CS204 Fall 2009

1. The ICMP Echo protocol (aka "ping") is used in network diagnostics to see whether or not a particular host is currently reachable over the Internet. What are the format of the Echo Request and Echo Response packets, assuming the hosts are equipped with Ethernet interfaces, as they appear to a hardware probe connected to "the wire". You must cite references from the appropriate standards document to explain the general format of an Ethernet frame, the ICMP packet carried in its payload, and the names and values of each option that is included.
   


2. NOTE: To answer this question, you will need the Internet Wayback Machine to view certain important web-accessible documents as they appeared in the past. (Isn't it nice to know that time travel for the web is already available -- as long as you want to go backwards only!)
   
1. Briefly explain the meaning of the IETF terminology "proposed standard", "draft standard" and "standard", and the relationship between the document naming conventions of the form "RFC-nnn" (i.e., "Request for Comments") and "STD-x" (i.e., STD-1"). As a specific standards project develops, how are different versions (prototype, first standard, revised standard, etc) identified. (You might want to use Wikipedia as a starting point, but you will need to go further....)
   
2. The Address Resolution Protocol (ARP) is defined in RFC-826. Since it is also an active IETF standard protocol, what is its Standard number? When were these document published?
3. RFC-826 does not specify the required protocol identifier (aka EtherType) that is required for encapsulating ARP packets over Ethernet, and merely refers to this critical value indirectly using the variable name "Protocol type=ether_type$ADDRESS_RESOLUTION".  The IETF convention was to collect such numbers together in a separate document called STD-2, the most recent versions of which were RFC-1700. Does this document, or any previous version of STD-2 back to the original creation date for ARP give the EtherType for ARP?
4. Find a copy of RFC-3232. What does it say about the contents of RFC-1700, and where else is the reader supposed to look for information like the EtherType for ARP?
5. Use the Wayback Machine to look at the history of http://www.iana.org/assignments/ethernet-numbers. Were there periods of time where the information about ARP was not provided?
   
6. Find the public EtherType listing at the IEEE Registration Authority. Look at how the information changed over time using the Wayback Machine. What information did it provide for a reader searching for ARP? NOTE: Do not be fooled by other protocols with ARP in their names. Look up the numerical value from RFC-1700 if necessary, to see what, if anything, the IEEE said about its assignment.
   
7. The IEEE "owns" the right to make EtherType assignments, but has no real control over what the recipient does with the number aftwards. The IETF "owns" the right to define the ARP protocol, but has no right to claim an EtherType value for itself. Which of these organizations should provide the definitive reference for the EtherType assignment to ARP? Explain your answer.
   

What to turn in.