SMI and the OID Tree
Structure of Management Information — the data definition language and naming scheme that every MIB module is written against. The IANA SMI Numbers registry administers the OID hierarchy rooted at 1.3.6.1, including standard MIBs under 1.3.6.1.2.1 and Private Enterprise Numbers under 1.3.6.1.4.1 (the namespace organizations use to publish their own MIBs).