Question: What is the primary purpose of the RRC Establishment Cause Information Element (IE) in the S1 Application Protocol (S1AP)?
Option 1: To notify the eNodeB about the UE's current location for paging purposes.
Option 2: To inform the MME about the UE's preferred network slice for service.
Option 3: To indicate to the MME the reason for RRC Connection Establishment or Resume as received from the User Equipment (UE).
Option 4: To request resource allocation from the eNodeB for an incoming call.
Explanation: The correct answer highlights the key function of the RRC Establishment Cause IE, conveying to the Mobility Management Entity (MME) the reason behind the User Equipment's (UE) establishment or resumption of an RRC connection. This information is crucial for network management and decision-making processes, such as authentication, authorization, and resource allocation, based on the context of the connection request.