One nifty feature of this interface is that you can send SMS using the MSC to switch the SMS traffic and the LTE/EUTRAN to transfer the messaging.
This means you don’t need Circuit Switched Fallback to send or receive SMS on LTE.
I assume this functionality was added to avoid the signalling load of constantly changing RAN technologies each time a subscriber sent or received an SMS, but I couldn’t find much about it’s history.
In order to get this to work you’ll essentially need the exact same setup I outlined in my CSFB example (Osmo-MSC, Osmo-STP, Osmo-HLR populated with the IMSI and MSISDN values you want to use for SMS), although you won’t actually need a GERAN / GSM radio network.
Once that’s in place you can just send SMS between subscribers,
Plus from the VTY terminal of OsmoMSC you can send SMS too:
OsmoMSC# subscriber msisdn 61487654321 sms sender msisdn 61412341234 send Hello World