---
type: SNMP Concept
title: "MIB Structure & SMI Syntax: How to Read a MIB File"
description: "How to read MIB files: SMIv2, OBJECT-TYPE, MAX-ACCESS, base types, and tables."
resource: "https://snmp-monitoring.info/what-is-snmp/mib/structure/"
tags: [what-is-snmp]
timestamp: 2026-07-10T00:00:00Z
---

# MIB Structure & SMI Syntax: How to Read a MIB File

How to read MIB files: SMIv2, OBJECT-TYPE, MAX-ACCESS, base types, and tables.

## Related concepts

- Up: [What Is a MIB in SNMP? Files, Structure & Usage](/what-is-snmp/mib/index.md)

## Frequently asked questions

### What language are MIBs written in?

SMI (Structure of Management Information), a specialized ASN.1-based notation. SMIv2 = RFC 2578 (with RFC 2579/2580 companions).

### What is OBJECT-TYPE?

The core SMI macro that declares a managed object: SYNTAX, MAX-ACCESS, STATUS, DESCRIPTION, and its OID assignment.

### What is MAX-ACCESS?

It states how the object may be used: e.g. read-only, read-write, not-accessible, read-create, accessible-for-notify.

### Counter32 vs Counter64?

Both are counters for delta/rate math. Counter64 is wider—needed when 32-bit wrap is too fast (classic high-speed interface problem).

## Source

Concept generated from https://snmp-monitoring.info/what-is-snmp/mib/structure/ — the SNMP Monitoring vendor-neutral knowledge base. Content is limited to what that page states (no external claims added here).