What are the three phases of DMVPN?

In its simplest form, DMVPN is a point-to-multipoint Layer 3 overlay VPN enabling logical hub and spoke topology supporting direct spoke-to-spoke communications depending on DMVPN design ( Phase 1, Phase 2 and Phase 3 ) selection.

What is the difference between DMVPN Phase 1 and 2 and 3?

The primary difference between DMVPN Phase I and DMVPN Phase II is that, in DMVPN Phase II, spoke routers are able to create dynamic tunnels with other spoke routers, whereas in DMVPN Phase I, they are not.

What are the steps to configure the DMVPN?

Four Steps to Fully Configure Cisco DMVPN

  1. Configure the DMVPN Hub.
  2. Configure the DMVPN Spoke(s)
  3. Protect the mGRE tunnels with IPSecurity (optional)
  4. Configure Routing Between DMVPN mGRE Tunnels (static routing or routing protocol)

What is DMVPN and how does it work?

A dynamic multipoint virtual private network (DMVPN) is a secure network that exchanges data between sites/routers without passing traffic through an organization’s virtual private network (VPN) server or router, located at its headquarters.

What is the difference between Dmvpn Phase 2 and 3?

In Phase 2: The traffic goes through the hub until an IPsec tunnel has been formed between the two communicating spokes. In Phase 3: The traffic goes through the hub until the spoke gets an NHRP resolution and the CEF next-hop is overwritten/changed.

What is Nhrp in Dmvpn?

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.

What is the difference between Dmvpn Phase 2 and Phase 3?

What is Nbma address in Dmvpn?

Since mGRE is treated by NHRP as NMBA medium, logical IP corresponds to the IP address “inside” a tunnel (“inner”) and the NBMA IP address corresponds to the “outer” IP address (the IP address used to source a tunnel).

What is the difference between DMVPN Phase 2 and 3?

Why do we need a DMVPN?

DMVPN is a combination of features that help reduce some of the complexities of communications between a central location and multiple branch locations. It uses multipoint GRE (mGRE) and Next-Hop Resolution Protocol (NHRP) to help create a hub and spoke. Security may or may not be involved.

What is NBMA in DMVPN?

The NBMA layer maps to “physical” underlying network while mGRE VPN is the “logical” network (tunnel internal IP addressing). In this case, mGRE uses NHRP for mapping “logical” or “tunnel inside” IP addresses to “physical” or real IP addresses.