Your browser failed to load CSS style sheets. Your browser or web proxy might not support elliptic-curve TLS

Building network automation solutions

9 module online course

Start now!

Upcoming Webinars and Events: October 2018

The fast pace of webinars continues in October 2018:

There are no on-site events planned until early December:

  • We’ll run another on-site workshop in Zurich on December 5th . This time we’ll focus on using VXLAN and EVPN to build multi-site fabrics;
  • I’ll talk about making SDN better with IPv6 on December 6th.

You can attend all upcoming webinars with an webinar subscription. Online courses and on-site events require separate registration.

Add comment

VXLAN Broadcast Domain Size Limitations

One of the attendees of my Building Next-Generation Data Center online course tried to figure out whether you can build larger broadcast domains with VXLAN than you could with VLANs. Here’s what he sent me:

I'm trying to understand differences or similarities between VLAN and VXLAN technologies in a view of (*cast) domain limitation.

There’s no difference between the two on the client-facing side. VXLAN is just an encapsulation technology and doesn’t change how bridging works at all (read also part 2 of that story).

read more see 3 comments

Smart or Dumb NICs on Software Gone Wild

Hardware vendors are always making their silicon more complex and feature-rich. Is that a great idea or a disaster waiting to happen? We asked Luke Gorrie, the lead developer of Snabb Switch (an open-source user-land virtual switch written in Lua) about his opinions on the topic.

TL&DL version: Give me a dumb NIC, software can do everything else.

If you want to know more, listen to Episode 93 of Software Gone Wild.

see 4 comments

Using CSR1000V in AWS Instead of Automation or Orchestration System

As anyone starting their journey into AWS quickly discovers, cloud is different (or as I wrote in the description of my AWS workshop you feel like Alice in Wonderland). One of the gotchas: when you link multiple routing domains (Virtual Private Clouds – the other VPC) you have to create static routing table entries on both ends. Even worse, there’s no transit VPC – you have to build a full mesh of relationships.

The correct solution to this challenge is automation:

read more see 7 comments

Infrastructure-as-Code, NETCONF and REST API

This is the third blog post in “thinking out loud while preparing Network Infrastructure as Code presentation for the network automation course” series. You might want to start with Network-Infrastructure-as-Code Is Nothing New and Adjusting System State blog posts.

As I described in the previous blog post, the hardest problem any infrastructure-as-code (IaC) tool must solve is “how to adjust current system state to desired state described in state definition file(s)”… preferably without restarting or rebuilding the system.

There are two approaches to adjusting system state:

read more see 5 comments

Data Point: Why Automation Won’t Replace Humans

Here’s a bit of good news for those of you scared of network automation replacing your jobs: even Elon Musk didn’t manage to pull it off, so I don’t think a networking vendor dabbling in intent will manage to do it (particularly considering the track record of networking vendors’ network management and orchestration systems).

read more see 1 comments

Worth Reading: Intent-Based Networking Taxonomy

This blog post was initially sent to the subscribers of my SDN and Network Automation mailing list. Subscribe here.

Saša Ratković (Apstra) published a must-read Intent-Based Networking Taxonomy which (not surprisingly) isn’t too far from what I had to say about the topic in a blog post and related webinar.

It’s also interesting to note that the first three levels of intent-based networking he described match closely what we’re discussing in Building Network Automation Solutions online course and what David Barroso described in Network Automation Use Cases webinar:

read more Add comment

Adjusting System State with Infrastructure as Code

This is the second blog post in “thinking out loud while preparing Network Infrastructure as Code presentation for the network automation course” series. If you stumbled upon it, you might want to start here.

An anonymous commenter to my previous blog post on the topic hit the crux of the infrastructure-as-code challenge when he wrote: “It's hard to do a declarative approach with Ansible and the nice network vendor APIs.” Let’s see what he was trying to tell us.

read more see 6 comments

Network Automation with Ansible for Undergraduate Students

Last year’s experiment generated so much interest that I decided to repeat it this year: if you’re an undergraduate or Master's student and manage to persuade us that you’re motivated enough to automate the **** out of everything, you’ll get a free seat in Ansible for Networking Engineers online course.

Interested? Check out the details, and apply before October 1st.

Too old? Please spread the word ;)

see 2 comments

Routing in Data Center: What Problem Are You Trying to Solve?

Here’s a question I got from an attendee of my Building Next-Generation Data Center online course:

As far as I understood […] it is obsolete nowadays to build a new DC fabric with routing on the host using BGP, the proper way to go is to use IGP + SDN overlay. Is my understanding correct?

Ignoring for the moment the fact that nothing is ever obsolete in IT, the right answer is it depends… this time on answer(s) to two seemingly simple questions “what services are we offering?” and “what connectivity problem are we trying to solve?”.

read more see 4 comments

Repost: Tony Przygienda on Valley-Free (or Non-ZigZag) Routing

Most blog posts generate the usual noise from the anonymous peanut gallery (if only they'd have at least a sliver of Statler and Waldorf in them), but every now and then there's a comment that's pure gold. The one made by Tony Przygienda (of RIFT fame) on Valley-Free Routing post is so good and relevant that I decided to republish it as a separate blog post. Enjoy!

read more see 3 comments

Worth Reading: IPv6 Renumbering == Pain in the …

Johannes Weber was forced to stress-test the IPv6 networks are easy to renumber nonsense and documented his test results – a must-read for everyone deploying IPv6.

He found out that renumbering IPv6 in his lab required almost four times as many changes as renumbering (outside) IPv4 in the same lab.

My cynical take on that experience: “Now that you’ve documented everything that needs to be changed, make sure it’s automated the next time ;)

see 9 comments

Valley-Free Routing

Reading academic articles about Internet-wide routing challenges you might stumble upon valley-free routing – a pretty important concept with applications in WAN and data center routing design.

If you’re interested in the academic discussions, you’ll find a pretty exhaustive list of papers on this topic in the Informative References section of RFC 7908; here’s the over-simplified version.

read more see 5 comments

Network Infrastructure as Code Is Nothing New

Following “if you can’t explain it, you don’t understand it” mantra I decided to use blog posts to organize my ideas while preparing my Networking Infrastructure as Code presentation for the Autumn 2018 Building Network Automation Solutions online course. Constructive feedback is highly appreciated.

Let’s start with a simple terminology question: what exactly is Infrastructure as Code that everyone is raving about? Here’s what Wikipedia has to say on the topic:

read more see 8 comments

Do We Need Leaf-and-Spine Fabrics?

