Full Fibre with Draytek 2862

[#1]

I have recently moved from ADSL to full fibre and am using my own router, a Draytek 2862, with its ADSL WAN disabled and its Ethernet WAN2 enabled as PPPoE with a static IP address.  I connect to my router via VPN regularly from remote sites.  I am having trouble with the link dropping and staying dropped after a variable amount of time ranging so far from 1-5 days.  When it drops it remains in this state indefinitely (only once did it revive itself somehow) and I usually have to restart the router to get it working again - obviously that is a problem if I am trying to connect remotely as it entails a site visit to reboot.  Has anyone else experienced this kind of behaviour? Incidentally when the router was connected via ADSL it was utterly reliable, staying up and connected for months on end.

[#2]

What speed is your full fibre?

[#3]

I'd suggest looking at the WAN Syslog to see what, if anything, is happening with the PPPoE re-negotiation when the connection drops https://www.draytek.com/support/knowledge-base/7528

[#4]

Speed is 74M

[#5]

I do have some logs but they are in a DB format from a synology NAS that the Draytek relays its syslog to. As I can't access the NAS at the moment I need to find out how to open them before I can investigate (I am remote from the Draytek and its currently down).  I have one exported html log showing WAN interaction but I think its at the beginning of a successful session and does not extend to the demise of that session so useful for me to learn the sequences but not diagnostic.

[#6]

A random thought, have you set the connection to be 'always on' ?

Broadband username or login name	yourusername@plusdsl.net
Connection type or encapsulation	PPPoE Always On
Password	The password you use to log in to the My Account
No VLAN tag is required

[#7]

It is not a setting I can choose for PPPoE but in the general setup for WAN it is automatically set to always on

[#8]

I trawled through 3 days of logs where nothing much was happening except LCP EchoReq and EchoRep until the point where it appears the router chooses to close the connection.  No indication of why that I can see.  Here is the last part of that log hope it posts ok... (There are IPv6 requests in this log, I've turned IPv6 off now but they were going on in this log file for 3 days so I dont think they are significant in the reasons for the termination)

2024-08-24	13:01:28	DrayTek	WAN2 PPPoE <== Protocol:LCP(c021) EchoReq Identifier:0x6E Magic Number: 0x2a79 5c 40 ##
2024-08-24	13:01:28	DrayTek	WAN2 PPPoE ==> Protocol:LCP(c021) EchoRep Identifier:0x6E Magic Number: 0x0 00 00 ##
2024-08-24	13:01:29	DrayTek	WAN2 PPPoE ==> Protocol:LCP(c021) TermReq Identifier:0x23 ##
2024-08-24	13:01:30	DrayTek	WAN2 PPPoE ==> Protocol:IPv6CP(8057) ConfReq Identifier:0x06 Interface Identifier: 00 1d aa ff fe 66 62 ba ##
2024-08-24	13:01:31	DrayTek	WAN2 PPPoE ==> Protocol:LCP(c021) TermReq Identifier:0x24 ##
2024-08-24	13:01:33	DrayTek	WAN2 PPPoE ==> Protocol:IPv6CP(8057) ConfReq Identifier:0x07 Interface Identifier: 00 1d aa ff fe 66 62 ba ##
2024-08-24	13:01:34	DrayTek	WAN2 PPPoE ==> Protocol:LCP(c021) TermReq Identifier:0x25 ##
2024-08-24	13:01:35	DrayTek	WAN2 PPPoE <== Protocol:LCP(c021) TermAck Identifier:0x25 ##

[#9]

@Dan_the_Van   assuming 'WAN2 PPPoE ==>' means outgoing from the 2862, then I agree, it looks like its terminating the PPPoE session. Is there no PADI requests after that ?

If the PPPoE had been dropped by the other end, you would expect the DRaytek to attempt to restart it with PADI broadcasts. It seems from the log , its just dropped the connection itself and therefore makes no attempt to restart it. 

If disabling IPV6 doesnt make any difference , then it looks like contact with Draytek support is the next step.

Next time it happens , might be worth trying a disable/enable of WAN2 (if possible) rather than a full restart, to see if that kicks it back to life.

[#10]

@SteveM84 just been looking through the manual... You haven't got the WAN Budget function enabled have you ?

[#11]

No I definitely did not enable WAN Budget, cannot at the moment check to see if it has become accidentally enabled, good call though.

[#12]

The plusnet Access Concentrators DO respond to LCP EchoReq I presume?

[#13]

I assume so. I'm running Openwrt and my PPPoE settings have an LCP Echo interval of 5 secs with a failure threshold of 6 i.e 6 consecutive failures to drop the connection.

PPPoE is currently showing with 21 days uptime. Prior to the last disconnect it was up for > 80 days.

I'm on FF900 .

[#14]

Yes they do respond, I have since found some EchoReqs from the router which all get a responce, they are rather irregular though ranging from 2 mins 7 secs to 16:29 and more, presumably because other traffic obviates their need in the eyes of the Draytek.  I cannot see one that does not get a response within the same second it is sent so I am still searching for what might have caused the PPP to drop

[#15]

Yes, the router will only send LCP Echo req when there's no other traffic.

This https://www.draytek.com/support/knowledge-base/7528 says the Draytek will shutdown PPPoE if it gets two LCP echo failures.

This https://www.draytek.com/support/knowledge-base/4809 says its 3 at 4 second intervals. It also suggests you can change the interval but not the failure threshold ?