The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  Network File and Resource Sharing Protocols and the TCP/IP Network File System (NFS)            9  TCP/IP Network File System (NFS)

TCP/IP Network File System (NFS) 1 2 3 NFS Architecture and Components

NFS Versions and Standards

Since it was initially designed and marketed by Sun, NFS began as a de facto standard. The first widespread version of NFS was version 2, and this is still the most common version of the protocol. NFS version 2 was eventually codified as an official TCP/IP standard when RFC 1094, NFS: Network File System Protocol Specification, was published in 1989.

NFS Version 3 was subsequently developed, and published in 1995 as RFC 1813, NFS Version 3 Protocol Specification. It is similar to version 2 but makes a few changes and adds some new capabilities. These include support for larger file transfers, better support for setting file attributes, and several new file access and manipulation procedures. NFS version 3 also provides support for larger files than version 2 did.

NFS Version 4 was published in 2000 as RFC 3010, NFS version 4 Protocol. Where version 3 of NFS contained only relatively small changes to version 2, NFSv4 is virtually a rewrite of NFS. It includes numerous changes, most notably the following:

• Reflecting the needs of modern internetworking, NFSv4 puts greater emphasis on security.
  
  
• NFSv4 introduces the concept of a Compound procedure, which allows several simpler procedures to be sent from a client to server as a group.
  
  
• NFSv4 almost doubles the number of individual procedures that a client can use in accessing a file on an NFS server.
  
  
• Version 4 also makes a significant change in messaging, with the specification of TCP as the transport protocol for NFS.
  
  
• Finally, NFS integrates the functions of the Mount protocol into the basic NFS protocol, eliminating it as a separate protocol as it is in versions 2 and 3.

The version 4 standard also has a lot more details about implementation and optional features than the earlier standards—it's 275 pages long. So much for simplicity! J RFC 3010 was later updated by RFC 3530, Network File System (NFS) version 4 Protocol, in April 2003. This standard makes several further revisions and clarifications to the operation of NFS version 4.

TCP/IP Network File System (NFS) 1 2 3 NFS Architecture and Components