8.9 GA-CSR Signalling and SMS Transport Procedures
3GPP43.318Generic Access Network (GAN)Release 17Stage 2TS
8.9.1 Network initiated CS Signalling
Figure 20: Downlink Control Plane Transport
1. For Network initiated signalling/SMS, the Core Network sends a MM/CC signalling or SMS message to the GANC via the A interface.
2. The GANC encapsulates the received message within a GA-CSR DL DIRECT TRANSFER message that is forwarded to the MS via the existing TCP connection.
8.9.2 MS initiated CS Signalling
Figure 21: Uplink Control Plane Transport
1. For MS initiated signalling/SMS, the MS GA-CSR receives a request from the NAS layer to transfer an uplink NAS signalling message or SMS message. The MS GA-CSR encapsulates the NAS message within a GA-CSR UL DIRECT TRANSFER message and sends the message to the GANC.
2. The GANC relays the received message to the Core Network encapsulated in DTAP.