Question: In a 3GPP-compliant network, where are encryption functions, specifically like those utilizing the allocated function f8, typically applied within the protocol stack for User Equipment (UE) and Radio Network Controller (RNC) communications?
Option 1: Transport Layer (Layer 4) of the UE and RNC, to secure end-to-end data transfer.
Option 2: Network Layer (Layer 3), ensuring routing information is encrypted between UE and RNC.
Option 3: Physical Layer (Layer 1), encrypting raw bit transmission for maximum security.
Option 4: Data Link Layer (Layer 2), specifically within the Medium Access Control (MAC) sublayer and Radio Link Control (RLC) sublayer.
Explanation: This is correct because, according to the provided context, encryption utilizing function f8 is applied in both the MAC and RLC sublayers. These sublayers are part of the Data Link Layer (Layer 2) of the OSI model, which is responsible for framing, error detection/correction, and flow control. Applying encryption at this layer ensures secure data transfer over the radio interface between the UE and the RNC, protecting against unauthorized access while maintaining network efficiency.