All Routing and switching related topics will come under this category.
⚠️ Legacy Technology Notice: This article covers legacy Cisco transparent bridging with IRB using deprecated bridge-group commands from classic IOS. These commands do not work on modern IOS-XE or IOS-XR platforms. This content is preserved for historical reference and exam…
In the dynamic world of network engineering, troubleshooting is a timeless skill. While protocols evolve and tools advance, the fundamental principles of packet analysis remain critical. This post, originally penned in 2011, explored a classic, albeit niche, trick to discover…
Today, we revisit a foundational Cisco feature: Optimized Edge Routing (OER), more commonly known now as Performance Routing (PfR). In 2011, we explored how this “brain” could monitor network paths and intelligently route traffic based on real-time metrics like jitter,…
Today we delve into the foundational architecture of MSDP with BGP IPv4 Multicast address-family. While initially published in 2011, the core principles of inter-Autonomous System (AS) multicast routing remain critical for understanding modern network designs. This updated post revisits the…
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…
A modern, multi‑vendor look at QinQ (802.1ad): correct TPIDs, MTU sizing, L2 protocol handling, and automated deployment at scale.