Content for  TS 23.558  Word version:  19.3.0

The announcing EES sends Announce common EAS request message to the receiving EES. The request message includes the requestor identifier [EESID], the security credentials, the selected common EAS information, the announcing EES endpoint, including common EAS endpoint, common EAS service KPI as specified in Table 8.2.5-1 and the Application group ID. When ACR happens, and announcing EES is targed EES, which can announce the determined EAS information.

Upon receiving the request from the announcing EES, the receiving EES checks if the announcing EES is authorized to provide the selected common EAS. The receiving EES stores the received selected EAS information and announcing EES endpoint along with the Application group ID. When receiving selected T-EAS and T-EES information, the receiving EES can determine whether to relocate the UE to the newly received EAS based on the newly received EAS KPI and EDN information, registered EAS KPI and EDN information, and inter-EAS communication performance of these EASs.

If the processing of the request was successful, the receiving EES sends Announce common EAS response to the announcing EES indicating a successful status; otherwise, the receiving EES shall indicate a failure status and include appropriate reasons. The response message contains the group connection information to indicate the whether the UE connect to the common EAS or not.