Diptanshu Singh wrote a nice explanation of the math behind reliability calculations. Definitely worth reading even if you hated statistics.

Dave Taht sent me a link to IRTT after I published a blog post on measuring end-to-end latency with an Ansible playbook. Definitely looks like a tool worth having in your toolbox.

A long while ago Marcel Wiget sent me an interesting email along the lines “I think you should do a Software Gone Wild podcast with Phil Shafer, the granddaddy of NETCONF”

Not surprisingly, as we started discovering the history behind NETCONF we quickly figured out that all the API and automation hype being touted these days is nothing new – some engineers have been doing that stuff for almost 20 years.

Here’s another idea from the Building Network Automation Solutions online course: Ruben Tripiana decided to implement a latency measurement tool. His playbook takes a list of managed devices from Ansible inventory, generates a set of unique device pairs, measures latency between them, and produces a summary report (see also his description of the project).

A while ago I helped a large enterprise redesign their data center fabric. They did a wonderful job optimizing their infrastructure, so all they really needed were two switches in each location.

Some vendors couldn’t fathom that. One of them proposed to build a “future-proof” (and twice as expensive) leaf-and-spine fabric with two leaves and two spines. On top of that they proposed to use EBGP as the only routing protocol because draft-lapukhov-bgp-routing-large-dc – a clear case of missing the customer needs.

One of my readers was so delighted that something finally happened after I wrote about a NX-OS bug that he sent me a pointer to another one that has been pending for a long while, and is now officially terminated as FAD (Functions-as-Designed… even documented in the Further Problem Description).

Here’s what he wrote (slightly reworded)…

Netfortius made an interesting comment to my Ansible playbook as a bash script blog post:

Ivan - aren't we now moving the "CLI"[-like] approach, upstream (the one we are just trying to depart, via the more structured and robust approach of RESTAPI).

As I explained several times, I don’t know where the we must get rid of CLI ideas are coming from; the CLI is root of all evil mantra is just hype generated by startups selling alternative approaches (the best part: one of them was actually demonstrating their product using CLI).

Whitespace handling is one of the most confusing aspects of Jinja2, thoroughly frustrating many attendees of my Ansible and Network Automation online courses.

I decided to fix that, ran a few well-controlled experiments, and documented the findings and common caveats in Whitespace Handling in Jinja2 video.

After explaining the basics of PowerShell, Mitja Robas described how to do implement the “Hello, World!” of network automation (collecting printouts from network devices) in PowerShell.

To watch all videos from this free webinar, register here.

You’ll need at least free ipSpace.net subscription to watch the video.

One of my friends wanted to design a nice-and-easy layer-3 leaf-and-spine fabric for a new data center, and got blindsided by a hyperconverged vendor. Here’s what he wrote:

We wanted to have a spine/leaf L3 topology for an NSX deployment but can’t do that because the Nutanix servers require L2 between their nodes so they can be in the same cluster.

I wanted to check his claims, but Nutanix doesn’t publish their documentation (I would consider that a red flag), so I’m assuming he’s right until someone proves otherwise (note: whitepaper is not a proof of anything ;).

Got this feedback on my Ansible for Networking Engineers webinar:

This webinar is very comprehensive compared to any other Ansible webinars available out there. Ivan does great job of mapping and using real life example which is directly related to daily tasks.

The Ansible online course is even better: it includes support, additional hands-on exercises, sample playbooks, case studies, and lab instructions.

However, Ansible is just a tool that shouldn’t be missing from your toolbox. If you need a bigger picture, consider the Building Network Automation Solutions online course (and register ASAP to save $700 with the Enthusiast ticket).

One of my readers sent me a question about his favorite annoyance:

During my long practice, I’ve never seen an Enterprise successfully managing the network device software upgrade/patching cycles. It seems like nothing changed in the last 20 years - despite technical progress, in still takes years (not months) to refresh software in your network.

There are two aspects to this:

Did you know there’s an RFC describing typical BGP route leaks? I didn’t until I stumbled upon this blog post.

I published the last part of my Optimize Data Center Infrastructure series: build an optimized data center fabric.

To learn more about data center fabric designs, check the new online course or enroll into the Spring 2018 session of Building Next-Generation Data Center course.

I first met Pluribus Networks 2.5 years ago during their Networking Field Day 9 presentation, which turned controversial enough that I was advised not to wear the same sweater during NFD16 to avoid jinxing another presentation (I also admit to be a bit biased in those days based on marketing deja-moo from a Pluribus sales guy I’d been exposed to during a customer engagement).

Pluribus NFD16 presentations were better; here’s what I got from them: