In reply to a post by Alexir:

After six weeks of stable 38meg we decided to test again with another torrent and downloaded around 30gig over a couple of days, leaving it running overnight but stopping during the day. Almost immediately our speed has been reduced to 23.6meg.

Is that a sync speed drop? It's interesting if it is. Perhaps I was correct - maybe an idle connection is really idle (or less active) at the DSL layer. That being the case there might be scope for fewer CRCs. A bit like an engine with a knackered fuel filter might tick over just fine but lacks power when you accelerate hard.

You definitely want to find out the sync speed - which you can do without unlocking the modem. Runa BT Wholesale speedtest, then click on "Further Diagnostics". The IP Profile there will be roughly 3% lower than the sync speed (on downlink).

If you can unlock the modem, then we can get the FEC and interleaving data, to see what is happening there too. We'll also be able to see the number of errors and (with multiple well-timed readings) be able to see the rate of errors.

Another good tool to visualise what is happening is with the TBB BQM (ping monitor) that runs 24/7, and gives you a good idea of latency and packet loss. It works well with a static IP.

Almost immediately our speed has been reduced to 23.6meg

what do you mean by "speed" in this context

In reply to a post by yarwell:

what do you mean by "speed" in this context

I mean as tested using any of the usual speed test tools eg http://speedtest.btwholesale.com/ which is now giving 23.77 (ie there seems to be a 24meg ceiling) whereas normally it would be giving 37ish.

In reply to a post by WWWombat:

Runa BT Wholesale speedtest, then click on "Further Diagnostics". The IP Profile there will be roughly 3% lower than the sync speed (on downlink).

Not sure if that only works on BT lines but it doesn't work for TalkTalk. I can run the speedtest but Further Diagnostics always produces an error (and always has, I've tried if before). TT fibre also uses dynamic IPs not static

In reply to a post by Alexir:

In reply to a post by WWWombat:

Runa BT Wholesale speedtest, then click on "Further Diagnostics". The IP Profile there will be roughly 3% lower than the sync speed (on downlink).

Not sure if that only works on BT lines but it doesn't work for TalkTalk. I can run the speedtest but Further Diagnostics always produces an error (and always has, I've tried if before). TT fibre also uses dynamic IPs not static

As you say, only BT Wholesale based services have the IP Profile. TalkTalk doesn't. Also although the initial test runs, with being on LLU phone that is why you can't get to the Further Diagnostics, as your phone number isn't recognised. I don't know if the Service ID(?) would work, but I doubt if TT Support would know what that was.

Without unlocking the modem (or buying one on ebay), the only tool left at your disposal is some kind of ping monitor.

TBB BQM isn't much use if your dynamic IP changes, but you could try f8lure, if you can set up a DDNS agent on either the router or PC.

In reply to a post by Alexir:

for a year I've had a pretty stable 38meg download, then about a month ago it started dropping off to 32 meg and then to 24meg with a 0.67 upload. These were firm ceilings so I guessed were set by DLM but I didn't know why. Around the same time my new flatmate had arrived and (I just found out) has be running P2P 24x7, downloading up to 20gig per day. Could this be connected to DLM setting caps or am I barking (up the wrong tree)?

It's just a coincidence that your sync speed dropped at the same time as you started generating heavy P2P traffic. The DLM algorithm is under the control of BT Openreach and doesn't monitor the traffic type of the end-user. The end-user could be a subscriber of any of the Comms Providers, and his application layer type (torrent, etc.) is not Openreach's concern.

Even when there is no meaningful traffic, there are still idle packets or frames being sent, containing dumb data. These are still checksummed in the normal way. So when they are in error they also add to the error counters, just like any other frame or packet with a proper payload.

cheers, a

selected wrong user to reply to

Edited by tommy45 (Sun 02-Jun-13 15:40:38)

Or maybe the modem is getting swamped by the number of connections ,and this is causing it to reboot ? But a single reboot or re sync should not cause DLM to intervene,

Also i find it strange that the throughput gets reduced by around 75% each time, I think it's down to talk talk , or the router /modem Although i would be surprised if the latter would keep the throughput low for weeks before returning to full steam ahead ,

Throttling (unofficially ) more likely , You could try torrenting using a secure VPN and see if the same problem occurs, if it doesn't then it firmly would point at talk talk , be they covertly throttling p2p , or be it some mis configuration their end , and ringing their useless script reading support won't get you any firm answers, better to try their members forums for help

The modem only has one connection. To the DSLAM. At the sync speed.

Or two if you include the Ethernet link to the user's router.

It hasn't any idea what is going through it.