Intent-based networking is a topic that has been talked about a lot in the past year. Cisco, being one of the biggest players in the networking market, has championed this concept. So, what is this intent-based networking?

Gartner analyst Andrew Lerner defined an intent-based networking solution (IBNS) as a system with the following characteristics:

• Translation and Validation: The system takes a higher-level business policy (what) as input from end users and converts it to the necessary network configuration (how). The system then generates and validates the resulting design and configuration for correctness.
• Automated Implementation: The system can configure the appropriate network changes (how) across existing network infrastructure. This is typically done via network automation and/or network orchestration.
• Awareness of Network State: The system ingests real-time network status for systems under its administrative control and is protocol- and transport-agnostic.
• Assurance and Dynamic Optimization/Remediation: The system continuously validates in real time that the original business intent of the system is being met and can take corrective actions (such as blocking traffic, modifying network capacity, or notifying) when desired intent is not met.

Based on the above points, and looking at what is available, an orchestrator that implements a closed-loop system and uses network-friendly declarative language, can meet these requirements quite nicely. This brings tangible benefits to the table. Current networks and install bases would not require replacing — they simply need an IBNS that is based on proper orchestration and will then be able to keep current infrastructure while enabling integration with next-generation networks and platforms.

But how would this be done?

First, let’s dive into points one and two: “Translation and Validation” and “Automated Implementation.” The basis of these bullet points is rooted in declarative orchestration and networking. Using declarative language to describe the network, users declare what they want to achieve. The orchestrator then processes that information and drives how it will be implemented.

There is also a distinction to be made between declarative orchestrators and declarative configuration engines. In order to satisfy these aspects of being an IBNS, the orchestration engine must go beyond mere configuration automation. I wrote a blog post about the power of declarative orchestration for networking.

In the post, I detailed exactly what is required, according to Gartner, to accommodate the first two points in creating an IBNS: “Translation and Validation, through the orchestrator’s DSL and “Automated Implementation,” through the orchestrator itself.

There are still two requirements: “Awareness of Network State” and “Assurance and Dynamic Optimization/Remediation.”

This is where closed loop orchestration architecture comes into play. In order to get the network state there is a need to collect metrics that represent the state and policy enforcement to dynamically change this state and provide remediation. Let’s take a closer look at closed-loop orchestration.

Closed-loop orchestration, also known as a feedback loop, is the ability to respond to an event (or set of events) by making a change to the system’s state. In order to make a change in a system’s state, it’s necessary to understand how it is modeled — and that is the job of the orchestrator.

Due to the ever-changing, dynamic nature of networking and NFV these days, closed-loop orchestration and feedback is a necessity. There is no need to scale virtual network functions (VNFs) up or down — the orchestrator is responsible for that with its closed-loop capabilities.

A closed-loop orchestrator is comprised of four main elements:

• Orchestrated resources
• Metrics collection
• Policy engine
• Orchestration engine

Some orchestrators have built-in metrics collection and policy engines, however, external sources can also be used for those elements. (Find a more detailed explanation of closed-loop automation on my blog.)

An intent-based networking solution can very much be achieved, according to the concepts brought by Gartner, using a proper orchestrator that possesses two specific capabilities: network-friendly declarative orchestration and closed-loop orchestration.

The reason this is so important is that telcos and others can use this type of solution to bring intent-based networking to their networks without ripping and replacing their existing hardware. As long as the various network elements have decent API’s and programming interfaces, a declarative language orchestrator can automate them and then manage their full lifecycle in a feedback loop.

So, don’t assume that rip-and-replace is the best way to make the network more intelligent. As long as there is an intelligent system to manage both legacy and new network hardware, save your money and find a better path.