Using network definitions to aid automation

The previous section explored the configuration stages and how we can rely on them to build a better network deployment pipeline. On the other hand, we have not covered another issue with the router configuration, which is related to router software versions and router vendors.

Using a router configuration as a source of truth has advantages if your network will not update, grow, or change vendors. If your network is not intended to change, you might not need a definition at all. However, as the majority of the network will need to upgrade or grow, it is important to think about getting away from vendor-specific solutions and create vendor-agnostic definitions of your network.

A router vendor has different configuration defaults, which means some configuration lines might not be necessary with one vendor but be required with the other vendor. For network automation, we want to avoid traps like that and have a network source of truth...