Evil CCIE left a lengthy comment on one of my blog posts including this interesting observation:

It's always interesting to hear all kind of reasons from people to deploy CLOS fabrics in DC in Enterprise segment typically that I deal with while they mostly don't have clue about why they should be doing it in first place. […] Usually a good justification is DC to support high amount of East-West Traffic....but really? […] Ask them if they even have any benchmarks or tools to measure that in first place :)

What he wrote proves that most networking practitioners never move beyond regurgitating vendor marketing (because that’s so much easier than making the first step toward becoming an engineer by figuring out how technology really works).

read more see 3 comments

Is BGP Good Enough with Dinesh Dutt on Software Gone Wild

In recent Software Gone Wild episodes we explored emerging routing protocols trying to address the specific needs of highly-meshed data center fabrics – RIFT and OpenFabric. In Episode 92 with Dinesh Dutt we decided to revisit the basics trying to answer a seemingly simple question: do we really need new routing protocols?

read more see 4 comments

Traditional Leaf-and-Spine Fabric Versus Cisco ACI

One of my subscribers wondered whether it would make sense to build a traditional leaf-and-spine fabric or go for Cisco ACI. He started his email with:

One option is a "standalone" Spine/Leaf VXLAN-with EVPN deployment based on Nexus equipment. This approach could probably be accompanied by some kind of automation like Ansible to ease operation/maintenance of the network.

This is what I would do these days if the customer feels comfortable investing at least the minimum amount of work into an automation solution. Having simpler technology + well-understood automation solution is (in my biased opinion) better than having a complex black box.

read more see 9 comments

Interview: Benefits of Network Automation (Part 2)

As promised, here’s the second part of my Benefits of Network Automation interview with Christoph Jaggi published in German on Inside-IT last Friday (part 1 is here).

What are some of the challenges?

The biggest challenge everyone faces when starting the network automation is the snowflake nature of most enterprise networks and the million one-off exceptions we had to make in the past to cope with badly-designed applications or unrealistic user requirements. Remember: you cannot automate what you cannot describe in enough details.

read more see 1 comments

Interview: Benefits of Network Automation (Part 1)

I had a great chat about the benefits of network automation with Christoph Jaggi a while ago, resulting in 2-part interview published by Inside-IT. As you might prefer to read the English original instead of using Google Translate, here it is (or you could practice your language skills and read the German version).

read more Add comment

Updated: Networking Modules in Building Next-Generation Data Centers Online Course

We migrated the self-study materials for the network infrastructure and services module of the Building Next-Generation Data Centers online course into the new format, and split the largest module of the course into manageable chunks: data center fabrics 101, designing leaf-and-spine fabrics, overlay virtual networking, IPv6 and network services.

Feedback on the new format is obviously highly welcome. Thank you!

Add comment

Security Aspects of SD-WAN Solutions

Christoph Jaggi, the author of Transport and Network Security Primer and Ethernet Encryption webinars published a high-level introductory article in Inside-IT online magazine describing security deficiencies of SD-WAN solutions based on the work he did analyzing them for a large multinational corporation.

As the topic might be interesting to a wider audience, I asked him to translate the article into English. Here it is…

read more see 6 comments

Reality Check: Self-Driving Networks

I stumbled upon an article with an interesting title (and worth reading): To Make Self-Driving Cars Safe, We Also Need Better Roads and Infrastructure… and thought about the claims along the lines of “if they managed to solve the self-driving cars challenge, it’s realistic to expect self-driving networks” made in Self-Driving Networks podcast episode. Turns out the self-driving cars problem is far far away from being solved.

read more see 2 comments

Upcoming Webinars and Events: Autumn 2018

The summer break is over, and we’ve already scheduled a half-dozen events and webinars in August and September:

We’ll run an event or webinar in almost every single week in September:

read more Add comment

Worth Reading: The Cargo Cult of Google Tools

Tom Hollingsworth published a great blog post summarizing Cloud Field Day presentation by Ben Sigelman.

TL&DR: You’re not Google, you don’t have their problems, and so you’re probably not a good match for their tools.

While this shouldn’t come as a surprise to regular readers of my blog (here’s what I wrote on the topic in 2016), it’s refreshing to see it spelled out so eloquently (and by an ex-Googler).

Add comment

GitOps in Networking

This blog post was initially sent to the subscribers of my SDN and Network Automation mailing list. Subscribe here.

Tom Limoncelli published a must-read article in ACM Queue describing GitOps – the idea of using Pull Requests together with CI/CD pipeline to give your users the ability to request changes to infrastructure configuration.

Using GitOps in networking is nothing new – Leslie Carr talked about this concept almost three years ago @ RIPE 71, and I described some of the workflows you could use in Network Automation 101 webinar.

read more see 1 comments

Updated: First Set of Building Next-Generation Data Centers Self-Study Materials

When I started the Building Next-Generation Data Centers online course, I didn’t have the automated infrastructure to support it, so I had to go with the next best solution: a reasonably-flexible Content Management System, and Mediawiki turned out to be a pretty good option.

In the meantime, we developed a full-blown course support system, included guided self-paced study (available with most online course), and progress tracking. It was time to migrate the data center material into the same format.

read more Add comment

Schneier’s Law Applied to Networking

A while ago I stumbled upon Schneier’s law (must-read):

Any person can invent a security system so clever that she or he can't think of how to break it.

I’m pretty sure there’s a networking equivalent:

Any person can create a clever network design that is so complex that she or he can't figure out how it will fail in production.

I know I’ve been there with my early OSPF network designs.

see 1 comments

Updated: Building Next-Generation Data Centers Live Sessions

After fixing the Building Network Automation Solutions materials, I decided to tackle the next summer janitorial project: creating standard curriculum pages for Building Next Generation Data Centers online course and splitting it into more granular modules (the course is ~150 hours long, and some modules have more than 40 hours of self-study materials).

read more Add comment

Another Benefit of Open-Source Networking Software

You probably know my opinion on nerd knobs and the resulting complexity, but sometimes you desperately need something to get the job done.

In traditional vendor-driven networking world, you might be able to persuade your vendor to implement the knob (you think) you need in 3 years by making it a mandatory requirement for a $10M purchase order. In open-source world you implement the knob, write the unit tests, and submit a pull request.

read more Add comment

Updated: Building Network Automation Solutions Materials and Descriptions

The materials and descriptions for the Building Network Automation Solutions online course got a slight makeover: all live session recordings are now part of self-study materials, and the module description pages use consistent format for self-study materials and live sessions.

