A high-level network protocol that provides the structure and language for file requests between clients and servers. It provides the commands for opening, reading, writing and closing files across the network and may also provide access to the directory services. Sometimes called a "client/server protocol," it functions at the application layer (layer 7 of the OSI model).

In order for a client to have access to multiple servers running different operating systems, either the client supports the file sharing protocol of each operating system or the server supports the file sharing protocol of each client. Software that adds this capability is very common and allows interoperability between Windows, Macintosh, NetWare and Unix platforms. See Samba. See also peer-to-peer network.

   Operating     Transport     File Sharing
   System        Protocol      Protocol

   DOS           NetBIOS       SMB
   Windows       NetBEUI       CIFS, SMB
   NetWare       IPX           NCP
   Macintosh     AppleTalk     AFP
   Unix          TCP/IP        NFS, Samba