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648 C
HAPTER
23: D
EVICE
M
ONITORING
Figure 82 Example of an RMON MIB Counter Object
The counter object information includes these items:
■
The name of the counter. In Figure 82, the counter is called
etherStatsPkts (Ethernet, Statistics, Packets).
■
Access level. In Figure 82, access is read-only.
■
The number of the counter’s column in the table. In Figure 82, the
counter is in column 5 of the
etherStatsEntry table.
The name of the table where the counter resides is 3CometherStatTable,
although this name does not appear in the display.
To manage a network, you do not need to know the contents of every
MIB object. Most network management applications, including Transcend
Network Control Services, make the MIB transparent. However, by
knowing how different management features are derived from the MIB
you can better understand how to use the information they provide.
MIBs include MIB-II, other standard MIBs (such as the RMON MIB), and
vendors’ private MIBs (such as enterprise MIBs from 3Com). These MIBs
and their objects are part of the MIB tree.
MIB Tree The MIB tree is a structure that groups MIB objects in a hierarchy and uses
an abstract syntax notation (ASN.1) to define manageable objects. Each
item on the tree is assigned a number (shown in parentheses after each
item), which creates the path to objects in the MIB. See Figure 83. This
path of numbers is called the object identifier (OID). Each object is
uniquely and unambiguously identified by the path of numeric values.
etherStatsPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
This is a total number of packets
received, including bad packets,
broadcast packets, and multicast
packets.
::= { etherStatsEntry 5 }