Next on the janitor’s list: a similar makeover for the Data Center online course.

Add comment

New Design

During the last weeks I migrated the whole site (apart from the workgroup administration pages) to the new design. Most of the changes should be transparent (apart from the pages looking better than before ;); I also made a few more significant changes:

read more Add comment

New on Interviews and Guest Podcasts

You can find most of the interviews and guest podcasts I did in the last few years on this web page (also accessible as Resources → Interviews from the new menu).

During the summer break, I’m publishing blog posts about the projects I’m working on – as you can see, they include web site maintenance and other janitorial tasks. Regular blog posts will return in autumn.

Add comment

Overview of Training Options

Describe the differences between various training options has been on my to-do list for ages, but I successfully managed to ignore it till I deployed the new top-level menu that contains training category.

Our designers never considered menu items without a corresponding link, so I got an ugly mess that needed to be cleaned up either by fixing the CSS or writing the overview document.

End result: a high-level document describing how webinars, courses and workshops fit into the bigger picture.

During the summer break, I’m publishing blog posts about the projects I’m working on. Regular blog posts will return in autumn.

Add comment

Free Webinars and Videos Are Now Easier to Spot

Another summer break project: replacing the stars next to webinar names in descriptions of various technology areas (example: Data Center) with something more useful. Turns out that marking the webinar title as being Free or having Free items works really well.

Bonus feature: clicking on show free content shows you the content available with free subscription.

During the summer break, I’m publishing blog posts about the projects I’m working on. Regular blog posts will return in autumn.

Add comment

Updated Design on

I synced the CSS used on with the one used on the main web site. There should be no visible changes apart from a few minor fixes in color scheme and the main column being a bit narrower, but if you spot any errors please let me know.

During the summer break, I’m doing much-needed web site maintenance. Regular blog posts will return in autumn.

see 2 comments

Review: Ansible for Networking Engineers

An engineer attending Ansible for Networking Engineers online course sent me this feedback:

This is a great place to learn Ansible and Network Automation from scratch. Starting with an emphasis on the fundamentals (YAML, JSON, Jinja2, how to group your network devices for automation, etc.) you progressively build up towards useful network automation.

He particularly liked the additional features that are part of any online course:

read more Add comment


It turns out that while I cannot bring myself to writing or creating other content during the summer break, it feels perfectly fine to be a janitor and fix small things on the web site.

One of the long-outstanding items: get rid of the free content web site that never went where I wanted it to go… one can do only so much in 24 hours. All the features available on are now part of the main web site including pointers to free content and list of free presentations.

During the summer break, I’m publishing blog posts about the projects I’m working on. Regular blog posts will return in autumn.

Add comment

Feedback: Data Center Infrastructure for Networking Engineers

When I created the Data Center Infrastructure for Networking Engineers webinar, I wanted to reach these goals:

  • Understand the data center acronym soup;
  • Build a conceptual framework of the data center technologies and solutions.

Every now and then I get feedback from a happy attendee telling me how the webinar helped them. Here’s what I got earlier this month:

read more Add comment

Network Infrastructure as Code in Network Automation Online Course

In mid-May, I ran an onsite network automation workshop, and the manager organizing the workshop for his team invited me to a dinner with his peers. Not surprisingly, they wanted to hear about the topics covered in the workshop, and as soon as I mentioned Network-Infrastructure-as-Code several of them said “yes, that definitely needs to be covered.

read more see 2 comments

Time for a Summer Break

So many things have happened since I wrote “this is what we’re going to do in 2018” blog post. We ran

We also did a ton of webinars:

read more see 4 comments

Upcoming Webinars and Events: Autumn 2018

On Tuesday I had the last webinar in spring 2018. One more online course session and it will be time for long summer break. In the meantime, we’re already planning the autumn events:

We also have the first webinars scheduled:

You can attend all these webinars with an webinar subscription.

Add comment

Worth Reading: Fake News in IT

Stumbled upon “Is Tech News Fake” article by Tom Nolle. Here’s the gist of his pretty verbose text:

When readers pay for news, they get news useful to readers.  When vendors pay, not only do the vendors get news they like, the rest of us get that same story.  It doesn’t mean that the story being told is a lie, but that it reflects the view of an interested party other than the reader.

High-quality content is not cheap, so always ask yourself: who’s paying for the content… and if it’s not you, you may be the product.

Full disclosure: is funded exclusively with subscriptions and online courses. Some of our guest speakers work for networking vendors, but we always point that out, and never get paid for that.

see 4 comments

Vertical Integration Musings

One of my readers asked me a question that came up in his business strategy class:

Why did routers and switches end up being vertically integrated (the same person makes the hardware and the software)? Why didn't they go down the same horizontal path as compute (with Intel making chips, OEMs making systems and Microsoft providing the OS)? Why did this resemble the pre-Intel model of IBM, DEC, Sun…?

Simple answer: because nobody was interested in disaggregating them.

read more

Worth Reading: Discovering Issues with HTTP/2

A while ago I found an interesting analysis of HTTP/2 behavior under adverse network conditions. Not surprisingly:

When there is packet loss on the network, congestion controls at the TCP layer will throttle the HTTP/2 streams that are multiplexed within fewer TCP connections. Additionally, because of TCP retry logic, packet loss affecting a single TCP connection will simultaneously impact several HTTP/2 streams while retries occur. In other words, head-of-line blocking has effectively moved from layer 7 of the network stack down to layer 4.

What exactly did anyone expect? We discovered the same problems running TCP/IP over SSH a long while ago, but then too many people insist on ignoring history and learning from their own experience.

see 3 comments

What Is Intent-Based Networking?

This blog post was initially sent to the subscribers of my SDN and Network Automation mailing list. Subscribe here.

Whenever someone mentions intent-based networking I try to figure out what exactly they’re talking about. Not surprisingly, I get a different answer every single time. Confused by all that, I tried to find a good definition, but all I could find was vendor marketing along the lines of “Intent-based networking captures and translates business intent so that it can be applied across the network,” or industry press articles regurgitating vendor white papers.

read more see 9 comments

Start with Business Requirements, not Technology

This is the feedback I got from someone who used ExpertExpress to discuss the evolution of their data center:

The session has greatly simplified what had appeared to be a complex and difficult undertaking for us. Great to get fresh ideas on how we could best approach our requirements and with the existing equipment we have. Very much looking forward to putting into practice what we discussed.

And here’s what Nicola Modena (the expert working with the customer) replied:

As I told you, the problem is usually to map the architectures and solutions that are found in books, whitepapers, and validated designs into customer’s own reality, then to divide the architecture into independent functional layers, and most importantly to always start from requirements and not technology.

A really good summary of what is all about ;) Thank you, Nicola!

see 14 comments

Avoid Summarization in Leaf-and-Spine Fabrics

I got this design improvement suggestion after publishing When Is BGP No Better than OSPF blog post:

Putting all the leafs in the same ASN and filtering routes sent down to the leafs (sending just a default) are potential enhancements that make BGP a nice option.

Tony Przygienda quickly wrote a one-line rebuttal: “unless links break ;-)

read more see 5 comments

Snabb Switch Update on Software Gone Wild

In 2014, we did a series of podcasts on Snabb Switch (Snabb Switch and OpenStack, Deep Dive), a software-only switch delivering 10-20 Gbps of forwarded bandwidth per x86 core. In the meantime, Snabb community slowly expanded, optimized the switching code, built a number of solutions on top of the packet forwarding core, and even forked a just-in-time Lua compiler to get better performance.

To find out the details, listen to Episode 91 of Software Gone Wild in which Luke Gorrie explained how far the Snabb project has progressed in the last four years.

see 1 comments

Automation Win: Document Cisco ACI Configuration

This blog post was initially sent to the subscribers of my SDN and Network Automation mailing list. Subscribe here.

A while ago I complained how the GUI- or API-based orchestration (or intent-based) systems make it hard to figure out what exactly has been configured because they can’t give you a single text configuration file that you could track with version-control software.

Dirk Feldhaus found the situation so ridiculous that he decided to create an Ansible playbook that collects and dumps tenant parameters configured on a Cisco ACI tenant as a homework assignment in the Building Network Automation Solutions online course. As he explained the problem:

read more see 8 comments

Integrating 3rd Party Firewalls with Amazon Web Services (AWS) VPC Networking

After figuring out how packet forwarding really works within AWS VPC (here’s an overview, the slide deck is already available to subscribers) the next obvious question should be: “and how do I integrate a network services device like a next-generation firewall I have to use because $securityPolicy into that environment?

Please don’t get me started on whether that makes sense, that’s a different discussion.

Christer Swartz, an old-time CCIE and occasional guest on Software Gone Wild podcast will show you how to do it with a Palo Alto firewall during my Amazon Web Services Networking Deep Dive workshop on June 13th in Zurich, Switzerland (register here).

see 1 comments

Is EBGP Really Better than OSPF in Leaf-and-Spine Fabrics?

Using EBGP instead of an IGP (OSPF or IS-IS) in leaf-and-spine data center fabrics is becoming a best practice (read: thing to do when you have no clue what you’re doing).

The usual argument defending this design choice is “BGP scales better than OSPF or IS-IS”. That’s usually true (see also: Internet), and so far, EBGP is the only reasonable choice in very large leaf-and-spine fabrics… but does it really scale better than a link-state IGP in smaller fabrics?

read more see 13 comments

Amazon Web Services Networking Overview

Traditional networking engineers, or virtualization engineers familiar with vSphere or VMware NSX, often feel like Alice in Wonderland when entering the world of Amazon Web Services. Everything looks and sounds familiar, and yet it all feels a bit different

I decided to create a half-day workshop (first delivery: June 13th in Zurich, Switzerland) to make it easier to grasp the fundamentals of AWS networking, and will publish high-level summaries as a series of blog posts. Let’s start with an overview of what’s different:

read more see 5 comments

Typical EVPN BGP Routing Designs

As discussed in a previous blog post, IETF designed EVPN to be next-generation BGP-based VPN technology providing scalable layer-2 and layer-3 VPN functionality. EVPN was initially designed to be used with MPLS data plane and was later extended to use numerous data plane encapsulations, VXLAN being the most common one.

Design Requirements

Like any other BGP-based solution, EVPN uses BGP to transport endpoint reachability information (customer MAC and IP addresses and prefixes, flooding trees, and multi-attached segments), and relies on an underlying routing protocol to provide BGP next-hop reachability information.

read more see 9 comments

Upcoming Webinars: June 2018 and Beyond

Wow. Where did the spring 2018 go? It’s almost June… and time for a refreshed list of upcoming webinars:

read more see 7 comments

Happy Eyeballs v2 (and how I Was Wrong Again)

In Moving Complexity to Application Layer I discussed the idea of trying to use all addresses returned in a DNS response when trying to establish a connection with a server, concluding with “I don’t think anyone big enough to influence browser vendors is interested in reinventing this particular wheel.

I’m really glad to report I was wrong ;) This is what RFC 8305 (Happy Eyeballs v2) says:

read more see 4 comments

Fun: Playing Battleships over BGP

BGP is the kitchen-sink of networking protocols, right? Whatever control-plane information you need to transport around, you can do it with BGP… including the battleship coordinates carried in BGP communities.

On the more serious front, it's nice to see at least some ISPs still care enough about the stability of the global Internet to use BGP route flap dampening.

see 2 comments

Video: SPB Fabric Use Cases

As part of his “how does Avaya implement data center fabrics” presentation, Roger Lapuh talked about use cases for SPB in data center fabrics.

I have no idea what Extreme decided to do with the numerous data center fabric solutions they bought in the last few years, so the video might have just a historic value at this point… but it’s still nice to see what you can do with smart engineering.

see 4 comments

Why is Network Automation So Hard?

This blog post was initially sent to the subscribers of my SDN and Network Automation mailing list. Subscribe here.

Every now and then someone asks me “Why are we making so little progress on network automation? Why does it seem so hard?

There are some obvious reasons:

However, there’s a bigger elephant in the room: every network is a unique snowflake.

read more see 16 comments

Dissecting IBGP+EBGP Junos Configuration

Networking engineers familiar with Junos love to tell me how easy it is to configure and operate IBGP EVPN overlay on top of EBGP IP underlay. Krzysztof Szarkowicz was kind enough to send me the (probably) simplest possible configuration (here’s another one by Alexander Grigorenko)

To learn more about EVPN technology and its use in data center fabrics, watch the EVPN Technical Deep Dive webinar.

read more see 17 comments

Response: Vendors Pushing Stretched Layer-2

Got this response to my Stretched Layer-2 Revisited blog post. It’s too good not to turn it into a blog post ;)

Recently I feel like it's really vendors pushing layer 2 solutions, rather than us (enterprise customer) demanding it.

