mGRE vs DMVPN (2024)

FAQs

What is the difference between mGRE and DMVPN? ›

DMVPN is a “routing technique” that relies on multipoint GRE and NHRP and IPsec is not mandatory. However since you probably use DMVPN with the Internet as the underlay network, it might be wise to encrypt your tunnels. In this lesson I'll show you how to configure IPsec to encrypt your multipoint GRE tunnels.

DVPN is still used in many networks. It requires the network administrator to understand and configure IPsec and dynamic routing protocol such as EIGRP.

Overall, MGRE enhances the functionality of DMVPN by providing scalability, traffic optimization, dynamic routing, IP multicast support, and tunnel protection. It simplifies network management, improves performance, and ensures secure communication between the hub and spokes in a DMVPN deployment.

Regular GRE tunnels are configured in a point-to-point arrangement, where each tunnel has two endpoints. Multipoint GRE or mGRE as the name implies allows us to have multiple endpoints, resulting in a point to multipoint topology.

A DMVPN allows organizations to build a VPN network with multiple sites, without the need to configure devices statically. VPNs connect each remote site to the company headquarters.

DMVPN supports Spoke-to-Spoke encrypted tunnels over the Internet which is less stable than carrier network. MPLS VPNs are typically in service provider networks and large campus networks where voice and video reliability is also key requirement.

DMVPN combines Generic Routing Encapsulation (GRE) tunnels, IPsec encryption, and Next Hop Resolution Protocol (NHRP). It provides IP routing for remote sites, while minimizing the overhead on the network devices.

DMVPN is an old ¹ Cisco-proprietary technology that combines NHRP, IPsec, IKEv2 and multipoint GRE tunnels to build dynamically-provisioned multi-access VPNs.

Understanding DMVPN

While a VPN acts as a connector between remote sites and HQ, or between different branches, the DMVPN creates a mesh VPN protocol that can be applied selectively to connections being utilized in the business already. Each different site (or spoke) can connect to one another securely.

The Graduate Record Examination, or GRE, is an important step in the graduate school or business school application process. The GRE is a multiple-choice, computer-based, standardized exam that is often required for admission to graduate programs and graduate business programs (MBA) globally.

What is the difference between mGRE and MPLS? ›

mGRE is a similar protocol with a single endpoint at one side of the tunnel connected to multiple endpoints at the other side of the tunnel. MPLS is a widely deployed VPN internet architecture. MPLS requires that all core routers in the network support MPLS.

GRE tunnels are essential for routing data efficiently and securely over multicast-enabled networks, particularly in Cisco technologies. Multipoint Generic Routing Encapsulation is a protocol used for creating Virtual Private Networks (VPNs) over a multicast-enabled network, particularly for Cisco technologies.

DMVPN requires more manual configuration and troubleshooting, but it also offers more granular control and flexibility. On the other hand, SD-WAN is simpler and more automated, and it can optimize WAN performance with multiple links and intelligent path selection.

Next Hop Resolution Protocol (NHRP) is a resolution protocol that allows a Next Hop Client (NHC) to dynamically register with Next Hop Servers (NHSs). With the Dynamic Multipoint Virtual Private Network (DMVPN) design, the NHC is the spoke router, and the NHS is the hub router.

Auto-discovery VPN (ADVPN) reminds me of Cisco's DMVPN except that ADVPN is a combo of Ike+IPSec while DMVPN is mGRE+IPSec but the behaviour is the same. Your enjoy the simplicity of setting up a hub and spoke topology, with the efficiency of a full mesh without its overhead.