Question: Which of the following statements is accurate regarding the X1 interface in the context of lawful interception architecture as per 3GPP security standards?
Option 1: The X1 interface is solely used for terminating interception and only exists between the ADMF and points of interception.
Option 2: Multiple X1 interfaces (X1_1, X1_2, X1_3) are defined, all of which must support ETSI TS 103 221-1 for message transport, with specific configurations overridden by default settings from the present document.
Option 3: The X1 interface is used exclusively for activating interception and only involves communication between the MF/DF2 and points of interception.
Option 4: There is a single X1 interface defined for all communications related to lawful interception, without any specified transport protocol requirements.
Explanation: This option correctly identifies that there are multiple X1 interfaces (X1_1, X1_2, X1_3) each serving different purposes within the lawful interception architecture. It also accurately notes the requirement for these interfaces to support ETSI TS 103 221-1 for transporting messages, while highlighting that default configurations from the present document take precedence over generic defaults from TS 103 221-1. This demonstrates a nuanced understanding of the X1 interface's role in managing lawful interception as outlined in 3GPP security standards.