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> If I have troubles receiving SMSs from Germany to German number while in US, would wifi calling icrease the chances of receiving the said SMSs? I'm not up to

> If I have troubles receiving SMSs from Germany to German number while in US, would wifi calling icrease the chances of receiving the said SMSs? I'm not up to date on the state of messaging infrastructure but it used to be the case that some providers would offer non-standard methods for sending messages over their network to intermediary providers. Rather than sending an SMS to a number, a business would ask the intermediary to send a message and the intermediary would use the non-standard method provided by the network provider. The non-standard methods work fine if you're connected to the network directly but if you're overseas that will not be the case and so you can't receive these non-standard messages. Don't quote me on any of that, though.

lxgr 2y ago
The non-standard method is to get the SMS to a delivering SMSC (which is the same network component that's used for mobile originated SMS delivery, which is standardized). Once it's enqueued in an SMSC, there is no more distinction between how it got there, as far as I understand (at least downstream from there; delivery reports to the sender might again be proprietary for non-mobile senders). > The non-standard methods work fine if you're connected to the network directly but if you're overseas that will not be the case and so you can't receive these non-standard messages. This is actually not particular to the way in which SMS have been enqueued, but rather to how they're delivered: The sending SMSC has to "dial" pretty deep into both the recipient's home and visited network in the original implementation. This means that they need a commercial agreement and technical integration with both of them. Usually, problems/inconsistencies occur when they do know how to deliver to the recipient number's home network (because if they can't, they'd probably have rejected the message at SMSC submission time), but are then redirected to a given visited network with which they don't have interconnectivity. This problem (and some others, including serious privacy concerns) is solved by a newer technology called "SMS home routing". In that model, there's something like a proxy in the recipient's home network that essentially poses as the receiving phone to the sending SMSC, and then uses the home network's resources to do actual delivery. This usually leads to more consistent experiences, and allows things like a "received message log". (Without a home router, the recipient's home network never sees the message content when the recipient is roaming!)

lxgr 2y ago

The non-standard method is to get the SMS to a delivering SMSC (which is the same network component that's used for mobile originated SMS delivery, which is standardized). Once it's enqueued in an SMSC, there is no more distinction between how it got there, as far as I understand (at least downstream from there; delivery reports to the sender might again be proprietary for non-mobile senders). > The non-standard methods work fine if you're connected to the network directly but if you're overseas that will not be the case and so you can't receive these non-standard messages. This is actually not particular to the way in which SMS have been enqueued, but rather to how they're delivered: The sending SMSC has to "dial" pretty deep into both the recipient's home and visited network in the original implementation. This means that they need a commercial agreement and technical integration with both of them. Usually, problems/inconsistencies occur when they do know how to deliver to the recipient number's home network (because if they can't, they'd probably have rejected the message at SMSC submission time), but are then redirected to a given visited network with which they don't have interconnectivity. This problem (and some others, including serious privacy concerns) is solved by a newer technology called "SMS home routing". In that model, there's something like a proxy in the recipient's home network that essentially poses as the receiving phone to the sending SMSC, and then uses the home network's resources to do actual delivery. This usually leads to more consistent experiences, and allows things like a "received message log". (Without a home router, the recipient's home network never sees the message content when the recipient is roaming!)