HOW TO USE AIX MIB

All of the mibs for AIX are defined in /etc/mib.defs.
There isn't a separate "hardware mib" table/definition. AIX is designed
to RFC 1213 and 1514.
You may View the /etc/mib.defs file.
For example, you have this definition:
sysDescr system.1 DisplayString read-only mandatory
To find out how this object is defined.
# grep sysDescr /usr/samples/snmpd/*
mibII.my: sysDescr OBJECT-TYPE
As you can see it is defined in the /usr/samples/snmpd/mibII.my file.
Some will be in different *.my files.
Kindly reference the mib.defs file and the *.my files, read the
description and see if this is something that you need or not.
# view /usr/samples/snmpd/mibII.my
sysDescr OBJECT-TYPE
SYNTAX DisplayString (SIZE (0..255))
ACCESS read-only
STATUS mandatory
DESCRIPTION
"A textual description of the entity. This value should include the full
name and version identification of the system's hardware type,software
operating-system, and networking software. It is mandatory that this
only contain printable ASCII characters."
::= { system 1 }
Take a look at all of the *.my files in /usr/samples/snmpd.
You can check the same if you query using snmpinfo:
# snmpinfo -m get -v sysDescr.0
following list
of snmp mib config files and mib.defs being main MIB file.
# ls -l /etc|egrep "mib|snmp"
-rw-r----- 1 root system 7825 Oct 1 2014 aixmibd.conf
-rw-r----- 1 root system 2298 Oct 1 2014 clsnmp.conf
-rw-r----- 1 root system 1964 Oct 1 2014 hostmibd.conf
-rw-r----- 1 root system 112300 Oct 1 2014 mib.defs
-rw-r--r-- 1 root system 37 Feb 24 15:31 snmpd.boots
-rw-r----- 1 root system 10128 Oct 1 2014 snmpd.conf
-rw-r----- 1 root system 2516 Oct 1 2014 snmpd.peers
-rw-r----- 1 root system 1541 Feb 24 15:24 snmpdv3.conf
drwxrwxr-x 2 root system 256 Oct 1 2014 snmpinterfaces
-rw-r----- 1 root system 1956 Oct 1 2014 snmpmibd.conf
mib.defs File Format
Provides descriptions of Management Information Base (MIB) variables for
the snmpinfo command.
http://www-01.ibm.com/support/knowledgecenter/ssw_aix_72/com.ibm.aix.fil
es/mib.defs.htm?lang=en