An emergency-management office wants scalable spoke routing on DMVPN without flooding IGP queries across every site. Why is BGP often chosen as the overlay routing protocol?
Select an answer to reveal the explanation.
Short Explanation
IGPs love to chat; hundreds of emergency spokes make that chat expensive. BGP keeps the overlay address book scalable — advertise what you mean to advertise — without EIGRP query storms. NHRP still handles the tunnel mappings; BGP does not replace it.
Full Explanation
BGP is frequently preferred on large DMVPN overlays because it scales prefix distribution with policy controls and does not exhibit IGP query or full-topology flood characteristics across many spokes. NHRP remains responsible for address resolution and shortcuts; BGP does not replace NHRP. Phase 3 is compatible with BGP overlays, and RDs are an MPLS VPN construct, not a DMVPN BGP requirement. Emergency-management WANs benefit from that scalable overlay routing choice.