Which two Layer 2 VPN methods support interworking between customer sites with different Layer 2 encapsulation at each end (for example, Frame Relay to Ethernet interworking)? (Choose two.)

Question

Options

• AAToM
• BVPLS
• CGET VPN
• DL2TPv3

• A
  89% (57)
• B
  8% (5)
• C
  3% (2)

Explanation

AToM (Any Transport over MPLS) and L2TPv3 both support Layer 2 interworking - the ability to connect sites using different L2 encapsulations (e.g., Frame Relay on one end, Ethernet on the other). AToM accomplishes this over MPLS by translating between encapsulation types using interworking pseudowires, while L2TPv3 does the same over native IP networks, making both flexible for mixed-encapsulation environments.

VPLS (B) is wrong because it only supports Ethernet-to-Ethernet connections across all sites - it's a multipoint Ethernet service with no interworking capability for other L2 types like Frame Relay or ATM.

GET VPN (C) is wrong because it's not a Layer 2 technology at all - it's a Layer 3 group encryption solution designed for MPLS networks to encrypt traffic without changing IP addressing, so it has nothing to do with L2 encapsulation bridging.

Memory tip: Think "AToM and L2TPv3 = ALternate Layer 2" - both support alternating (mismatched) L2 types at each end. If you see "interworking" or "different encapsulation" in a question, those two are your picks. VPLS only speaks Ethernet; GET VPN doesn't speak Layer 2 at all.

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