An **Identifier** type is a unique ID assigned to a node within the OPC-UA server. It is used to directly reference 
specific nodes without navigating through the namespace hierarchy.

The **Identifier** type in the OPC-UA connector configuration can be used in various forms to uniquely reference nodes 
in the OPC-UA server's address space. Identifiers can be of different types, such as numeric (`i`), string (`s`), 
byte string (`b`), and GUID (`g`). Below is an explanation of each identifier type with examples.

- ##### Numeric Identifier (`i`)
  A **numeric identifier** uses an integer value to uniquely reference a node in the OPC-UA server.

  ###### Example:
  Gateway expects that the node exist.

  _Expression:_

  **`ns=2;i=1236`**

- ##### String Identifier (`s`)
  A **string identifier** uses a string value to uniquely reference a node in the OPC-UA server.

  ###### Example:
  Gateway expects that the node exist.

  _Expression:_

  **`ns=3;s=TemperatureSensor`**

- ##### Byte String Identifier (`b`)
  A **byte string identifier** uses a byte string to uniquely reference a node in the OPC-UA server. This is useful for binary data that can be converted to a byte string.

  ###### Example:
  Gateway expects that the node exist.

  _Expression:_

  **`ns=4;b=Q2xpZW50RGF0YQ==`**

- ##### GUID Identifier (`g`)
  A **GUID identifier** uses a globally unique identifier (GUID) to uniquely reference a node in the OPC-UA server.

  ###### Example:
  Gateway expects that the node exist.

  _Expression:_

  **`ns=1;g=550e8400-e29b-41d4-a716-446655440000`**
