What Is Network As Code?

network as code

Software infrastructure is configured, managed, and monitored by automating scripts known as infrastructure as code, or IaC. An open-source software repository, such as Git, stores the scripts. Automated processes can create an entire application infrastructure without manual intervention by checking out and executing the scripts.

When the physical infrastructure of the environment is standardized, IaC is the most suitable environment for implementation. Automated tests are added to applications and supporting infrastructure. Continuous integration and continuous deployment are terms used to describe this process. A defective application update can be deployed more quickly with this method.

How does network infrastructure as code work?

Underlay and overlay networks can be created and maintained using IaC for networking. The configuration templates and variables are stored in a network configuration repository, such as Git. A change in the storage triggers the automation tools. A new configuration definition is checked out, variables are replaced, and the updated configurations are deployed in the resulting automation. To achieve this, teams need to anticipate the amount of effort required compared to creating a few simple scripts that perform simple automation tasks.

The adoption of network IaC is more manageable when physical and virtual networks are standardized. The web comprises several building blocks, including branch sites, data center pods, internet access blocks, and office Wi-Fi segments. A well-defined interface or link between the building blocks connecting the components.

The following are some of the benefits of this building-block approach:

  • There is a reduction in variability.
  • Creating test environments is easier.
  • Troubleshooting and monitoring that is repeatable.
  • The material bill is clearly defined.
  • Consistent configuration is of the utmost importance.

Ansible can be used to develop an IaC implementation for a network from scratch, but this is unnecessary. It is possible to simplify this process using the APIs provided by commercial networking configuration automation products. A software-defined WAN, data centers, wireless, and security system can all be integrated by APIs, depending on the controller’s functionality.

Integrating and deploying networks continuously

Continuous integration and deployment are the rest of the processes involved in implementing IaC. Run a set of automatic tests on all of the application VMs and some test clients. The application should be deployed into production if all tests pass.

Physical hardware often includes features not present in virtual implementations in the networking field. A physical test lab containing this hardware can take considerable time and money. Test traffic generation and testing a network’s functionality when pushing configuration updates into a production environment presents challenges. These challenges can be mitigated through the use of standard building blocks.

A code-based approach to network infrastructure

Technically, network IaC adoption can be completed quickly by most organizations. It is the culture change that poses the most significant challenge. In some cases, site implementations may use building block designs that are more expensive than nonstandard options. The expense is common to offset by reducing operational costs and risk.

Network teams must adopt an IaC mindset before changing any network how it is designed to be deployable and that no manual changes can be made on a network before it can be deployed. A practical network validation test becomes essential to the project’s success, and creating sufficiently comprehensive examinations can be challenging.

As a network engineer, you should be familiar with the function of creating the changes and identifying the test parameters. Neither a software developer nor someone with software development skills is required to provide automation.

Using infrastructure as code for networks has many benefits

Many benefits can be derived from implementing network IaC, including:

  • Keep track of changes.

A failed configuration change can be identified and reverted easily since the changes are made within network configuration templates.

  • Maintain a regular deployment of small changes.

Regularly deploying small changes is easy with an automated process with validation testing. Many configuration changes, including some that may interplay, should not be carried out during big maintenance windows.

  • Easy to use.

Changing things in a small way makes it easier to understand, automate, and test, and fewer side effects are associated with more minor changes.

  • Errors are less common.

By eliminating manual processes, Network IaC removes the possibility of human error.

  • Perform a state validation before a change. 

You can ensure the network performs as expected before applying a change by performing unit tests.

  • Perform a state verification post-change.

The purpose of unit tests is to verify that the network is operational in the correct state once the change has been implemented.

  • An environment for testing. 

The change proposal is validated in a test environment before being deployed to the production network, significantly reducing the risk of inadequate implementation.

Ultimately, the business benefits from network IaC. Firstly, network configuration changes are significantly reduced. As well as supporting Agile business processes, it gives the company a competitive advantage over its competitors.

As the name suggests, Network as Code (NaC) is an application of the Infrastructure as Code concept to the network domain, covering traditional data centers, campus networks, wide area networks, and cloud environments.  An enterprise’s adoption of NetDevOps includes implementing NaC successfully.  The way network design and operations are thought about, the culture around changes. Of course, the tools and technologies used to configure and build networks will change significantly as part of the transition.  Three principles can sum up a requirement for Network as Code within NetDevOps.

Principles of Network as Code

  • Maintain a source control repository for network configurations.
  • Truth can only be found through Source Control.
  • Using programmatic APIs, you can deploy configurations.

Adopting DevOps Processes

When implementing the Network as Code approach, configurations must be standardized and put in a template. As a result, adding new locations or buildings becomes as simple as changing variables rather than having to overwrite specific configurations for each new device. An engineer in the network prides themselves on having all the knowledge in their head, remembering IP addresses for many large sites, and writing configures from scratch easily. A more modern approach has replaced the cowboy-style method.

