Question: In UTRAN Iu interface RANAP signalling, what does the Source ID Information Element (IE) primarily identify in the context of SRNS relocation?
Option 1: The target cell for handover in a UMTS-GSM relocation scenario.
Option 2: The type of relocation procedure (e.g., UMTS-UMTS, UMTS-LTE, UMTS-GSM).
Option 3: The source of the relocation, which could be a specific RNC-ID or Serving Area Identity (SAI) depending on the relocation type.
Option 4: The reason for initiating the SRNS relocation procedure.
Explanation: The Source ID IE identifies the source of the SRNS relocation, which can vary in format (e.g., RNC-ID for UMTS-UMTS or UMTS-LTE relocations, and SAI for UMTS-GSM relocations), crucial for managing handover between different network technologies or cell types.