How writing has turned walls into windows

Those who have read my blog know that I am not a professional writer. I’m a novice at best, blissfully blurting mediocre sentence structure in cyber space. These words have never really been for anyone other than myself, so who cares if I’m overly generous with commas, or underwhelmingly inept with word diversity? I mean, no one will ever be as critical as I am to myself. This hasn’t stopped me. In fact, I continue to write despite barriers and walls, for this has opened my mind far beyond what I could have imagined. It’s all about the content. (more…)

Fireflies, Synchronicity and SD-WAN

Imagine a warm summer night away from the city hustle and techno grind. Moon is new, sky is clear, air is crisp, mind is easy. Peering out towards a bank of pines that border the woodland, you notice a few fireflies start to flash their bulbs. Your eyes are opened wide, equipped like a sharp shooters, honing in on the next flash. More start to blink into existence, matching the rhythmic nature of the others that have already joined the mantra. It’s as though an endless number of blinking fireflies are entering the night, breathing in epic unison.

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ONUG – What is it, and why am I here?

If you’ve ever seen a film with audio engineering by THX, you’ve experienced that brief, immersive surround sound that captivates your senses, completely eradicating your thoughts while the mind basks in weightless bliss. Much like the beginning of a George Lucas film, the networking industry is currently in a state of THX, steadily swelling with that warm buzz, fantasizing about the potential for bliss. Software-Defined Networking (SDN), Software-Defined WAN (SD-WAN), Network Function Virtualization (NFV), Hybrid Clouds, Virtual Overlays and Containerization are at the crest of this tsunami of change, promised to radically disrupt the way businesses develop and operate their networks. But change is risky, especially in regards to bleeding technologies. Companies need better opportunities to understand their options and share experiences with each other. Enter ONUG.

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802.11ac Wave 2, MGig and Cisco’s 2800 & 3800 Series Access Points

Several weeks ago I attended a presentation on Cisco’s new 2800 and 3800 Series access points. I’m quite impressed with some of the new capabilities these APs bring to the market. The presenters, Mark Denny and Brian Levin, were passionate regarding the implications this has for wireless networks. I felt I needed to take a step back to really understand why some of these enhancements and new features are so important to wireless infrastructure. I’ll run through a few of the capabilities that I personally feel are most significant. I’ll attempt to keep it concise.

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The roof, the roof, the roof is on IP

What is Digital Ceiling?

Looking back at the evolution of the network in the past decade, we see a constant trend of devices migrating to Ethernet, resulting in a migration to IP. IP telephony took off in 2005 and is now the de facto standard for any phone system. Coax-connected cameras migrated to IP surveillance in the late 2000s. Legacy building management systems using BACnet started migrating to low-voltage PoE systems in the early 2010s. Within the past year, we’ve seen a new trend of high-voltage systems like lighting start migrating towards low-voltage PoE, dubbed “Smart Lighting”. This move towards digitization makes sense on all fronts. It’s cheaper, scalable, extensible, can easily be managed and monitored, and opens the door for new experiences with intelligent buildings. (more…)

Cisco Linguistics & The Grumpy Old Router

Traveller

I’m a first time traveler to another country. I’m aware of multiple languages, but I don’t know how to speak any other than English. It’s one of those things that I’ve always wanted to learn, but just never got around to. So, I’m aboard an aircraft to Germany, and the first conversation I had on the plane was with a flight attendant. It went a little something like this:

Her: Ist das Ihre rote Tasche dort?
Me: … <wishing I knew what she was saying>
Her: …
Me: English?
Her: Is that your red bag over there?
Me: Nein

It started out weak and embarrassing, I didn’t know what she was saying. There was a very brief moment, just a second or two, where my brain was attempting with futility to decipher the foreign tongue, returning a meandering blank stare, followed by the simple one-worded question: “English?”. The flight attendant immediately responded in my native language, and I clearly understood her. I responded confidently with a German “nein”. She smiled. (more…)

Simple Yes No Function in Python

Preface

I’m a Network Engineer learning Python, and these are purely my notes. I’m not an expert by any means. Feel free to use any of these examples and improve upon them. Feel free to call me out where things can be done better.

Onward

I regularly need a simple yes/no function in Python when interacting with users. This function uses sets of data to represent “yes” and “no”. Sets are unordered collections of elements, and can be used similarly to lists (e.g. x in set). The function will take in an answer (yes/no). This will be converted to lowercase and then checked against each set. Result is returned. (more…)

Replace Words in Files or Strings using Python

Preface

Onward

A common task I need to do is replace words in a file with something else. For example:

hostname $hostname
interface Gig0/1
 ip address $ip 255.255.255.252

Where $hostname and $ip should be variables that needs replacing. This post looks at how to accomplish this on the Python interpretor, and via a script file using a Python function.

To keep things relatively simple, I’m only going to perform the replacement on a single file, using a single set of attributes. (more…)

Search a List of Dictionaries in Python

Preface

Onward

This post is sort of a follow-up to my last one regarding CSVs converted to dictionaries. So, I have this big list of dictionaries, these key/value pairs, and I want to do things with them. In this case, I’d like to be able to search this list and return just the key/values for a specific device. This will later be used when building network device configuration files. (more…)

Convert a CSV to a Dictionary in Python

Preface

Onward

I have a CSV full of device-specific variables that I need to use in a script built for generating network device configurations. For example:

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