300-420 Question 156
Single answerA large enterprise wants to connect multiple branch offices to its data center over a Layer 2 VPN service provided by a service provider. The design must ensure that the branches appear to be on the same LAN segment and support broadcast, multicast, and unicast traffic across the VPN. Which Layer 2 VPN technology should the enterprise use to achieve this?
- A
Virtual Private LAN Service (VPLS)
- B
Point-to-Point Protocol (PPP)
- C
Generic Routing Encapsulation (GRE)
- D
MPLS Layer 3 VPN
Show answer and explanation
Correct answer: A
Explanation
Virtual Private LAN Service (VPLS) is the correct technology as it provides a Layer 2 VPN solution that allows multiple sites to communicate as if they are on the same Ethernet LAN. Unlike point-to-point technologies or Layer 3 VPNs, VPLS enables broadcast, multicast, and unicast traffic across the VPN, meeting the enterprise's requirements.
- A. Correct.
Virtual Private LAN Service (VPLS) allows multiple sites to be connected over a wide area network and appear as if they are on the same Ethernet LAN. It supports Layer 2 broadcast, multicast, and unicast traffic.
- B. Incorrect.
Point-to-Point Protocol (PPP) is a Layer 2 technology designed for point-to-point links. It does not support multi-site connectivity or Layer 2 broadcast and multicast traffic.
- C. Incorrect.
Generic Routing Encapsulation (GRE) is a tunneling protocol that encapsulates Layer 3 packets for transport across an IP network. It does not function as a Layer 2 VPN solution.
- D. Incorrect.
MPLS Layer 3 VPN provides Layer 3 connectivity between sites by routing IP traffic. It does not maintain the Layer 2 attributes needed for broadcast and multicast traffic.