SMI provides the common definitions for the structure and identification of management information for TCP/IP-based internets.
SMI is the language used to define MIB modules used by SNMP. MIB modules are the the structured, textual specifications of objects providing management information, derived data types used by those objects, notifications, groups and other related information. There are two versions of SMI: SMIv1, defined by RFCs 1065 , 1155 , 1212 and 1215 , and SMIv2 defined by RFCs 2576 , 2578 , 2579 and 2580 . Both are similar to (and based largely on) ASN.1, but they are actually an "adapted subset" (meaning there are parts that come from ASN.1, but there are also parts that are not strictly legal ASN.1).