VoWiFi drops on RT-AC1200G+

[random1zed]

Hell everyone,

I'm having an issue with the router in the title (latest firmware) and at least 2 phones (Xiaomi Redmi Note 9 Pro/Moto G7 Power) when it comes to the VoWiFi calling. It's probably more of a niche thing. The router seems to be functioning quite flawlessly without any drops and issues, capable of very long uptimes (3 months+) and it's stable, yet I have these WiFi calling drops that I can't "fix" without a router reboot. Here's how things happen and how I test/troubleshoot.

The router cannot cover the whole apartment at good signal strength, so VoWiFi will occasionally switch to VoLTE. When I would move closer to the router, it would switch back to VoWiFi - and the call drops on the spot, 100% reproduction. No logged event for the router. Rebooting the router allows the phones to switch flawlessly between VoLTE and VoWiFi, no more drops. But after a while (it was 5 days uptime when I noticed), the drops start again unless I reboot.

I've tried setting the Internet to On/Off in the router. I tried switching the radio, both 5GHz and 2.4 to off and on, still drops. The router works absolutely fine in all other ways, I have 2 PCs, 2 TVs, a set-top box, 2 phones, some wired, some wireless, no issues at all but these VoWiFi call drops. I've also tried other wireless settings like setting a channel instead of Auto for both 5/2.4, or just using 40 MHz instead of 20/40 etc. No effect, sadly, just the reboot would fix it.

The way I found it easiest to test is to call some customer service robot with the phone's WiFi turned off, so it uses VoLTE. After the call connects, I would turn WiFi back on and go in the router room where the signal is strong, and it would switch to VoWiFi. Unless the router has been rebooted somewhat recently, call will drop 100% of the times when the switch occurs. On the other end of the call it just goes quiet and then drops there too.

Any ideas what's going on? Since the router reboot seems to fix things, it seems that this is where I should focus my attention, instead of trying to call the ISP or phone manufacturer.

Thanks a lot, please let me know if you need other data, like more concrete settings I'm using etc.

 

[ATLga]

Hell everyone,

I'm having an issue with the router in the title (latest firmware) and at least 2 phones (Xiaomi Redmi Note 9 Pro/Moto G7 Power) when it comes to the VoWiFi calling. It's probably more of a niche thing. The router seems to be functioning quite flawlessly without any drops and issues, capable of very long uptimes (3 months+) and it's stable, yet I have these WiFi calling drops that I can't "fix" without a router reboot. Here's how things happen and how I test/troubleshoot.

The router cannot cover the whole apartment at good signal strength, so VoWiFi will occasionally switch to VoLTE. When I would move closer to the router, it would switch back to VoWiFi - and the call drops on the spot, 100% reproduction. No logged event for the router. Rebooting the router allows the phones to switch flawlessly between VoLTE and VoWiFi, no more drops. But after a while (it was 5 days uptime when I noticed), the drops start again unless I reboot.

I've tried setting the Internet to On/Off in the router. I tried switching the radio, both 5GHz and 2.4 to off and on, still drops. The router works absolutely fine in all other ways, I have 2 PCs, 2 TVs, a set-top box, 2 phones, some wired, some wireless, no issues at all but these VoWiFi call drops. I've also tried other wireless settings like setting a channel instead of Auto for both 5/2.4, or just using 40 MHz instead of 20/40 etc. No effect, sadly, just the reboot would fix it.

The way I found it easiest to test is to call some customer service robot with the phone's WiFi turned off, so it uses VoLTE. After the call connects, I would turn WiFi back on and go in the router room where the signal is strong, and it would switch to VoWiFi. Unless the router has been rebooted somewhat recently, call will drop 100% of the times when the switch occurs. On the other end of the call it just goes quiet and then drops there too.

Any ideas what's going on? Since the router reboot seems to fix things, it seems that this is where I should focus my attention, instead of trying to call the ISP or phone manufacturer.

Thanks a lot, please let me know if you need other data, like more concrete settings I'm using etc.

