RIPv2’s automatic network summarization feature is easy to misunderstand, which can be a recipe for disaster in a production environment or on the CCIE R&S lab exam. Let’s analyze the exact beh...
Deep Dive - IEEE 802.1D Spanning Tree Topology Change
While reviewing the IEEE 802.1D Spanning Tree Protocol Topology Change Notification mechanism, I felt some confusion as to the exact behavior that each bridge exhibits when a topology change occurs...
Quick Mystery - Spanning Tree Priority
One aspect of Spanning Tree Protocol I became curious about during my CCIE studies was the exact behavior behind how Spanning Tree bridge priorities are modified using the spanning-tree vlan {vlan-...
Bringing The Gap - Frame Relay
When the ICND1, ICND2, and CCNA R&S composite exams were updated to their latest versions on August 20th, 2016, Frame Relay technology was removed from the exam topics. However, network enginee...
Basics of IOS XR Software
This article highlights the basics of IOS XR software, with the end goal being the education of an individual who desires to understand and upgrade the software of an IOS XR device. Topics that are...
Auto-MDIX Capabilities on Cisco 1800s, 2800s, and 3800s
A common question I have seen asked is what models of Cisco 1800s, 2800s, and 3800s support auto-MDIX, a feature that allows for Ethernet cables with almost any pinout to connect devices together. ...
Cisco TCL Script Not Running Configure Replace
During the research phase of my networking homelab initial configuration automation article, I explored many different options on how to easily deploy a base configuration to devices that had been ...
Automating Base Configuration in a Cisco Networking Homelab
Let’s face it: resetting Cisco devices in your homelab to factory defaults is painful. The process of plugging in a console cable, erasing the contents of the NVRAM, reloading the device, then init...
Configuring SuperPuTTY to open web browser telnet hyperlinks
I recently installed SuperPuTTY and spent more time than I should have configuring it so that telnet hyperlinks (such as telnet://10.0.0.1) will automatically open a SuperPuTTY tab. This guide seek...
Cisco Nexus 7700 – Line card’s Status LED flashing red instantly on insertion
A few weeks ago, a coworker of mine asked for my assistance with an odd Nexus 7700 issue. He brought me over to an N77-C7702, where I found a SUP2E humming along while an N77-F348XP-23 line card sa...