Hi all.

So I deployed a Draytek Vigor 2862 (that I sourced online) at clients a few weeks ago (Running firmware 3.9.9.9 BT) and initially the VDSL speeds were extremely low due (4Mbps down/0.7Mbps up) to past historic issues where the old previous TP-Link modem router had been on the end of a very long and old telephone extension line which had other stuff like an hardwired intruder alarm connected in the middle of the telephone extension line. The Vigor 2862 is connected directly to the DSL side of VDSL filter plate/BT master socket combo over a short 5 meter twisted pair cable.

Anyway, following getting a DLM profile reset on the line so the modem in the 2862 could retrain to the DSLAM in the high street cabinet, the DSL speeds gradually came up in a few stages over a few days with the odd brief drop out and eventually reached a healthy speed of 36Mbps down and 9Mbps up which remained connected and stable for 36 hours all through Sunday 23rd to 07:19AM on Monday 24th.

Of course on Sundays most people don't work and yet come Monday morning, things go south, so makes me me wonder if things are going on with Openreach or the ISP.

I have also been informed by the client that that Openreach engineers keep being sent out them (who knows if they are doing stuff in the road to without being sent out to the client) recently, and I have also seen many connection drops in the last 24-36 hours. There where 6 Internet (VDSL) connection drops yesterday on the 24th and 4 today so far on the 25th. The speeds have also dropped considerable since Sunday to 16Mbps down and 4Mbps up.

Could the modem in the 2862 be faulty, or something suspicious going on upstream of the 2862.

I have also seen in the last 24hrs that the 2862 has reported the actual rate being higher than the attainable rate, which seems rather odd and counter intuitive to me. See below for this.


So advice would be much appreciated where you think the issue is. I do have a spare Vigor 2862, however I'm not totally convinced that the issue is with the DrayTek but upstream of it.

Regards: Elliott.
 

From experience, DrayTek modems don't work well on Huawei cabinets which this one is connected to. Higher actual rate to attainable rate can be due to the modem code used, especially if the line is on fastpath. Try a different modem version - more conservative - to see if this stabilises the connection. On a good line, your modem should run on 3db no probs, but it depends on ISPs, too, with some having 6db as default. Once you get the modem code right, you can then try to experiment with reducing SNR. Remember some modem codes don't support vectoring. I had written a post on here a few years ago about different modem codes so you might find it helpful. It depends on your cabinet but the more the line drops the lower the speed and the higher the SNR. On my cabinet, I could deliberately disconnect 100 times per day and that wouldn't have the effect, but I know some other lines/cabinets can be banded. Also recommend the Kitz forum for a more detail discussion on line problems.

On my noisy line at the time, any little outbursts of noise would cause the line to drop. Swapping DrayTek with Fritzbox improved the situation for me big time. 

What are the rest of the stats like? 

The other thing to consider is the latest series of attacks on DrayTek routers, so make sure the firmware is up to date and SSL VPN off. Two ISPs have noted issues recently:

https://www.ispreview.co.uk/index.php/2025/03/broadband-isps-report-uk-connectivity-problems-with-vulnerable-draytek-routers.html

Would getting a old Huawei HG612 and putting that inline with WAN 2 help? I'm using two of the HG612's myself on my own 2962 without issue.

Of course I would rather not change the modem code remotely in case it fails to reconnect. The options I have are AnnexA_779517_773F01 (default/current) and AnnexA_77B507_775401.

Apparently connecting a modem with a broadcom chipset helps if you're on Huawei cabinet, but I think the issue is that there may be a problem with the DSL line or Draytek's modem codes, not the chipset/cabinet compatibility. So, no harm trying an old Huawei modem. I'd not update firmware remotely. You can find other versions of firmware on other international sites. The BT one is just one of those versions that has been tested on BT lines and deemed appropriate.

I installed a Huawei HG612 DSL modem on Friday connected to WAN 2 of the 2862, replacing the DSL connection on WAN 1. Will see how it goes over the next few days.

Below are the current stats of the Huawei: