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Category Archives for "ipSpace.net"

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.

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

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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:

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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.

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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.

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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.

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 ipSpace.net subscription to watch the video.

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.

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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.

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.

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Network Automation with 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: Brigade, an interesting network automation tool we discussed in Episode 90 of Software Gone Wild.

Notes:

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:

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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).

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