Service Model

Service Model Overview

When using the RESTCONF YANG interface to provision Provider Connectivity Assurance, the configuration is built according to the YANG service model described in this article. This model consists of three distinct tiers and a set of associated configuration objects and relations.

In this model, the service-endpoint represents the entity or device performing a test function, as a sender of a throughput (SAT) test or a reflector of a TWAMP session. The service-endpoints hold information such as the IP addresses, ports, and human-readable names of the endpoints.

A test session represents the test itself and is always referencing two service-endpoints, but one endpoint can be part of more than one session.

At the top level is the service object, which connects one or more sessions into an overall service group. With this grouping, actions and settings can be performed on the service-level that then propagate to many sessions.

Network diagram of a basic service with two sessions using three service endpoints.

Service Object

The YANG tree for the service object is shown below:

module: Accedian-service
  +--rw services
     +--rw service* [service-id]
     |  +--rw service-id            acdt:id
     |  +--rw service-name?         acdt:id
     |  +--rw group-id?             acdt:id
     |  +--rw description?          string
     |  +--rw type?                 identityref
     |  +--rw service-definition
     |  +--rw sessions* [session-id]
     |  |  +--rw session-id    -> /acdses:sessions/session/session-id
     |  +--rw metadata
     |     +--rw key-value* [key-name]
     |        +--rw key-name    -> /acdmeta:metadata-config/metadata-key/key-name
     |        +--rw value?      string
     +--rw alerts* [alert-policy-id]
        +--rw alert-policy-id    -> /acda:alert-policies/alert-policy/policy-id

Service Object Parameters

Note A text field of type acdt:id allows the following characters and symbols: '[a-zA-Z0-9][a-zA-Z0-9._-]*'

The fields of the service object are non-editable with PATCH operations, so before creating a service object, the session and endpoint objects must be created.

Session Object

The session object defines the path to be tested between two service-endpoint objects.

The following two types of sessions are supported in the current version of the model:

• TWAMP stateless / stateful see TWAMP for details on TWAMP sessions
• SAT rfc2544 / y.1564 see [SAT] (/v1/docs/sat) for details on SAT test sessions

YANG tree for the session object is shown below:

module: Accedian-session
  +--rw sessions
     +--rw session* [session-id]
        +--rw session-id           acdt:id
        +--rw session-name?        acdt:id
        +--rw group-id?            acdt:id
        +--rw description?         string
        +--rw session-type         identityref
        +--rw service-endpoints* [endpoint-id]
        |  +--rw endpoint-id         -> /acdsep:service-endpoints/service-endpoint/endpoint-id
        |  +--rw session-protocol
        +--rw metadata
        |  +--rw key-value* [key-name]
        |     +--rw key-name    -> /acdmeta:metadata-config/metadata-key/key-name
        |     +--rw value?      string
        +--rw alerts* [alert-policy-id]
        |  +--rw alert-policy-id    -> /acda:alert-policies/alert-policy/policy-id
        +--ro status
        +---x start
        +---x stop

Session Object Parameters

Note A text field of type acdt:id allows the following characters and symbols: '[a-zA-Z0-9][a-zA-Z0-9._-]*'

The individual fields of the session object are non-editable with PATCH operations after the object has been created, so before instantiating a session object, the corresponding endpoint objects must be created.

Service-endpoint Object

The service-endpoint defines the sender or receiver/reflector of a test session. Provider Connectivity Assurance sensors supported via the RESTCONF YANG interface currently are Sensor SFP and Sensor Agent (actuate and throughput).

YANG tree for the endpoint objects most common leafs shown below:

module: Accedian-service-endpoint
  +--rw service-endpoints
     +--rw service-endpoint* [endpoint-id]
        +--rw endpoint-id      acdt:id
        +--rw endpoint-name?   acdt:id
        +--rw group-id?        acdt:id
        +--rw description?     string
        +--rw geo-location
        |  +--rw latitude?    decimal64
        |  +--rw longitude?   decimal64
        +--rw type?            identityref
        +--rw config
          +--rw ne-config
          +--rw nid-config

Endpoint Object Parameters

See Endpoint for full details on the Endpoint object parameters

Endpoint RESTCONF Example

An example RESTCONF message to create a new endpoint object is shown below:

RESTCONF POST :: PCA-INSTANCE/restconf/data/Accedian-service-endpoint:service-endpoints
             {
                 "Accedian-service-endpoint:service-endpoint":[{
                     "endpoint-id":"my-endpoint-agent-1",
                     "endpoint-name":"my-endpoint-agent-1",
                     "description":"This is an agent",
                     "type":"Accedian-service-endpoint-type:ne-endpoint",
                     "config":{
                         "Accedian-service-endpoint-ne:ne-config":{
                             "ne-id":"nso-demo-agent-1",
                             "ip":"192.168.0.4"
                         }
                     }
                 }]
             }