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Reserve Your Seat TodayIn this article, you'll learn what MIBs are and you'll have a quick SNMP guide.
Management Information Base, or MIB, is a formatted text file that lists the data objects used by a particular piece of SNMP equipment.
When you buy a device that uses SNMP (for example, a managed switch), you'll tell it to send messages to your central SNMP manager. But there are tens of thousands of different SNMP devices and your manager doesn't natively understand each one.
The manufacturer of your managed device will supply you with a file (usually a download from their website) that you'll load ("compile") into your SNMP manager (If you've ever installed a device driver on a PC, you understand this concept). Without the management information base for message translation, communication simply won't happen.
A MIB contains definitions and info about the properties of managed resources and the services that the agents (devices) support. The features of resources, as defined in a Management Information Base, are called "managed objects" or "management variables".
A management station gets and sets objects in the Management Information Base, and an agent notifies the management station of events using messages called (somewhat oddly) "traps". All message exchanges between the management station and its agents take place using SNMP. The Management Information Base at the management station contains network management info. This info is taken from the MIBs of all the managed parts in the network.
Your SNMP manager needs the MIB in order to process messages from your devices. This is a critical step in network monitoring. The Management Information Base is also your best guide to the real capabilities of an SNMP device. You need to be able to read the MIB so that you can have a good idea of what assets you do have.
Updating MIB objects is essential for maintaining and enhancing the functionality of network monitoring systems, especially when using devices like SNMP-based RTUs. To update MIB objects:
By updating your MIB objects, you can uphold your network's ability to monitor infrastructure, whether that's handling new devices, supporting protocols, or just basic efficient functioning.
The MIB monitors various objects that reflect the operational status and performance of network devices. Examples include interface status (ifOperStatus), which indicates whether a network interface is up or down. Another example is CPU utilization (hrProcessorLoad), which tracks the percentage of CPU usage on a device to help identify potential performance issues. These monitored objects are important for maintaining the health and efficiency of network operations.
Scalar and tabular MIBs differ primarily in how they represent data within the MIB structure. Scalar MIBs define single-instance objects. This means each object has only one instance and thus represents a single piece of information. For example, an object that holds the system uptime (sysUpTime) is scalar because there is only one uptime value for the entire system.
Tabular MIBs define multiple-instance objects, which are organized in tables. Each entry in the table corresponds to a row that can have multiple instances of data, such as a list of network interfaces where each interface has attributes like status, speed, and IP address. These tabular MIBs are used for representing repetitive information in a structured way. This allows multiple related data points to be accessed through indexed rows.
One of the best tactics for addressing MIB problems is to simply read through the file. As the file is just ASCII text, you can view it in any word processor or text editor (even Notepad). Some manufacturers provide grouped files in binary format, but those aren't readable. You want the raw ASCII version of the Management Information Base file.
An easier way to get started with Management Information Bases can be to use MIB browsers. These are software programs that allow you to view it in a more friendly format, commonly a tree containing each MIB object.
Do you need to download DPS' MIBs, Cisco MIBs, or even Chronos MIBs? We have an extensive library with a list of MIBs supported by different vendors. There, you can download these files for free.
The Simple Network Management Protocol, or SNMP, is a standard protocol, developed by The Internet Engineering Task Force (IETF).
SNMP is used for monitoring and management of network devices that span firewalls or embedded devices (known as SNMP agents).
SNMP exposes management data in the form of variables on the managed systems. These describe the system configuration. These variables can then be sorted (and sometimes set) by managing applications.
SNMP uses several key operations to manage and monitor network devices:
These operations enable SNMP to effectively monitor and manage network devices by retrieving, setting, and reporting data.
SNMP messages are structured with key components that aid communication between network management systems and devices. Each message includes:
The PDU contains the operation to be performed (such as GET or SET), along with fields like request ID, error status, and error index. It also includes variable bindings (VarBinds), which are pairs of Object Identifiers (OIDs) and their corresponding values, specifying the data to be accessed or modified. This structured format ensures precise and efficient network management.
There are several SNMP versions, but the most common by far are SNMP v1, v2c, and v3.
The SNMP v1 network management architecture contains:
SNMP v2c specs include the following new capabilities:
SNMP v3 specs include the encryption required by security-conscious organizations. Most networks have large amounts of SNMP gear already, though, and must find another way to deploy v3 for security?
With an SNMPv3 mediator, it's possible to upgrade older SNMP-enabled devices to SNMPv3. It's pretty simple equipment in concept, but only offered by a few manufacturers.
Download White Paper: "How to Read and Understand the SNMP MIB"
Part 2: Tactics for resolving common MIB problems
Part 3: Why is the MIB important?