SIP ↠  ExamplesGrammarsPresence ⇾  MainServicesTransactionDialogIMS
TS 24.228§7.2.4§7.3.5§7.4.3   List   Prev   Next
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IMS S3 signalling flow - Session Initiation: Origination in CS Network, and Mobile termination in home network - IMS S3-1a. SIP INVITE request (UE1 to UE2): from MGCF1 to I-CSCF1
  • Request-URI: Contains the international E.164 number from the user, as obtained from CS Networks signalling.
  • Via: Contains the IP address or FQDN of the originating MGCF.
  • P-Asserted-Identity: The MGCF inserts the TEL URL containing the subscriber number, as received from the CS network.
  • P-Charging-Vector: The MGCF inserts this header and populates the icid parameters with a globally unique value.
  • Contact: SIP URI that contains the IP address or FQDN of the MGCF.
  • SDP: Contains a preconfigured set of codecs supported by the MGW.