I had that feeling for years. Yes, there are environment with legacy challenges (running COBOL applications on OS/370 with emulated TN3270 terminals comes to mind), but in most cases it’s the vendors trying to peddle unique high-priced non-interoperable warez.

read more see 6 comments

Automation Example: Deploy MPLS/VPN Services

Steve Krause created a full-blown network services deployment solution, including post-deployment validation of OSPF and BGP routing, while attending Building Network Automation Solutions online course (I prefer course attendees working on real-life problems instead of artificial ones).

Hope you’ll enjoy exploring it ;)

Add comment

Get Familiar with Leaf-and-Spine Fabrics

An attendee of my Building Next-Generation Data Center online course asked me what the best learning path might be for a total (data center) beginner that has to design and install a small leaf-and-spine fabric in a near future.

This blog post was written for subscribers who want to get the most out of content. If you’re only interested in free stuff, you might feel it’s a waste of your time. You’ve been warned ;)

read more see 4 comments

Worth Reading: Manual Work Is a Bug

This blog post was initially sent to the subscribers of my SDN and Network Automation mailing list. Subscribe here.

Tom Limoncelli wrote a great article about starting an automation journey from sysadmin perspective. Not surprisingly, his recommendations aren’t that far off from what I’m telling networking engineers in my network automation presentations, Network Automation 101 webinar, and introductory part of Building Network Automation Solutions online course:

read more see 1 comments

Is OSPF or IS-IS Good Enough for My Data Center?

Our good friend mr. Anonymous has too many buzzwords and opinions in his repertoire, at least based on this comment he left on my Using 4-byte AS Numbers with EVPN blog post:

But IGPs don't scale well (as you might have heard) except for RIFT and Openfabric. The others are trying to do ECMP based on BGP.

Should you be worried about OSPF or IS-IS scalability when building your data center fabric? Short answer: most probably not. Before diving into a lengthy explanation let's give our dear friend some homework.

read more see 14 comments

What Is EVPN?

EVPN might be the next big thing in networking… or at least all the major networking vendors think so. It’s also a pretty complex technology still facing some interoperability challenges (I love to call it SIP of networking).

To make matters worse, EVPN can easily get even more confusing if you follow some convoluted designs propagated on the ‘net… and the best antidote to that is to invest time into understanding the fundamentals, and to slowly work through more complex scenarios after mastering the basics.

read more see 5 comments

Worth Reading: Cognitive Dissonance

I always wondered why it’s so hard to accept that someone might not find your preferred solution beautiful but would call it complex or even harmful (or from the other side, why someone could not possibly appreciate the beauty of your design)… and then stumbled upon this blog post by Scott Adams describing cognitive dissonance (the actual topic they’re discussing in the mentioned video doesn’t matter – look for the irrational behavior).

You might say “but we could politely agree to disagree” but unfortunately that implies that at least one of us is not fully rational due to Aumann’s Agreement Theorem.

see 3 comments

Video: Use Network Device REST API with PowerShell

More and more network devices support REST API as the configuration method. While it’s not as convenient as having a dedicated cmdlet, it’s possible to call REST API methods (and configure or monitor network devices) directly from a PowerShell script, as Mitja Robas demonstrated during the PowerShell for Networking Engineers webinar.

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

Add comment

Layers of Single-Pane-of-Glass Abstractions Won’t Solve Your Problems

This blog post was initially sent to the subscribers of my SDN and Network Automation mailing list. Subscribe here.

We’ve been told for years how we’re over-complicating networking, and how the software-defined or intent-based whatever will remove all that complexity and remove the need for networking engineers.

What never ceases to amaze me is how all these software-defined systems are demonstrated: each one has a fancy GUI that looks great in PowerPoint and might even work in practice assuming you’re doing exactly what they demonstrated… trying to be creative could result in interesting disasters.

read more see 9 comments

Autumn 2018 Network Automation Course Starts on September 18th

When the Spring 2018 Building Network Automation Solutions online course started, we didn’t know whether we’d run another course in 2018, so we offered engineers who wanted to get an early start Believer price.

The wait is over: the autumn 2018 course starts on September 18th. The schedule of the live sessions is already online, and we also have the first guest speakers. We’ll announce them in early June at which time you will no longer be able to get the Enthusiast price, so register ASAP.

see 1 comments

Using 4-Byte BGP AS Numbers with EVPN on Junos

After documenting the basic challenges of using EBGP and 4-byte AS numbers with EVPN automatic route targets, I asked my friends working for various vendors how their implementation solves these challenges. This is what Krzysztof Szarkowicz sent me on specifics of Junos implementation:

To learn more about EVPN technology and its use in data center fabrics, watch the EVPN Technical Deep Dive webinar.

read more see 15 comments

Network Automation with Nornir (formerly Brigade) on Software Gone Wild

David Barroso was sick-and-tired of using ZX Spectrum of Network Automation and decided to create an alternative with similar functionality but a proper programming language instead of YAML dictionaries masquerading as one. The result: Nornir, an interesting network automation tool formerly known as Brigade we discussed in Episode 90 of Software Gone Wild.

read more see 3 comments

Automation Win: Zero-Touch Provisioning

Listening to the networking vendors it seems that zero-touch provisioning is a no-brainer … until you try to get it working in real life, and the device you want to auto-configure supports only IP address assignment via DHCP, configuration download via TFTP, and a DHCP option that points to the configuration file.

As Hans Verkerk discovered when he tried to implement zero-touch provisioning with Ansible while attending the Building Network Automation Solutions course you have to:

read more see 8 comments

Update: Automatic EVPN Route Targets in EBGP Environments

After I posted the EVPN Route Target Considerations section of BGP in Data Center Fabrics document Lukas Krattiger pointed out another option available with Cisco Nexus-OS: it can rewrite ASN portion of EVPN Route Target in incoming EBGP updates. Updated version of the affected section is already online.

see 3 comments

We Have to Learn How to Manage the Cattle

Not long after I published the blog post arguing against physical appliances, Oven wrote a very valid comment: "But then you'd have 20 individual systems to manage, add licenses to for additional features, updates etc."

