A network engineer needs to select a VPN type that provides the most stringent security, multiple security associations for the connections, and efficient VPN establishment with the least bandwidth consumption. Why should the engineer select either FlexVPN or DMVPN for this environment?
FlexVPN should be selected because it supports IKEv2, which provides enhanced security features, including multiple Security Associations (SAs) for better connection management. This is crucial for meeting the requirements of stringent security and efficient VPN establishment. DMVPN primarily uses IKEv1 but can also support IKEv2, contrary to what some might believe. However, FlexVPN is specifically designed to leverage the benefits of IKEv2, making it a more appropriate choice for environments where multiple SAs and stringent security are necessary.
IKEv2 Multi-SA The IKEv2 Multi-SA feature allows an IKEv2 Dynamic Virtual Tunnel Interface (DVTI) session on the IKEv2 responder to support multiple IPsec Security Associations (SA). The maximum number of IPsec SAs per DVTI session is either obtained from AAA authorization or configured on the IPsec profile. The value from AAA has a higher priority. Any change to the max-flow-limit argument in the IPsec profile is not applied to the current session but is applied to subsequent sessions. The IKEv2 Multi-SA feature makes the configuration of the IKEv2 profile in the IPsec profile optional. This optional configuration allows IPsec DVTI sessions using the same virtual template to have different IKEv2 profiles, thus saving the number of virtual template configurations. Note The IKEv2 Multi-SA feature allows multiple IPsec SAs that have non-any-any proxies. However, when the IPsec SA proxies are any-any, a single IPsec SA is allowed. For more information, see the “Multi-SA Support for Dynamic Virtual Tunnel Interfaces for IKEv2” module in the Security for VPNs with IPsec Configuration Guide.
DMVPN can be configured with IKEv2, so answer is not C. I wasn't able to find Cisco documentation to back this up, but found this configuration example: https://journey2theccie.wordpress.com/2020/03/13/ikev1-ikev2-configuration-in-dmvpn/
What is the difference between FlexVPN and DMVPN? IPSec: One key difference between FlexVPN and default Dynamic Multipoint VPN (DMVPN) is the protocol used for negotiating IPsec Security Associations (SAs). While DMVPN defaults to using Internet Key Exchange version 1 (IKEv1), FlexVPN utilizes IKEv2.
ANswer is C
But DMVPN definitely support IKEv2, and Answer C says "...DMVPN does not". Therefore answer is likely D.
The answer is C
Really like the comment on following link for this discussion, per say- it looks like Answer is C https://community.cisco.com/t5/network-security/what-is-the-difference-between-dmvpn-and-flexvpn/td-p/3438913