Blog Posts in July 2013

More Private AS Numbers

Have you ever tried to implement a large-scale DMVPN or MPLS/VPN network using BGP as the routing protocol? If you tried to stitch more than ~1000 sites together you’re well aware of all the pain caused by a small range of private AS numbers defined in RFC 1930. We can kludge our way around the limitation by reusing the same AS number on multiple sites (and using allowas-in when we need full routing information on every site), but such a design clearly sucks.

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Unreadable IPv6 Addresses Might Be Good For Us in the Long Run

One of the first arguments used by networking engineers living in IPv6 denial and trying to justify their stance is “IPv6 addresses are unreadable. We will never migrate to IPv6; it’s much easier to deal with IPv4 addresses.”

That’s absolutely true. If you use RFC 1918 addresses in a small(ish) network, the first two octets don’t change, and it’s easy to remember the remaining two numbers … but the unreadable IPv6 addresses just might change the way we approach network configuration and monitoring.

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Where’s the Revolutionary Networking Innovation?

In his recent blog post Joe Onisick wrote “What network virtualization doesn’t provide, in any form, is a change to the model we use to deploy networks and support applications. [...] All of the same broken or misused methodologies are carried forward. [...] Faithful replication of today’s networking challenges as virtual machines with encapsulation tunnels doesn’t move the bar for deploying applications.

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First-Hop IPv6 Security Features in Cisco IOS

I wanted to figure out how to use IPv6 DAD proxy in PVLAN environments during my seaside vacations, and as I had no regular Internet access decided to download the whole set of IPv6 configuration guides while enjoying the morning cup of coffee in an Internet café. Opening the IPv6 First-Hop Security Configuration Guide was one of the most pleasant (professional) surprises I had recently.

One word summary: Awesome.

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Smart Fabrics Versus Overlay Virtual Networks

With the recent plethora of overlay networking startups and Cisco Live Dynamic Fabric Architecture announcements it’s time to revisit a blog post I wrote a bit more than a year ago, comparing virtual networks and voice technologies.

They say a picture is worth a thousand words – here are a few slides from my Interop 2013 Overlay Virtual Networking Explained presentation.

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The Tools That I Use (Drawings)

Continuing from the previous Tools That I Use post, here’s what I’m using to generate the hand drawings in blog posts and case studies.

Wacom Cintiq with SketchBook Pro has been indispensable for high-resolution drawings I used in case studies. I’ve tried to import router symbols in SketchBook Pro and make them look like they would be hand-drawn, but my illustrating skills are almost non-existent.

Typical SketchBook Pro drawing

Typical SketchBook Pro drawing

SketchBook Pro is an overkill for low-resolution blog post drawings … and it forces me to sit down with my computer, so I prefer to draw all other diagrams on an iPad. My fingers are way too clumsy and fat (supposedly rock climbing helps to make them oversized), so I’m relying on Apple Pencil to get some reasonable precision.

Paper 53 was my favorite drawing program, particularly due to its interesting brush-resembling strokes, but they stopped enhancing it years ago (or so it seems), so I switched to Procreate.

Typical Paper 53 drawing

Typical Paper 53 drawing

Procreate allows me to import icons, duplicate them, place them onto a grid, use layers… close to ideal for what I need.

Typical Procreate drawing

Typical Procreate drawing

Getting the drawings from the iPad to the laptop where I do all my writing has been a royal pain (the best I could do was sending them via email). Situation got way better in recent years, with most drawing programs being able to save individual images directly to Dropbox … where they miraculously appear on my laptop ready to be published in a blog post.

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Summer seems to have arrived

The current weather around Central Europe doesn’t exactly support this conclusion, but I do get many more “I’m on vacation” responses than usual, so it’s time to reduce the blogging frequency to keep your RSS reader from overloading (you did switch from Google Reader to something like Feedly, didn’t you?).

However, if you’re looking for some really heavy reading, do pick up The Hidden Reality and explore various multiverse proposals. There’s also a beach-friendly version of multiverse discussion: The Long Earth by the one-and-only Terry Pratchett.

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