There are many OIDs and MIBs on the Internet to get same information from devices.. i guess because there are many different version of the devices.

In my case, i solved with below OIDs.

OIDs for CPU & Memory

ALL CPU Current CPU Free Memory
1.3.6.1.4.1.9.9.618.1.4.1.0 1.3.6.1.4.1.14179.1.1.5.1.0 1.3.6.1.4.1.14179.1.1.5.3.0

You should divide the “Free System Memory : 482672640” / 1024 bytes to get 471,360 Bytes to be closed the result of SNMP

on CISCO web site, the OID number is 1.3.6.1.4.1.14179.1.1.5.3.

If you do not insert 0 to end of the OID, you will get “No Such Instance” Message.

there are two MIBs, CISCO-LWAPP-SYS-MIB & AIRESPACE-SWITCHING-MIB.

The OIDs i wrote are from AIRESPACE-SWITCHING-MIB and the OIDs on the Internet are usually from CISCO-LWAPP-SYS-MIB.

I searched what AIRESPACE is, and it was a vendor that CISCO merged in 2005.

I guess at least, by Ver.7.0.98.0 in WLC OS would associate with AIRESPACE-SWITCHING-MIB. and this MIB might not support the number of associated AP and client.

I strongly recommend you to upgrade OS.