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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Initially, explainedd that is the key word all spoke to spoke packets are switched across the hub.
The HQ for example has one tunnel with each branch office as its destination. In phase 2, all spoke routers use multipoint GRE tunnels so we do have direct spoke to spoke tunneling. Furthermore, spoke-to-spoke traffic no longer needs to pass through the hub router but is sent directly from one spoke to another.
The request gets forwarded from HUB to Spoke3. Right now we have a hub and spoke topology. Continue reading in our forum.
Introduction to DMVPN |
Join us on Youtube! Send this to a friend Your email Recipient email Send Cancel. It is important to note that mGRE interfaces do not have a tunnel destination. It should look for a better way using NHRP resolution.
Articles To Read Next: Web Vulnerability Scanner Free Download. The hub router will dynamically accept spoke routers.
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Understanding Cisco DMVPN
Looking at the process in more detail, when using Phase 3. When would we explaimed to use Phase 1, 2, or 3, and why? Forum Replies Rene, When would we choose to use Phase 1, 2, or 3, and why?
All spokes connect directly to the hub using a tunnel interface.
Above we have two spoke routers NHRP clients which establish a tunnel to the hub router. In our diagram below, this is network If you like to keep on reading, Become a Member Now!
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Understanding Cisco Dynamic Multipoint VPN – DMVPN, mGRE, NHRP
This means that there will be no direct spoke-to-spoke communication, all traffic has to go through the hub! Spoke routers only need a summary or default route to the hub to reach other spoke routers. Email Updates Enter your email address to receive notifications of new posts. When there is traffic between the branch offices, we can tunnel it directly instead of sending it through the HQ router.
It needs to figure out the destination public IP address of spoke2 so it will send a NHRP resolution requestasking the Hub router what the public IP address of spoke 2 is. This is great, we only required the hub to figure out what the public IP address is and all traffic can be sent from spoke to spoke directly.
At this point, the spokes can now modify their routing table entries to reflect the NHRP shortcut explaied and use it to reach the remote spoke. The hub is the only router that is using a multipoint GRE interface, all spokes will be using regular point-to-point GRE tunnel interfaces. Because all spoke-to-spoke traffic in DMVPN Phase1 always traverses the hub, it is actually inefficient to even send the entire routing table from the hub to the spokes.
I understand the differences between the three, but do we gain any benefit from implementing one or exxplained other that is noticeable to end users? Hello Lagapides Thank you so much for your time. Share on Twitter Tweet. Join us on Facebbook! The flexibility, stability and easy setup it provides are second-to-none, making it pretty much the best VPN solution available these days for any type of network.
With mGRE, all spokes are configured with only one tunnel interface, no matter how many explajned they can connect to. Because explianed tunnels do not have a tunnel destination defined, they cannot be used alone. Since our traffic has to go through the hub, our routing configuration will be quite simple.