6 ms·

VoWiFi

108 points by zdw 5y ago

aftbit 5y ago
Interesting discussion on telephone numbers. I didn't know that Mexico has 2 and 3 digit area codes, or that +1 includes more than just USA.
mdb31 5y ago
Yes, when roaming, VoWiFi or VoLTE can have quite unexpected results due to your 'data' being backhauled to your 'home' provider, for both billing and dialing. Former you can't do much about, except complain when things go wrong, but as for numbers: always store (and dial) these in +countrycode-subscribernumber (minus the leading 0, unless it's an Italian number, +39) format, and you'll be mostly* fine. *Unless visiting countries that have providers with woefully misconfigured dial plans, say, Nigeria...
- AshamedCaptain 5y ago
  This is not related to LTE, just to roaming itself. In fact, even the manual of the first GSM phone I ever bought said as much (to store your numbers with the international prefix on the address book -- otherwise, they could fail to be matched while roaming).
  - mdb31 5y ago
    Well, it is related to LTE, in the sense that VoLTE calls are treated as 'data' (and thus backhauled to your 'home' provider, as per your (e)SIM), whereas 'voice' calls are handled by whichever provider you happen to be connected to. But the advice to always dial calls in 'international' format is helpful.
    - AshamedCaptain 5y ago
      In fact the author is describing the opposite situation, where his "LTE calls" require the international prefix while the "Wi-Fi" calls do not require it (not sure if VoWifi or plain VoIP, it's not clear from the description, and I don't know of any phone provider which allows true VoWifi while roaming). Note most modern dialing programs (and likely all of the VoLTE-capable ones) will silently add some prefix to your calls anyway, so it's really hard to know what's going on behind the scenes. But you usually can't dial your provider's special phone numbers "as if your calls where backhauled to their network through VoIP" when you are roaming, even with VoLTE. To e.g. check voicemail you will still need to dial your provider's roaming-specific number, which will come with an international prefix.
  - nathancahill 5y ago
    The fact that iOS (not sure about Android) doesn't automatically add the local international prefix when you store a new contact is surprising. Seems like an easy quality of life win.
    - kevincox 5y ago
      Android also doesn't automatically store numbers in international format (at least for the default and Google contacts apps). Maybe the reason is either: 1. The phone doesn't always know the international prefix. 2. This raises the risk of accidental long-distance calls and may piss of users.
- th3typh00n 5y ago
  Always storing contacts using the full international phone number is definitely the way to go. As someone who, at least before the pandemic, used to travel a fair amount this basically eliminates all issues and makes everything "just work" everywhere. To be honest I'm surprised that phones doesn't do this automatically when you type in a local number.
  - kevincox 5y ago
    I was also surprised by this. I moved country and was shocked that none of my phonebook worked and I needed to run a script to add a +1 to all of the non-international numbers in my phonebook. Maybe phones don't necessarily know the current international prefix?
AshamedCaptain 5y ago
You don't need eUICC or anything of the sort to do roaming, which is just what he's describing. Even the behavior with the international prefix on numbers. Also, the simultaneous data + voice story is kinda more complicated. You couldn't do simultaneous voice+data on 2G phones. You could do it on UMTS/HSDPA for sure (it was one of the marketing points...). Then when LTE came, for a time phones could not do phone calls over LTE (VoLTE) (something which I was told was just a "missing software thing") so they had to drop down to some 3G standard during any phone call. If your 3G standard didn't have support for simultaneous voice+data, like it used to be on CDMA networks, then you just didn't have data (see CDMA iPhone 5). But it was just fine on GSM ones.
- avianlyric 5y ago
  > You don't need eUICC or anything of the sort to do roaming, which is just what he's describing. Even the behavior with the international prefix on numbers. I don’t think the author made this claim at all. He just mentioned that he thinks that Google are using eUICC to make roaming on Google Fi cheaper than traditional roaming agreements. And he’s basing this on the fact that the dat connection can drop out for a little while as the phone roams internationally, presumably because it’s reprogramming the eUICC. I would assume that if you’re running a service like GoogleFi, where the phone number isn’t associated with an actual phone network, then you can do international roaming cheaper because you just setup direct agreements with local telecoms to provide local data access, and then route the “shadow number” assigned to the SIM to a local Google endpoint. Thus you can create a setup where international roam is achieved by having local only carrier agreements, and doing clever call routing to local Google forwarding numbers, which Google then routes over its own network to the destination country, where a local Google endpoint then pushes the call back into the local telco network. Doing this completely removes the need to have a traditional roaming agreement where carrier backhaul alien subscribes back to their home carrier, charging a hefty fee for the privilege. And instead replaces it all with local only call and data routing, with Google infrastructure providing international transit, and Google software masquerading the local subscriber identities, so GoogleFi customers don’t see the messy details underneath.
  - 5y ago
mindslight 5y ago
Tangentially related, does anybody have experience with libre SIP over LTE (eg native Android VoIP dialer)? With the partial 4G shutdown in the US, I'm reluctant to buy a new pocket communicator. LTE data continues to work just fine, and I've already got an Asterisk setup for my home phones. VoLTE seems like it's doing the exact same thing just with the carrier's blessing, and the less proprietary crap in my life the better. My current plan is to try out SIP over wireguard [0] over LTE, and see how that treats me. The biggest problem I foresee is a lack of QoS, but given that carriers' main concern seems to be streaming video, I'm hoping that best effort on a lower bandwidth stream will work alright. [0] Wireguard is to solve the NAT issues, make QoS predictable on different networks, and gain secure calls to home as a bonus.
