Data Models

What is YANG? Why is it useful? Where can I store my data? When should I start using a database instead of text files? What about Excel spreadsheets? What’s the difference between relational and NoSQL databases? You’ll get answers to all these questions in this section.

You’ll also learn how to build a data model describing your network and how you can transform a network- or services-focused data model into a device-focused data model (and when that would be useful).

The guest presentation by Marcel Wiget (Juniper) describes YANG data models, briefly introduces NETCONF, and shows how you can use OpenConfig or your custom data model (described in YANG) to configure Junos devices.

While configuring network devices with OpenConfig sounds really interesting, don't expect to be able to do it any time soon - the vendors are (as usual) very reluctant to add yet another layer of indirection on top of their already-bloated software.

David Barroso decided to fix that problem within NAPALM, and wrote a set of libraries (napalm-yang) that perform translation between OpenConfig (or any other) YANG data model and device configurations.

You won’t be able to follow the rest of this module without a thorough understanding of Ansible. If you haven’t completed the Ansible for Networking Engineers online course, please do it now, and focus on the data modeling part of DMVPN case study.

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In this part of the Network Automation Use Cases webinar David Barroso walks you through layers of network automation abstraction: from abstracting vendor-specific APIs with NAPALM to abstracting device configuration differences, and finally abstracting device state into infrastructure data model.

Most of the intent-based systems are nothing more than a fancy orchestration system with an abstraction layer. This section describes the many levels of abstraction you can implement in such a system, and the data models you would need to do it.

Orchestration systems with an abstraction layer usually use network- and services data models to describe the desired system functionality, and device (or node) data models to describe the target state of the system.

In every such system, someone has to perform the mapping between the high-level and low-level data models, and this section describes how you can do that with Ansible.

In another network automation use case Dinesh Dutt talked about automated data center fabric deployments. Focus on how simple his data model is and how he builds a whole fabric from just a few configurable parameters.

In the hands-on exercises you’ll build a data model for your network automation solution and store it in one or more YAML files.

If you want to know more about NETCONF, watch at least the first part of NETCONF and YANG webinar with David Gee (~ 1 hour if you skip the hands-on part).

You might also want to watch the NETCONF Deep Dive section to understand the NETCONF protocol details.

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