2. YANG Modules Overview
2. YANG Modules Overview
The main YANG module, "ietf-service-assurance" (Section 3), defines objects for assuring network services based on their decomposition into so-called subservices. The subservices are hierarchically organized by dependencies. The subservices, along with the dependencies, constitute an assurance graph. This module should be supported by an agent that is able to interact with the devices in order to produce the health statuses and symptoms for each subservice in an assurance graph. This module is intended for the following use cases:
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Assurance graph configuration:
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Subservices: Configure a set of subservices to assure by specifying their types and parameters.
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Dependencies: Configure the dependencies between the subservices, along with their types.
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Assurance telemetry: Export the assurance graph with health statuses and symptoms for each node.
The module is also intended to be exported by the SAIN collector that aggregates the output of several SAIN agents to provide the global assurance graph. In that case, only the telemetry export use case is considered.
The modules presented in this document conform to the Network Management Datastore Architecture (NMDA) defined in [RFC8342].
The second YANG module, "ietf-service-assurance-device" (Section 5), augments the "ietf-service-assurance" module by adding support for the device subservice. Additional subservice types might be added following a similar approach.
The third YANG module, "ietf-service-assurance-interface" (Section 6), augments the "ietf-service-assurance" module as well by adding support for the interface subservice.
We provide additional examples in the appendix. The module "example-service-assurance-device-acme" (Appendix A) augments the "ietf-service-assurance-device" module to customize it for devices of the fictional Acme Corporation. Additional vendor-specific parameters might be added following a similar approach. We also provide the modules "example-service-assurance-ip-connectivity" and "example-service-assurance-is-is" (Appendix B) to model the example in Figure 2 from Section 3.1 of [RFC9417].