A company uses a Metro Ethernet WAN with an Ethernet LAN service. Also the company headquarters plus 20 remote sites connected to the service. The enterprise uses OSPF at all sites, with one router connected from each site. Which of the following are true about the Layer 3 details most likely used with this service and design?
(Choose all that apply)

(A) The WAN uses one IP subnet
(B) The WAN uses 20 or more IP subnets
(C) A remote site router would have one OSPF neighbor
(D) A remote site router would have 20 OSPF neighbors

A and D are the correct answers.

An ELAN service is one in which the Metro Ethernet service acts as if the WAN were a single Ethernet switch so that each device can communicate directly to every other device. As a result, the routers sit in the same subnet. With one headquarters router and 20 remote sites, each router will have 20 OSPF neighbors.