Whether you are learning about computer networking through practice labs or are a veteran network administrator, you may have noticed that occasionally, when you test reachability to a specific dev...
How to Create a Simple, Free Blog with Jekyll and GitHub Pages
Authoring technical content is a skill. Like any skill, the only way to improve it is to practice. An easy way to author and share technical content is to create a blog and share your technology ex...
TAC Tales - How IP SLA and Static Routes Ruined Christmas
It was Christmas Day of 2019, and I was working the holiday shift in Cisco TAC. Working Christmas is enjoyable - it tends to be quiet, and in the rare case you need to assist with an issue or outag...
Practical Python - Identifying Congested Interfaces of Nexus 5500 Switches
Overview A common support case I have seen during my career in Cisco TAC is where customers observe intermittently incrementing input discard counters on one or more interfaces of a Cisco Nexus 55...
Static Route with Same Administrative Distance as Dynamic Routing Protocol
Overview In the Discord server operated by sysengineer, the community has a Discord bot maintained by Terranova Tech that quizzes people studying for their CCNA and CCNP certifications. The bot as...
Cisco Modeling Labs IOS-XE Virtual Router Bootstrap Configuration
Configuration This is the Cisco IOS-XE configuration I use to bootstrap CSR1000v and Catalyst 8000v virtual routers within Cisco Modeling Labs (CML). Whenever I create a topology involving Cisco I...
TAC Tales - Saving Configuration is for Quitters
In December of 2019, a customer opened a TAC case where the copy running-config startup-config command would hang and time out after several minutes on a few brand-new Nexus switches. The command r...
ICMP Redirects - How Data Plane Traffic Can Become Control Plane Traffic
Note: If you are not familiar with the concepts of the data plane and control plane on network devices, I highly recommend reviewing my Understanding the Data, Control, and Management Planes of ...
Understanding Control Plane Packet Loss due to CoPP
Note: If you are not familiar with the concepts of the data plane and control plane on network devices, I highly recommend reviewing my Understanding the Data, Control, and Management Planes of ...
Understanding the Data, Control, and Management Planes of Network Devices
While troubleshooting connectivity issues and packet loss in computer networks, network engineers often misunderstand the difference between the data plane and control plane. This can lead to fault...