Problem
1. Host A sends a timestamp-request message to host B and never receives a reply. Discuss three possible causes and the corresponding course of action.
2. Why is there a restriction on the generation of an ICMP message in response to a failed ICMP error message?
3. Host A sends a datagram to host B. Host B never receives the datagram and host A never receives notification of failure. Give two different explanations of what might have happened.