DECnet

Phase V is compatible with the previous release, Phase IV. Phase IV was similar to OSI routing, but Phase V implements full OSI routing including support for End System-to-Intermediate System (ES-IS) and Intermediate System-to-Intermediate System (IS-IS) connections.

An End System (ES) is a nonrouting network node; an Intermediate System (IS) refers to a router. ESIS support allows ESs and ISs to discover each other. IS-IS provides routing between ISs only.

Phase V is compatible with the previous release, Phase IV. Phase IV was similar to OSI routing, but Phase V implements full OSI routing including support for End System-to-Intermediate System (ES-IS) and Intermediate System-to-Intermediate System (IS-IS) connections.