This topic

Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

Tiyuri — Wed, 14 Oct 2020 14:45:16 GMT

So last night a new firmware version was pushed to my router, which ultimately bricked the router. After trying to resolve the issue with the router for a couple of hours (A deep dive into tftp, 30/30/30 resets, etc) I decided to give up and purchased a new router/modem.

With the new router everything is working as it should. But the line speed has dropped drastically. After some troubleshooting I think I've ruled everything out aside from DLM. I've had similar issues in the past where a router fault caused DLM to detect dropouts and reduce line speed.

Now that everything is up and running again. What's the best way for me to request a DLM reset given current circumstances? Online chat isn't available and I'm unsure whether phone support will be able to help me.

Any recommendations would be great!

Thank you

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

imjolly — Wed, 14 Oct 2020 14:48:09 GMT

the router should recover speed in a few weeks if the connection remains stable

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

Tiyuri — Wed, 14 Oct 2020 14:56:09 GMT

A few weeks is quite a long time! Particularly given that I'm working from home right now due to Covid. I know engineers are able to perform a DLM reset but it seems it might be possible remotely? I'm wondering who might be best to contact.

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

licquorice — Wed, 14 Oct 2020 15:03:17 GMT

Engineers can't perform a reset themselves, they can only request one, and then only after having cleared a line fault.

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

Tiyuri — Wed, 14 Oct 2020 15:06:24 GMT

A few years ago I had a similar issue with a router causing DLM to kick in. I had an engineer in the property, explained the issue to them, and right then and there they requested the DLM reset and I had my speed instantly restored...

Is this still my only option? I'm assuming getting an engineer visit is very difficult right now

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

licquorice — Wed, 14 Oct 2020 15:11:52 GMT

If you line hasn't been banded, it shouldn't take too long for DLM to relent. You can tell if you have been banded as your speed will be at a round figure rather than some random speed.

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

Tiyuri — Wed, 14 Oct 2020 15:12:48 GMT

Sadly it's been almost exactly halved. It's hard capped at 25mbit on a bt infinity 2 plan.

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

licquorice — Wed, 14 Oct 2020 15:19:32 GMT

But is it exactly 25.0 or a random figure? I don't think 25M is a band profile in any case, it would be either 20.0 or 27.4

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

Tiyuri — Wed, 14 Oct 2020 15:28:54 GMT

My router conducting a speed test (via speedtest.net / google) is reporting precisely 25mbit down and 1mbit up. These don't match the line speeds reported by the router, which are below:

Quick edit:

I know the noise values here aren't ideal. But I've been getting 50mbit for years with zero issues. The only thing that's changed is the router bricking and causing a ton of disconnects on trying to fix its firmware. Also this is a new router obviously, but I can't see any reason why it would reduce bandwidth by 50%. It's an Archer VR2800 if anyone has any ideas there.

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

licquorice — Wed, 14 Oct 2020 15:30:20 GMT

Of course not, download speed will always be lower than sync speed due to protocol overheads. Looking at your stats, you have a 3dB noise margin, therefore DLM is perfectly happy with your line and hasn't reduced your speed. you are getting your maximum speed possible.

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

Tiyuri — Wed, 14 Oct 2020 15:37:24 GMT

I'm honestly not sure how else to explain the real world drop from 50mbit to 25mbit. This is over an ethernet cable plugged directly into the router. This is also a real world figure that's significantly higher than the router reported line speed.

The only other explanation as far as I can tell is that this router is just delivering a much lower speed. But it's rated for 1gbit and is a fairly high end tp-link router. Unless I've somehow configured the router wrong in a way that would somehow limit speed I'm not sure what else to look into?

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

licquorice — Wed, 14 Oct 2020 15:42:38 GMT

Have you still got a BT hub you could connect to see what sync speed that gives?

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

Tiyuri — Wed, 14 Oct 2020 15:47:19 GMT

Sadly not, I actually usually entirely rely on nest wifi throughout my home and my BT home hub died a long time ago so I just replaced the router and moved on.

I'm only currently connected to the router because of this speed issue. Generally the router is just a modem that supplies connection to nest wifi.

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

licquorice — Wed, 14 Oct 2020 15:55:19 GMT

All I can suggest is see if you can borrow a BT hub or other router to try. If what the router is reporting is accurate, a DLM reset will do nothing.

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

Tiyuri — Wed, 14 Oct 2020 16:06:05 GMT

I'll see if I can find one somewhere I suppose! I appreciate all of the help.

Does anything here look wrong:

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

licquorice — Wed, 14 Oct 2020 16:12:57 GMT

You could try setting DSL Annex type to Annex B to see if that makes any difference.

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

Tiyuri — Wed, 14 Oct 2020 16:31:02 GMT

Sadly only Annex A is available in VDSL mode.

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

licquorice — Wed, 14 Oct 2020 16:36:20 GMT

Annex A is correct anyway, just something to try.

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

imjolly — Wed, 14 Oct 2020 17:27:36 GMT

The username is normally

bthomehub@btbroadband.com

Re: Router fault has caused DLM to reduce line speed by 50%. How can I get this reset quickly?

imjolly — Wed, 14 Oct 2020 17:31:40 GMT

Enter your phone number and post results. Delete number when posting

https://www.broadbandchecker.btwholesale.com/#/ADSL