Service Instance Overview

A service instance is a detailed description about a service. Typically written in the JSON or YAML format, a service instance defines the elements of a service. For example, an L3VPN service instance defines elements such as the customer name, service topology, and the sites where the L3VPN service is to be deployed. You create service instances for onboarding devices and defining network services, based on the corresponding service designs that Routing Director provides.

A service order is an instruction to provision a service instance in the network. Routing Director generates a service order when you create or modify a service instance and provision the instance. A service order is also generated for deleting or deprovisioning a service instance. Each type of service order (create, modify, and delete) has an automated workflow associated with it. A service instance can have many service orders associated with it.

When you create or modify a service instance and save it, the instance is uploaded to the Routing Director database as a candidate. A candidate is a draft version of the service instance that is saved in the database but not provisioned in the network. You can review and update the candidate version before provisioning in the network.

On the Service Instances page (Orchestration > Service > Instances > Service Instances), the Pending Changes column displays Yes for a candidate and NO for a service instance. The Order State and Status for a candidate are Not Available.

After a service instance is provisioned, you can modify it and save the changes as a new candidate version of the service instance. If a service instance has a candidate, the Pending Changes column displays Yes.

When you update placements for a service instance, the resources are allocated to the candidate version of a service instance, and not directly to the service instance. If no candidate exists, Routing Director creates a new candidate and allocates the placement resources to the candidate version of the service instance. If a candidate already exists, the placement resources are applied to the existing candidate.

You can either commit or discard the candidate. When you commit changes, the updated configuration saved in the candidate is provisioned in the network. When you discard changes, the candidate is deleted and the resources reserved for the candidate are released back to the resource pools.

The status of the service instance is Uploaded. To generate a service order for the instance and activate the automated workflow associated with the service order, you must provision the service instance. Routing Director automatically provisions and monitors the service after a provisioning workflow is successfully executed. The workflow includes a series of tasks such as transforming the service order, committing device configuration, and so on, for provisioning the service.

The Service Instances page (Orchestration > Service > Instances) lists all the service instances created in an organization.