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Unformatted text preview: 40] Chapter 25. SNMP: Simple Network Management Protocol Figure 25.8 Simple variables in udp group.
We'll use this format to describe all the MIB variables in this chapter. The column labeled "R/W" is
empty if the variable is read-only, or contains a bullet (*) if the variable is read-write. We always
include this column, even if all the variables in a group are read-only (since they are in the udp
group) to reiterate that none of the variables can be set by the manager. Also, when the data type is
an INTEGER with bounds, we specify the lower limit and upper limit, as we do for the UDP port
number in the next figure.
Figure 25.9 describes the two simple variables in the udpTable.
UDP listener table, index = < udpLocalAddress >.< udpLocalPort >
Name Datatype udpLocalAddress lpAddress
udpLocalPort [0..65535] R/W Description
Local IP address for this listener. 0.0.0.0 indicates
the listener is willing to receive datagrams on any
Local port number for this listener. Figure 25.9 Variables in udpTable.
Each time we describe the variables in an SNMP table, the first row of the figure indicates the value
of the "index" used to reference each row of the table. We show some examples of this in the next
There is a relationship between the first three counters in Figure 25.8. Case Diagrams [Case and
Partridge 1989] visually illustrate the relationships between the various MIB variables in a given
group. Figure 25.10 is a Case Diagram for the UDP group. Figure 25.10 Case Diagram for UDP group.
What this diagram shows is that the number of UDP datagrams delivered to applications
(udpInDatagrams) is the number of UDP datagrams delivered from IP to UDP, minus
udpInErrors, minus udpNoPorts. Also, the number of UDP datagrams delivered to IP
(udpOutDatagrams) is the number passed to UDP from the applications. This illustrates that
udpInDatagrams does not include udpInErrors or udpNoPorts. file:///D|/Documents%20and%20Set...
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.
- Spring '12