1. Essentials Guide
  2. Oracle USM Supporting the IMS Core
  3. HSS Server Assignment
  4. Server Assignment Messages

Server Assignment Messages

The Oracle Communications Unified Session Manager sends a Server Assignment Request (SAR) to the HSS requesting to confirm the SIP or SIPS URI of the SIP server that is currently serving the user. The SAR message also serves the purpose of requesting that the Diameter server send the user profile to the SIP server. The SAR's AVPs are populated as follows:

  • Public-User-Identity—the SIP AOR of the endpoint being registered (same as UAR)
  • Private-User-Identity—the username from the SIP authorization header, if it is present. If not, this value is the public User ID. (Same as UAR)
  • Server-Name—the home server route parameter in the sip-registrar configuration element. It is the FQDN or IP address used to identify and route to this Oracle Communications Unified Session Manager sent as a URI.
  • Server-Assignment-Type—the value of this attribute depends upon the registration state:
    • REGISTRATION (1)—for all new and refreshing registrations.
    • Set to TIMEOUT_DEREGISTRATION (4)—when the contact is unregistered due to expiration. This occurs if the force-unregistration option is configured in the sip config.
    • USER_DEREGISTRATION (5)—when the contact is unregistered by the user (contact parameter expires=0).
  • User-Data-Already-Available—always set to USER_DATA_ALREADY_AVAILABLE (1)