300-420 Question 188
Single answerAn enterprise network design includes a Layer 2 VPN solution to interconnect two remote data centers over a service provider MPLS network. The solution must ensure that VLAN tags are preserved across the network and provide support for Ethernet-based multicast traffic. Which Layer 2 VPN technology would best meet these requirements?
- A
Virtual Private LAN Service (VPLS)
- B
Ethernet over MPLS (EoMPLS)
- C
Point-to-Point Protocol (PPP)
- D
Generic Routing Encapsulation (GRE)
Show answer and explanation
Correct answer: A
Explanation
VPLS is the most appropriate technology for this scenario because it extends Ethernet LANs over MPLS, preserves VLAN tags, and supports Ethernet-based multicast traffic. EoMPLS, while useful for point-to-point connections, lacks the full LAN emulation capability needed. PPP and GRE are not suitable for this type of Layer 2 VPN design.
- A. Correct.
Virtual Private LAN Service (VPLS) is the correct choice because it enables the extension of Ethernet LANs over an MPLS network, supports VLAN tag preservation, and allows multicast traffic to function correctly across the Layer 2 VPN.
- B. Incorrect.
Ethernet over MPLS (EoMPLS) provides a point-to-point Layer 2 VPN service but does not inherently support multicast traffic or emulate a full LAN environment like VPLS does.
- C. Incorrect.
Point-to-Point Protocol (PPP) is a Layer 2 protocol for connecting two devices but is not suitable for extending Ethernet LANs or preserving VLAN tags in a Layer 2 VPN.
- D. Incorrect.
Generic Routing Encapsulation (GRE) is a tunneling protocol primarily used for IP traffic and is not designed to preserve VLAN tags or support Ethernet-based multicast traffic in a Layer 2 VPN.