Network Management final exam study guide

Dordal   

You will again be given a copy of most of the RFC 1213 MIB-2 (the same as on the midterm). However, this exam will not focus much on the actual content of that MIB file.

You may bring up to three pages of your own notes.  
Material to be covered:
 
Basics on traversing SNMP tables
 
RMON [very limited]
You do not have to know any specific facts about any of the RMON groups (statistics, history, matrix, etc). However, if I give you a description of one such group, you should be able to answer questions about it.
 
 
SNMPv3


Software Defined Networking

    
NMS         
    basics of NMSs
    How OpenNMS works; how it identifies devices, how it monitors software services using "poller-monitors"


Basics of iptables

Basics of iproute2
I won't ask detailed questions about iproute2. I may ask questions about iptables, but will give you the basic syntax.


Basics of fair queuing, hierarchical queuing and token bucket


Linux Traffic Control
You will not be required to know exact command syntax.
 
Integrated Services v Differentiated Services [limited]
       

Some questions

Partial answers are here.

1. Consider the hierarchical queuing discipline using weighted fair queuing; each node is marked with its bandwidth fraction.  
 
             root
             /  \
            /    \
           /      \
         60%      40%
        /  \      /  \
       /    \    /    \
      33%  67%  50%   50%
      |     |    |     |
      A     B    C     D
       
What fraction would each of A, B, C, and D get if all senders were active?
What fraction would each of A, B, and C get if they were the only ones active?
 
 
2. In the diagram above, suppose only A and C are active, and hence A gets 60% and C gets 40%. All packets are the same size; packets might be sent in the sequence a1 a2 a3 c1 c2 a4 a5 a6 c3 c4 (or perhaps a1 a2 c1 a3 c2 a4 a5 c3 a6 c4).  
Now suppose B starts in; what might the sending pattern be? (Assume the packets are numbered from 1).  
 
 
3. Compare SNMP, OpenNMS-style pollers (java programs), and high-level shell scripts for discovering network information.
 
 
4. For the following SDN (OpenFlow) switches, give rules for unknown-destination traffic (either flood-all-traffic or no-flooding) for each switch so that traffic does not circulate endlessly.

(a).
    A---------B
    |         |
    |         |
    D---------C
 
(b).
    A---------B---------C
    |         |         |
    |         |         |
    D---------E---------F

 
5. How are SNMPv3 keys different from passwords? How are keys exchanged, after they are set up initially, using the authentication-only (no encryption) style?
 
 
6. How does SNMPv2 GetBulk differ from SNMPv1 GetNext?
 
 
7. Outline the row-creation mechanism built into SNMPv2, including the RowStatus field, and give an example of how RMON uses row creation.
 
 
8. In SNMPv1, the manager had to store the "community" password for each agent (though many agents used the same password). How is this password-keeping requirement different in SNMPv3?


9.(a) Outline how initial accounts are created in SNMPv3 agents
(b) Outline how that initial account can be cloned, using SNMPv3.


10. How does fair queuing differ from using one layer of HTB?


11. Suppose you are using priority queuing to route VOIP traffic ahead of other TCP  traffic. What do you have to do to ensure that the other TCP traffic does not "starve"?


12. Consider each of the following iptables commands on box S. Which will block responses to pings? Which will block pings even being received?
   (a) iptables --table filter -A INPUT -p icmp -j DROP
   (b) iptables --table filter -A OUTPUT -p icmp -j DROP
   (c) iptables --table filter -A FORWARD -p icmp -j DROP