MIBs and Network Management
S e n d d o c u m e n t a t i o n c o m m e n t s t o n x 5 0 0 0 - d o c f e e d b a c k @ c i s c o . c o m
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Object Identifiers
The MIB structure is logically represented by a tree hierarchy. The root of the tree is unnamed and splits
into three main branches: Consultative Committee for International Telegraph and Telephone (CCITT),
International Organization for Standardization (ISO), and joint ISO/CCITT.
These branches and those branches that fall below each category have short text strings and integers to
identify them. Text strings describe object names, while integers allow the computer software to create
compact, encoded representations of the names.
Each MIB variable is assigned with an object identifier. The object identifier is the sequence of numeric
labels on the nodes along a path from the root to the object. For example, the MIB variable tftpHost is
indicated by the number 1. The object identifier for tftpHost is
iso.org.dod.internet.private.enterprise.cisco.workgroup products.stack group.tftp group.tftpHost or
.1.3.6.1.4.1.9.5.1.5.1. The last value is the number of the MIB variable tftpHost.
Tables
When network management protocols use names of MIB objects in messages, each name has an
appended suffix. This suffix is called an instance identifier. It identifies one occurrence of the associated
MIB object. For simple scalar objects, the instance identifier 0 refers to the instance of the object with
that name (for example, sysUpTime.0).
A MIB can also contain tables of related objects. For example, ifOperStatus is a MIB object inside the
ifTable from the IF-MIB. It reports the operational state for an interface on a switch. Because switches
may have more than one interface, it is necessary to have more than one instance of ifOperStatus. This
instance value is added to the end of the MIB object as the instance identifier (for example,
ifOperStatus.2 reports the operational state for interface number 2).
Each object in a table is constructed with a set of clauses defined by the SMI. These clauses include the
SYNTAX clause, MAX-ACCESS clause, STATUS clause, and DESCRIPTION clause.
An excerpt of the information in the VSAN table (known as vsanTable) from CISCO-VSAN-MIB
follows:
vsanTable OBJECT-TYPE
vsanEntry OBJECT-TYPE
VsanEntry ::= SEQUENCE {
Cisco Nexus 5000 Series MIB Quick Reference
4
AGENT-CAPABILITIES, page 5
SYNTAX
SEQUENCE OF VsanEntry
MAX-ACCESS not-accessible
STATUS
current
DESCRIPTION
"A table of VSANs configured on this device."
::= { vsanConfiguration 3 }
SYNTAX
VsanEntry
MAX-ACCESS not-accessible
STATUS
current
DESCRIPTION
"An entry (conceptual row) in the vsanTable."
INDEX { vsanIndex }
::= { vsanTable 1 }
vsanIndex
vsanName
}
VsanIndex,
SnmpAdminString,
OL-16784-01
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