NFS Protocol Sequence.pdf

+ Open Port 111 for UDP and TCP
+ Port mapper starts listening on UDP and TCP port 111
+ Register Mountd and NFSD daemons with port mapper

NFS Mount:
1. Application initiates mounting of a file system
2. Mount API invokes RPC get_port request to port mapper
3. Port mapper replies with Mount Port Number
4. RPC MOUNT request to Mountd daemon
5. Mountd daemon authenticates client, performs local mount, and replies with File Handle

Opening a File:
1. Application uses OS API to open a file
2. OS parses file name, finds NFS mounted file system, and initiates NFS file open processing
3. Client requests NFS port number from port mapper
4. Client hierarchically parses path, obtains file handle using GETATTR and LOOKUP NFS commands

* Reading File Contents:
1. Application initiates read for the file
2. Client performs multiple READ RPC calls to NFS server, specifying file name and starting offset
3. NFS server reads standard block size and returns to client
4. Client maintains application state and performs multiple reads to complete file read operation