- dragontamer 5y ago
  I had a friend try VoIP on a dataplan a few years ago. > The biggest problem I foresee is a lack of QoS, Bingo. QoS for voice is about jitter and consistency of your stream. > I'm hoping that best effort on a lower bandwidth stream will work alright. Lets put it this way: you don't care if your webpage loads 0.2 seconds slower. But a few random 0.2 second delay in your conversations will make them utterly, and completely unintelligible. Low QoS is something data can afford because little "sprints" of high bandwidth is good for webpages and streaming video. But "live", and "realtime" voice communications, the jitter is just too awful. If no one else is on the cell-tower, you might be fine. But every now and then, you'll just get completely terrible phone calls that are unusable.
- leeoniya 5y ago
  the biggest issue i ran into when trying voip with a cell phone is lack of functioning mms (and therefore also group sms). that ended up being the dealbreaker.
  - sinancan2 5y ago
    Check out https://jmp.chat https://jmp.chat with their Cheogram app. It supports everything you want.
- 5y ago
xenadu02 5y ago
I wasn't aware Mexico had intended to join NANA and use the NANP. It's a shame they didn't. For non North Americans: the telephone networks use an international numbering plan so Canada, the US, and about 18 smaller countries use a single numbering scheme and issue area codes out of the same pool. So for me in the US dialing Canada or Bermuda is the same as dialing somewhere in the US. It is much nicer than the international dialing system where each country has its own rules about what parts of the number are area, local exchange, etc. I wish the old ATT had designed a larger scale numbering plan that could have been worldwide and everyone could have adopted it. (Imagine if IP addresses were different lengths and subnets were described differently based on the country of connection)
- msh 5y ago
  Why would you ever care about area codes? At least if not for ancient carrier billing practices.
- smachiz 5y ago
  Hard disagree - it's actually pretty awful from a mobile user's perspective. You dial a number that is +1 and looks like a normal 10 digit phone number.... and bam, you're paying $3/minute to call Canada (back when everyone charged more for Canada) or Bermuda that is still expensive I think on every carrier. Everyone could use 10 digit dialing and have their own country codes still... it's silly that 19 countries are sitting behind +1 and that they might have a significant surcharge to call.
Kwpolska 5y ago
> It seems to be a general trend that countries with variable-length area codes lack well agreed upon phone number formatting conventions. In the UK, for example, there is also variability (albeit much less of it). This speaks to one of the disadvantages of variable-length area codes: they make digit grouping more difficult, as there's a logical desire to group around the "area code" but it's not obvious what part of the number that is. It’s trivial for computers. For example, using Google’s libphonenumber [0]. For example, Poland uses `000 000 000` for mobiles, and `00 000 00 00` for landlines. libphonenumber knows how to handle this [1]:  <numberFormat pattern="(\d{3})(\d{3})(\d{3})"> <leadingDigits> 21| 39| 45| 5[0137]| 6[0469]| 7[02389]| 8(?: 0[14]| 8 ) </leadingDigits> <format>$1 $2 $3</format> </numberFormat>  <numberFormat pattern="(\d{2})(\d{3})(\d{2})(\d{2})"> <leadingDigits> 1[2-8]| [2-7]| 8[1-79]| 9[145] </leadingDigits> <format>$1 $2 $3 $4</format> </numberFormat> [0]: https://github.com/google/libphonenumber https://github.com/google/libphonenumber [1]: https://github.com/google/libphonenumber/blob/master/resources/PhoneNumberMetadata.xml#L23657 https://github.com/google/libphonenumber/blob/master/resourc...
kevincox 5y ago
I also find it annoying that basically all roaming works by tunneling traffic back home. I guess it kinda makes sense for calls where it needs to be routed by the home carrier but for data it adds a lot of latency and cost. In Canada our data is stupidly expensive such that as a fairly small data user I was considering getting a PAYG "global data plan" instead of a monthly local phone plan (I don't use a local number anyways, so I just need data). And while it would be cheaper for me (and be extraordinarily cheaper when traveling) basically all of these sims have a "home" country that traffic is routed to. Not only is this slower but it also results in funny behaviour for sites that try to optimize/block users based on GeoIP. If one of these global sim providers could do local egress I would be all over that plan.
- andix 5y ago
  This behavior can make your internet on the phone really slow, especially if your SIMs home country is on the other end of the world. But with 5G there is a mode for routing IP traffic directly to the internet during roaming, without sending it „home“ first. Let’s see if providers will implement that.
ggeorgovassilis 5y ago
A few updates ago VoWiFi seems to have disappeared from Android. Anyone know how to get it back?
- stavros 5y ago
  For Xiaomi, ##869434##, I'm not sure about other devices. Mine doesn't work, for some reason, but everyone else's works fine. I think my SIM is somehow misconfigured.
  - genewitch 5y ago
    My Xiaomi refused to make calls with VoWiFi but sms worked. Not MMS. This was straighttalk - beginning of last month when they forced everyone off 3G. At&t users will feel the same pain. I switched to TMO and a garbage unlocked Nord N200 for now I miss my Xiaomi's cameras...
psim1 5y ago
For those of us in the VoIP industry, VoWiFi offers no surprises. The phone establishes an IPSEC tunnel back to the provider for secure calling using the SIP/IMS stack. Much of the time when I am at home and not planning to go out, I turn on airplane mode then enable WiFi. Calling, SMS, MMS, etc. all work fine. It's a battery saver.
kim0 5y ago
Wondering if it's possible to use VoWIFI from a third party provider that's not my phone service provider?

