OID value: 1.3.6.1.2.1.2.2.1.1
OID description:
ifIndex OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION "A unique value for each interface. Its value ranges between 1 and the value of ifNumber. The value for each interface must remain constant at least from one re-initialization of the entity's network management system to the next re- initialization." ::= { ifEntry 1 }
See also the OID Repository website reference for 1.3.6.1.2.1.2.2.1.1