I've a Vigor 2865 - primarily using full fibre via WAN2 ethernet, but with a SoGEA back-up on WAN1 (which was the primary connection for many years).
WAN1 has been absolutely stable for years until a few months ago.
Then I started noticing frequent (1 - 2 times per day) reconnects.
This deteriorated to becoming complete connection drops.
Going into DSL status shows it in a loop of TRAINING > FAIL > READY
Doing adsl reboot command on the console brings it back to life, as does disconnecting and reconnecting the DSL lead.
ISP has tested the line and says it's all good. I've tried a new DSL lead - no change, and had a new Master Socket installed (nothing else connected to it, and for a while I had the faceplate removed and the DSL lead straight into the "test" socket.
Firmware is 4.4.6.1_BT, DSL version 8D1B17_A/B/C HW: A
I'd be minded to believe it's a line fault - albeit the ISP says not, and not sure why an adsl reboot would resolve that?

 

Hi Richard,

I encountered a similar issue with my Vigor 2862 router on a SoGEA FTTC line. Like you, I found that rebooting the ADSL connection or reconnecting the DSL lead temporarily restored the connection. However, the problem persisted, even after replacing the DSL lead and installing a new master socket.

Upon further investigation, I discovered that the firmware version 4.4.6.1_BT might have compatibility issues with certain SoGEA lines. After downgrading to firmware version 4.4.5.1, the stability improved significantly, and the connection drops became less frequent.

Additionally, I adjusted the DSL settings to use 'Fast Path' instead of 'Interleaved' mode, which reduced latency and improved overall performance.

If you're still experiencing issues, you might want to consider reaching out to DrayTek support for further assistance or explore alternative firmware versions that could offer better compatibility with your line.

Let me know if you need more details or assistance with the firmware downgrade process.

Best regards

Thanks - I'll experiment with different firmware versions.
I think the start of the issues may well have been consistent with the firmware update to 4.4.6.1

Did you manage to get anywhere with this?
I am in a similar situation with a Vigor 2866ax.
I have been plagued with disconnections and resyncs for the best part of two months. Openreach have been four times and are now blaming the Draytek. The timeline probably fits with when I upgraded to 4.4.6.1_BT, but I am clutching at straws. I am now running 4.4.6.2_BT but still having the same problems. Some days it will disconnect and reconnect 3-5 times, other days there are too many to count.
I have raised a support ticket today and have setup the syslog...
Any info would be appreciated.

It seems to have improved it - but to be honest, I'm not sure what change did it.
I'm now on 4.4.6.2_BT - but not sure if the firmware update was the solution.
I'm suspicious about this potentially being a cabinet side change - possibly a change to the DLM rules? Has Openreach inadvertently introduced a compatibility issue from their end?
Previously my line was DLM limited to 35mbps for years. Prior to getting the issues the DLM limit stepped up to 40bps. What's surprised me is that despite the frequent disconnections the DLM did not force it back down. I'm fairly sure in the past even modest error rates were seeing DLM throttle the line back down. I'm also now seeing a ~ weekly ~ 3am resync ..... didn't used to get that, but I know DLM used to force resyncs where required in the 3am - 4am window. Is DLM trying to apply a lower profile, but failing to do so, and just triggering a resync instead .... no idea, I'm grasping at straws, but fingers crossed, it seems to have stabilised.