sounds good at first, but to stop the resyncs happening the settings would have to make the normal sync equal to, or even lower than, the worst sync he gets when this happens. Which rather defeats the object.

As he said, loss of connection for a short period doesn't bother him. It's the fact a low sync occurs and screws the IP Profile.

I am the OP on this thread and I'm back to close out the problem in case I can help anyone that gets in here from Google.

Since I posted this the intermittent disconnects and line noise were getting progressively worse. The noise was only evident when the ADSL connection was active. A BT engineer was called out.

He attached a Hawk scope to the line and a blip showed up where the outside line from the pole meets the house. He changed that connection for new and bingo everything is fixed and I have a perfect line.

He logged it as an "HR dis" high resistance fault and said that as a voice engineer his normal tests would not have caught it, but he ran additional tests that a broadband engineer would do and it showed up.

Cheers!
Andy