VoWiFi - while abroad

Sinbad2000 · 3 Feb 2023 at 11:17

Do any UK networks support Vowifi while you're outside the country?

I can't understand why they wouldn't allow it. I can understand that they can't guarantee call quality over a high latency/low bandwidth connection, but that's not a reason to actively block it surely?
Is it revenue protection so they can continue gouging on roaming charges? Surely savvy people will get a local prepaid sim/esim for their destination to avoid this, so they're not losing out on revenue - only preying on the unaware?

DarkBahamut · 3 Feb 2023 at 12:04

It will depend on the agreements with the local networks, as it's up to the roaming carrier to let your device use WiFi calling while on their network.

Wifi calls are charged the same as standard calls, so you wouldn't save any money (and nor would they lose any), so I doubt it's cost motivated outside of what the roaming provider is trying to charge for giving the feature.

Sinbad2000 · 3 Feb 2023 at 12:16

DarkBahamut said:
It will depend on the agreements with the local networks, as it's up to the roaming carrier to let your device use WiFi calling while on their network.

Wifi calls are charged the same as standard calls, so you wouldn't save any money (and nor would they lose any), so I doubt it's cost motivated outside of what the roaming provider is trying to charge for giving the feature.

There's no roaming carrier with wifi calling. You're just on the internet, however that may be (most likely via hotel wifi or similar).
All I want is for my ID Mobile sim to log onto the id mobile network via wifi as if I were at home. There's no technical difference between my IP connectivity at home and my IP connectivity at my parents' house in south africa, and so no technical barriers (apart from as I said latency/jitter).
The money comes in when you ACTUALLY roam on a foreign mobile network. The idea is to avoid this completely...

Orcvader · 3 Feb 2023 at 14:37

Sinbad2000 said:
There's no roaming carrier with wifi calling. You're just on the internet, however that may be (most likely via hotel wifi or similar).
All I want is for my ID Mobile sim to log onto the id mobile network via wifi as if I were at home. There's no technical difference between my IP connectivity at home and my IP connectivity at my parents' house in south africa, and so no technical barriers (apart from as I said latency/jitter).
The money comes in when you ACTUALLY roam on a foreign mobile network. The idea is to avoid this completely...

But it still uses your SIM to authenticate you onto the system, and it'll recognise you're out of the country, even with VoWiFi. You're better off using something like WhatsApp/etc to do voice calls.

Sinbad2000 · 3 Feb 2023 at 14:40

Orcvader said:
But it still uses your SIM to authenticate you onto the system, and it'll recognise you're out of the country, even with VoWiFi. You're better off using something like WhatsApp/etc to do voice calls.

That's my point. Why do they care that I'm out of the country? It should not be relevant. Where the IP packets come from doesn't matter at all - unless they are implementing geoblocking (or there's some kind of GPS location data in the vowifi handshake).
lol at the end of the day it's just SIP hidden inside an ipsec tunnel, on further investigation

Terminal_Boy · 3 Feb 2023 at 14:44

As above, use an application which doesn’t need any cellular network interaction.

Sinbad2000 · 3 Feb 2023 at 14:49

Terminal_Boy said:
As above, use an application which doesn’t need any cellular network interaction.

This does not solve the use case of receiving text messages (GSM style, not whatsapp style), or receiving calls from the UK telephone network, or making calls to non-whatsapp recipients.

Some further thinking on this...
We tried to get this working via an OpenVPN tunnel from my wife's phone while she was in SA to my local firewall, and it didn't work, which led me to speculate that there was some kind of GPS/location based blocking going on. However, I've been reading up some more on this and it turns out that openvpn does not support tunneling of ipsec traffic - and hence the traffic still appeared to originate from her SA IP address which EE apparently geoblock. So I can probably find a technical way around all this (using a different vpn) BUT, again, why would the network providers do this geoblocking?

Orcvader · 3 Feb 2023 at 15:09

Sinbad2000 said:
This does not solve the use case of receiving text messages (GSM style, not whatsapp style), or receiving calls from the UK telephone network, or making calls to non-whatsapp recipients.

Some further thinking on this...
We tried to get this working via an OpenVPN tunnel from my wife's phone while she was in SA to my local firewall, and it didn't work, which led me to speculate that there was some kind of GPS/location based blocking going on. However, I've been reading up some more on this and it turns out that openvpn does not support tunneling of ipsec traffic - and hence the traffic still appeared to originate from her SA IP address which EE apparently geoblock. So I can probably find a technical way around all this (using a different vpn) BUT, again, why would the network providers do this geoblocking?

Money.

Sinbad2000 · 3 Feb 2023 at 15:12

Orcvader said:
Money.

Once again - how?
If I can't get this working, I'm not going to roam, I am just going to get a cheap prepaid eSim in my destination country and ignore the UK phone aspect while I'm overseas (and use whatsapp calling). There's no way they can financially benefit from me by depriving me of this. I can only think they're, as I said before, preying on the non-savvy.

Terminal_Boy · 3 Feb 2023 at 15:17

Sinbad2000 said:
This does not solve the use case of receiving text messages (GSM style, not whatsapp style), or receiving calls from the UK telephone network, or making calls to non-whatsapp recipients.

SMS can only be sent over a cellular connection. VoWifi enablement requires your phone to register with your home network‘s HLR via the roaming network’s VLR using a cellular connection. Depending on the roaming agreement between home and roaming networks, either network can decline the registration for VoWifi. The roaming network may choose to do this as it requires their resources for each re-registration and they can’t bill you for it as it’s control plane traffic (signalling).

Sinbad2000 · 3 Feb 2023 at 15:30

Terminal_Boy said:
SMS can only be sent over a cellular connection. VoWifi enablement requires your phone to register with your home network‘s HLR via the roaming network’s VLR using a cellular connection. Depending on the roaming agreement between home and roaming networks, either network can decline the registration for VoWifi. The roaming network may choose to do this as it requires their resources for each re-registration and they can’t bill you for it as it’s control plane traffic (signalling).

Weird. My stepson received SMSs and calls just fine while we were in California, on his SA-based simcard which had no international roaming enabled, but vowifi enabled.

O2 UK Expects to Add SMS Support to WiFi Calling in 2021

Mobile operator O2 (Telefonica UK) has informed ISPreview.co.uk that, after a long wait, they intend to join the other primary operators by adding the ability t

www.ispreview.co.uk

Please remember there's no roaming network involved here - I am assuming the device is connected to a wifi network. NOT a GSM/LTE/5G network. Vowifi is touted as a solution to mobile phone coverage in your home country where you have poor to no cellular reception... How is that different to being out of range of your nearest "home" tower by a few thousand miles?