An emergency switch replacement can ruin your day. However, having network config backups is not enough. Restoring full service may not be as easy as just copying the running configuration from your RANCID CVS repo, or your colleagues hard drive. Restoring the ‘identity’ of your original switch is a multi-step and somewhat complicated process.
I don’t want a software defined network, I want a software-assisted network. I want tools that will help prevent common but straightforward mistakes and make it easier to baseline a network. These tools have to work on real networks. Those messy, brownfield, imperfect networks that everyone maintains, but not everyone admits to owning. I’ve listed five tools below that I wish I had freely available when working on enterprise networks.
No, I’m not starting a naming war. Not really. I don’t care if you use ! or # or >> or {} to mark your interface descriptions. I don’t care if you use all-caps or lowercase, or if you feel a fundamentalist zeal about other punctuation. I want to brave the flames of a naming war to propose that we include ‘hidden’ or ‘undiscoverable’ devices in our interface descriptions. If there is a hidden device, a bump in the wire for example, between…
If you need regular console port access then nothing beats a fixed console router. However there are many times when that simply isn’t an option. For occasional console connections I use a Keyspan USB/Serial adaptor with my MacBook. It’s an acceptable solution but not sometimes is far from ideal. You can find yourself tethered to the rack in question, often sitting on the floor or a crappy stool, dealing with datacenter noise and temps and have console cables traipsed…
Every now and again you see a snippet of complex CLI syntax that gives you pause for thought. Last week I saw the command below in a change procedure. The command was being used to verify baseline BGP neighbor state and re-verify after a policy change. 1 2 3 show ip bgp peer-template eBGP_Peers | egrep default | sed ‘s/default://’ \ | tr -s ‘ |\n’ | tr -s ‘ ‘ ‘\n’ | sed ‘s/^/show ip bgp nei /’ \…
A few months back I wrote a post about checklists, and promised to follow up with a few of my own. Here is my first attempt at a checklist, trying to address the common pitfalls I see when people are making network changes. I’m not sure I follow all the guidance in the ‘Checklist Manifesto’ but here goes.
This post is a short one, but hopefully still valuable. I spent 30 minutes troubleshooting a flapping switch port in the lab this week. I was attaching a headless test device to a 3750G and I couldn’t see the status of the NIC from the tester’s perspective. So one crash cart and a bit of port-swapping later, I found the problem. It was a dodgy switch port and swapping to another port (with identicial config) solved the issue. Then it…
We’re in the midst of a networking boom at the moment and new technologies are being released at a rapid pace. So much so that network engineers need a suite of knowledge management tools to navigate the daily deluge of articles, documents, twikis and notes. That said, how much of your day-to-day activities are markedly different than they were two years ago? As I see it, the role of the network engineer is largely unchanged. One still has to gather…
Why talk about network power connectors? Here at Network Sherpa base camp, we’re all about removing confusion and saving time. I’ve always had a bit of difficulty differentiating between the connector types, PDU’s, inlets outlets and country specific power cords. In this post I share my learnings. In the video below I focus on the commonly used low power IEC 320 series C13/14 connectors. If you want further detail or more info about other connectors, then check out NetworkingNerds’s great…
Corrupted frames are the devils spawn. A few noisy links causing frame corruption can quickly degrade network performance, and troubleshooting them is getting harder. These integrity errors generally occur when signal noise causes a binary ‘1’ to be mistaken for a binary ‘0’ or vice-versa. This post takes a look at integrity errors and the impacts of corrupted frames in a cut-through switched network. Throughout this post I’ll use the term ‘CRC errors’ term to refer to frame integrity errors which…