Remarks:

A GUID NodeId uses a Globally Unique Identifier (GUID) to identify a node. A GUID is a 128-bit value that is highly unlikely to be duplicated and can be used across all computers and networks wherever a unique identifier is required. In the context of OPC UA, it ensures that the identifier is unique not just within the scope of a single server, but globally.

GUID NodeIds are particularly useful in large, distributed systems where nodes might be replicated across different servers or where the system must integrate with other systems that might use similar identifiers. The global uniqueness of GUIDs helps prevent identifier collisions.

While GUIDs offer uniqueness, they do not provide human-readable or meaningful identifiers. This can make debugging or manual configuration more challenging, as the identifiers do not convey information about the node they represent.

In OPC UA, a GUID NodeId might be used to identify a specific sensor or actuator in a factory setting, ensuring that the identifier remains unique even if the system is scaled up or integrated with other systems.

The value of this enum member is 3.

The value of this enum member is 0.

Remarks:

The numeric identifier is an unsigned integer.

Numeric NodeIds are commonly used for their simplicity and efficiency. They are especially suitable for environments where performance is critical, as comparing and processing integers is generally faster than dealing with strings or GUIDs. Numeric NodeIds are often used in systems with a well-defined and stable set of nodes, where the identifiers can be assigned and managed systematically.

While Numeric NodeIds are efficient, they are not inherently descriptive. Unlike string-based NodeIds, numeric identifiers do not provide any hint about the node's role or type. This can make configuration and debugging more challenging, as additional documentation or lookup mechanisms may be required to understand the significance of each NodeId.

In a manufacturing process control system, a Numeric NodeId might be used to identify a specific temperature sensor in a reactor. The Numeric NodeId could be a simple integer, like 511, within a specific namespace that groups all sensor-related nodes.

The value of this enum member is 1.

Remarks:

Opaque identifiers are identifiers that are free-format byte strings that might or might not be human interpretable.

The value of this enum member is 4.

The value of this enum member is 2.