108 points by zdw 5y ago

Interesting discussion on telephone numbers. I didn't know that Mexico has 2 and 3 digit area codes, or that +1 includes more than just USA.

mdb31 5y ago

Yes, when roaming, VoWiFi or VoLTE can have quite unexpected results due to your 'data' being backhauled to your 'home' provider, for both billing and dialing. Former you can't do much about, except complain when things go wrong, but as for numbers: always store (and dial) these in +countrycode-subscribernumber (minus the leading 0, unless it's an Italian number, +39) format, and you'll be mostly* fine. *Unless visiting countries that have providers with woefully misconfigured dial plans, say, Nigeria...

AshamedCaptain 5y ago
This is not related to LTE, just to roaming itself. In fact, even the manual of the first GSM phone I ever bought said as much (to store your numbers with the international prefix on the address book -- otherwise, they could fail to be matched while roaming).
- mdb31 5y ago
  Well, it is related to LTE, in the sense that VoLTE calls are treated as 'data' (and thus backhauled to your 'home' provider, as per your (e)SIM), whereas 'voice' calls are handled by whichever provider you happen to be connected to. But the advice to always dial calls in 'international' format is helpful.
  - AshamedCaptain 5y ago
    In fact the author is describing the opposite situation, where his "LTE calls" require the international prefix while the "Wi-Fi" calls do not require it (not sure if VoWifi or plain VoIP, it's not clear from the description, and I don't know of any phone provider which allows true VoWifi while roaming). Note most modern dialing programs (and likely all of the VoLTE-capable ones) will silently add some prefix to your calls anyway, so it's really hard to know what's going on behind the scenes. But you usually can't dial your provider's special phone numbers "as if your calls where backhauled to their network through VoIP" when you are roaming, even with VoLTE. To e.g. check voicemail you will still need to dial your provider's roaming-specific number, which will come with an international prefix.
- nathancahill 5y ago
  The fact that iOS (not sure about Android) doesn't automatically add the local international prefix when you store a new contact is surprising. Seems like an easy quality of life win.
  - kevincox 5y ago
    Android also doesn't automatically store numbers in international format (at least for the default and Google contacts apps). Maybe the reason is either: 1. The phone doesn't always know the international prefix. 2. This raises the risk of accidental long-distance calls and may piss of users.
th3typh00n 5y ago
Always storing contacts using the full international phone number is definitely the way to go. As someone who, at least before the pandemic, used to travel a fair amount this basically eliminates all issues and makes everything "just work" everywhere. To be honest I'm surprised that phones doesn't do this automatically when you type in a local number.
- kevincox 5y ago
  I was also surprised by this. I moved country and was shocked that none of my phonebook worked and I needed to run a script to add a +1 to all of the non-international numbers in my phonebook. Maybe phones don't necessarily know the current international prefix?

