Exercises

29.1	In Figure 29.7 we saw that `tcpdump` interpreted the packets as NFS requests and replies, printing the XID. Can `tcpdump` do this for any RPC request or reply?
29.2	On a Unix system, why do you think RPC server programs use ephemeral ports and not well-known ports?
29.3	An RPC client calls two server procedures. The first server procedure takes 5 seconds to execute, and the second procedure takes 1 second to execute. The client has a timeout of 4 seconds. Draw a time line of what's exchanged between the client and server. (Assume it takes no time for messages from the client to the server, and vice versa.)
29.4	What would happen in the example shown in Figure 29.9 if, while the NFS server were down, its Ethernet card were replaced ?
29.5	When the server reboots in Figure 29.9, it handles the request starting at byte offset 65536 (lines 168 and 171), and then handles the next request starting at offset 66560 (lines 172 and 173). What happened to the request starting at offset 73728 (line 167)?
29.6	When we described idempotent NFS procedures we gave an example of a REMOVE reply being lost in the network. What happens in this case if TCP is used, instead of UDP?
29.7	If the NFS server used an ephemeral port instead of 2049, what would happen to an NFS client when the server crashes and reboots?
29.8	Reserved port numbers (Section 1.9) are scarce , since there are a maximum of 1023 per host. If an NFS server requires its clients to have reserved ports (which is common) and an NFS client using TCP mounts N filesystems on N different servers, does the client need a different reserved port number for each connection?