/**
\mainpage Open62541 Developer Documentation

<a href="http://en.wikipedia.org/wiki/OPC_Unified_Architecture">OPC UA</a>
(short for OPC Universal Architecture) is a communication protocol originally
developed in the context of industrial automation. OPC UA has been released as
an “open” standard (meaning everybody can buy the document) in the IEC 62541
series. As of late, it is marketed as the one standard for non-realtime
industrial communication.

Remote clients can interact with a \ref server by calling remote \ref services.
(The services are different from a remote procedure call that is provided via
the "Call" service.) The server contains a rich information model that defines
an object system on top of an ontology-like set of nodes and references between
nodes. The data and its "meta model" can be inspected to discover variables,
objects, object types, methods, data types, and so on. Roughly, the \ref
services provide access to

- Session management
- CRUD operations on the node level
- Remote procedure calls to methods defined in the address space
- Subscriptions to events and variable changes where clients are notified via push messages.

The data structures the services process as in- and output can be encoded either
as a binary stream or in XML. They are transported via a TCP-based custom
protocol or via Webservices. Currently, open62541 supports only the binary
encoding and TCP-based transport.

*/