SNMP SMI Compiler for Python#

The PySMI library and tools are designed to parse, verify and transform SNMP SMI MIB modules from their original ASN.1 form into JSON or PySNMP representation.

This library is highly modular. The top-level component is called compiler and it acts as main user-facing object. Most of other components are plugged into the compiler object prior to its use.

Normally, users ask compiler to perform certain transformation of named MIB modules. The compiler will:

  • Search its data sources for given MIB module (identified by name) noting their last modification times.

  • Search compiler-managed repositories of already converted MIB modules for modules that are more recent than corresponding source MIB module.

  • If freshly transformed MIB module is found, processing stops here.

  • Otherwise compiler passes ASN.1 MIB module content to the lexer component.

  • Lexer returns a sequence of tokenized ASN.1 MIB contents. Compiler then passes that sequence of tokens to the parser component.

  • Parser runs LR algorithm on tokenized MIB thus transforming MIB contents into Abstract Syntax Tree (AST) and also noting what other MIB modules are referred to from the MIB being parsed.

  • In case of parser failure, what is usually an indication of broken ASN.1 MIB syntax, compiler may attempt to fetch pre-transformed MIB contents from configured source. This process is called borrowing in PySMI.

  • In case of successful parser completion, compiler will pass produced AST to code generator component.

  • Code generator walks its input AST and performs actual data transformation.

  • The above steps may be repeated for each of the MIB modules referred to as parser figures out. Once no more unresolved dependencies remain, compiler will call its writer component to store all transformed MIB modules.

The location of ASN.1 MIB modules and flavor of their syntax, as well as desired transformation format, is determined by respective components chosen and configured to compiler.

PySMI software is free and open-source. Project source code is hosted at PySMI GitHub repository. This library is being distributed under 2-clause BSD License.

Quick Start#

You already know something about SNMP SMI and have no courage to dive into this implementation? Try out quick start page!


You can find conceptual and API documentation in the following section.


We have a collection of sample scripts to help you get started with PySMI.


If you are having trouble with PySMI, please check the following section.


Best way is usually to

pip install pysmi-lextudio

If that does not work for you for some reason, you might need to read the following page.


Release Notes#

We maintain the detailed log of changes to our software.

MIB Files Archive#

The PySMI project maintains a collection of publicly available ASN.1 MIB files collected over the Internet at You are welcome to use this MIBs archive however we can’t guarantee any degree of consistency or reliability when it comes to these MIB modules.

The mibdump tool as well as many other utilities based on PySMI are programmed to use this MIB repository for automatic download and dependency resolution.

You can always reconfigure PySMI to use some other remote MIB repository instead or in addition to this one.


In case of questions or troubles using PySMI library, please open up a GitHub issue at GitHub or ask on Stack Overflow .

For other inquiries, please contact LeXtudio Inc..

More information about support options can be found in the following section.