Ivan Pepelnjak

Author Archives: Ivan Pepelnjak

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.

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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:

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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.

Review: Ansible for Networking Engineers

An engineer attending Ansible for Networking Engineers online course sent me this feedback:

This is a great place to learn Ansible and Network Automation from scratch. Starting with an emphasis on the fundamentals (YAML, JSON, Jinja2, how to group your network devices for automation, etc.) you progressively build up towards useful network automation.

He particularly liked the additional features that are part of any ipSpace.net online course:

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Goodbye, content.ipspace.net

It turns out that while I cannot bring myself to writing or creating other content during the summer break, it feels perfectly fine to be a janitor and fix small things on the web site.

One of the long-outstanding items: get rid of the free content web site that never went where I wanted it to go… one can do only so much in 24 hours. All the features available on content.ipspace.net are now part of the main ipSpace.net web site including pointers to free content and list of free presentations.

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

Time for a Summer Break

So many things have happened since I wrote “this is what we’re going to do in 2018” blog post. We ran

We also did a ton of webinars:

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Upcoming Webinars and Events: Autumn 2018

On Tuesday I had the last webinar in spring 2018. One more online course session and it will be time for long summer break. In the meantime, we’re already planning the autumn events:

We also have the first webinars scheduled:

You can attend all these webinars with an ipSpace.net webinar subscription.

Worth Reading: Fake News in IT

Stumbled upon “Is Tech News Fake” article by Tom Nolle. Here’s the gist of his pretty verbose text:

When readers pay for news, they get news useful to readers.  When vendors pay, not only do the vendors get news they like, the rest of us get that same story.  It doesn’t mean that the story being told is a lie, but that it reflects the view of an interested party other than the reader.

High-quality content is not cheap, so always ask yourself: who’s paying for the content… and if it’s not you, you may be the product.

Full disclosure: ipSpace.net is funded exclusively with subscriptions and online courses. Some of our guest speakers work for networking vendors, but we always point that out, and never get paid for that.

Vertical Integration Musings

One of my readers asked me a question that came up in his business strategy class:

Why did routers and switches end up being vertically integrated (the same person makes the hardware and the software)? Why didn't they go down the same horizontal path as compute (with Intel making chips, OEMs making systems and Microsoft providing the OS)? Why did this resemble the pre-Intel model of IBM, DEC, Sun…?

Simple answer: because nobody was interested in disaggregating them.

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Worth Reading: Discovering Issues with HTTP/2

A while ago I found an interesting analysis of HTTP/2 behavior under adverse network conditions. Not surprisingly:

When there is packet loss on the network, congestion controls at the TCP layer will throttle the HTTP/2 streams that are multiplexed within fewer TCP connections. Additionally, because of TCP retry logic, packet loss affecting a single TCP connection will simultaneously impact several HTTP/2 streams while retries occur. In other words, head-of-line blocking has effectively moved from layer 7 of the network stack down to layer 4.

What exactly did anyone expect? We discovered the same problems running TCP/IP over SSH a long while ago, but then too many people insist on ignoring history and learning from their own experience.

What Is Intent-Based Networking?

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

Whenever someone mentions intent-based networking I try to figure out what exactly they’re talking about. Not surprisingly, I get a different answer every single time. Confused by all that, I tried to find a good definition, but all I could find was vendor marketing along the lines of “Intent-based networking captures and translates business intent so that it can be applied across the network,” or industry press articles regurgitating vendor white papers.

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