[UK ISP] Virgin Media issues with RT-AX88U ?

MrRederick

Occasional Visitor
Hi all,
I'm using a (new in Dec 2019) RT-AX88U with Merlin 384.18 firmware, and previously 384.17 etc. I've always been running Merlin on this box. This is probably the ISP problem, but has anyone else had problems with ASUS routers when using this ISP in the last two months?

For those not in the UK this is a cable ISP and provides a DOCSIS 3.0 all in one router / modem made by Arris, and branded the "Hub 3.0". This box comes in router mode, with AC dual band WiFi and 4 ethernet ports. It also offers, an easy to find in the web GUI, a Modem mode, which gets rid of the router features, and passes the public IP to the first downstream ethernet device. (in my case, my AX88U). No PPP is required, this is a DHCP environment on the WAN port.

This setup had worked perfectly from mid Dec through to early May, then the ISP had a weekend major outage, and since then things have been tempremental, with several disconnections per day, requiring multiple reboots of modem and AX88U to return to service, sometimes only for as long as 5 minutes before existing connections (e.g. a Webex Call) continue, but I can no longer ping public DNS such as 8.8.8.8 or 9.9.9.9. However if I switch the Hub into Router mode, the only way ISP support will talk to me, then everything works for days at a time.

The ISP has checked the logs, and says nothing wrong on the coax side, so I'm assuming something incompatible between the ASUS AX88U and the ISP network?

Anyone else?
 

tekrich

Regular Contributor
I'm running the same set up, my virgin media router is in modem mode and connected to my AX88U.

But have had no issues since I brought it, January this year.

Its running the latest Merlin firmware. No issues. Although, we have the very old 1st gen hub!

I want to assume its an issue their end. If it happens again, check the Virgin hub and see if the blue connection light is stable.
 

MrRederick

Occasional Visitor
Thank you for the confirmation the set up works. I have no blue lights on the Hub 3, but a handful of lights, including WiFi that change colour as it boots, and eventually go off, and a steady light at the bottom which they call the power light. This is either green (booting), white (router mode) or purple (modem mode). When I've had a "strange event" I get a red light on my ASUS and a report the DHCP has failed, and the Hub 3 shows nothing wrong. Rebooting the ASUS doesn't fix, but rebooting the Hub AND the ASUS does.

I have just read there is apparently an "approved sequence" in using modem mode, which I assume is not technically accurate, but I tried it:
* Power off third party router
* Configure Virgin Media hub in modem mode, let it reboot and wait 5 minutes
* Power on third party router
After doing that, late tonight, things have been stable for the last hour.

Much better than double NAT, which I've used for the last 24 hours to prove the connection - but that breaks my VoIP !
 

muffintastic

Regular Contributor
It maybe down to Virgin, try logging in online in your account and running some tests.

Or maybe nuclear reset the router.

Running Virgin on a RTAC68U no issues.

Try swapping the ethernet cable from the WAN port also.
 

MrRederick

Occasional Visitor
I've been on hold with tech support the last day, they've run all sorts of test on the hub remotely, including getting me to do the "PIN Reset" of the Hub, but only when I switched it to Router mode. I left it like that for 24hours without any disconnects. That led me to post here.

Good thinking on cable, I have an ethernet tester, and good idea on the nuclear reset of the AX88U if the problems persist.

Thanks!
 

tekrich

Regular Contributor
Mmm,

It's strange that everything was fine before the outage. Does your WAN IP change frequently?

EDIT: I like the look of that script in the post above...
 

MrRederick

Occasional Visitor
Thanks, I've got modmon installed, but not sure how to interpret the graphs, it only works in modem mode, the last few hours have had no data, as I was in router mode for tech support.

Downstream power graphs, screen grab:
https://imgur.com/a/yS55ZGa


Wan IP is the same as it has been for month with the ASUS as the DHCP client, I get a different IP with a different device (e.g. a PC, or the Hub in router mode)
 

Jack Yaz

Part of the Furniture
Thanks, I've got modmon installed, but not sure how to interpret the graphs, it only works in modem mode, the last few hours have had no data, as I was in router mode for tech support.

Downstream power graphs, screen grab:
https://imgur.com/a/yS55ZGa


Wan IP is the same as it has been for month with the ASUS as the DHCP client, I get a different IP with a different device (e.g. a PC, or the Hub in router mode)
While this is an older guide, I think it's still relevant for the suggested "safe" ranges: https://community.virginmedia.com/t...ICAL-PRIMER-updated-October-2016/td-p/2271297
 

MrRederick

Occasional Visitor
Since Friday everything had been working as expected, Hub 3 in modem mode, and RT-AX88U in Automatic IP. But about 14:30 UK time, my Spotify music stopped playing, and from my PC I couldn't ping the Hub (192.168.100.1) or public DNS (8.8.8.8 or 9.9.9.9) but after 20 or 30 seconds, it came back. That happened twice. Then about 14:50, it dropped and did not come back and the Asus showed "Disconnected". The Hub 3 showed no difference in lights.