AshamedCaptain 5y ago

You don't need eUICC or anything of the sort to do roaming, which is just what he's describing. Even the behavior with the international prefix on numbers. Also, the simultaneous data + voice story is kinda more complicated. You couldn't do simultaneous voice+data on 2G phones. You could do it on UMTS/HSDPA for sure (it was one of the marketing points...). Then when LTE came, for a time phones could not do phone calls over LTE (VoLTE) (something which I was told was just a "missing software thing") so they had to drop down to some 3G standard during any phone call. If your 3G standard didn't have support for simultaneous voice+data, like it used to be on CDMA networks, then you just didn't have data (see CDMA iPhone 5). But it was just fine on GSM ones.

avianlyric 5y ago
> You don't need eUICC or anything of the sort to do roaming, which is just what he's describing. Even the behavior with the international prefix on numbers. I don’t think the author made this claim at all. He just mentioned that he thinks that Google are using eUICC to make roaming on Google Fi cheaper than traditional roaming agreements. And he’s basing this on the fact that the dat connection can drop out for a little while as the phone roams internationally, presumably because it’s reprogramming the eUICC. I would assume that if you’re running a service like GoogleFi, where the phone number isn’t associated with an actual phone network, then you can do international roaming cheaper because you just setup direct agreements with local telecoms to provide local data access, and then route the “shadow number” assigned to the SIM to a local Google endpoint. Thus you can create a setup where international roam is achieved by having local only carrier agreements, and doing clever call routing to local Google forwarding numbers, which Google then routes over its own network to the destination country, where a local Google endpoint then pushes the call back into the local telco network. Doing this completely removes the need to have a traditional roaming agreement where carrier backhaul alien subscribes back to their home carrier, charging a hefty fee for the privilege. And instead replaces it all with local only call and data routing, with Google infrastructure providing international transit, and Google software masquerading the local subscriber identities, so GoogleFi customers don’t see the messy details underneath.
- 5y ago

mindslight 5y ago

Tangentially related, does anybody have experience with libre SIP over LTE (eg native Android VoIP dialer)? With the partial 4G shutdown in the US, I'm reluctant to buy a new pocket communicator. LTE data continues to work just fine, and I've already got an Asterisk setup for my home phones. VoLTE seems like it's doing the exact same thing just with the carrier's blessing, and the less proprietary crap in my life the better. My current plan is to try out SIP over wireguard [0] over LTE, and see how that treats me. The biggest problem I foresee is a lack of QoS, but given that carriers' main concern seems to be streaming video, I'm hoping that best effort on a lower bandwidth stream will work alright. [0] Wireguard is to solve the NAT issues, make QoS predictable on different networks, and gain secure calls to home as a bonus.

dragontamer 5y ago
I had a friend try VoIP on a dataplan a few years ago. > The biggest problem I foresee is a lack of QoS, Bingo. QoS for voice is about jitter and consistency of your stream. > I'm hoping that best effort on a lower bandwidth stream will work alright. Lets put it this way: you don't care if your webpage loads 0.2 seconds slower. But a few random 0.2 second delay in your conversations will make them utterly, and completely unintelligible. Low QoS is something data can afford because little "sprints" of high bandwidth is good for webpages and streaming video. But "live", and "realtime" voice communications, the jitter is just too awful. If no one else is on the cell-tower, you might be fine. But every now and then, you'll just get completely terrible phone calls that are unusable.
leeoniya 5y ago
the biggest issue i ran into when trying voip with a cell phone is lack of functioning mms (and therefore also group sms). that ended up being the dealbreaker.
- sinancan2 5y ago
  Check out https://jmp.chat https://jmp.chat with their Cheogram app. It supports everything you want.
5y ago

