«... Management Information Base (MIB) is a virtual database, which is used to manage objects in a communication network. The most frequently, this notion is related to Simple Network Management Protocol (SNMP). At the same time, it is used in a wider sense meaning a network management model OSI/ISO. Despite the fact a term MIB is not designed to denote all available information about an object, it is also often used to mark a particular subset, which can be more correctly named the MIB module.
A database has got a hierarchical (tree) structure. It is possible to address records using object identifiers OID. MIB bases are discussed in RFC documentation, particularly RFC 1155 and corresponding RFC 1213 and RFC 1157 (derived from the material named «Management Information Base» from Wikipedia) …»
MIB Files for NetPing Devices
Each firmware version has its MIB file [Pub] DKSF X.X.X MB.mib, which is available for downloading at the pages with a description of NetPing devices in the section «Files». MIB file is a text file with the information about all SNMP resources supported by NetPing devices. The MIB file has got a specific hierarchic structure. You are welcome to read more on it in «Management Information Base» on Wikipedia.
Working with MIB Files of NetPing Devices
A lot of network monitoring systems, as well as specific software (particularly MIB browsers), can read MIB files. For example, one of the most popular MIB browsers is «iReasoning MIB browser», which is used as an example for retrieving data and controlling NetPing devices using the MIB file. You can download a free software version from the official website of a developer.
After installing «iReasoning MIB browser» software, there is a need to run it. Download the MIB file of a necessary model of NetPing device into the software. To do this, click the tab «File» in a main horizontal menu of the software, and choose «Load MIBs» from the dropdown menu. Then indicate a location of the file on PC:
After the MIB file has been successfully downloaded, a hierarchic (tree) structure with its SNMP OID (object identifiers) will be displayed in the software area «SNMP MIBs»:
To browse particular object identifiers with their description in a file structure, there is a need to click «+» in a branch of the MIB tree and choose a required SNMP OID. In the example, browsing SNMP OID «npRelayMemo» is shown at the screenshot. This is an identifier, which stores a relay memo specified in the settings of a device web interface:
1 is a name of an SNMP OID in a hierarchic (tree) structure of the MIB file;
2 is a numeric object identifier (OID) in a hierarchic (tree) structure of the MIB file;
3 is a summary and specifications of an object identifier (OID) in a hierarchic (tree) structure of the MIB file. A text description, as well as a name, a type, a status and other parameters, can be browsed here.
Now there is a need to configure a connection to receive the information from the sensors plugged to NetPing devices and control devices via an SNMP:
- specify an IP address of a NetPing device in the line «Address:»
- indicate a port of an SNMP agent (on default 161) in the settings «Advanced...» as well as community reads/writes (on default NetPing devices have the set value «SWITCH») and a version of an SNMP protocol (chose the version 1 for NetPing devices)
- save additional parameters by clicking the button «Оk»
Let us consider receiving a current status of an IO line in NetPing devices via an SNMP.
To do this, choose OID «npIoLevelIn» by a right button of a mouse in a hierarchic structure of the MIB file. Click the method «Get Next» from the dropdown context menu:
As a result of requesting a status of an IO line, the information at the tab «Result Table» will be displayed in response:
Name/OID is a name of SNMP OID, in the example «npIoLevelIn.1» corresponds to the line IO1;
Value is a current value, in the example a logic level of the line IO1 is set to «1»;
Type is a type of an object identifier, in the example it is «Integer»;
IP:Port is an IP and SNMP port of the NetPing device
In addition, «iReasoning MIB browser» software has got a possibility to receive the information in a slightly different way. For example, there is a need to know a current status of the line IO5 of the NetPing device. To do this, there is a need to choose the OID «npIoLevelIn» in a hierarchic structure of the MIB file. In the line «OID:» add the value «.5» to the end of the identifier that appeared. The value after the point indicates a number of an IO line. Then choose the method «Get» from the drop-down list «Operations:» and click the button «Go». As a result, the software will display a current status of the line IO5 of the NetPing device at the tab «Result Table»:
If there is a need to get a current status of all IO lines of the NetPing device at once, then there is a need to choose the method «Get Subtree» in a dropdown context menu when choosing OID «npIoLevelIn»:
As a result, a current status of all IO lines will be displayed at the tab «Result Table»:
Let us examine a process of controlling a built-in relay of the NetPing device via an SNMP.
To do this, there is a need to highlight OID «npRelayMode» for controlling a relay in a hierarchic structure of the MIB file. Click the tab «Operations» in the main horizontal menu of the software and choose the item «Set»:
In the settings of the window «SNMP SET» in the field «OID» add the value, for example, «.1» to the end of the present identifier, where 1 is an ordinal number of a built-in relay of the NetPing device. Hence, controlling any relay can be specified. Indicate a numeric value corresponding to a certain relay status in the field «Value» (a description of numeric values can be seen in the description of the OID in the field «Desc»). In the example the value «1» is set, which corresponds to the status «Manual On». Sending the command «Set» (i.e. recording a configured value into OID) is implemented by clicking the button «Ok»: