Skip to main content

5. Subservice Augmentation: "ietf-service-assurance-device" YANG Module

5. Subservice Augmentation: "ietf-service-assurance-device" YANG Module​

5.1. Tree View​

The following tree diagram [RFC8340] provides an overview of the "ietf-service-assurance-device" module.

module: ietf-service-assurance-device

  augment /sain:subservices/sain:subservice/sain:parameter:
    +--rw parameters
       +--rw device    string

A complete tree view of the base module with all augmenting modules presented in this document is available in Appendix B.3.

5.2. Concepts​

As the number of subservices will grow over time, the YANG module is designed to be extensible. A new subservice type requires the precise specifications of its type and expected parameters. Let us illustrate the example of the new device subservice type. As the name implies, it monitors and reports the device health, along with some symptoms in case of degradation.

For our device subservice definition, the new identity "device-type" is specified as an inheritance from the base identity for subservices. This indicates to the assurance agent that we are now assuring the health of a device.

The typical parameter for the configuration of the device subservice is the name of the device that we want to assure. By augmenting the parameter choice from the "ietf-service-assurance" YANG module for the case of the "device-type" subservice type, this new parameter is specified.

5.3. YANG Module​

<CODE BEGINS> file "[email protected]"
module ietf-service-assurance-device {
  yang-version 1.1;
  namespace
    "urn:ietf:params:xml:ns:yang:ietf-service-assurance-device";
  prefix sain-device;

  import ietf-service-assurance {
    prefix sain;
    reference
      "RFC 9418: YANG Modules for Service Assurance";
  }

  organization
    "IETF OPSAWG Working Group";
  contact
    "WG Web:   <https://datatracker.ietf.org/wg/opsawg/>
     WG List:  <mailto:[email protected]>
     Author:   Benoit Claise  <mailto:[email protected]>
     Author:   Jean Quilbeuf   <mailto:[email protected]>";
  description
    "This module augments the ietf-service-assurance module with
     support of the device subservice.

     Copyright (c) 2023 IETF Trust and the persons identified as
     authors of the code.  All rights reserved.

     Redistribution and use in source and binary forms, with or
     without modification, is permitted pursuant to, and subject
     to the license terms contained in, the Revised BSD License
     set forth in Section 4.c of the IETF Trust's Legal Provisions
     Relating to IETF Documents
     (https://trustee.ietf.org/license-info).

     This version of this YANG module is part of RFC 9418; see the
     RFC itself for full legal notices.  ";

  revision 2023-07-11 {
    description
      "Initial revision.";
    reference
      "RFC 9418: YANG Modules for Service Assurance";
  }

  identity device-type {
    base sain:subservice-base;
    description
      "Identity of device subservice.";
  }

  augment "/sain:subservices/sain:subservice/sain:parameter" {
    when "derived-from-or-self(sain:type, 'device-type')";
    description
      "Augments the parameter choice from the ietf-service-assurance
       module with a case specific to the device subservice.";
    container parameters {
      description
        "Parameters for the device subservice type.";
      leaf device {
        type string;
        mandatory true;
        description
          "Identifier of the device to monitor. The
           identifier (e.g., device id, hostname, or management IP)
           depends on the context.";
      }
    }
  }
}
<CODE ENDS>
Last updated on