MIB Browser with PRTG

MIB stands for “Management Information Base”. MIB files contain information you need to monitor and control a router, switch, or other specific network device. An OID or “object identifier”, on the other hand, is a series of numbers that identifies an object in the MIB hierarchy and that can be read via SNMP. Think of it this way: a MIB is like a house you want to get to, and an OIB is the set of coordinates you pop into your GPS so you can reach it without getting lost.

A Management Information Base (MIB) is a virtual database used for managing the entities in a computer network. It is an essential component of network management protocols like SNMP (Simple Network Management Protocol).

Structure:

• The MIB is organized hierarchically, often depicted as a tree structure. Each node in the tree represents a specific network object or a collection of related objects.
• The top levels of the tree are defined by international standards bodies, like ISO, while the lower levels are defined by vendors or network administrators.

Object Identifiers (OIDs):

• Each object in the MIB is identified by an Object Identifier (OID). An OID is a series of numbers separated by dots (e.g., 1.3.6.1.2.1.1.5), which trace the path from the root of the tree to the specific object.
• OIDs are used to uniquely identify managed objects in the MIB, such as system details, network interfaces, IP addresses, or any other network-related data.

Managed objects:

• A managed object is essentially a variable that represents a specific attribute of a network entity, such as the number of packets sent by a router interface.
• Managed objects typically have a name (like sysName for the system name), a type (like String or Integer), and a value (like "Router1").

Usage:

• Network management systems (NMS) use MIBs to request and change information on network devices.
• For instance, an NMS might query a router to get the status of its interfaces by reading values from the MIB, or it might set certain parameters (like enabling or disabling an interface).

MIB files:

• MIB files are plain text files that define the structure of the MIB and the MIB objects. These files are used by SNMP management software to interpret and interact with the managed objects.

Because devices from different manufacturers all work differently, it's impossible for monitoring software to cover every possible scenario. MIB files enable you to tailor monitoring sensors to your specific device and situation.

A MIB converter typically refers to a tool or software that translates Management Information Base files from one format to another. These converters facilitate compatibility between different network management systems or devices that might use different MIB file formats.

Cisco, Juniper, Dell, and other reputable device manufacturers usually make MIB files available in the downloads section of their websites. The Internet Engineering Task Force, or IETF for short, has published a global MIB standard, and included MIBs in more than 300 of its first 5,000 RFCs.

SNMP (Simple Network Management Protocol) is a widely used protocol for managing and monitoring devices on a network. It provides a standardized way for network administrators to collect and organize information about SNMP-enabled devices on their network, such as routers, switches, servers, printers, and more, as well as to configure these devices remotely.

There are three versions of SNMP:

SNMPv1: The original version, offering basic features and limited security (plaintext community strings).

SNMPv2c: An improved version with better performance, additional protocol operations, and more data types, but still relying on simple community strings for security.

SNMPv3: The latest version, providing enhanced security features, including message integrity, authentication, and encryption.

Key components of SNMP include:

Managed devices:

• These are network devices that contain an SNMP agent and can be monitored and managed using SNMP. Examples include routers, switches, servers, and workstations.

SNMP agents:

• An SNMP agent is software running on the managed device that collects information about the device's status and configuration. It communicates with the network management system (NMS) using SNMP.
• The agent uses the Management Information Base (MIB) to organize and manage the information.
• The agent can send an unsolicited alert (SNMP trap) to the NMS when certain predefined events occur, such as a device failure or a significant change in status.

Network Management System (NMS):

• The NMS is a central software platform that monitors and controls managed devices using SNMP. It sends requests to SNMP agents and processes the responses to gather network information.
• The NMS can also send commands to the agents to modify the behavior of the managed devices, such as changing configurations or rebooting a device.

Management Information Base (MIB):

• As explained earlier, the MIB is a database of managed objects that the SNMP agents use to store information about the managed devices. The NMS queries or updates these objects via SNMP.

In PRTG, “sensors” are the basic monitoring elements. One sensor usually monitors one measured value in your network, for example the traffic of a switch port, the CPU load of a server, or the free space on a disk drive. On average, you need about 5-10 sensors per device or one sensor per switch port.