Question: What is the primary requirement for securing PMIP (Proxy Mobile IP) messages between the Mobility Access Gateway (MAG) and the Local Mobility Anchor (LMA)?
Option 1: Only confidentiality protection using end-to-end encryption
Option 2: Integrity protection with optional confidentiality protection through security associations
Option 3: Mandatory strong access authentication without IP layer security measures
Option 4: Either a chain of hop-by-hop security associations or one end-to-end security association per direction for all PMIP messages, with required integrity and optional confidentiality protection
Explanation: This option correctly reflects the requirements outlined for securing PMIP messages. It highlights the flexibility in implementing security (either hop-by-hop or end-to-end) while emphasizing the necessity of integrity protection and the optionality of confidentiality protection, aligning with the principles of Network Domain Security (NDS) for IP network layer security in telecom networks.