Spanning Tree Protocol (STP) remains a critical Layer 2 defense mechanism, even in the age of advanced network fabrics. The STP Root Guard feature is an indispensable tool for preventing rogue switches from becoming the root bridge, thus maintaining network…
While much of the networking world has shifted towards automation and API-driven recovery, there are still situations where understanding fundamental device recovery procedures is critical. This guide, originally published in 2011 and updated in 2021, focuses on the console-based recovery…
As a network engineer, I’ve broken configs enough times to know the value of a solid rollback strategy. One of the most powerful, yet sometimes underutilized, commands in the Cisco IOS and IOS-XE toolkit is configure replace. While it might…
The backbone of inter-Autonomous System (AS) communication on the internet relies heavily on External Border Gateway Protocol (eBGP). As networks evolve, so do the best practices and methods for configuring, securing, and automating eBGP peering. This updated guide dives into…
Ah, 802.1X authentication – a true veteran in network security, often affectionately (or sometimes exasperatedly) known as Dot1x. I remember configuring my first Dot1x setup way back in the day, and it felt like unlocking a new level of control…
When I first wrote about QinQ tunneling (or IEEE 802.1ad, formally known as Provider Bridging) back in 2011, it was an absolutely foundational technology for service providers. Fast forward to today, and while the network landscape has evolved dramatically with…
As a senior network engineer, I’ve witnessed firsthand the dramatic evolution of network technologies. While innovations like SD-WAN and cloud networking are now standard, fundamental concepts like MPLS remain vital, especially in service provider and large enterprise networks. Understanding MPLS…
OSPF /32 Issue in MPLS VPN Scenario: A Modern Troubleshooting and Automation Perspective =========================== Recently, while collaborating with a colleague on an MPLS Layer 3 VPN deployment, we encountered a deceptively simple issue that caused considerable head-scratching. It turned out…
As a network engineer, I often find myself fine-tuning routing protocols to optimize traffic flow and ensure network resilience. One of the fundamental ways we influence Open Shortest Path First (OSPF) behavior is through cost manipulation. While the core principles…
Hi guys! I’m back, and as always, it’s great to connect. Life, as a network engineer, often pulls us into deep dives and complex projects, but I always make it a point to share what I learn. Today, we’re revisiting…