Even though the blog post (and the comment) was written in 2013, not much has changed in the meantime.

read more see 8 comments

Avoid Write-Only Code

You probably know that fantastic feeling when you think your newly-discovered tool is a Hammer of Thor, capable of solving every problem (or at least crashing through it). I guess you’re also familiar with that sinking feeling when you’re trying to use your beloved hammer to whitewash a bikeshed.

Not surprisingly, the cruder the tool is, the quicker you’ll hit its limits, like when you try to do data processing in Jinja2 (hint: don’t).

read more see 4 comments

Is OSPF Unpredictable or Just Unexpected?

I was listening to very interesting Future of Networking with Fred Baker a long while ago and enjoyed Fred’s perspectives and historical insight, until unfortunately Greg Ferro couldn’t possibly resist the usual bashing of traditional routing protocols and praising of intent-based (or flow-based or SDN or…) whatever.

Here’s what I understood he said around 35:17

read more see 12 comments

Upcoming Webinars: May and June 2018

Another month has swooshed by and it’s time for a refreshed list of upcoming webinars:

All you need to have to attend all these live sessions is a current webinar subscription.

Add comment

Found on the Web: Your CLI Should Be a Server

Guess what I found: a software developer trying to persuade his peers that they need an API version of their CLI tool. Yes, I checked and it’s still 2018, and the year CLI dies seems to be a bit further out than some people thought.

I’d guess this proves that the rest of the world is not so far ahead of us lowly network engineers as blabbering pundits and vendor marketers would have us believe.

Needless to say, the engineers architecting Junos knew this almost 20 years ago.

see 4 comments

OpenFabric with Russ White on Software Gone Wild

Continuing the series of data center routing protocol podcasts, we sat down with Russ White (of the CCDE fame), author of another proposal: OpenFabric.

As always, we started with the “what’s wrong with what we have right now, like using BGP as a better IGP” question, resulting in “BGP is becoming the trash can of the Internet”.

read more see 5 comments

Why Can’t We All Use Provider-Independent IPv6 Addresses?

Here’s another back-to-the-fundamentals question I received a while ago when discussing IPv6 multihoming challenges:

I was wondering why enterprise can’t have dedicated block of IPv6 address and ISPs route the traffic to it. Enterprise shall select the ISP's based on the routing and preferences configured?

Let’s try to analyze where the problem might be. First the no-brainers:

read more see 3 comments

Pragmatic Data Center Fabrics

I always love to read the practical advice by Andrew Lerner. Here’s another gem that matches what Brad Hedlund, Dinesh Dutt and myself (plus numerous others) have been saying for ages:

One specific recommendation we make in the research is to “Build a rightsized physical infrastructure by using a leaf/spine design with fixed-form factor switches and 25/100G capable interfaces (that are reverse-compatible with 10G).”

There’s a slight gotcha in that advice: it trades implicit complexity of chassis switches with explicit complexity of fixed-form switches.

read more see 8 comments

Should I Take CCIE DC or Data Center Online Course?

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.

read more see 4 comments Subscription Now Available with PayPal

Every second blue moon someone asks me whether they could buy 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.

Add comment

Worth Reading: The Death of Expertise

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 ;)

see 3 comments

Video: Automatic Diagramming with PowerNSX

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 subscription to watch the video.

see 3 comments

EVPN Route Target Considerations in EBGP Environment

The proponents of the “let’s run EVPN over EBGP underlay” idea often ignore an interesting challenge: EVPN advocates 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.

see 3 comments

New in IPv6: The Next Chapter in IPv6 Multihoming 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.

read more see 9 comments

Couldn’t Resist: Cheat-Proofing Certifications

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:

read more see 10 comments

Container Security through Segregation

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.

read more see 3 comments

Worth Reading: Automation: Easy Button vs Sentient Voodoo Magic Button

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!

see 1 comments

Video: Tools and Knobs to Use when Tweaking TCP Performance

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?

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

see 3 comments

Don't Get Obsessed with REST API

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?

read more see 6 comments

New in IPv6: Stable Random IPv6 Addresses on OpenBSD

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).

read more see 14 comments

Data Center Routing with RIFT on Software Gone Wild

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).

read more see 12 comments

VXLAN Limitations of Data Center Switches

One of my readers found this Culumus Networks article that explains why you can’t have more than a few hundred VXLAN-based VLAN segments on every port of 48-port Trident-2 data center switch.

Expect to see similar limitations in most other chipsets. There’s a huge gap between millions of segments enabled by 24-bit VXLAN Network Identifier and reality of switching silicon. Most switching hardware is also limited to 4K VLANs.

read more see 5 comments

Could We Build an IXP on Top of VXLAN Infrastructure?

Andy sent me this question:

I'm currently playing around with BGP & VXLANs and wondering: is there anything preventing from building a virtual IXP with VXLAN? This would be then a large layer 2 network - but why have nobody build this to now, or why do internet exchanges do not provide this?

There was at least one IXP that was running on top of VXLAN. I wanted to do a podcast about it with people who helped them build it in early 2015 but one of them got a gag order.

read more see 11 comments

Upcoming Webinars, Online Courses and Live Events

The pace of live webinar sessions will slow down a bit in April 2018 due to the onslaught of European spring holiday season. Nonetheless, you’ll be able to enjoy:

On April 19th we’ll have the first DIGS event in 2018, starting with introduction to SDDC and VMware NSX in the morning and NSX workshop in the afternoon.

read more see 1 comments

Dunning-Kruger in IT Infrastructure

Sitting in a taxi driving to CLEUR 2018 in Barcelona we couldn’t resist but complain about the stuff we’re seeing in real-life networks, resulting in someone exclaiming something along the lines of “I can’t understand how someone could do so many stupid things”

Welcome to the wonderful world of Dunning-Kruger Effect.

read more see 2 comments

Presentation and Video: Real-Life Automation Wins

The networking engineers attending the Building Network Automation Solutions online course created numerous amazing automation solutions, most of them already deployed in production networks.

I described some of them in my Troopers 2018 Real-Life Automation Wins talk. The presentation is online and the video has been published on YouTube a few days ago. I hope you’ll find it as inspirational as the Troopers attendees did.

Did you create an awesome automation solution? I’d like to hear about it!

This blog post was initially sent to the subscribers of my SDN and Network Automation mailing list. Subscribe here.

see 1 comments

Is MLAG an Alternative to Stackable Switches?

Alex was trying to figure out how to use Catalyst 3850 switches and sent me this question:

Is MLAG an alternative to use rather than physically creating a switch stack?

