Blog Posts in July 2015

Big Flowering Things and Lego Bricks

Matt Oswalt wrote a great blog post complaining about vendors launching ocean-boiling solutions instead of focused reusable components, and one of the comments his opinion generated was along the lines of “I thought one of the reasons people wanted SDN, is because they wanted to deal with The Network – think about The Network's Performance, Robustness and Services instead of dealing with 100s or 1000s of individual boxes.

The comment is obviously totally valid, so let me try to reiterate what Matt wrote using Lego bricks ;)

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Explaining the Pervasive Kludgeitis

I found a great explanation for hodgepodge of kludges found in "organically grown" solutions (legacy precursors to SD-WAN come to mind):

In a long-lived project, components are being replaced. Nice reusable components are easy to replace and so they are. Ugly non-reusable components are pain to replace and each replacement means both a considerable risk and considerable cost. Thus, more often then not, they are not replaced. As the years go by, reusable components pass away and only the hairy ones remain. In the end the project turns into a monolithic cluster of ugly components melted one into another.

Note: You really should read the whole blog post.

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Is Linux TCP/IP Stack Really That Slow?

Most people casually involved with virtual appliances and network function virtualization (NFV) believe that replacing Linux TCP/IP stack with user-mode packet forwarding (example: Intel’s DPDK) boosts performance from meager 1 Gbps to tens of gigabits (and thus makes hardware forwarding obsolete).

Having data points is always better than having opinions; today let’s look at Receiving 1 Mpps with Linux TCP/IP Stack blog post.

2015-07-18: The blog post was updated based on feedback by Kristian Larsson.

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Can You Avoid Networking Software Bugs?

One of my readers sent me an interesting reliability design question. It all started with a catastrophic WAN failure:

Once a particular volume of encrypted traffic was reached the data center WAN edge router crashed, and then the backup router took over, which also crashed. The traffic then failed over to the second DC, and you can guess what happened then...

Obviously they’re now trying to redesign the network to avoid such failures.

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Why Should I Care About Networking?

A month ago I was asked to deliver a short presentation on “something interesting about networking” at my local university. The temptation to talk about network automation and SDN was huge, but I quickly figured out that would make no sense (the audience were students in their freshman year) and decided to talk about a fundamental question: why should a programmer care about networking.

Unfortunately the presentation wasn’t recorded, but you can browse the slide deck on the public content web site.

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Some Ridiculous SD-WAN Claims

SDx Central is usually a pretty good web site that I love to read, but even they occasionally manage to publish a gem like this one:

The problem with MPLS and similar technologies is that they weren’t designed with today’s business challenges in mind. Today, a company may need to launch an overseas R&D office overnight, or it may acquire a startup and want to immediately network with offices in distant regions and countries. Older technologies just don’t have the flexibility to do this on the fly.

Not surprisingly, the above paragraph triggered a severe case of Deja-Moo.

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Routing Protocols and SD-WAN: Apples and Furbies

Ethan Banks recently wrote a nice blog post detailing the benefits and drawbacks of traditional routing protocols and comparing them with their SD-WAN counterparts.

While I agree with everything he wrote, the comparison between the two isn’t exactly fair – it’s a bit like trying to cut the cheese with a chainsaw and complaining about the resulting waste.

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Save the Date: Designing Infrastructure for Private Clouds Workshop in Switzerland

Gabi Gerber (the wonderful mastermind behind the Data Center Day event) is helping me bring my Designing Infrastructure for Private Clouds workshop (one of the best Interop 2015 workshops) to Switzerland.

This is the only cloud design workshop I’m running in Europe in 2015. If you’d like to attend it, this is your only chance – register NOW.

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