What is a difference between FlexVPN and DMVPN?

FlexVPN and DMVPN are both Cisco technologies that use point-to-point GRE tunnels to create dynamic VPN networks. However, they differ in some aspects, such as:

FlexVPN is a newer solution that requires newer hardware and IOS versions, while DMVPN is more widely supported on older devices1.

FlexVPN is based on IKEv2, which is a more robust and efficient protocol than IKEv1, which is used by DMVPN (although DMVPN can also use IKEv2)2.

FlexVPN uses static or virtual access interfaces for GRE tunnels, while DMVPN uses a single multipoint GRE interface. This allows more flexibility and visibility for FlexVPN tunnels2.

FlexVPN does not require NHRP registration for spokes to communicate with the hub, while DMVPN does. This simplifies the configuration and reduces the overhead of NHRP3.

FlexVPN has only one standard mode of operation, while DMVPN has three phases with different characteristics and configurations2.

References := 1: what is the difference between dmvpn and flexvpn 2: Cisco FlexVPN DMVPN, Part 1 - Overview and Design 3: DMVPN to FlexVPN Soft Migration Configuration Example