I've just noticed my Asus was configured to Ping wikipedia to see if it had internet access or not. I have disabled this check, and wonder if that will help it recover from a Virgin "issue" in the future.

I turned off Asus and Hub and after 2 minutes turned Hub back on again, let it boot until the internet light went out and power light on pink. Then powered up the Asus, and everything is working again.

Does anyone have any ideas as this only seems to occur in Modem mode, and then randomly as above? If I put the Hub 3 in router mode, everything is stable.

A snapshot of thinkbroadband BQM shows the brief problems, and the power off recovery:
https://www.thinkbroadband.com/broa...b0056dbbf5946eee80fbed458586284cf7-05-07-2020

The Hub 3 log implies T3 timeouts and no ranging response, but nothing in the table or on modmon's stats:
05/07/2020 13:44:7 Warning! RCS Partial Service;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:44:7 critical No Ranging Response received - T3 time-out;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:43:59 Warning! RCS Partial Service;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:43:58 critical No Ranging Response received - T3 time-out;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:43:58 Warning! RCS Partial Service;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:43:19 critical No Ranging Response received - T3 time-out;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:42:55 critical Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:42:55 critical Ranging Request Retries exhausted;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:42:13 critical No Ranging Response received - T3 time-out;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:42:13 Warning! RCS Partial Service;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:42:11 critical No Ranging Response received - T3 time-out;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:42:6 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:35:12 Warning! RCS Partial Service;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:23:49 notice LAN login Success;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:11:38 Warning! RCS Partial Service;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:11:37 critical No Ranging Response received - T3 time-out;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:10:1 critical SYNC Timing Synchronization failure - Loss of Sync;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:09:54 Warning! RCS Partial Service;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:09:52 critical No Ranging Response received - T3 time-out;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
05/07/2020 13:09:48 Warning! RCS Partial Service;CM-MAC=xxxx;CMTS-MAC=xxxx;CM-QOS=1.1;CM-VER=3.0;
 

Vexira

Part of the Furniture
Is your ISP using dhcp to authenticate, you might be interested in trying the new Merlin alpha and setting up continuous mode under wan it's just food for thought.
 

MrRederick

Occasional Visitor
Is your ISP using dhcp to authenticate, you might be interested in trying the new Merlin alpha and setting up continuous mode under wan it's just food for thought.
That is an idea, I've just seen my ASUS show "Disconnected" for Internet Status, will investigate. Thanks!

EDIT - I've seen the Telnet/SSH command, so have issued that and the udhcpc parameters have changed after a reboot. Keeping fingers crossed.
 
Last edited:

ColinTaylor

Part of the Furniture
This is a problem with your modem and/or Virgin because you can see in the modem's log lots of "Partial Service" messages. That means your modem lost its connection. Either because Virgin were performing planned maintenance or because there is a fault on your connection (which is usually signal levels). This can only be fixed by Virgin Media.
 

MrRederick

Occasional Visitor
This can only be fixed by Virgin Media.
I wondered as much. Their helpdesk on Friday was not very useful, and said there was no problem with my logs. I think they don't want to support people in Modem Mode !

I will have to go back to Router mode, and wait for the issue to reoccur, and then post (again) the logs on the Community Forum, at least their they can see my logs posted, unlike the call centre.

Thanks!
 

ColinTaylor

Part of the Furniture
Switching the Hub to router mode often "hides" the problem to such an extent that the end user is not aware of it. For example, if you're not actively using the internet when the partial service occurs you won't notice it (the Asus is not aware of the problem). Whereas if you're in modem mode the Asus will immediately detect the problem and attempt to correct it by restarting its WAN interface, redirecting client requests, etc. But in either case the fault is there.
 

MrRederick

Occasional Visitor
Switching the Hub to router mode often "hides" the problem to such an extent that the end user is not aware of it. For example, if you're not actively using the internet when the partial service occurs you won't notice it (the Asus is not aware of the problem). Whereas if you're in modem mode the Asus will immediately detect the problem and attempt to correct it by restarting its WAN interface, redirecting client requests, etc. But in either case the fault is there.
I tend to notice when there is an issue as my VPN drops, and my streaming music stops. I don't want router mode, but the community forum folk said you need to be in router mode to get VM staff to act.

Maybe its all this sunshine that has done something to the external cables :)
 

MrRederick

Occasional Visitor
For anyone following this thread, I had a technician visit today, whom found a fault in the street, corroded point, and has moved my line to a different point. That was 10am this morning. Now its nearly 8pm, I'm going to risk switching back to modem mode, and keep fingers crossed!
 

JemTheWire

Senior Member
T3 time-outs could be noise on you upstream. That’s between the SuperDud 3 and the VM network. Nothing to do with your Asus router.

Update: I really must learn to read the full thread before I jump in feet first. At least my diagnostic was right.
 

MarkyPancake

Senior Member
I still can't believe with the Intel Puma Chipset debacle that the VM SH3 never got recalled.
 

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