Network Management Midterm Study Guide   

Dordal
 
You will be given copies of the mib-2 system and interfaces group definitions from this slightly edited version of the RFC1213 MIB.

You may also bring up to two pages of your own notes. Small printing is allowed.
 
The midterm covers up through SNMP version 2.
 

Answers are here.
 
(For some of these examples, you may need to look at the answer to figure out what I'm talking about. On the exam, you could ask me. And remember that you will have some MIB file (probably part of RFC1213) to use as a syntax reference.)

You should also be familiar with the following:
 
 
1. Suppose we want to create a new snmp table, called carTable. The prefix is vehicles::= 1.5.4.3.2. The carTable is to consist of sets of entries of form
    horsePower
    make (gm, chrysler, ford, nissan, toyota)
    modelNumber
    seating
The index is to be a field carNum.
    
Give an ASN.1 definition for carTable, carEntry, and the entry fields. Model it after ifTable.

(This is a general problem on how to define tables)
 
 
2. What is the problem with conventional switches and a loop topology, and how are OpenFlow/SDN switches able to accommodate this?

    s1------s2
    |       |
    s4------s3
  
 
3. What is the simplest way, using SNMP, to
  (a) retrieve a single row of a table (say row 3, where the columns are T.1 through T.7)
  (b) retrieve a single column of a table (say column 5, with pseudo-header T.5, and 6 rows)
 
 
4. Explain how you could determine whether a device is a workstation or a router using SNMP.
 
 
5. In the IP group, mib2.4, part of RFC1213-MIB, there are several tables:
    ipAddrTable
    ipRouteTable
    ipNetToMediaTable
The following apply to the last table.
(a). List the columns under ipNetToMediaEntry.
(b). Draw a table representing these entries. Create at least two rows. Make up plausible values.  
 
 
6. You own the ABC company that sells hats and jackets. You have obtained an Object Identifier of 6525 under enterprises (1.3.6.1.4.1); that is, your company's entries begin 1.3.6.1.4.1.6525. You have two locations, branch1 and branch2. Each branch has the following inventory and attributes:
    hats: scalar hatQuantity
    jackets: table jacketTable,  
        with entries jacketsSize (INDEX) and jacketQuantity.

(a). Create a MIB module for your company that indicates how the respective inventories can be accessed with SNMP. Define OIDs for branch1 and branch2, and create separate MIB entries for each branch. That is, define OIDs for branch1, branch2, branch_1_hats, b1jacketTable, etc. Use the OBJECT IDENTIFIER and OBJECT-TYPE macros; follow the syntax of any MIB file. Note that hats get a scalar under each branch, but jackets need a sub-table.

(b). What would be an advantage for having a table of branches, branch1 ... branchN, versus entries for specific branches? (The tricky part here is that you can't have a table of tables; that is, you can't have jacketTable be a column of branchTable.)  
 

7. Suppose you are on a subnet. One workstation on the subnet is also a router to the outside world. How could you determine which workstation is the router using SNMP?

What if the workstation were a switch and not a router?
 
 
8. Account for the differences between TCP and UDP in the RFC1213-MIB (mib-2). That is, explain the differences and explain why they are there.
 
 
9. Consider a simplified version of the RFC1213-MIB Interfaces table (some columns described in M&S, p 349), with entries for ifIndex, ifDescr, and ifSpeed.
(a). Give the OIDs for the columns themselves.
(b). Suppose the table has the following data: 

ifIndex
 ifDescr
 ifSpeed
1
 eth0
 10,000,000
2
 eth1
 100,000,000

Give the full OIDs for each of these six table entries.

You may express the OIDs as either 1.3.6.1.2.1._________ or as mib-2.________
 
 
10. Consider the ETHERLIKE-MIB for ethernet-like nodes, and
(a) identify how to find the number of collisions
(b) identify how to determine if any host is violating the 1500-byte maximum packet size
(c) identify how to determine the rate of collisions per good packet.


11. Be familiar with get-next traversal, and at least somewhat familiar with the get-bulk extension. In what order will values be retrieved from the following table?

                           |
                      +---------+
                      |         |
                      |    T    |
                      |         |
                      +---------+
                           |
                           |
                      +---------+
                      |         |
                      |    E    |
                      |         |
                      +---------+
                           |
                           |
         +-----------------+-----------------+
         |                 |                 |
    +---------+       +---------+       +---------+
    |         |       |         |       |         |
    | T.E.1.1 |       | T.E.2.1 |       | T.E.3.1 |
    |         |       |         |       |         |
    +---------+       +---------+       +---------+
         |                 |                 |
    +---------+       +---------+       +---------+
    |         |       |         |       |         |
    | T.E.1.2 |       | T.E.2.2 |       | T.E.3.2 |
    |         |       |         |       |         |
    +---------+       +---------+       +---------+
         |                 |                 |
    +---------+       +---------+       +---------+
    |         |       |         |       |         |
    | T.E.1.4 |       | T.E.2.4 |       | T.E.3.4 |
    |         |       |         |       |         |
    +---------+       +---------+       +---------+