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+.. This work is a derivative of https://wiki.onap.org/display/DW/Modeling+Concepts#Concepts-2026349199
+.. This work is licensed under a Creative Commons Attribution 4.0
+.. International License. http://creativecommons.org/licenses/by/4.0
+.. Copyright (C) 2020 Deutsche Telekom AG.
+
+External Systems support
+------------------------
+
+Interaction with **external systems** is made **dynamic** and **plug-able**
+removing development cycle to support new endpoint.
+In order to share the external system information, TOSCA provides a way to create macros using **dsl_definitions**:
+Link to TOSCA spec:
+`info 1 <http://docs.oasis-open.org/tosca/TOSCA-Simple-Profile-YAML/v1.2/csd01/TOSCA-Simple-Profile-YAML-v1.2-csd01.html#_Toc494454160>`_,
+`info 2 <http://docs.oasis-open.org/tosca/TOSCA-Simple-Profile-YAML/v1.2/csd01/TOSCA-Simple-Profile-YAML-v1.2-csd01.html#_Toc494454173>`_.
+
+Use cases:
+* Resource resolution using **REST** (see tab Node Type) or **SQL** (see tab Node Type) external systems
+* **gRPC** is supported for remote execution
+* Any REST endpoint can be dynamically injected as part of the scripting framework.
+
+Here are some examples on how to populate the system information within the package:
+
+.. list-table::
+   :widths: 100
+   :header-rows: 1
+
+   * - token-auth
+   * - .. code-block:: json
+
+        {
+          . . .
+          "dsl_definitions": {
+          "ipam-1": {
+            "type": "token-auth",
+            "url": "http://netbox-nginx.netprog:8080",
+            "token": "Token 0123456789abcdef0123456789abcdef01234567"
+          }
+        }
+
+.. list-table::
+   :widths: 100
+   :header-rows: 1
+
+   * - basic-auth
+   * - .. code-block:: json
+
+        {
+          . . .
+          "dsl_definitions": {
+            "ipam-1": {
+               "type": "basic-auth",
+               "url": "http://localhost:8080",
+               "username": "bob",
+               "password": "marley"
+            }
+          }
+          . . .
+        }
+
+.. list-table::
+   :widths: 100
+   :header-rows: 1
+
+   * - ssl-basic-auth
+   * - .. code-block:: json
+
+        {
+          . . .
+          "dsl_definitions": {
+            "ipam-1": {
+               "type" : "ssl-basic-auth",
+               "url" : "http://localhost:32778",
+               "keyStoreInstance": "JKS or PKCS12",
+               "sslTrust": "trusture",
+               "sslTrustPassword": "trustore password",
+               "sslKey": "keystore",
+               "sslKeyPassword: "keystore password"
+            }
+          }
+          . . .
+        }
+
+.. list-table::
+   :widths: 100
+   :header-rows: 1
+
+   * - grpc-executor
+   * - .. code-block:: json
+
+        {
+          . . .
+          "dsl_definitions": {
+            "remote-executor": {
+              "type": "token-auth",
+              "host": "cds-command-executor.netprog",
+              "port": "50051",
+              "token": "Basic Y2NzZGthcHBzOmNjc2RrYXBwcw=="
+            }
+          }
+          . . .
+        }
+
+.. list-table::
+   :header-rows: 1
+
+   * - maria-db
+   * - .. code-block:: json
+
+        {
+          . . .
+          "dsl_definitions": {
+            "netprog-db": {
+               "type": "maria-db",
+               "url": "jdbc:mysql://10.195.196.123:32050/netprog",
+               "username": "netprog",
+               "password": "netprog"
+            }
+          }
+          . . .
+        }