Your customer needs to communicate between four remote sites using Ethernet and would like to maintain IP reachability between devices using a single /24 network. The customer will need to use ARP from one site to another.
Which solution will meet these requirements?
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A. B. C. D.C
VPLS is an Ethernet-based point-to-multipoint L2VPN where all locations can be part of the same /24 network.
The customer wants to communicate between four remote sites using Ethernet and maintain IP reachability between devices using a single /24 network. ARP is also required for communication between sites.
A Layer 2 VPN (Answer A) would provide connectivity at the Data Link layer (Layer 2) and encapsulate the Ethernet frames between sites using a virtual private network ( VPN). However, this solution would not maintain IP reachability between devices, as IP is a Network layer (Layer 3) protocol.
A Layer 2 circuit (Answer B) is a dedicated point-to-point link between two sites, typically provided by a service provider. It can be used to extend a VLAN across sites, but it would not provide connectivity between more than two sites.
A virtual private LAN service (VPLS) (Answer C) is a Layer 2 service that emulates a LAN over a service provider's network. It allows for a single broadcast domain across multiple sites and maintains MAC address learning across sites. However, VPLS does not provide IP routing, so it would not maintain IP reachability between devices.
A Layer 3 VPN as defined in RFC 4364 (Answer D) provides connectivity at the Network layer (Layer 3) and allows for routing between sites. It can maintain IP reachability between devices, even if they are on different subnets, and allows for ARP to be resolved between sites. This solution would meet the customer's requirements.
Therefore, the correct answer is D, a Layer 3 VPN as defined in RFC 4364.