Providing clients access to a server service using an OPC unified architecture (OPC-UA)

A client having an OPC-UA communication stack which is configured to insert a data item into registration data which are transmitted to the server and which are intended to register the client for a server service, the data item indicating the client is a client supporting multicast subscriptions in order to register the client for the server service.

A server having an OPC-UA server stack which is configured to create, for the server service, a subscription structure having a unique subscription ID and a Transmission Control Protocol/Internet Protocol multicast group which is associated with this subscription structure and which has a unique multicast address, configured to communicate the multicast address and the subscription ID to each client registering for the server service via a subscription registration, and configured to transmit each value change in a value of each variable of the server service to the unique multicast address using a multicast message via a network;

• wherein an OPC-UA communication stack of each client inserts a data item into registration data transmitted to the server, which data item indicates the client is a client supporting multicast subscriptions, in order to register each client for the server service.

A network comprising:

• at least one client having an OPC-UA communication stack which is configured to insert a data item into registration data which are transmitted to the server and which are intended to register the client for the server service, the data item indicating the client is a client supporting multicast subscriptions in order to register a client for the server service;
• and
• at least one server having an OPC-UA server stack which is configured to create, for the server service, a subscription structure having a unique subscription ID and a Transmission Control Protocol/Internet Protocol multicast group which is associated with this subscription structure and which has a unique multicast address, configured to communicate the multicast address and the subscription ID to each client registering for the server service via a subscription registration, and configured to transmit each value change in a value of each variable of the server service to the unique multicast address using a multicast message via a network.