uaCap:Discovery Subnet

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URN:          https://opcfoundation.org/wiki/index.php/Discovery/Subnet

Description
Subnet discovery is based on the multicast DNS protocol that allows OPC UA Clients to find OPC UA Servers connected to the local subnet. The list of Servers can be filtered by capability acronyms.

Usage Considerations

  • Automatic detection instead of querying each node on the network
  • Filtering by capability to lookup the appropriate Servers.
  • Requires that the network has multicasting enabled.
  • The Local Discovery Server with multicast extension (LDS-ME) available from the OPC Foundation enables subnet discovery.

Conformance Testing

Client Server

The Discovery Client Facet includes two alternative Conformance Units (CUs) for this capability:

  1. With LDS: Conformance Unit Discovery Client Find Servers on Network
  2. Without LDS: Conformance Unit Discovery Client Find Servers on Network using mDNS
  1. With LDS: Servers register themselves by calling the Register2 Service.
  2. Without LDS: Servers announce themselves using mDNS as defined in Subnet Discovery Facet.