Let’s start with some terminology.

Link Aggregation Group (LAG) is the ability to bond multiple Ethernet links into a single virtual link. LAG (as defined in 802.1ax standard) can be used between a pair of adjacent nodes. While that’s good enough if you need more bandwidth it doesn’t help if you want to increase redundancy of your solution by connecting your edge device to two switches while using all uplinks and avoiding the shortcomings of STP. Sounds a bit like trying to keep the cake while eating it.

read more see 11 comments

Meet Me at VMware NSX Deep Dive Event in Zurich

When VMware launched the first version of NSX for vSphere more than four years ago, the NSBU team reached out to me and asked me to create a sponsored webinar describing NSX fundamentals, its architecture, and high-level deployment guidelines.

In the meantime we discussed updating the materials, but nothing ever happened. Time to fix that, this time from a vendor-neutral perspective. We’ll start with a day-long event on April 19th 2018 in Zurich, Switzerland.

read more Add comment

How Do You Get Information from Network Devices?

One of the biggest challenges of network automation is getting usable information from network devices… or as asked by a student in my Building Network Automation Solutions online course in the course Slack team:

How do I get specific information from a specific command from a device without an Ansible Network Module? Is Python the only suggested approach?

I described how hard it is to get structured information from network devices in great details in this section of the Ansible for Networking Engineers webinar and online course. Here are a few more thoughts on the topic:

read more see 5 comments

Worth Reading: Magical Thinking in Internet Security

Someone pointed me to this article by dr. Paul Vixie (of the DNS fame). The best part (as I’m not a security person):

The TCO of new technology products and services, including security-related products and services, should be fudge-factored by at least 3X to account for the cost of reduced understanding. That extra 2X is a source of new spending: on training, on auditing, on staff growth and retention, on in-house integration.

In case you didn’t get it: figure out how much you think the magic unicorn-based software-defined solution will cost, then multiply it by three. Of course nobody wants to admit that.

see 1 comments

Video: Automated Data Center Fabric Deployment Demo

I was focused on network automation this week, starting with a 2-day workshop and continuing with an overview of real-life automation wins. Let’s end the week with another automation story: automated data center fabric deployment demonstrated by Dinesh Dutt during his part of Network Automation Use Cases webinar.

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

Add comment

Speakers in the Spring 2018 Building Next-Generation Data Center Online Course

We managed to get another awesome lineup of speakers for the Spring 2018 Building Next-Generation Data Center online course.

Russ White, one of the authors of CCDE and CCAr programs and highly respected book author will start the course with a topic everyone should always consider when designing new infrastructure: how do you identify tradeoffs and manage complexity, making sure you meet the customer requirements while at the same time having an easy-to-operate infrastructure.

read more Add comment

I Can’t Choose the Gear for You

One of my readers sent me a question along these lines after reading the anti-automation blog post:

Your blog post has me worried as we're currently reviewing offers for NGFW solution... I understand the need to keep the lid on the details rather than name and shame, but is it possible to get the details off the record?

I always believed in giving my readers enough information to solve their challenges on their own (you know, the Teach a man to fish idea).

read more Add comment

Streaming Telemetry Standards: So Many to Choose From

Continuing the Streaming Telemetry saga, let’s focus on presentation formats and transport mechanisms.

I already mentioned three presentation formats: XML (used by NETCONF), JSON (used by RESTCONF) and Protocol Buffers (used by gRPC). Two of them are text-based, the third one (Protocol Buffers) is binary encoding not unlike ASN.1 BER used by SNMP. That can’t be good in a JSON-hyped world, right?

read more see 3 comments

Should You Build or Buy an Automation Solution?

One of the most important aspects of the introductory part of my Building Network Automation Solutions online course is the question should I buy a solution or build my own?

I already described the arguments against buying a reassuringly-expensive single-blob-of-complexity solution from a $vendor, but what about using point tools?

read more see 3 comments

Worth Reading: How to Talk to a C-Level Executive

Ever wondered who manages to produce deja-moo like this one and why they’d do it?

We unveiled a vision to create an intuitive system that anticipates actions, stops security threats in their tracks, and continues to evolve and learn. It will help businesses to unlock new opportunities and solve previously unsolvable challenges in an era of increasing connectivity and distributed technology.

As Erik Dietrich explains in his blog post, it’s usually nothing more than a lame attempt to pretend there are some clothes hanging on the emperor.

Just in case you’re interested: we discussed the state of Intent-Based Majesty’s wardrobe in Network Automation Use Cases webinar.

Add comment

Linux Interfaces on Software Gone Wild

Continuing the Linux networking discussion we had in Episode 86, we focused on Linux interfaces in Episode 87 of Software Gone Wild with Roopa Prabhu and David Ahern.

We started with simple questions like “what is an interface” and “how do they get such weird names in some Linux distributions” which quickly turned into a complex discussion about kernel objects and udev, and details of implementing logical interfaces that are associated with ASIC front-panel physical ports.

read more Add comment

Before Commenting on Someone Mentioning RFC1925 ;)

Some of my readers got annoyed when I mentioned Google’s BeyondCorp and RFC 1925 in the same sentence (to be perfectly clear, I had Rule#11 in mind). I totally understand that sentiment – reading the reactions from industry press it seems to be the best thing that happened to Enterprise IT in decades.

Let me explain in simple terms why I think it’s not such a big deal and definitely not something new, let alone revolutionary.

read more see 2 comments

Who’s Pushing Layer-2 VPN Services?

Here’s another great point Tiziano Tofoni raised in his comment to my EVPN in small data center fabrics blog post:

I cannot understand the usefulness of L2 services. I think that the preference for L2 services has its origin in the enterprise world (pushed by well known $vendors) while ISPs tend to work at Layer 3 (L3) only, even if they are urged to offer L2 services by their customers.

Some (but not all) ISPs are really good at offering IP transport services with fixed endpoints. Some Service Providers are good at offering per-tenant IP routing services required by MPLS/VPN, but unfortunately many of them simply don’t have the skills needed to integrate with enterprise routing environments.

read more see 9 comments

Model-Driven Telemetry Isn’t as New as Some People Think

During the Campus Evolution with Cat9K presentation (I hope I got it right - the whole event was an absolute overload) the presenter mentioned the benefits of brand-new model-driven telemetry, which immediately caused me to put my academic hat on and state that we had model-driven telemetry for at least 30 years.

