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Modem random drop-outs

mdubash
Dabbler
Posts: 11
Registered: ‎11-04-2016

Modem random drop-outs

Connection: FTTC VDSL 2

Router: Asus RT-AX58U with OpenWRT - standard set up, nothing special.

Modem: Huawei HG612 with latest Kitz forum reflashed firmware

Discussion: System, which is recent install, works fine most of the time, I'm getting full throughput compared to my old FritzBox, which worked for years but showed signs of giving up, hence the new hardware. DSLStats reports no problems. This problem manifested itself from the beginning of the new hardware's installation.

Problem: Randomly, the link between modem and router seems to fail, for just ten seconds or so while the router re-authenticates. It looks like a problem with the line card as authentication takes a fairly short time, while retraining takes much longer - and it's not doing that.

Fixes tried - all made no difference:

  • New router
  • Replacing the Ethernet cable
  • Re-orienting the modem to allow for better heat dissipation

Suggestions welcome, please!

7 REPLIES 7
Townman
Superuser
Superuser
Posts: 23,982
Thanks: 10,189
Fixes: 175
Registered: ‎22-08-2007

Re: Modem random drop-outs

In the absence of helpful router stats, given that you have seen similar with different kit - consider REIN n SHINE.  See Kitz.

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

MisterW
Superuser
Superuser
Posts: 16,239
Thanks: 6,217
Fixes: 447
Registered: ‎30-07-2007

Re: Modem random drop-outs

@mdubash 

Randomly, the link between modem and router seems to fail, for just ten seconds or so while the router re-authenticates. It looks like a problem with the line card as authentication takes a fairly short time, while retraining takes much longer - and it's not doing that.

Are you absolutely sure the modem isnt retraining ?

If you are, then check the openwrt kernel log for the WAN ethernet port (eth<n>) status. You may see something like

[9086704.622979] mtk_soc_eth 1e100000.ethernet eth0: Link is Down
[9086717.102934] mtk_soc_eth 1e100000.ethernet eth0: Link is Up - 1Gbps/Full - flow control off

I had a similar problem with a Mediatek chipset based router. It would occasionally 'glitch' and drop the eth port and then immediately recover. Problem was it would cause the pppoe to drop. I fixed it by setting 'force link' on the advanced settings for the WAN interface. In that way it won't drop PPPoE due to a short 'carrier' ( the eth<n interface ) drop but if connection is lost for any length of time then PPPoE will time out due to LCP echo not received.

For info, I have LCP echo threshold set to 6 and LCP echo interval set to 5, so a 30 sec timeout in total

 

 

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

mdubash
Dabbler
Posts: 11
Registered: ‎11-04-2016

Re: Modem random drop-outs

Thanks for the feedback. Here are the DSL stats (no errors):

Stats recorded 04 Dec 2024 17:25:50

DSLAM/MSAN type:            IFTN:0xb206 / v0xb206
Modem/router firmware:      AnnexA version - A2pv6C038m.d24j
DSL mode:                   VDSL2
Status:                     Showtime
Uptime:                     4 hours 49 min 59 sec
Resyncs:                    0 (since 04 Dec 2024 12:09:17)
            
                Downstream    Upstream
Line attenuation (dB):      13.1        0.0
Signal attenuation (dB):    Not monitored        
Connection speed (kbps):    71131        19996
SNR margin (dB):            6.3        6.0
Power (dBm):                2.1        2.0
Interleave depth:           1        1
INP:                                

RSCorr/RS (%):              0.0000        N/A
RSUnCorr/RS (%):            0.0000        N/A
ES/hour:                    0        0

mdubash
Dabbler
Posts: 11
Registered: ‎11-04-2016

Re: Modem random drop-outs

The modem's DSL light stays on and it takes just 10 seconds for the WAN connection to return. Also, there's no sign in the modem's logs of the DSL line going down - or in fact of any event at all. It is noticed only by the router, which returns this error message as the line goes down:

I've tried increasing the retries  (PPP Echo Max Failures) but it seems to make little difference. PPP Echo is set to 10.

How would I set 'force link'?

MisterW
Superuser
Superuser
Posts: 16,239
Thanks: 6,217
Fixes: 447
Registered: ‎30-07-2007

Re: Modem random drop-outs

 

How would I set 'force link'?

It's a check box on the Advanced settings tab for the Wan interface. The same page as the LCP echo settings

 

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MisterW
Superuser
Superuser
Posts: 16,239
Thanks: 6,217
Fixes: 447
Registered: ‎30-07-2007

Re: Modem random drop-outs

@mdubash  using Luci goto Network->Interfaces, select Edit for the WAN interface, then select the Advanced settings tab. It should look something like this

openwrt_wan_advanced.png

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

mdubash
Dabbler
Posts: 11
Registered: ‎11-04-2016

Re: Modem random drop-outs

Thanks - I must be going blind because I can see no such option on the WAN settings page. There's no 'Advanced' tab, nor a 'force link' option.

 

Edit: PS: Just discovered Luci - will investigate. Years of using the simple FritzBox interface have left me out of this loop Smiley