This document describes the Network File System (NFS) version 4 minor version 1@ including features retained from the base protocol (NFS version 4 minor version 0@ which is specified in RFC 3530) and protocol extensions made subsequently. Major extensions introduced in NFS version 4 minor version 1 include Sessions@ Directory Delegations@ and parallel NFS (pNFS). NFS version 4 minor version 1 has no dependencies on NFS version 4 minor version 0@ and it is considered a separate protocol. Thus@ this document neither updates nor obsoletes RFC 3530. NFS minor version 1 is deemed superior to NFS minor version 0 with no loss of functionality@ and its use is preferred over version 0. Both NFS minor versions 0 and 1 can be used simultaneously on the same network@ between the same client and server.