Chapter 2 Why Automate the Network?

o Portfast.  802.1x or port-security commands.  Data and voice VLANs.  QoS settings.  CDP settings.  Power over Ethernet (PoE) settings.  Native VLAN established.  Native VLAN applied on trunk ports.  NTP source.  Security banner presented at login.  AAA.  RADIUS / TACACS+.  ACLs on management ports.  VLAN 1 disabled.

Security requirements, if missed or incorrectly applied, lead to vulnerabilities and threats within the network. These vulnerabilities can be exploited, lead to outages, or bring about data loss in certain scenarios. Having a guaranteed templated configuration ensures that important security components are hard-coded into every template and applied to both the device’s global configuration as well as every interface configuration. Every access port throughout the campus can now be configured the same way and will automatically include security posture standards.

Agility

In an on-demand world networks continue to be the bottleneck of many projects. One of the driving factors for moving to automation is the agility it offers. Most of the common changes to the network become updates to existing data models. When new feature requirements arise, such as the need for multicast, new templates along with new data model variables will be developed. The feature is then released and incorporated into the orchestration of playbooks as a new task. A very repeatable, modular, process evolves which provides the agility to deliver projects more efficiently.

Design Traditional network design often centers around the device configuration commands. While these commands are essential at implementation, it is the data that should drive network design. Network engineers' new responsibilities include crafting human-readable data models and the logic that drives the dynamic templates. Existing or new dynamic documentation should reflect new features as templates are added or updated. Thinking about data first, and the configuration second, network design evolves.

Deployment

The biggest advantages found in network automation are often on the operational side of network management. Large-scale changes are often very difficult to roll out to an enterprise. Introducing QoS to a network, for example, means touching all devices in all layers of the network, often with different code per platform. Devices using Multi-Layer Switching (MLS) or Modular Quality of Service Command Line (MQC) leads to different requirements and configuration commands by platform. Operations receives approved, finalized, network designs, along with deployment steps, from the network engineers. This often requires weeks or months to then complete the delivery to campus from start to end. Network automation, even a hybrid model where operators run Ansible playbooks manually, solves operational