A pharmaceutical company needs a hub-and-spoke VPN topology.

In the context of theDesigning Cisco Security Infrastructure (300-745 SDSI)blueprint,Dynamic Multipoint VPN (DMVPN)is the specialized architectural solution designed for scalable hub-and-spoke topologies that require the flexibility to evolve into partial or full mesh overlays. DMVPN leverages a combination of Multipoint GRE (mGRE) tunnels, Next Hop Resolution Protocol (NHRP), and IPsec encryption to create a dynamic environment.

The primary advantage of DMVPN is its ability to establish "on-demand" tunnels between spoke sites. In a traditional hub-and-spoke model, traffic between two spokes must transit the hub, which introduces latency and increases hub resource consumption. With DMVPN, spokes can use NHRP to discover the public IP addresses of other spokes and build direct tunnels between them automatically. This allows the pharmaceutical company to maintain a simple hub-and-spoke management model while benefiting from the performance of afull meshwhen traffic patterns demand it.

WhileSSL VPNs(Option D) andL2TP(Option B) are excellent for individual remote access, they are not designed for site-to-site mesh scalability.Crypto maps(Option C) represent the legacy method of building IPsec tunnels, which requires static, manual configuration of every peer relationship—making a full mesh practically impossible to manage at scale. DMVPN fulfills the Cisco SDSI objective of designing highly available and flexible secure infrastructure by automating the complexity of large-scale tunnel management.