Describe the structure of RFC documents and explain the significance of the terms
‘must’, ‘should’ and ‘may’ in the RFC context. What relationships can exist between
different RFC documents? (3 Marks)
Find the RFC that describes the (ver 4) Internet Control Message Protocol (ICMP)
on the Internet. Describe the method used to find it, the location of the document
and the numbers and broad content of any RFCs which are related to it. (2 Marks)
Describe, using the current (ver 4) ICMP RFC, how the ICMP protocol works and
include a description of the ICMP message field and a summary of the defined
types of ICMP message. (2 marks)
Describe how ICMP can be used to create a program that can report the route taken
by a packet from one host to another. (1 mark)
Choose non-zero values for the parameters required in an ICMP(ver 4) ECHO
message (choose 32 bits of data) and compute the checksum. Change a random bit
in the ICMP message and show how the checksum can be used by the receiver to
detect the error. Full details of the checksum calculations must be given. (1 mark)
Suggest an application for the ICMP timestamp message indicating briefly how it
would be implemented. (1 mark)
