Resumen
Both the IRIS-DNS System and the PORTAL-DOORS System share a common architectural style for pervasive metadata networks that operate as distributed metadata management systems with hierarchical authorities for entity registering and attribute publishing. Hierarchical control of metadata redistribution throughout the registry-directory networks constitutes an essential characteristic of this architectural style called Hierarchically Distributed Mobile Metadata (HDMM) with its focus on moving the metadata for who what where as fast as possible from servers in response to requests from clients. The novel concept of multilevel metadata about metadata has also been defined for the PORTAL-DOORS System with the use of entity, record, infoset, representation and message metadata. Other new features implemented include the use of aliases, priorities and metaresources.