- This procedure is used to carry SMS messages in an encapsulated form between UE and the MME.
- Can be initiated by the UE or the network and can only be used when UE is attached for “EPS services and Non EPS services” or “EPS services with SMS only” and UE in connected mode.
UE initiated:
- To send an SMS UE iniates UPLINK NAS TRANSPORT message including the SMS message in NAS message container IE.
Network Initiated:
- Network sends DOWNLINK NAS TRANSPORT message which will be sent to SMS entity by EMM entity at the UE.
Generic NAS transport message :
- Used to send other type of data, example an LCS application to send LPP message or a location service message.
- Should not send uplink NAS transport message when timer T3346 is running unless
i)
UE configured to use access class AC11-AC15
ii)
UE has PDN connection established for emergency
services.