In the Simple Network Management Protocol (SNMP), OID stands for "Object Identifier." An OID is an address used to uniquely identify managed devices and their statuses.
Why OID values are used ?
OID values are used in SNMP monitoring tools to monitor and manage network devices connected over an IP network, such as firewalls, switches, and routers.
How OID values are used ?
SonicWall firewalls have predefined OID values that can be used in SNMP monitoring for tracking various activities.
Simple Network Management Protocol (SNMP) is an application-layer protocol that allows for the exchange of monitoring and managing information between network devices. An Object Identifier (OID) is an address used to uniquely identify managed devices and their statuses.
EXAMPLE: The format of an OID tree can be confusing at first. It's a long string of numbers like this:
OID will be the same for every piece of equipment which is defined as below :

SonicWall OIDs can be found in the MIB files available on the MySonicWall.com portal. These files can be uploaded into any MIB browser engine to view them. Click the link below to see how to download the MIB files for the SonicWall firewall.
Where can I download the SNMP MIB files?
EXAMPLE: The screenshot below is taken from the ManageEngine MIB browser, which is available as a free download on the internet:

Example of an OID Value for Current RAM Utilization:
OID : .1.3.6.1.4.1.8741.1.3.1.4
Description: Instantaneous RAM Utilization in percent
Hierarchy for OID: .iso.org.dod.internet.private.enterprises.sonicwall.sonicwallFw.sonicwallFwStatsModule.sonicwallFwStats.sonicCurrentRAMUtil
The SonicWall Gen7 does not support SNMP OIDs related to routing information with the OID value 1.3.6.1.2.1.4.21.x.x, these SNMP OIDs are still supported on Gen6.