First, get a look at this site, offering a large compilation of mibs : http://www.oidview.com/mibs/detail.html

Find your equipment dealer, click on its name then chose to download the ASN.1 zip file. It will contail every mib file you choosed.
Thanks !!

Then, if you are running Solaris, copy the mibs file to /etc/sma/snmp/mibs
Then, when doing your snmpwalk,  use the « -m all » option to use all of the mibs files :

 $ snmpwalk -m all -v2c -c public mlx1- 1.3.6.1.4.1.1991.1.1.1.1   
FOUNDRY-SN-AGENT-MIB::snChasSerNum.0 = STRING: "QSFDSF444"
FOUNDRY-SN-AGENT-MIB::snChasPwrSupplyStatus.0 = INTEGER: 268
FOUNDRY-SN-AGENT-MIB::snChasFanStatus.0 = INTEGER: 24
FOUNDRY-SN-AGENT-MIB::snChasEnablePwrSupplyTrap.0 = INTEGER: enabled(1)
FOUNDRY-SN-AGENT-MIB::snChasEnableFanTrap.0 = INTEGER: enabled(1)
FOUNDRY-SN-AGENT-MIB::snChasIdNumber.0 = STRING: "SDSD33DF"
FOUNDRY-SN-AGENT-MIB::snChasEnableTempWarnTrap.0 = INTEGER: enabled(1)
FOUNDRY-SN-AGENT-MIB::snChasFlashCard.0 = INTEGER: 0
FOUNDRY-SN-AGENT-MIB::snChasFlashCardLeds.0 = INTEGER: 0
FOUNDRY-SN-AGENT-MIB::snChasNumSlots.0 = INTEGER: 4
FOUNDRY-SN-AGENT-MIB::snChasArchitectureType.0 = INTEGER: 4
FOUNDRY-SN-AGENT-MIB::snChasProductType.0 = INTEGER: 12

More to come soon (I hope) on Foundry snmp monitoring…