![Ticket#9 - WAN Flap Detection: DMVPN Phase 2 Tunnel Up/Down Issue Fixed [CCNP Enterprise]](https://networkjourney.com/wp-content/uploads/2025/07/nj-blog-post-Ticket-9.jpg)
Problem Summary The enterprise monitoring tool detected flapping tunnels between remote branch routers and the HQ hub.Ticket Priority: HighIssue: DMVPN Phase 2 Tunnel intermittently goes UP/DOWN, causing loss of reachability to HQ and apps like VoIP. Symptoms Observed Symptom Description Tunnel state flapping Tunnel interface […]
![Dual Stack vs Tunneling: Which IPv6 Transition Strategy is Right for You? [CCNP ENTERPRISE]](https://networkjourney.com/wp-content/uploads/2025/07/nj-blog-post-Dualstack.jpg)
If you’re reading this, you’re probably at that point in your IPv6 learning journey where the real challenge isn’t IPv6 itself—it’s the transition from IPv4. The world isn’t flipping a switch overnight. Most networks still run IPv4, and we need mechanisms to make IPv6 work […]
![Hub-and-Spoke in Modern WANs: Still Relevant in 2025?[ccnp enterprise]](https://networkjourney.com/wp-content/uploads/2025/06/Slide1.jpg)
Today we’re going back to one of the core building blocks of WAN design — the Hub-and-Spoke topology. Even in today’s era of SD-WAN and cloud-first networks, the hub-and-spoke model remains relevant, especially for centralized security, legacy MPLS, and hybrid branch setups. Whether you’re starting […]
![How Can GRE Tunnel Help Connect Remote Sites? Full Cisco Setup Guide [CCNP Enterprise]](https://networkjourney.com/wp-content/uploads/2025/06/How-Can-GRE-Tunnel-Help-Connect-Remote-Sites_networkjourney.png)
I’m bringing you one of the most essential yet often misunderstood technologies in networking — GRE Tunnels. I’ve seen students struggle to understand why or how GRE is used, and I completely understand! When I first came across GRE, I kept wondering how traffic magically […]
