Which protocol is used in a DMVPN network to map logical IP address to physical IP addresses?

Which protocol is used in a DMVPN network to map logical IP address to physical IP addresses?
A . BGP
B . LLDP
C . EIGRP
D . NHRP

Answer: D

Explanation:

Next Hop Resolution Protocol (NHRP), defined in RFC 2332, is a Layer 2 address resolution protocol and cache, like Address Resolution Protocol (ARP). NHRP is used by a branch router connected to an on-broadcast, multi-access (NBMA) sub-network to determine the IP address of the ”NBMA next hop”; in this case, the headend router or the destination IP address of another branch router.

NHRP is used to map tunnel IP addresses to ”physical or ”real” IP addresses, used by endpoint routers. It resolves private addresses (those behind mGRE and optionally IPSEC) to a public address. NHRP is layer 2 resolution protocol and cache, much like Address Resolution Protocol (ARP) or Reverse ARP (Frame Relay).