NFS uses RPC to provide the access primitives from client to server. The NFS model of the world is of stateless Servers.
Servers keep no track of whether any clients exist, or who they are if they do.
Instead, client retry is relied on to provide reliability. The model of the actual filesystem is that of Unix. The name space is a hierarchy which consists of directories or files. Directories are everything except the leaf nodes. Thus, NFS looks up one component of a pathname at a time.