Unit Four Objectives        CSCI 361      Introduction to Computer Networks
Tobin Maginnis				  Updated: 8-Apr-08

Computer Networks, 4th ed - Chapter 5 - The Network Layer - A. S. Tanenbaum
 1)List three ways the network layer architecture migrates from physical to
   logical networking protocol.
 2)Give four design tradeoffs when making a selection between virtual
   circuits and datagrams.  Also, explain how the protocol stack can
   "mix-n-match" virtual circuits and datagrams.
Omit)Contrast router algorithm "robustness" versus "stability."
Omit)Explain how fairness and optimality are conflicting design goals and give
   a compromise design that decreases the amount of conflict in three ways.
 5)Define "sink tree" and be able to draw one from Figure 5-5 based on a
   node other than node B, (e.g., node O).
 6)Describe the role of the "shortest path" algorithm and list four
   possible parameters which may contribute to this abstraction.
 7)Describe the three basic steps in the shortest path algorithm.
 8)Define "flooding," give two ways it can be controlled and  explain
   why flooding is not practical for general networking yet there
   seem to be three special situations where it could be employed.  
Omit)Be able to provide comments the shortest path program code.
10)Explain how distance vectoring builds a sink tree and the subsequent problem
   with good versus bad news.
11)What are the two problems with distance vectoring and give the five steps
   in Link State Routing.
12)Explain why routers attached to a LAN require a pseudo node to perform
   link state routing.
13)Contrast "load" versus "bandwidth," and explain how incorporating load
   into the shortest path algorithm can lead to oscillation.
14)Define "link state packet" and give the five aspects of packet distribution.
Omit)Describe hierarchical routing and give its design tradeoff.
16)Describe three implementation steps to RPF and give three reasons why it
   is better than flooding.
17)Describe how one might design a mobile network management scheme (4 parts)
18)Define the nature of ad-hoc routing and it four basic implementation steps.
19)Define hash, node identifier, key, and finger table.  Explain how these 
   concepts can be used to implement a peer-to-peer network.
20)Define "congestion" and explain how the solution is a "balance."
Omit)Contrast congestion control versus flow control.
22)Describe the "self-regulating" nature of ACKs and its impact upon congestion,
   and describe how well-meaning researchers may still lead the Internet down
   the path to congestion.
23)Describe the four steps of "choke" control between two nonadjacent nodes. 
24)Describe how multimedia applications need special routing characteristics.
25)Explain how a multi-protocol router allows "tunneling" and give an example.
26)Define "fragmentation" and describe four related problems.
   a)Dividing one IP segment into two or more IP packets because the segment
     will not fit into a given type of datalink frame.
   b)Extra packet headers sent through the subnet consume limited bandwidth.
   c)Extra packets generate CPU interrupts and unnecessarily slow systems.
   d)Extra packets fill limited buffer space in routers thereby slowing or
     preventing other connections.
   e)Extra packets for one virtual circuit may consume limited buffers
     and "starve" other existing virtual circuits that do not fragment.
Omit)Explain the problem (limitation) with the IP header IHL field.
28)Describe the IP header "type of service" options and how they are used.
29)Explain the relationship among IP header ID, DF, MF, and FO fields.
30)Explain the role of time-to-live and protocol fields in the IP header.
31)Explain the confusion about Internet "classes," and give the design
   tradeoff.
32)Describe the role of "special" IP addresses.
33)Define CIDR and give it's design tradeoff. Explain how in one sense IP
   addresses are scarce, yet in another there are plenty to go around.
34)Describe the basic table columns entries and explain how packet NAT is
   implemented.
   Full connection - Transport Protocol, Local IP, port, Remote IP, port
   Protocol   Private   Private     Destination  Dest  Firewall  Flipped
   TCP or     IP Addr   Ephemeral   IP Address   Port  Public    Port Num
   UDP                  Port Num                       IP Addr
35)Contrast the error messages "destination unreachable" and "connection
   refused" and explain how they originate.
36)Explain how "ping" and "traceroute" are implemented and how they are
   fundamentally different from other network applications.