Introduction. In this blog, I aim to go a little deeper into how the different DMVPN phases work and how to properly configure the routing. DMVPN Explained. DMVPN stands for Dynamic Multipoint VPN and it is an effective solution for dynamic secure overlay networks. In short. Learn what DMVPN is, mechanisms used (NHRP, mGRE, IPSec) to achieve of the audience’s potential knowledge levels and explained it in terms that don’t.
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Understanding Cisco Dynamic Multipoint VPN – DMVPN, mGRE, NHRP
The request gets forwarded from HUB to Spoke3. If you like to keep on reading, Become a Member Now! At this point, the spokes can now modify their routing table entries to reflect the NHRP shortcut route and use it to reach the remote spoke. Spoke routers only need a summary or default route to the hub to reach other spoke routers.
All spokes connect directly to the hub using a tunnel interface. Forum Replies Rene, When would we choose to use Phase 1, 2, or 3, and why? All tunnel interfaces are part of the same network.
Understanding Cisco DMVPN
Right now we have a hub and spoke topology. Unified Communications Components – Understanding Your The following requirements have been calculated for a traditional VPN network of a company with a central hub and 30 remote offices.
In seven years several things have explaindd Deal with bandwidth spikes Free Download. If you continue to use this site we will assume that you are happy with it. Lastly, traffic between spokes in a point-to-point GRE VPN network must pass through the hub, wasting valuable bandwidth and introducing unnecessary bottlenecks. Above we explakned two spoke routers NHRP clients which establish a tunnel to the hub router.
In addition, the hub router has three GRE tunnels configured, one for each spoke, making the overall configuration more complicated. In phase 2, all spoke routers use multipoint GRE tunnels so we do have direct spoke to spoke tunneling.
Share on Digg Share. I understand the differences between the three, but do we gain any benefit from implementing one or the other that is noticeable to end users? The hub router is configured with three separate tunnel interfaces, one for each spoke:.
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So when a hub receives an IP packet inbound on its interface and switches it out of the same interface, it sends a special NHRP redirect message to the source indicating that this is a suboptimal path. When we use them, our picture could look like this:. In our diagram below, this is network Each router is connected to the Internet and has a public IP address:. Mdvpn there is traffic between the branch offices, we can tunnel it directly instead of sending it through the HQ router.
This means that there will be no direct spoke-to-spoke communication, all traffic has to go through the hub! Because mGRE tunnels do not have a tunnel destination defined, they cannot be used alone.