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Category Archives for "ipSpace.net"

Network Automation Is Much More than Configuration Management

Most network automation presentations you can find on the Internet focus on configuration management, either to provision new boxes, or to provision new services, so it’s easy to assume that network automation is really a fancy new term for consistent device configuration management.

However, as I explained in the Network Automation 101 webinar, there’s so much more you can do and today I’d like to share a real-life example from Jaakko Rautanen, an alumni of my Building Network Automation Solutions online course.

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Let’s Drop Some Random Commands, Shall We?

One of my readers sent me a link to CCO documentation containing this gem:

Beginning with Cisco NX-OS Release 7.0(3)I2(1), Cisco Nexus 9000 Series switches handle the CLI configuration actions in a different way than before the introduction of NX-API and DME. The NX-API and DME architecture introduces a delay in the communication between Cisco Nexus 9000 Series switches and the end host terminal sessions, for example SSH terminal sessions.

So far so good. We can probably tolerate some delay. However, the next sentence is a killer…

2017-04-05: The wonderful information disappeared from Cisco's documentation within 24 hours with no explanation whatsoever. However, I expected that and took a snapshot of that page before publishing the blog post ;)

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NETCONF on Cisco Campus Switches on Software Gone Wild

During Cisco Live Europe (huge thanks to Tech Field Day crew for bringing me there) I had a chat with Jeff McLaughlin about NETCONF support on Cisco IOS XE, in particular on the campus switches.

We started with the obvious question “why would someone want to have NETCONF on a campus switch”, continued with “why would you use NETCONF and not REST API”, and diverted into “who loves regular expressions”. Teasing aside, we discussed:

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Railroads and Cars: a Fairy Tale

Imagine a Flatworld in which railways are the main means of transportation. They were using horses and pigeons in the past, and experimenting with underwater airplanes, but railways won because they were cheaper than anything else (for whatever reason, price always wins over quality or convenience in that world).

As always, there were multiple railroad tracks and trains manufacturers, and everyone tried to use all sorts of interesting tricks to force the customers to buy tracks and trains from the same vendor. Different track gauges and heptagonal wheels that worked best with grooved rails were the usual tricks.

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Update: Virtual Switches in vSphere Environment

Just FYI: a week after I wrote this (don't forget to go through the comments), VMware made it official:

…we’ve found that VMware’s native virtual switch implementation has become the de facto standard for greater than 99% of vSphere customers today. … Moving forward, VMware will have a single virtual switch strategy that focuses on two sets of native virtual switch offerings – VMware vSphere® Standard Switch and vSphere Distributed Switch™ for VMware vSphere, and the Open virtual switch (OVS).

Updated: User Authentication in Ansible Network Modules

Ansible network modules (at least in the way they’re implemented in Ansible releases 2.1 and 2.2) were one of the more confusing aspects of my Building Network Automation Solutions online course (and based on what I’m seeing on various chat sites we weren’t the only ones).

I wrote an in-depth explanation of how you’re supposed to be using them a while ago and now updated it with user authentication information.

Why Didn’t We Have Leaf-and-Spine Fabrics a Decade Ago?

One of my readers watched my Leaf-and-Spine Fabric Architectures webinar and had a follow-up question:

You mentioned 3-tier architecture was dictated primarily by port count and throughput limits. I can understand that port density was a problem, but can you elaborate why the throughput is also a limitation? Do you mean that core switch like 6500 also not suitable to build a 2-tier network in term of throughput?

As always, the short answer is it depends, in this case on your access port count and bandwidth requirements.

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