There used to be a belief that network engineers were irreplaceable and had a lot of power, but that’s no longer the reality. You should see yourself as fully in control of your environment if you have all your network configurations in one place in a templated format. If you decide to change jobs, your networking knowledge will not disappear. The network code will contain it instead.

Next, a version control system needs to be implemented. A single version control system should track every work on the network, and a single production build should be created for each change. All parties can request and approve changes to the web, and once they support the changes, they are pushed to production builds. By implementing this process, operations teams can move away from weekly meetings during which managers review changes without considering their impact and only wish to get a general sense of what is happening.

Taking IaaS to the next level

Infrastructure as a Service (IaaS) is having your infrastructure managed by someone else. You must keep an eye on your networking needs when using Google as your infrastructure provider. Cloud-based infrastructure doesn’t mean someone else will handle your needs.

IaaS could be a straightforward process for organizations that already treat their networks as code. You will have to extend your migration window if your network topologies have to be determined, configurations must be validated, and inconsistencies must be resolved within the network.

Modelling Network Services

In addition to being able to model network services, Network as Code offers other brilliant benefits. There are more possibilities to simulate your live network as a virtual test environment with many network devices available.

A simulated test network could be used to validate any changes before deploying them to production networks. A network change will be more likely to cause no issues if this is done, increasing the level of assurance that change managers will have. When the changes have passed the test environment, a few current systems will integrate them into production. Some pending approvals still need to be made before they can be put into production. Your network’s size will determine how much of it can be replicated in a virtual environment. This ultimate testing nirvana is becoming more and more familiar as more devices are virtualized.

Integrating and delivering continuously

The CI/CD solution monitors code repositories using the software. As soon as the software detects changes in specific holds, it performs other tasks, such as pushing the changes and updating the repository database. Imagine a network engineer is instructed to create a new VLAN across multiple switches. The engineer would change the variables in the code repository for that site. A network owner or administrator is then required to approve the change. Once approved, the difference will be verified, supported, and uploaded to the production code repository. CI/CD recognizes a shift in site A’s configuration, generates new code, builds it, and pushes it to the site’s test environment. 

Then, network tests will be generated to determine whether the change has affected connectivity. The network administrator must approve the final test result to push the transition into production. Network engineers require no manual configuration, making typing errors almost impossible. Using a template that has already been proven to work with previous changes, the template processed the configuration change request.

Now that the production code has been rolled back one step in the version control system, if any issues are observed, they can be reverted by redeploying the code. Multiple engineers make no unexpected change without accountability associated with each configuration change. Each configuration change pushes production-verified code.

A single point of truth and automated policies

The organization should now have completed a version-controlled production code build managed through the network automation system instead of different text files and distributed among various engineers’ laptops. With this code now in place, enforcement can begin.

It is common for various devices on an extensive network to change. The device consistency may change over time, for example, after a few months or years. Consequently, significant deviations are exposed whenever a global change is needed across all devices. All code is reviewed during an upgrade to uncover this type of issue.

Continuous Integration/Continuous Delivery enables policy enforcement at regular intervals such as hourly, daily, and weekly when production configurations are applied to all devices. Ad hoc changes to the network without approval will be overwritten as a result of ensuring all devices match the production-approved structure.

As part of this practice, organizations should establish a single source of truth (SSOT). An IP address, subnet, device location, and other information about network devices can be stored in a central repository. An out-of-control spreadsheet is typically not very capable of being incorporated into a network automation system if it has grown out of control over the years. 

An SSOT solution must be implemented once a network has grown beyond spreadsheets. The software can provide all necessary device information by integrating the API or directly referencing device information. The Network as a Code practice can be used in various ways and is another puzzle piece.

Configuration templates for specific sites need only reference Access-Switches-Site-A when deploying changes. Devices matching these criteria are requested to be returned to the SSOT repository. Afterward, the production code is run for all-access switches at site A.

Dynamic devices should also be taken into consideration. Networks used to be made of metal boxes with permanent IP addresses and names. The proliferation of software-defined and on-demand network devices raises the question of how to keep track of IP addresses and names? 

There is a possibility that LB89-resource-site-1-vpc2 is the typical firewall device deployed in the cloud. Dynamic inventories are helpful in these situations. Each time a device is spun up in the cloud, it is tagged with its function and location. The SSOT repository collects this information. Rather than pushing configuration changes to individual devices, sites and tags are used to test the changes to the devices.

Even if all these tasks could be performed manually, they would eventually become unmanageable. The manual process of updating dynamically spun-up device inventory files is not something most network engineers enjoy doing during work hours. Consider the network as code instead.


Even though this might seem overly idealistic, the reality is that this is happening right now, and network management is increasingly becoming DevOps-driven. 

The configuration of a network is essentially coded anyway. By treating them as code and following all the processes developers have used for years, we will be able to make them much easier to use.

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