Last week a large European financial institution had a bad hair day. My friend Christoph Jaggi asked for my opinion, and I decided not to focus on the specific problem (that’s what post-mortems are for) but to point out something that’s often forgotten: don’t believe your system won’t fail, be prepared to deal with the failure.

I keep getting questions along the lines of “should I go with VMware NSX or should I deploy Cisco ACI” every single week, and as you know it’s hard to answer anything but it depends without spending hours on the topic.

That’s exactly what we plan to do in Zurich next Tuesday (May 16th) in a DIGS workshop that will run in parallel with the Data Center & Cloud Day (part of the SIGS Technology Conference).

Not long after I published the let’s drop some configuration commands rant I got a very nice email from Nicolas Delecroix, Technical Marketing Engineer in Cisco INSBU, effectively saying “Would you have time for a short WebEx call to discuss the root cause of the problem and what we did to fix it?”

Of course I agreed and here’s what they told me:

An engineer watching my IPv6 Transition Mechanisms webinar sent me this question:

We would appreciate any insight you might have as to which transitional mechanisms the ISPs are actually deploying.

All of them ;)

One of my readers sent me this question (slightly rephrased):

Assume you have A,B and C connected in a triangle (with an alternate longer path to C). What happens if C loses its links to A and B? Won’t the traffic to C loop between A and B for a while?

As always, it depends.

The awesome Troopers crew published conference videos, including my Securing Network Automation presentation (more, including slide deck).

One of my readers was considering Dell/EMC hyperconverged solutions and sent me this question:

Just wondering if you have a chance to check out VxRail.

I read the data sheet and spec sheet, but have never seen anyone using it (any real-life experience highly welcome – please write a comment).

Ansible, Puppet, Chef, Git, GitLab… the list of tools you can supposedly use to automate your network is endless, and there’s a new kid on the block every few months.

In Episode 77 of Software Gone Wild we explored Salt, its internal architecture, and how you can use it with Mircea Ulinic, a happy Salt user/contributor working for Cloudflare, and Seth House, developer @ SaltStack, the company behind Salt.

Jordan Martin published a nice summary of what I’ve been preaching for years: centralized control plane doesn’t work (well) while controller-based network orchestration makes perfect sense.

While I totally agree with what he wrote he got the hype angle wrong:

Short update for those that read the original blog post: it turns out that the answer to the question “Is it possible to run VMware NSX on redundantly-connected hosts in a pure L3 data center fabric?” is still NO.

VTEPs from different ESXi hosts can be in different subnets, but while a single ESXi host might have multiple VTEPs, the only supported way to use them is to put them in the same subnet. I removed the original blog post.