For the purposes of this document the following terms and definitions as well as the terms and definitions given in The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments and errata) applies.The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments and errata) applies.

OPC 10000-1, OPC 10000-2, OPC 10000-3, OPC 10000-4, OPC 10000-6 and OPC 10000-9 apply.

a software application that manages the Certificates used by Applications in an administrative domain.

a context used to describe the Trust List and Certificate(s) associated with an Application.

a PKCS #10 encoded structure used to request a new Certificate from a Certificate Authority.

a unique identifier and a secret used to access a Server, an Authorization Service or a Broker.

Note 1 to entry: a user name and password is an example of a credential.

a software application that provides KeyCredentials needed to access a Server, an Authorization Service or a Broker.

a software application, or a set of applications, that stores and organizes information about resources such as computers or services.

an Application that maintains a list of OPC UA Servers that are available on the network and provides mechanisms for Clients to obtain this list.

a URL for a network Endpoint that provides the information required to connect to a Client or Server.

a DiscoveryServer that maintains a list of OPC UA Applications available in an administrative domain.

Note 1 to entry: a GDS may also provide certificate management services.

a unique number assigned to a network interface that allows Internet Protocol (IP) requests to be routed to that interface.

Note 1 to entry: An IPAddress for a host may change over time.

a DiscoveryServer that maintains a list of all Servers that have registered with it.

Note 1 to entry: Servers normally register with the LDS on the same host.

a LocalDiscoveryServer that includes the MulticastExtension.

an extension to a LocalDiscoveryServer that adds support for the mDNS protocol.

a network that allows multicast packets to be sent to all nodes connected to the network.

Note 1 to entry: a MulticastSubnet is not necessarily the same as a TCP/IP subnet.

a secured resource on a network that provides functionality used by Clients and/or Servers.

Note 1 to entry: an Authorization Service (AS) is an example of a Network Service.

a short identifier which uniquely identifies a set of discoverable capabilities supported by a Server.

Note 1 to entry: the list of the currently defined ServerCapabilityIdentifiers is in Annex D.