Which configuration correctly sets interface ge-0/0/4 in trunk mode, carrying VLANs v10 and v20?

• A. A. ge-0/0/4 { unit 0 { family ethernet-switching { vlan { members [ v10 v20 ]; } } } }
• B. B. ge-0/0/4 { unit 0 { family ethernet-switching { port-mode trunk; vlan { members [ v10 v20 ]; } } } }
• C. C. ge-0/0/4 { vlan-tagging; unit 0 { family ethernet-switching { port-mode trunk; vlan { members [ v10 v20 ]; } } } }
• D. D. ge-0/0/4 { unit 10 { family ethernet-switching; } unit 20 { family ethernet-switching; } }

Answer: (B)

The correct configuration for setting interface ge-0/0/4 in trunk mode while allowing it to carry VLANs v10 and v20 involves specifying the port mode as 'trunk' along with the VLAN membership settings.

In this context, stating the port mode as 'trunk' is essential because, in trunk mode, the interface can carry traffic for multiple VLANs. By setting the port mode to 'trunk' and then specifying the VLAN members, this configuration ensures that both VLANs v10 and v20 can traverse the trunk link without any issues. The structure of the command clearly organizes the port mode and VLAN memberships within the appropriate syntax for the Ethernet switching family, making it functional and easy to interpret.

The elements in other configurations might lack specific requirements or misplace elements. For instance, not declaring the port mode explicitly as 'trunk' or not utilizing the correct unit configuration would not allow proper trunking functionality. This precise arrangement in configuration B meets all requirements for the desired functionality.