Build the Next-Generation Data Center
6 week online course starting in spring 2017

Building a L3-Only Data Center with Cumulus Linux

Dinesh Dutt was the guest speaker in the second Leaf-and-Spine Fabric Design session. After I explained how you can use ARP/ND information to build a layer-3-only data center fabric that still support IP address mobility Dinesh described the details of Cumulus Linux redistribute ARP functionality and demoed how it works in a live data center.

Would You Use Avaya's SPBM Solution?

Got this comment to one of my L2-over-VXLAN blog posts:

I found the Avaya SPBM solution "right on the money" to build that L2+ fabric. Would you deploy Avaya SPBM?

Interestingly, I got that same question during one of the ExpertExpress engagements and here’s what I told that customer:

Finding Excuses to Avoid Network Automation

My Network Automation in Enterprise Environments blog post generated the expected responses, including:

Some of the environments I am looking at have around 2000-3000 devices and 6-7 vendors for various functions and 15-20 different device platform from those vendors. I am trying to understand what all environments can Ansible scale up to and what would be an ideal environment enterprises should be looking at more enterprise grade automation/orchestration platforms while keeping in mind that platform allows extensibility.

Luckily I didn’t have to write a response – one of the readers did an excellent job:

Worth Reading: So You Want to Become a Cloud Provider

My friend Robert Turnšek published an interesting blog post pondering whether it makes sense to become a cloud provider.

I loved reading it, particularly the Trap for System Integrators part, because I know a bit of the history, and could easily identify two or three failed or stalled projects per paragraph (like: “Just adding some blade servers and storage to the existing server environment won’t make you a cloud provider”). Hope you’ll have as much fun as I did.

Q&A: Ingress Traffic Flow in Multi-Data Center Deployments

One of my readers was watching the Building Active-Active Data Centers webinar and sent me this question:

I'm wondering if you have additional info on how to address the ingress traffic flow issue? The egress is well explained but the ingress issue wasn't as well explained.

There’s a reason for that: there’s no good answer.

StackStorm 101 on Software Gone Wild

A few weeks ago Matt Oswalt wrote an interesting blog post on principles of automation, and we quickly agreed it’s a nice starting point for a podcast episode.

In the meantime Matt moved to StackStorm team so that became the second focus of our chat… and then we figured out it would be great to bring in Matt Stone (the hero of Episode 13).

Testing Ansible Playbooks with Cisco VIRL

Cisco VIRL is the ideal testing environment when you want to test your Ansible playbooks with various Cisco network operating systems (IOS, IOS XE, NX-OS or IOS XR). The “only” gotcha: how do you reach those devices from the outside world?

It was always possible to reach the management interface of devices running with VIRL, and it got even simpler with VIRL release 1.2.

Worth Reading: Creating the Future, One Press Release at a Time

Russ White wrote a great blog post about our failure to predict the future. The part I love most:

If the definition of insanity is doing the same things over and over again, each time expecting different results, what does that say about the world of network engineering?


Q&A: Big Switch SDN

Got this set of questions from one of my readers:

I just met up with DELL guys for Big Switch SDN. They claim there is no routing running on leaf switches, the BCF is purely OpenFlow.

Almost true. It is based on OpenFlow, but they use tons of their own OpenFlow extensions to get stuff to work. That’s also why you have to install their agent on the switches.

First Speakers in Building Network Automation Solutions Online Course

Like with the Next-Generation Data Center course, the live sessions in the Building Network Automation Solutions course include guest speakers, Q&A discussions, and solutions to sample challenges that you’ll be able to use to complete your homework assignments.

The guest speakers for the January 2016 course include:

Video: Docker Networking Options

After introducing the fundamentals of Docker networking, Dinesh Dutt focused on various Docker networking options, including multi-host networking with overlays.

After watching the video, you might also want to listen to Episode 49 of Software Gone Wild with Brent Salisbury, Dave Tucker and Madhu Venugopal.

Can VMware NSX and Cisco ACI Interoperate over VXLAN?

I got a long list of VXLAN-related questions from one of my subscribers. It started with an easy one:

Does Cisco ACI use VXLAN inside the fabric or is something else used instead of VXLAN?

ACI uses VXLAN but not in a way that would be (AFAIK) interoperable with any non-Cisco product. While they do use some proprietary tagging bits, the real challenge is the control plane.

Network Automation Course for Environments Using $Vendor Platform

One of my readers wondered whether it makes sense to attend my Building Network Automation Solution course even if they plan to deploy a $Vendor platform.

It depends, this time on how fast and how far you want to proceed with network automation.

Worth Reading: DNS Is Part of the TCP/IP Stack

Another great blog post by Russ White: DNS is part of the TCP/IP stack, get used to it.

You might also want to tell application developers hard-coding IP addresses or anyone else believing in using /etc/hosts files instead of DNS that those things stopped being sexy around 1980.

Reliability of Clustered Solutions: Another Data Point

A while ago I wrote:

I haven’t seen any hard data, but intuition suggests that apart from hardware failures a standalone firewall might be more stable than a state-sharing firewall cluster.

Guillaume Sachot (working for a web hosting company) sent me his first-hand experience on this topic:

Becoming a Programmer on Software Gone Wild

During our summer team-building podcast we agreed it would be fun to record a few episodes along the “how do I become a programmer” theme and figured out that Elisa Jasinska would be a perfect first candidate.

A few weeks ago we finally got together and started our chat with campfire stories remembering how we got started with networking and programming.