There are two reasonable ways of building a layer-2 leaf-and-spine fabric: use VXLAN (the direction almost everyone in the industry is taking at the moment), or routing-on-layer-2 technology like TRILL or SPB.

My friend Christoph Jaggi published new versions of his Metro- and Carrier Ethernet Encryptor documents:

• Technology introduction, including an overview of encryption mechanisms, Carrier Ethernet connectivity models, typical deployments, and key management challenges.
• Market overview, including standards, control- and data plane considerations, key- and system management, and network integration.

Enjoy!

A network engineer interested in attending the Building Network Automation Solutions online course sent me this question:

Does the course cover only Ansible, or does it also cover other automation tools like Python?

The course focuses on how you’d build a network automation solution. Selecting the best tool for the job is obviously one of the major challenges, and so one of the self-study modules describes various automation tools and where you could use them to build a full-blown solution.

Rich sent me a question about temporary traffic blackholing in networks where every router is running IGP (OSPF or IS-IS) and iBGP.

He started with a very simple network diagram:

A network architect working for a system integrator sent me a number of questions along the lines of “what would be an interesting alternative to pursuing another CCxE certification?”

He wrote:

One of the use cases we covered in Network Automation Use Cases webinar is a fully-automated data center fabric deployment. Dinesh Dutt (Cumulus Networks) started this section with an overview of challenges you might face in data center fabric deployments.

John Allspaw wrote an interesting blog post describing how he dealt with requests to introduce new technologies or design patterns. While he’s writing from the software development perspective, the ideas apply equally well to network architecture, so go and read what he has to say (and how he defines what engineering method is).

One of the engineers going through my Ansible for Networking Engineers online course sent me this question:

In the Introduction section, you mention a use case of upgrading software. Do you have an example playbook?

Unfortunately, I don’t. Upgrading software is one of those things that’s almost impossible to simulate in a virtual lab.

We’re almost done with our data center infrastructure optimization journey. In this step, we’ll virtualize the network services.

Eyvonne Sharp wrote an interesting blog post describing the challenges Cisco might have integrating Viptela acquisition, particularly the fact that Viptela has a software solution running on low-cost hardware.

Guess what… Cisco IOS also runs on low-cost hardware, it’s just that Cisco routers are sold as a software+hardware bundle masquerading as expensive hardware.