xenadu02 5y ago

I wasn't aware Mexico had intended to join NANA and use the NANP. It's a shame they didn't. For non North Americans: the telephone networks use an international numbering plan so Canada, the US, and about 18 smaller countries use a single numbering scheme and issue area codes out of the same pool. So for me in the US dialing Canada or Bermuda is the same as dialing somewhere in the US. It is much nicer than the international dialing system where each country has its own rules about what parts of the number are area, local exchange, etc. I wish the old ATT had designed a larger scale numbering plan that could have been worldwide and everyone could have adopted it. (Imagine if IP addresses were different lengths and subnets were described differently based on the country of connection)

msh 5y ago
Why would you ever care about area codes? At least if not for ancient carrier billing practices.
smachiz 5y ago
Hard disagree - it's actually pretty awful from a mobile user's perspective. You dial a number that is +1 and looks like a normal 10 digit phone number.... and bam, you're paying $3/minute to call Canada (back when everyone charged more for Canada) or Bermuda that is still expensive I think on every carrier. Everyone could use 10 digit dialing and have their own country codes still... it's silly that 19 countries are sitting behind +1 and that they might have a significant surcharge to call.

Kwpolska 5y ago

> It seems to be a general trend that countries with variable-length area codes lack well agreed upon phone number formatting conventions. In the UK, for example, there is also variability (albeit much less of it). This speaks to one of the disadvantages of variable-length area codes: they make digit grouping more difficult, as there's a logical desire to group around the "area code" but it's not obvious what part of the number that is. It’s trivial for computers. For example, using Google’s libphonenumber [0]. For example, Poland uses `000 000 000` for mobiles, and `00 000 00 00` for landlines. libphonenumber knows how to handle this [1]:  <numberFormat pattern="(\d{3})(\d{3})(\d{3})"> <leadingDigits> 21| 39| 45| 5[0137]| 6[0469]| 7[02389]| 8(?: 0[14]| 8 ) </leadingDigits> <format>$1 $2 $3</format> </numberFormat>  <numberFormat pattern="(\d{2})(\d{3})(\d{2})(\d{2})"> <leadingDigits> 1[2-8]| [2-7]| 8[1-79]| 9[145] </leadingDigits> <format>$1 $2 $3 $4</format> </numberFormat> [0]: https://github.com/google/libphonenumber https://github.com/google/libphonenumber [1]: https://github.com/google/libphonenumber/blob/master/resources/PhoneNumberMetadata.xml#L23657 https://github.com/google/libphonenumber/blob/master/resourc...

kevincox 5y ago

I also find it annoying that basically all roaming works by tunneling traffic back home. I guess it kinda makes sense for calls where it needs to be routed by the home carrier but for data it adds a lot of latency and cost. In Canada our data is stupidly expensive such that as a fairly small data user I was considering getting a PAYG "global data plan" instead of a monthly local phone plan (I don't use a local number anyways, so I just need data). And while it would be cheaper for me (and be extraordinarily cheaper when traveling) basically all of these sims have a "home" country that traffic is routed to. Not only is this slower but it also results in funny behaviour for sites that try to optimize/block users based on GeoIP. If one of these global sim providers could do local egress I would be all over that plan.

andix 5y ago
This behavior can make your internet on the phone really slow, especially if your SIMs home country is on the other end of the world. But with 5G there is a mode for routing IP traffic directly to the internet during roaming, without sending it „home“ first. Let’s see if providers will implement that.

ggeorgovassilis 5y ago

A few updates ago VoWiFi seems to have disappeared from Android. Anyone know how to get it back?

stavros 5y ago
For Xiaomi, ##869434##, I'm not sure about other devices. Mine doesn't work, for some reason, but everyone else's works fine. I think my SIM is somehow misconfigured.
- genewitch 5y ago
  My Xiaomi refused to make calls with VoWiFi but sms worked. Not MMS. This was straighttalk - beginning of last month when they forced everyone off 3G. At&t users will feel the same pain. I switched to TMO and a garbage unlocked Nord N200 for now I miss my Xiaomi's cameras...

psim1 5y ago

For those of us in the VoIP industry, VoWiFi offers no surprises. The phone establishes an IPSEC tunnel back to the provider for secure calling using the SIP/IMS stack. Much of the time when I am at home and not planning to go out, I turn on airplane mode then enable WiFi. Calling, SMS, MMS, etc. all work fine. It's a battery saver.

kim0 5y ago

Wondering if it's possible to use VoWIFI from a third party provider that's not my phone service provider?