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Internetworking perspectives by Ivan Pepelnjak
Updated: 2 hours 43 min ago

Campfire story: Using the wrong tool for the job

July 22, 2014 - 11:07pm

Summer is the perfect time for campfire stories – here’s one about using the wrong tool for the job.

A Long time ago in an IT organization far, far away Artificial Intelligence (AI) was the coolest kid on the block.

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Layer-3 Switching over VXLAN Revisited

July 20, 2014 - 10:12pm

My Trident 2 Chipset and Nexus 9500 blog post must have hit a raw nerve or two – Bruce Davie dedicated a whole paragraph in his Physical Networks in Virtualized Networking World blog post to tell everyone how the whole thing is a non-issue and how everything’s good in the NSX land.

It’s always fun digging into more details to figure out what’s really going on behind the scenes; let’s do it.

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Next Chapter in Data Center Design Case Studies

July 17, 2014 - 10:55pm

When I published the Data Center Design Case Studies book almost exactly a month ago, three chapters were still missing – but that was the only way to stop the procrastination and ensure I’ll write them (I’m trying to stick to published deadlines ;).

The first one of the missing chapters is already finished and available to subscribersand everyone who bought the book or Designing Private Cloud Infrastructure webinar (you’ll also get a mailing on Sunday to remind you to download the fresh copy of the PDF).

The Amazon Kindle version will be updated in a few days.

Network Automation @ Spotify on Software Gone Wild

July 16, 2014 - 10:56pm

What can you do if you have a small team of networking engineers responsible for four even-growing data centers (with several hundred network devices in each of them)? There’s only one answer: you try to survive by automating as much as you can.

In the fourth episode of Software Gone Wild podcast David Barosso from Spotify explains how they use network automation to cope with the ever-growing installed base without increasing the size of the networking team.

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There Is no Paradigm Shift – Good Applications Were Always Network-Aware

July 14, 2014 - 10:50pm

Someone left the following comment on one of my blog posts:

There is a paradigm shift that I don’t think most application developers understand. In a traditional enterprise model, the network is built around the application requirements, now we are saying the application has to build around the network.

I would say there’s no paradigm shift – developers of well-performing applications were always aware of laws of physics.

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How Big Will Your Cloud Be?

July 10, 2014 - 9:52pm

The last generations of high-end servers are amazing: they can have terabyte (or more) of RAM, dozens of CPU cores, and four (or more) 10GE uplinks. It’s easy to pack 100+ well-behaved VMs on a single server, reducing the whole data center into a private cloud that fits into a single rack.

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The F-Script with John Herbert on Software Gone Wild

July 8, 2014 - 10:11pm

The use of tools has accelerated human evolution and made us what we are today. Networking is no different, and yet there aren’t that many tool builders among the networking engineers… or maybe all you need is a nudge and some hints on how to get started.

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The Virtual Design Master Is Starting Today

July 7, 2014 - 11:03pm

A while ago I was listening to a podcast describing Project Runway for geeks – the Virtual Design Master – and decided to do what I could to help them ;)

The second season is starting today – the list of participants is already online (and you might watch the videos of the first season while waiting for the first challenge).

Data Center Design Case Studies on Amazon Kindle

July 6, 2014 - 9:59pm

If you’re an avid Kindle user, you can buy the Data Center Design Case Studies book on Amazon. Here’s the link, search should find it on most other Amazon marketplaces.

However, if you can survive reading the PDF version, please buy it straight off my web site. Here’s why:

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The summer office is finally operational...

July 3, 2014 - 11:33pm

Expect a significantly reduced blogging frequency ;)

Build a Cloud in Three Easy Steps

July 2, 2014 - 10:15pm

Occasionally I get a question about some totally impossible implementation detail (example: can we use OpenStack OVS plugin on VMware to avoid buying NSX?). These questions are often coming from people who painted themselves into a corner and are now desperately looking for MacGyver’s shoelaces to pull themselves out.

It’s easy to blame the engineer who tries to do the obviously impossible, but it’s often not his fault – these days a lot of technical people get pulled into the game of Build a Cloud in Three Easy Steps.

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Network Programmability with David Gee on Software Gone Wild

July 2, 2014 - 2:01am

For the second episode of Software Gone Wild I got a truly interesting guest: David Gee, a network engineer already working on numerous network programmability and orchestration deployment.

During our half-hour chat we couldn’t avoid the question of whether every networking engineer will become a programmer and David provided an interesting answer: you don’t have to program, but you’ll definitely have to start thinking more like a good programmer.

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What Is This API Thingy?

June 30, 2014 - 10:04pm

A reader sent me this question:

I am hearing a lot about API in reference to SDN. I do not have any software or programming background but would like to understand this API in practical way. Could you help me?

TL&DR: API is CLI for program-to-program communication

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Mice, Elephants and Virtual Switches

June 30, 2014 - 5:09am

The Mice and Elephants is a traditional QoS fable – latency-sensitive real time traffic (or request-response protocol like HTTP) stuck in the same queue behind megabytes of file transfer (or backup or iSCSI) traffic.

The solution is also well known – color the elephants pink (aka DSCP marking) and sort them into a different queue – until the reality intervenes.

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A Long Trip down the Memory Lane

June 29, 2014 - 4:01am

True old-timers might appreciate the analogies I got while writing the Network Infrastructure as Code article. Let’s start with “do you remember this thingy?”

Source: Wikipedia

If you recognized the state-of-the-art (in those days) box in the picture, you might be able to relate to this screenshot:

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It works, but is it scalable?

June 28, 2014 - 12:17am

This is pretty close to some SDN architectures I was privileged to see in the last three years.

Source: strategic humor @ HBR

Virtual Routers 101

June 26, 2014 - 10:50pm

I was asked to do a presentation at the recent Slovenian NOG (SINOG) meeting. I did an SDN one at the previous meeting, making NFV the next obvious choice… but I decided to put an interesting spin on it and focused on virtual routers.

View the presentation

Infrastructure as Code Actually Makes Sense

June 25, 2014 - 10:16pm

When I heard people talking about “networking infrastructure as code” I dismissed that as yet another Software-Defined-Everything one-controller-to-rule-it-all hype. Boy was I wrong.

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Snabb Switch and NFV on OpenStack in Software Gone Wild

June 24, 2014 - 10:49pm

Last September I received a peculiar tweet from Luke Gorrie pointing me to a software switch pushing 200 Gbps through an Intel server literally hours after I’d watched the Deutsche Telekom Terastream presentation, so I mentioned Luke’s Snabb Switch as a potential performance solution in an email to Ian Farrer… and before Ian managed to reply, Luke was already working for Deutsche Telekom.

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Unnumbered OSPF Interfaces in Quagga (and Cumulus)

June 24, 2014 - 10:43am

Carlos Mendioroz sent me an interesting question about unnumbered interfaces in Cumulus Linux and some of the claims they make in their documentation.

TL&DR: Finally someone got it! Kudos for realizing how to use an ancient trick to make data center fabrics easier to deploy (and, BTW, the claims are exaggerated).

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