Ivan Pepelnjak

Author Archives: Ivan Pepelnjak

MUST Read: Operational Security Considerations for IPv6 Networks (RFC 9099)

After almost a decade of bickering and haggling (trust me, I got my scars to prove how the consensus building works), the authors of Operational Security Considerations for IPv6 Networks (many of them dear old friends I haven’t seen for way too long) finally managed to turn a brilliant document into an Informational RFC.

Regardless of whether you already implemented IPv6 in your network or believe it will never be production-ready (alongside other crazy stuff like vaccines) I’d consider this RFC a mandatory reading.

MUST Read: Operational Security Considerations for IPv6 Networks (RFC 9099)

After almost a decade of bickering and haggling (trust me, I got my scars to prove how the consensus building works), the authors of Operational Security Considerations for IPv6 Networks (many of them dear old friends I haven’t seen for way too long) finally managed to turn a brilliant document into an Informational RFC.

Regardless of whether you already implemented IPv6 in your network or believe it will never be production-ready (alongside other crazy stuff like vaccines) I’d consider this RFC a mandatory reading.

OpenFlow Realities, 2021 Edition

I thought I was too harsh every now and then, but I’m a complete amateur when compared to Minh Ha’s take on OpenFlow.


Indeed Quantum Computing and OpenFlow have a lot in common. They both create stories that have emotional appeal, they both require invention of new physics, and they’re both filled with grand vision, grandstanding, and empty promises. But there’s no shortage of PhDs, high hopes, cash infusion from VCs, and a Cambrian explosion of research papers, many of which content is not even worth the papers it’s printed on.

OpenFlow Realities, 2021 Edition

I thought I was too harsh every now and then, but I’m a complete amateur when compared to Minh Ha’s take on OpenFlow.


Indeed Quantum Computing and OpenFlow have a lot in common. They both create stories that have emotional appeal, they both require invention of new physics, and they’re both filled with grand vision, grandstanding, and empty promises. But there’s no shortage of PhDs, high hopes, cash infusion from VCs, and a Cambrian explosion of research papers, many of which content is not even worth the papers it’s printed on.

Designing Networks: From Tricycles to Aircraft Carriers

I planned to take my summer break seriously and stop blogging until late August, but then I shouldn’t have looked at my Twitter feed (my bad), where the AI algorithms selected just the right morsel to trigger the maximum rantiness. I would strongly recommend you read the original tweet and all the responses first – it looks like it was a serious suggestion, not a trolling exercise.

Designing Networks: From Tricycles to Aircraft Carriers

I planned to take my summer break seriously and stop blogging until late August, but then I shouldn’t have looked at my Twitter feed (my bad), where the AI algorithms selected just the right morsel to trigger the maximum rantiness. I would strongly recommend you read the original tweet and all the responses first – it looks like it was a serious suggestion, not a trolling exercise (here’s a copy of the original idea in case the tweets get lost in the mists of time).

Thank You for Everything Irena, We’ll Miss You Badly

In February 2018, Irena Marčetič joined ipSpace.net to fix the (lack of) marketing. After getting that done, she quickly took over most of sales, support, logistics, content production, guest speaker coordination… If you needed anything from us in the last few years, it was probably Irena answering your requests and helping you out.

She did a fantastic job and transformed ipSpace.net from Ivan and an occasional guest speaker to a finely tuned machine producing several hours of new content every month. She organized our courses, worked with guest speakers, podcast guests and hosts, participated in every guest speaker webinar to take notes for the editing process, managed content editing, watched every single video we created before it was published to make sure the audio was of acceptable quality and all the bloopers were removed… while answering crazy emails like I need you to fill in this Excel spreadsheet with your company data because I cannot copy-paste that information from your web site myself and solving whatever challenges our customers faced.

Unfortunately, Irena decided to go back to pure marketing and is leaving ipSpace.net today. Thanks a million for all the great work – we’ll badly miss you.

Thank You for Everything Irena, We’ll Miss You Badly

In February 2018, Irena Marčetič joined ipSpace.net to fix the (lack of) marketing. After getting that done, she quickly took over most of sales, support, logistics, content production, guest speaker coordination… If you needed anything from us in the last few years, it was probably Irena answering your requests and helping you out.

She did a fantastic job and transformed ipSpace.net from Ivan and an occasional guest speaker to a finely tuned machine producing several hours of new content every month. She organized our courses, worked with guest speakers, podcast guests and hosts, participated in every guest speaker webinar to take notes for the editing process, managed content editing, watched every single video we created before it was published to make sure the audio was of acceptable quality and all the bloopers were removed… while answering crazy emails like I need you to fill in this Excel spreadsheet with your company data because I cannot copy-paste that information from your web site myself and solving whatever challenges our customers faced.

Unfortunately, Irena decided to go back to pure marketing and is leaving ipSpace.net today. Thanks a million for all the great work – we’ll badly miss you.

Webinars in the First Half of 2021

It’s time for another this is what we did in the last six months blog post. Instead of writing another wall-of-text, I just updated the one I published in early January. Here are the highlights:

That’s about it for the first half of 2021. I’ll be back in early September.

Webinars in the First Half of 2021

It’s time for another this is what we did in the last six months blog post. Instead of writing another wall-of-text, I just updated the one I published in early January. Here are the highlights:

That’s about it for the first half of 2021. I’ll be back in early September.

Video: Typical Large-Scale Bridging Use Cases

In the previous video in the Switching, Routing and Bridging section of How Networks Really Work webinar we compared transparent bridging with IP routing. Not surprisingly (given my well-known bias toward stable solutions) I recommended using IP routing as much as possible, but there are still people out there pushing large-scale transparent bridging solutions.

In today’s video we’ll look at some of the supposed use cases and stable solutions you could use instead of stretching a virtual thick yellow cable halfway across a continent.

The video is available with Free ipSpace.net Subscription.

Video: Typical Large-Scale Bridging Use Cases

In the previous video in the Switching, Routing and Bridging section of How Networks Really Work webinar we compared transparent bridging with IP routing. Not surprisingly (given my well-known bias toward stable solutions) I recommended using IP routing as much as possible, but there are still people out there pushing large-scale transparent bridging solutions.

In today’s video we’ll look at some of the supposed use cases and stable solutions you could use instead of stretching a virtual thick yellow cable halfway across a continent.

The video is available with Free ipSpace.net Subscription.
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