Don’t believe me? Have you ever looked at an SNMP MIB description? Did it look like random prose to you or did it seem to have some internal structure?

read more see 7 comments

Not Interested in Network Automation? No Problem (for now)

In the Business Impact of Network Automation podcast Ethan Banks asked an interesting question: “what will happen with older networking engineers who are not willing to embrace automation

The response somewhat surprised me: Alejandro Salisas said something along the lines “they’ll be just fine” (for a while).

Let me recap his argument and add a few twists of my own:

read more see 1 comments

Worth Reading: There Are No Enterprises and Service Providers

Russ White wrote a great article along the lines of what we discussed a while ago. My favorite part:

There are companies who consider the network an asset, and companies that consider the network a necessary evil.


On a tangential topic: Russ will talk about network complexity in the Building Next-Generation Data Center online course starting on April 25th.

Add comment

Video: Create an NSX Logical Switch with PowerNSX

After introducing PowerNSX Anthony Burke illustrated how easy it is to use with a Hello, World equivalent: creating a logical switch (VXLAN segment).

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

Want to know more about VMware NSX? We’ll run an NSX-focused event and a NSX Deep Dive workshop in Zurich on April 19th 2018, an overview webinar comparing NSX, ACI and EVPN on March 1st, and a deep dive in VMware NSX architecture later in 2018.

Add comment

Lack of Fast Convergence in SD-WAN Products

One of my readers sent me this question:

I'm in the process of researching SD-WAN solutions and have hit upon what I believe is a consistent deficiency across most of the current SD-WAN/SDx offerings. The standard "best practice" seems to be 60/180 BGP timers between the SD-WAN hub and the network core or WAN edge.

Needless to say, he wasn’t able to find BFD in these products either.

Does that matter? My reader thinks it does:

read more see 24 comments

Single-Image Systems or Automated Fabrics

In the Network Automation 101 webinar and Building Network Automation Solutions online course I described one of the biggest challenges the networking engineers are facing today: moving from thinking about boxes and configuring individual devices to thinking about infrastructure and services, and changing data models which result in changed device configurations.

The $1B question is obviously: and how do we get from here to there?

read more see 8 comments

Upcoming Events

In March 2018, we’ll continue the crazy content producing pace you’ve seen in January and February:
  • We’ll have the first part of NSX, ACI or EVPN webinar on March 1st. This session will cover the basics (don’t expect too many details), a follow-up session on April 24th with Mitja Robas will go into design considerations;
  • The EVPN Technical Deep Dive series with Dinesh Dutt starts on March 6th;
  • Elisa and Paolo will run the final part of Network Visibility with Flow Data on March 8th;
  • Last webinar in March: another installment in the leaf-and-spine saga – Multi-Pod and Multi-Site Fabrics with Lukas Krattiger on March 29th;
March is also the Troopers month. I’ll run a Hands-On Network Automation workshop there and have a motivational presentation during the main conference.
read more Add comment

Anti-Automation from the Antimatter Universe

One of my readers sent me a vivid description of his interactions with one of the so-called next-generation firewall vendors. Enjoy!

We’re using their highly promoted Next Generation Firewall (NGFW) management solution. New cutting edge software, centralized manager… but no CLI for configuration (besides some initial bootstrap commands). "You don't need that because everything is managed from our centralized manager GUI", says $vendor sales managers.

read more see 13 comments

EVPN with MPLS Data Plane in Data Centers

Mr. Anonymous (my most loyal reader and commentator) sent me this question as a comment to one of my blog posts:

Is there any use case of running EVPN (or PBB EVPN) in DC with MPLS Data Plane, most vendors seems to be only implementing NVO to my understanding.

Sure there is: you already have MPLS control plane and want to leverage the investment.

read more see 8 comments

Big Red Button for Network Automation

A while ago I was enjoying a few beers with a longtime friend of mine who happens to be running the networking team for one of the rare companies that understands how infrastructure should be built and operated.

Of course, I had to ask him what he thinks about the imminent death of CLI and all-encompassing automatic provisioning from some central orchestration system. Here’s the gist of his response:

read more see 2 comments

How Useful Is Microsegmentation?

Got an interesting microsegmentation-focused email from one of my readers. He started with:

Since every SDDC vendor is bragging about need for microsegmentation in order to protect East West traffic and how their specific products are better compared to competition, I’d like to ask your opinion on a few quick questions.

First one: does it even make sense?

read more see 9 comments

Automation Isn’t About Building a Button to Press

This is a guest blog post by Carl Buchmann, Managing Solution Consultant at TeraMach. Carl attended the Building Network Automation Solutions online course in 2017.

There is one thing I regret not doing sooner during my automation journey, and that is adopting Git and a proper IDE/text editor that has built-in source control management. I personally use Microsoft Visual Studio Code, as it has Git built in and has many great extensions to validate code syntax.

read more Add comment

Worth Reading: Whiteboxes for Everyone

Gian Paolo Boarina wrote a blog post describing why it’s so ridiculous to see everyone excited about the latest thing Netflix (or Google or Amazon or…) managed to pull off. Absolutely worth reading.

On a similar topic: did you notice that Google started promoting clientless SSL VPN as the next great thing? RFC 1925 anyone?

see 4 comments

[Video] Configure Data Center Devices with PowerShell

PowerShell started as a tool to automate Windows servers. It was picked up by VMware (and others) as a platform on which they built their own solutions (PowerCLI and PowerNSX)… but did you know you can use it to configure data center infrastructure, including NX-OS switches, SAN networks, and Cisco UCS?

In the Configuring Data Center Devices with PowerShell video, Mitja Robas described how to do that, and provided source code for all his examples.

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

Add comment

How Self-Sufficient Do You Want to Be?

The first car I got decades ago was a simple mechanical beast – you’d push something, and a cable would make sure something else moved somewhere. I could also fix 80% of the problems, and people who were willing to change spark plugs and similar stuff could get to 90+%.

Today the cars are distributed computer systems that nobody can fix once they get a quirk that is not discoverable with level-1 diagnostic tools.

read more see 3 comments

ExpertExpress Evolved into a Team of Experts

Years ago, I decided to try out another idea: solving real-life challenges with the help of an easy-to-consume online consulting service. When I discussed the idea with my friends during one of the early Networking Field Day events the opinion was pretty unanimous: “this will never work”

Fortunately, they were wrong. Not only did ~100 customers decided to use it in the meantime, the simple idea grew to a point where I couldn’t do it all on my own.

read more Add comment