Question: In an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), how does a Master eNodeB (MeNB) select a Secondary Cell Group (SCG) for Dual Connectivity (DC) when considering roaming and access restrictions?
Option 1: Based on the roaming and access restriction information received from the Mobility Management Entity (MME) via S1 signalling, selecting the serving PLMN ID of the SCG.
Option 2: Randomly selecting an available SCG without considering roaming and access restrictions.
Option 3: Using default settings predefined in the MeNB's configuration for all UEs.
Option 4: Always prioritizing the SCG with the strongest signal strength regardless of roaming and access restrictions.
Explanation: The correct answer is Option 1 because, according to E-UTRAN protocols, the MeNB's selection of an SCG for DC indeed relies on the up-to-date roaming and access restriction information provided by the MME. This ensures that the network respects the subscriber's roaming agreements and access permissions when configuring dual connectivity.