Question: In the context of E-UTRAN, which direction(s) is/are applicable for the transmission of the EN-DC X2 SETUP REQUEST message between nodes capable of interacting for EN-DC (EUTRA-NR Dual Connectivity)?
Option 1: eNB to en-gNB only
Option 2: Both eNB to en-gNB and en-gNB to eNB
Option 3: en-gNB to eNB only
Option 4: Neither eNB to en-gNB nor en-gNB to eNB
Explanation: The correct answer is Option 2 because the EN-DC X2 SETUP REQUEST message can be sent in both directions (eNB to en-gNB and en-gNB to eNB) between nodes capable of interacting for EUTRA-NR Dual Connectivity, facilitating initialization of a TNL association in either scenario, supporting flexible network architecture configurations for efficient dual connectivity setups.