MIB files (Management Information Base) are written with a particular syntax, the SMI syntax (Structure of Management Information). There are currently two versions for this syntax, SMIv1 and SMIv2. A third version, SMIng (Next Generation) is still under specification.
SMI syntax of MIB files (version 1 or 2) is a subset of ASN.1 and this syntax is defined by a set of ASN.1 recommendations:
- ITU-T Recommendation X.680, Abstract Syntax Notation One (ASN.1): Specification of basic notation
- ITU-T Recommendation X.681, Abstract Syntax Notation One (ASN.1): Information object specification
- ITU-T Recommendation X.682, Abstract Syntax Notation One (ASN.1): Constraint specification
- ITU-T Recommendation X.683, Abstract Syntax Notation One (ASN.1): Parameterization of ASN.1 specifications
Unfortunately, it is very common to find syntax errors in MIB files. This section lists the errors most commonly encountered even in MIB files supplied by wellknown manufacturers: