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OmniSMSF

OmniSMSF is the 5G SMS Function (SMSF) for the Omnitouch 5G Core. It carries SMS over NAS: it terminates the SMS transport a UE runs over the 5G control plane and relays each message to and from the operator's SMS centre, so texting works on a 5G-only (SMS-over-NAS) attach without falling back to circuit-switched or IMS delivery.

The SMSF is defined by 3GPP TS 23.501 §6.2.13; its role in SMS-over-NAS is specified in 3GPP TS 23.502 §4.13.3, and the Nsmsf_SMService service is specified in 3GPP TS 29.540.

Documentation​

Architecture Overview​

OmniSMSF sits between the AMF (which relays the UE's SMS-over-NAS transport) and OmniMessage (the SMSC-facing southbound). It registers with the NRF as NFType SMSF so the AMF can discover it, registers itself with the UDM for each UE it serves, and relays message content between the UE and the operator's SMS centre.

Features Overview​

Core Functionality​

  • Nsmsf_SMService (Activate) - PUT /nsmsf-sm/v1/ue-contexts/{supi} creates an ephemeral UE SMS context (201 Created).
  • Nsmsf_SMService (Deactivate) - DELETE /nsmsf-sm/v1/ue-contexts/{supi} tears it down (204 No Content).
  • Nsmsf_SMService (UplinkSMS) - POST /nsmsf-sm/v1/ue-contexts/{supi}/sendsms relays a mobile-originated SMS for an active context.
  • CP/RP relay (TS 24.011) - Decodes uplink CP-DATA/RP-DATA/SMS-SUBMIT and builds downlink SMS-DELIVER/RP-DATA/CP-DATA using the sms_ex codec.
  • Mobile-terminated delivery - Delivers network-originated SMS to the UE via the AMF (Namf_Communication_N1N2MessageTransfer, n1MessageClass=SMS).
  • NRF registration - Registers as NFType SMSF and heartbeats; discovers AMF and UDM via the NRF.

Integration Points​

  • AMF (Nsmsf_SMService / Namf_Communication) - Relays the UE's SMS-over-NAS transport to OmniSMSF and carries mobile-terminated SMS to the UE.
  • NRF (SBI) - OmniSMSF registers as NFType SMSF, heartbeats, and discovers the AMF and UDM.
  • UDM (Nudm_UECM / Nudm_SDM) - SMSF registration/deregistration and SMS-management subscription lookup (fail-open).
  • OmniMessage - SMSC-facing SMS submit/deliver southbound; OmniSMSF registers as a frontend, submits MO messages, and polls/marks MT messages.

Configuration Summary​

All configuration lives under the :omnismsf application key.

config :omnismsf,
  sbi_scheme: "http",
  sbi_addr: "127.0.0.30",
  sbi_port: 7777,
  nrf_uri: "http://127.0.0.10:7777",
  mcc: "999",
  mnc: "70",
  heartbeat_interval: 10_000,
  udm_uri: "http://127.0.0.12:7777",
  amf_uri: "http://127.0.0.18:7777",
  omnimessage_base_url: "http://127.0.0.40:8080"

See the Configuration Reference for the complete parameter tables.

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