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How those alerts work technically? They are SMS with special header or entirely separate message type? (eg. in Poland alerts are sent as plain old SMS)
by garaetjjte 7y ago
How those alerts work technically? They are SMS with special header or entirely separate message type?
(eg. in Poland alerts are sent as plain old SMS)
- theluketaylor 7y agoIt's cell broadcast which is related to SMS but slightly different. https://en.wikipedia.org/wiki/Cell_Broadcast https://en.wikipedia.org/wiki/Cell_Broadcast
- jsjohnst 7y agoNo, they are not done like SMS. Think of SMS like a normal IP packet, it has a source and destination. Belaboring the analogy, the WEA messages are more multicast packets. WEA messages are encapsulated in Cellular Broadcast data (CB Data) payloads which are then encapsulated in System Information Blocks (SIB12 specifically). The way they are “routed” to your phone is by being near a tower in the coverage area of the alert. Even if you weren’t in range of the tower when the alert initially went off, you’ll still receive the message as soon as you are within range of the tower(s) broadcasting it (assuming the alert hasn’t been cleared). Each payload has the equivalent of a payload ID which is supposed to prevent duplicate notification on your device of the same alert (but for different reasons, isn’t always done right).