A while ago I did an interview about programmable infrastructure that got published as an article in mid-March. As you might expect, my main message was “technology will never save you unless you change your processes to adapt to its benefits.”

Hope you’ll enjoy it!

Got this question from a networking engineer who couldn’t decide whether to go for CCIE Data Center certification or attend my Building Next-Generation Data Center online course:

I am considering pursuing CCIE DC. I found your Next-Generation DC course very interesting. Now I am bit confused trying to decide whether to start with CCIE DC first and then do your course.

You might be in a similar position, so here’s what I told him.

Every second blue moon someone asks me whether they could buy ipSpace.net subscription with PayPal. So far, the answer has been no.

Recently we started testing whether we could use Digital River to solve a few interesting challenges we had in the past, and as they offer PayPal as a payment option, it seemed to be a perfect fit for a low-volume trial.

The only product that you can buy with PayPal during the trial is the standard subscription – just select PayPal as the payment method during the checkout process.

Finally: the first three subscribers using PayPal will get extra 6 months of subscription.

Bruno Wollman pointed me to an excellent article on the ignorance of expertise and confidence of the dumb. Here’s the TL&DR summary (but you should really read the whole thing):

• The expert isn’t always right;
• An expert is far more likely to be right than you are;
• Experts come in many flavors – usually you need a combination of education and expertise;
• In any discussion, you have a positive obligation to learn at least enough to make the conversation possible. University of Google doesn’t count;
• While you’re entitled to have an opinion, having a strong opinion isn’t the same as knowing something.

Enjoy ;)

Here's a trick question: how often do your Visio diagrams match what's really implemented in your network?

Wouldn't it be great to be able to create or modify them on-the-fly based on what's really configured in the network? That's exactly what Anthony Burke demonstrated in the PowerNSX part of PowerShell for Networking Engineers webinar (source code).

You’ll need at least free ipSpace.net subscription to watch the video.

The proponents of the “let’s run EVPN over EBGP underlay” idea often ignore an interesting challenge: EVPN advocates the use of automatically-generated Route Targets, which might not work when every leaf switch uses a different AS number.

I explored this particular can of worms in the EVPN Route Target Considerations section of the Using BGP in a Data Center Leaf-and-Spine Fabric saga.

Remember the IPv6 elephant in the room – the inability to do small-site multihoming without NAT (well, NPT66)? IPv6 is old enough to buy its own beer, but the elephant is still hogging the room. Tons of ideas have been thrown around in IETF (mostly based on source address selection tricks), but none of that spaghetti stuck to the wall.

Stumbled upon this paragraph on Russ White’s blog:

I don’t really know how you write a certification that does not allow someone who has memorized the feature guide to do well. How do you test for protocol theory, and still have a broad enough set of test questions that they cannot be photographed and distributed?

As Russ succinctly explained the problem is two-fold:

One of my readers sent me a container security question after reading the Application Container Security Guide from NIST:

We are considering segregating dev/test/prod environments with bare-metal hardware. I did not find something in the standard concerning this. What should a financial institution do in your opinion?

I am no security expert and know just enough about containers to be dangerous, but there’s a rule that usually works well: use common sense and identify similar scenarios that have already been solved.

I’m always telling network engineers attending my network automation workshops and online courses that there’s no magic bullet or 3-steps-to- success.

You cannot automate a process until you can describe it with enough details so that someone who has absolutely no clue what should be done can execute it.

David Gee published a long (and somewhat ranty) version of that statement. Enjoy!

In the second half of his Networks, Buffers, and Drops webinar JR Rivers focused on end systems: what tools could you use to measure end-to-end TCP throughput, or monitor performance of an individual socket or the whole TCP stack?

REST API is the way of the world and all network devices should support it, right? Well, Ken Duda (Arista) disagreed with this idea during his Networking Field Day presentation, but unfortunately there wasn’t enough time to go into the details that would totally derail the presentation anyway.

Fixing that omission: should we have REST API on network devices or not?

My BGP in EVPN-Based Data Center Fabrics blog post generated numerous comments from engineers disagreeing with my views on using IBGP-over-EBGP.

As usual, there were three kinds of comments:

The idea of generating random IPv6 addresses (so you cannot be tracked across multiple networks based on your MAC address) that stay stable within each subnet (so you don’t pollute everyone’s ND cache every time you open your iPad) is pretty old: RFC 7217 was published almost exactly four years ago.

Linux was quick to pick it up, OpenBSD got RFC 7127 support a few weeks ago. However, there’s an Easter egg in the OpenBSD patches that implement it: SLAAC on OpenBSD now works with any prefix length (not just /64).

Years ago Petr Lapukhov decided that it’s a waste of time to try to make OSPF or IS-IS work in large-scale data center leaf-and-spine fabrics and figured out how to use BGP as a better IGP.

In the meantime, old-time routing gurus started designing routing protocols targeting a specific environment: highly meshed leaf-and-spine fabrics. First in the list: Routing in Fat Trees (RIFT).