What is "latest firmware"

 

[random1zed]

What is "latest firmware"

3.0.0.4.382_52272-g73d3ea2

Version 3.0.0.4.382.52272
2020/06/29 15.1 MBytes
ASUS RT-AC1200G+ Firmware version 3.0.0.4.382.52272
Security update
- Fixed CVE-2020-12695 (CallStranger)
- Fixed Reflected XSS vulnerability.
- Fixed Directory traversal vulnerability.
- Fixed CVE-2017-15653.

 

[ATLga]

Hell everyone,

I'm having an issue with the router in the title (latest firmware) and at least 2 phones (Xiaomi Redmi Note 9 Pro/Moto G7 Power) when it comes to the VoWiFi calling. It's probably more of a niche thing. The router seems to be functioning quite flawlessly without any drops and issues, capable of very long uptimes (3 months+) and it's stable, yet I have these WiFi calling drops that I can't "fix" without a router reboot. Here's how things happen and how I test/troubleshoot.

The router cannot cover the whole apartment at good signal strength, so VoWiFi will occasionally switch to VoLTE. When I would move closer to the router, it would switch back to VoWiFi - and the call drops on the spot, 100% reproduction. No logged event for the router. Rebooting the router allows the phones to switch flawlessly between VoLTE and VoWiFi, no more drops. But after a while (it was 5 days uptime when I noticed), the drops start again unless I reboot.

I've tried setting the Internet to On/Off in the router. I tried switching the radio, both 5GHz and 2.4 to off and on, still drops. The router works absolutely fine in all other ways, I have 2 PCs, 2 TVs, a set-top box, 2 phones, some wired, some wireless, no issues at all but these VoWiFi call drops. I've also tried other wireless settings like setting a channel instead of Auto for both 5/2.4, or just using 40 MHz instead of 20/40 etc. No effect, sadly, just the reboot would fix it.

The way I found it easiest to test is to call some customer service robot with the phone's WiFi turned off, so it uses VoLTE. After the call connects, I would turn WiFi back on and go in the router room where the signal is strong, and it would switch to VoWiFi. Unless the router has been rebooted somewhat recently, call will drop 100% of the times when the switch occurs. On the other end of the call it just goes quiet and then drops there too.

Any ideas what's going on? Since the router reboot seems to fix things, it seems that this is where I should focus my attention, instead of trying to call the ISP or phone manufacturer.

Thanks a lot, please let me know if you need other data, like more concrete settings I'm using etc.

Honestly it does sound like a cell carrier/phone issue with the handoff from wifi to Cellular. Some phones/carriers are better at it than others. The fact that it goes X amount of days is strange, but probably some weird coincidence. There are some members here that use WiFi calling extensively and hopefully they'll jump in here with some ideas. Sorry I'm not more helpful.

 

[random1zed]

Honestly it does sound like a cell carrier/phone issue with the handoff from wifi to Cellular. Some phones/carriers are better at it than others. The fact that it goes X amount of days is strange, but probably some weird coincidence. There are some members here that use WiFi calling extensively and hopefully they'll jump in here with some ideas. Sorry I'm not more helpful.

It is possible. The Xiaomi phone for example responds very well to the router reboot (I've tried two times to troubleshoot the issue), the Motorola G7 Power is more awkward, as in it is not fully predictable, it takes a while until it no longer drops the call after I reboot the router. The Xiaomi phone however is very reliably reproducing the issue (once it occurs). This is one of the problems, I don't know how to make it appear, I assumed it was fixed after both phones worked fine when I first rebooted the rooter for this 5 days ago. I had a dropped call today, so I started troubleshooting it again, and the Xiaomi phone dropped the call each time I switched off the WiFi during a WiFi call, just like 5 days ago, tried about 10 times. Rebooted the router, 0 drops, tried a dozen times already, router uptime is now 2:30 hrs, and all is still OK.
Unsure what else to say, would be happy to try other troubleshooting steps. If (when, I guess) the issue occurs again I'll try to troubleshoot on the Moto phone instead as it seems to be somewhat slow when it comes to WiFi connectivity in general compared to the Xiaomi and responds much slower to network changes and fluctuations, getting an IP, even downloading off the Store. I'll definitely ask the ISP too, it's generally a very reliable and fast one, but the VoWiFi thing is still rather new, a year or so, so it could have some imperfections for sure.