SNMP is based on the manager/agent model consisting of a manager, an agent, a database of management information, managed objects and the network protocol. The manager provides the interface between the human network manager and the management system. The agent provides the interface between the manager and the physical device(s) being managed, such as bridges, hubs, routers or network servers, these managed objects might be hardware, configuration parameters, performance statistics, and so on. These objects are arranged in what is known as a virtual information database, called a Management Information Base, also called MIB. SNMP allows managers and agents to communicate for the purpose of accessing these objects.
The manager and agent use a Management Information Base and a relatively small set of commands to exchange information. The MIB is organized in a tree structure with individual variables, such as point status or description, being represented as leaves on the branches. A long numeric tag or object identifier (OID) is used to distinguish each variable uniquely in the MIB and in SNMP messages.
The MIB lists the unique object identifier of each managed element in an SNMP network. The SNMP manager canít monitor devices unless it has compiled their MIB files. The MIB is also a guide to the capabilities of SNMP devices. For example, if MIB lists OIDs for Traps but not for GetResponse messages, it will report alarms, but will not respond to alarm polls.
Each SNMP element manages specific objects with each object having specific characteristics. Each object / characteristic has a unique object identifier consisting of numbers separated by decimal points (i.e., 188.8.131.52.4.1.2682.1). These object identifiers naturally form a tree as shown below. The MIB associates each OID with a readable label and various other parameters related to the object. The MIB then serves as a data dictionary or code book that is used to assemble and interpret SNMP messages.
Below you find list of vendors that offer MIB files to monitor their devices. Click on a vendor to find more information on the MIB.