Remember Nicky Davey describing how he got large DMVPN deployment back on track with configuration templating? In his own words…:

Configuration templating is still as big win a win for us as it was a year ago. We have since expanded the automation solution, and reading the old blog post makes me realise how far we have come. I began working with this particular customer in May 2017, so 2 years now. At that time the new WAN project was on the horizon and the approach to network configuration was entirely manual.

Here’s how far he got in the meantime:

Last week I covered network security groups, application security groups and user-defined routes in the second live session of Azure Networking webinar.

We also had a great guest speaker on the Network Automation course: Damien Garros explained how he used central source-of-truth based on NetBox and Git to set up a network automation stack from the grounds up.

Recordings are already online; you’ll need Standard ipSpace.net Subscription to access the Azure Networking webinar, and Expert ipSpace.net Subscription to access Damien’s presentation. Azure Networking webinar is also part of our new Networking in Public Clouds online course.

This is a guest blog post by Philippe Jounin, Senior Network Architect at Orange Business Services.

You could use track objects in Cisco IOS to track route reachability or metric, the status of an interface, or IP SLA compliance for a long time. Initially you could use them to implement reliable static routing (or even shut down a BGP session) or trigger EEM scripts. With a bit more work (and a few more EEM scripts) you could use object tracking to create time-dependent static routes.

Cisco IOS 15 has introduced Enhanced Object Tracking that allows first-hop router protocols like VRRP or HSRP to use tracking state to modify their behavior.

I have exciting news I’d love to share with you: we’re launching a new online course focused on networking in public clouds starting in February 2020 (I’ve been mulling over this idea and polishing the concept for almost 18 months, and finally it all came together ;)

With Go To The Cloud becoming the answer to all questions (regardless of what the question is), you can find tons of materials describing various aspects of public clouds, so you might wonder why I decided to enter the fray. The answer is simple: with everyone being focused on developers, there’s not much that an infrastructure engineer could use to help him survive when the developers move on and he’s left to manage whatever they put in place.

Every few weeks I stumble upon an article (or twitter storm) in which someone claims you don’t need formal education to get started as a Software Engineer (or whatever else) - all you need is a coding academy/bootcamp and you're all set.

George V. Neville-Neil wrote a hilarious rebuttal of this idea followed by some pretty good advice. Hope you’ll enjoy it as much as I did ;)

A long while ago Daniel Dib wrote a nice blog post on “SDN will make the networking engineers obsolete” theme. While it sounds like beating a dead horse, the SDN craze isn’t subsiding, so another healthy dose of common sense might come handy.

Hint: if you’re not following Daniel’s blog, you should… even though he decided to make old farts’ life harder by publishing on LinkedIn.

Sick-and-tired of intent-based GUIs that are barely better than CiscoWorks on steroids? How about asking Siri-like assistant queries about network state in somewhat-limited English and getting replies back in full-blown sentences?

Warning: you might be reentering the land of unicorns driving flying DeLoreans... but then keep in mind what Arthur Clarke had to say on this topic ;).

Welcome to Net2Text, another proof-of-concept tool created by the group led by Laurent Vanbever… who joined us for a short chat to discuss it, resulting in Episode 105 of Software Gone Wild.

A while ago Ruben Tripiana tried to configure BGP on Cisco IOS using IETF YANG data models… and failed. In Spring 2019 Building Network Automation Solutions online course Chris Crook decided to deploy BGP routing on multiple platforms using YANG data models instead of configuration templates. Not only did he succeed, he also documented his work and the tools he used, and published the solution so you can replicate his efforts.

You can find many more network automation solutions created by the attendees of our automation course in solutions showcase.

Two weeks ago I replied to a battle-scar reaction to 7-layer OSI model, this time I’ll address a much more nuanced view from Russ White. Please read his article first (as always, it’s well worth reading) and when you come back we’ll focus on this claim:

The OSI Model does not accurately describe networks.

Like with any tool in your toolbox, you can view the 7-layer OSI model in a number of ways. In the case of OSI model, it can be used:

People who can explain complex topics in simple terms, or focus on the essentials of a particular topic are exceedingly rare… and two of the best are Randall Munroe of the XKCD fame and Julia Evans, the mastermind behind WizardZines. I loved her recent curl and git exercises, and I’m guessing a lot of people in this industry would benefit from her latest HTTP zine.

Similarly to what I did a long time ago with ipSpace.net, Julia recently decided to go all-in, leaving her job and focusing on explaining things. I hope it will work out and we’ll keep enjoying her tidbits of wisdom for years to come.

After identifying some of the challenges every network solution must address (part 1, part 2, part 3) we tried to tackle an interesting question: “how do you implement this whole spaghetti mess in a somewhat-reliable and structured way?”

The Roman Empire had an answer more than 2000 years ago: divide-and-conquer (aka “eating the elephant one bite at a time”). These days, we call it layering and abstractions.

In the Need for Network Layers video, I listed all the challenges we have to address and then described how you could group them in meaningful modules (called networking layers).

I had a fantastic chat with David Bombal a while ago in which we covered tons of network automation topics including “should I use Nornir or NAPALM or Netmiko?”

The only answer one can give would be “it depends… on what you’re trying to do” as these three tools solve completely different challenges.

Paramiko is SSH implementation in Python. It’s used by most Python tools that want to use SSH to connect to other hosts (including networking devices).

In Never-Ending Story of IP Fragmentation I described how you could use TCP Maximum Segment Size to minimize the impact of IP fragmentation and PMTUD blackholes (more details on TCP MSS clamping)… but one has to wonder how people use TCP MSS in the wild and what values you might see.

As is often the case, Geoff Houston found a way to measure them, and published the answer: TCP MSS Values

Someone working for a network automation startup desperately tried to persuade me how cool their product is. Here’s what he sent me:

We let network engineers build their own network automation solutions in no time without requiring coding or scripting knowledge. It’s all GUI based, specifically geared towards network engineers - they can simply model services or roll-out networks “as-designed”.

The only problem: I’ve seen that same argument numerous times…

Last week we started the Microsoft Azure Networking saga that will eventually mirror the AWS Networking materials.

I recorded the hands-on demos in advance so we had plenty of time to discuss Azure API and CLI, geographies, regions and availability zones, high-availability concepts, and deployments models… and spent the second half of the live session focusing on virtual networks, subnets, interface, and IP addresses. The videos are already online and accessible with Standard ipSpace.net Subscription.

Next step (on September 24th): network security and user-defined routes.