Refresher

The initial UAC, the side that sends the INVITE, can set itself to be the refresher (uac) or the Oracle® Enterprise Session Border Controller as the refresher (uas). Whoever is the refresher is indicated in the 200 OK. If the UAC does not specify any refresher, the Oracle® Enterprise Session Border Controller uses it’s response-refresher value in the 200 OK. If that value is set to uas, the Oracle® Enterprise Session Border Controller creates and sends a re-INVITE toward the UAC with previously negotiated session expiration values.

Once the Oracle® Enterprise Session Border Controller becomes the refresher, it does not relinquish that role. Then, when the Oracle® Enterprise Session Border Controller sends refresh requests, it does not change any parameters (refresher role & timers) from the initial request negotiation.