Section: 10.5.4.35 Network-initiated Service Upgrade indicator
Content: The purpose of the Network-initiated Service Upgrade indicator information element is to indicate to the mobile station that the in-call modification procedure is due to a network-initiated upgrade from speech to UDI/RDI multimedia (see 3GPP TS 23.172[ Technical realization of Circuit Switched (CS) multimedia service UDI/RDI fallback and service modification; Stage 2 ]  [97]). The Network- initiated Service Upgrade indicator information element is coded as shown in figure 10.5.118f/3GPP TS 24.008[ Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ] . The Network-initiated Service Upgrade indicator is a type 2 information element with a length of 1 octet. Figure 10.5.118f/3GPP TS 24.008[ Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ]  Network-initiated Service Upgrade indicator information element