Exercises

Exercises

4.1	In the commands we typed to generate the output shown in Figure 4.4, what would happen if, after verifying that the local ARP cache was empty, we type the command bsdi % rsh svr4 arp -a to verify that the ARP cache is also empty on the destination host? (This command causes the arp -a command to be executed on the host svr4. )
4.2	Describe a test to determine if a given host handles a received gratuitous ARP request correctly.
4.3	Step 7 in Section 4.2 can take a while ( milliseconds ) because a packet is sent and ARP then waits for the response. How do you think ARP handles multiple datagrams that arrive from IP for the same destination address during this period?
4.4	At the end of Section 4.5 we mentioned that the Host Requirements RFC and Berkeley-derived implementations differ in their handling of the timeout of an active ARP entry. What happens if we're on a Berkeley-derived client and keep trying to contact a server host that's been taken down to replace its Ethernet board? Does this change if the server issues a gratuitous ARP when it bootstraps?