Discovery in a global scope requires unique PublisherIds. Publishers shall use the default PublisherIds as defined in for the following discovery messages.

These messages use the standard discovery address if defined for the transport protocol mapping like the IANA registered IPv4 multicast address for UDP.

Other announcements below PubSubConnection level can use different PublisherIds for different transport protocol mappings. Such PubSubConnection specific PublisherIds could be two Byte PublisherIds for the Ethernet transport protocol mapping. These PublisherIds are known from the payload of the PubSubConnection configuration announcement messages.