Ivan Pepelnjak

Author Archives: Ivan Pepelnjak

Traditional Leaf-and-Spine Fabric Versus Cisco ACI

One of my subscribers wondered whether it would make sense to build a traditional leaf-and-spine fabric or go for Cisco ACI. He started his email with:

One option is a "standalone" Spine/Leaf VXLAN-with EVPN deployment based on Nexus equipment. This approach could probably be accompanied by some kind of automation like Ansible to ease operation/maintenance of the network.

This is what I would do these days if the customer feels comfortable investing at least the minimum amount of work into an automation solution. Having simpler technology + well-understood automation solution is (in my biased opinion) better than having a complex black box.

Read more ...

Interview: Benefits of Network Automation (Part 2)

As promised, here’s the second part of my Benefits of Network Automation interview with Christoph Jaggi published in German on Inside-IT last Friday (part 1 is here).

What are some of the challenges?

The biggest challenge everyone faces when starting the network automation is the snowflake nature of most enterprise networks and the million one-off exceptions we had to make in the past to cope with badly-designed applications or unrealistic user requirements. Remember: you cannot automate what you cannot describe in enough details.

Read more ...

Updated: Networking Modules in Building Next-Generation Data Centers Online Course

We migrated the self-study materials for the network infrastructure and services module of the Building Next-Generation Data Centers online course into the new format, and split the largest module of the course into manageable chunks: data center fabrics 101, designing leaf-and-spine fabrics, overlay virtual networking, IPv6 and network services.

Feedback on the new format is obviously highly welcome. Thank you!

Security Aspects of SD-WAN Solutions

Christoph Jaggi, the author of Transport and Network Security Primer and Ethernet Encryption webinars published a high-level introductory article in Inside-IT online magazine describing security deficiencies of SD-WAN solutions based on the work he did analyzing them for a large multinational corporation.

As the topic might be interesting to a wider audience, I asked him to translate the article into English. Here it is…

Read more ...

Reality Check: Self-Driving Networks

I stumbled upon an article with an interesting title (and worth reading): To Make Self-Driving Cars Safe, We Also Need Better Roads and Infrastructure… and thought about the claims along the lines of “if they managed to solve the self-driving cars challenge, it’s realistic to expect self-driving networks” made in Self-Driving Networks podcast episode. Turns out the self-driving cars problem is far far away from being solved.

Read more ...

Upcoming Webinars and Events: Autumn 2018

The summer break is over, and we’ve already scheduled a half-dozen events and webinars in August and September:

We’ll run an event or webinar in almost every single week in September:

Read more ...

Worth Reading: The Cargo Cult of Google Tools

Tom Hollingsworth published a great blog post summarizing Cloud Field Day presentation by Ben Sigelman.

TL&DR: You’re not Google, you don’t have their problems, and so you’re probably not a good match for their tools.

While this shouldn’t come as a surprise to regular readers of my blog (here’s what I wrote on the topic in 2016), it’s refreshing to see it spelled out so eloquently (and by an ex-Googler).

GitOps in Networking

This blog post was initially sent to the subscribers of my SDN and Network Automation mailing list. Subscribe here.

Tom Limoncelli published a must-read article in ACM Queue describing GitOps – the idea of using Pull Requests together with CI/CD pipeline to give your users the ability to request changes to infrastructure configuration.

Using GitOps in networking is nothing new – Leslie Carr talked about this concept almost three years ago @ RIPE 71, and I described some of the workflows you could use in Network Automation 101 webinar.

Read more ...

Updated: First Set of Building Next-Generation Data Centers Self-Study Materials

When I started the Building Next-Generation Data Centers online course, I didn’t have the automated infrastructure to support it, so I had to go with the next best solution: a reasonably-flexible Content Management System, and Mediawiki turned out to be a pretty good option.

In the meantime, we developed a full-blown course support system, included guided self-paced study (available with most ipSpace.net online course), and progress tracking. It was time to migrate the data center material into the same format.

Read more ...

Another Benefit of Open-Source Networking Software

You probably know my opinion on nerd knobs and the resulting complexity, but sometimes you desperately need something to get the job done.

In traditional vendor-driven networking world, you might be able to persuade your vendor to implement the knob (you think) you need in 3 years by making it a mandatory requirement for a $10M purchase order. In open-source world you implement the knob, write the unit tests, and submit a pull request.

Read more ...

New my.ipspace.net Design

During the last weeks I migrated the whole my.ipspace.net site (apart from the workgroup administration pages) to the new ipSpace.net design. Most of the changes should be transparent (apart from the pages looking better than before ;); I also made a few more significant changes:

Read more ...

Overview of ipSpace.net Training Options

Describe the differences between various ipSpace.net training options has been on my to-do list for ages, but I successfully managed to ignore it till I deployed the new top-level menu that contains training category.

Our designers never considered menu items without a corresponding link, so I got an ugly mess that needed to be cleaned up either by fixing the CSS or writing the overview document.

End result: a high-level document describing how ipSpace.net webinars, courses and workshops fit into the bigger picture.

During the summer break, I’m publishing blog posts about the projects I’m working on. Regular blog posts will return in autumn.

Free Webinars and Videos Are Now Easier to Spot

Another summer break project: replacing the stars next to webinar names in descriptions of various technology areas (example: Data Center) with something more useful. Turns out that marking the webinar title as being Free or having Free items works really well.

Bonus feature: clicking on show free content shows you the content available with free subscription.

During the summer break, I’m publishing blog posts about the projects I’m working on. Regular blog posts will return in autumn.

Updated Design on blog.ipspace.net

I synced the CSS used on blog.ipspace.net with the one used on the main web site. There should be no visible changes apart from a few minor fixes in color scheme and the main column being a bit narrower, but if you spot any errors please let me know.

During the summer break, I’m doing much-needed web site maintenance. Regular blog posts will return in autumn.