The parameter AuthenticationProfileUri of DataType String allows the selection of the authentication protocol used by the transport implementation. This maps to the ProfileUri Property in the KeyCredentialConfigurationType instance selected through the ResourceUri and AuthenticationProfileUri Strings.

This parameter is optional. If more than one ProfileUri describing the protocol to use for authentication is configured and this value is null, the transport will choose one. If the transport cannot fine a suitable authentication mechanism in the ProfileUri array, the transport sets the State of the PubSubConnection is set to Error_3.