Build the Next-Generation Data Center
6 week online course starting on September 1st

Unexpected Recovery Might Kill Your Data Center

Here’s an interesting story I got from one of my friends:

  • A large organization used a disaster recovery strategy based on stretched IP subnets and restarting workloads with unchanged IP addresses in a secondary data center;
  • Once they experienced a WAN connectivity failure in the primary data center and their disaster recovery plan kicked in.


Software-Defined Security and VMware NSX Events

I’m presenting at two Data Center Interest Group Switzerland events organized by Gabi Gerber in Zurich in early June:

  • In the morning of June 7th we’ll talk about software-defined security, data center automation and open networking;
  • In the afternoon of the same day (so you can easily attend both events) we’ll talk about VMware NSX microsegmentation and real-life implementations.

I hope to see you in Zurich in a bit more than a month!

Response: Are Open-Source Controllers Ready for Carrier-Grade Services?

My beloved source of meaningless marketing messages led me to a blog post with a catchy headline: are open-source SDN controllers ready for carrier-grade services?

It turned out the whole thing was a simple marketing gig for Ixia testers, but supposedly “the response of the attendees of an SDN event was overwhelming”, which worries me… or makes me happy, because it’s easy to see plenty of fix-and-redesign work in the future.

Setting Terminal Width in Cisco IOS

This must be old news to most of you (I managed to stay away from CLI for way too long), but I was pleasantly surprised that you can set terminal width (not just length) in Cisco IOS.

More Open-Source Network Management Tools on Software Gone Wild

After listening to Open-Source Network Engineer Toolbox Nick Buraglio sent me an email saying “we should do another podcast on open-source network management tools…” and so we did. In Episode 56 of Software Gone Wild Nick, Elisa Jasinska and myself discussed a whole range of network management challenges and open-source tools you can use to address them.

Implementing BGP-Based SDN Controller

One of my readers sent me this observation while reviewing my BGP-Based SDN Solutions webinar:

I am a bit surprised the SDN controller can actually be so lightweight.

Well, that's the benefit of augmenting an existing well-developed ecosystem instead of reinventing the wheel and reimplementing every single bit of functionality we had to develop to make networks work throughout the last 5 decades.

Optimize Your Data Center: Virtualize Your Servers

A month ago I published the video where I described the idea that “two switches is all you need in a medium-sized data center”. Now let’s dig into the details: the first step you have to take to optimize your data center infrastructure is to virtualize all servers.

For even more details, watch the Designing Private Cloud Infrastructure webinar, or register for the Building Next-Generation Data Center course.

Scalability of OpenFlow Control Plane Network

This article was initially sent to my SDN mailing list. To register for SDN tips, updates, and special offers, click here.

I got an interesting question from one of my readers:

If every device talking to a centralized control plane uses an out-of-band channel to talk to the OpenFlow controller, isn’t this a scaling concern?

A year or so ago I would have said NO (arguing that the $0.02 CPU found in most networking devices is too slow to overload a controller or reasonably-fast control-plane network).

Some People Don’t Get It: It Will Eventually Fail

Mark Baker left this comment on my Stretched Firewalls across Layer-3 DCI blog post:

Strange how inter-DC clustering failure is considered a certainty in this blog.

Call it experience or exposure to a larger dataset. Anything you build will eventually fail; just because you haven’t experienced the failure yet doesn’t mean that the system will never fail but only that you were lucky so far.

PCEP Usage Scenarios

After covering the details of PCEP protocol in the BGP-LS and PCEP Deep Dive webinar Julian Lucek focused on how a controller would use PCEP to build MPLS TE paths across a network.

Oh, and don’t forget to explore the rest of the PCEP webinar and other SDN webinars after watching the video ;)

First Guest Speaker in Building Next-Generation Data Center Course

When I started thinking about my first online course, I decided to create something special – it should be way more than me talking about cool new technologies and designs – and the guest speakers are a crucial part of that experience.

The first guest speaker is one of the gurus of network design and complexity, wrote numerous books on the topic, and recently worked on a hardware-independent network operating system.

More on Reading and Writing Books

Russ White wrote a great response to my “Do You Really Want to Write that Book?” blog post and I couldn’t agree more with what he wrote. Unfortunately, he seems to be a bit over-idealistic when analyzing why the market for high-end content is so small.

You know I usually have a cynical explanation handy, so here it is: too many people calling themselves engineers for no particular reason simply don’t care. It’s way easier to Google-and-paste your way around than to invest time in understanding the fundamentals.

Zero Bandwidth Traffic Engineering

Oliver Steudler from Juniper sent me a link to an interesting Juniper blog post describing zero-bandwidth traffic engineering.

Read the blog post first and then come back for some opinionated rambling ;)

Is the problem real? Yes.

Shortest Path Bridging (SPB) and Avaya Fabric on Software Gone Wild

A few months ago I met a number of great engineers from Avaya and they explained to me how they creatively use Shortest Path Bridging (SPB) to create layer-2, layer-3, L2VPN, L3VPN and even IP Multicast fabrics – it was clearly time for another deep dive into SPB.

It took me a while to meet again with Roger Lapuh, but finally we started exploring the intricacies of SPB, and even compared it to MPLS for engineers more familiar with MPLS/VPN. Interested? Listen to Episode 54 of Software Gone Wild.

Open-Source Software Could Have Great Documentation

During one of my Network Automation workshops one of the attendees said: “Why are you using open-source software? It’s so poorly documented and impossible to set up.

I totally understood what he was trying to say (I’ve seen too many examples of just read the code approach), but fortunately there are still people who understand the value of documentation.

Host-to-Network Multihoming Kludges

Continuing our routing-on-hosts discussions, Enno Rey (of the Troopers and IPv6 security fame) made another interesting remark “years ago we were so happy when we finally got rid of gated on Solaris” and I countered with “there are still people who fondly remember the days of running gated on Solaris” because it’s a nice solution to host-to-network multihoming problem.

Quoting RFC1925, “It’s easier to move a problem around than to solve it” and people have been extremely good at moving this particular problem around for decades.