SNMP OID
Here you can set up SNMP templates that are then assigned to particular devices.
Create template
| Title |
The name of a given template |
| SNMP | The SNMP version used (SNMP v1 or SNMP v2c) If data are being gathered correctly during the router connection test, yet the graph is not being plotted, choose SNMP v1. Default for testing: SNMP v1 |
| Graph size |
The size of a graph in pixels Default: 520 x 140 px |
|
Minimum value of the graph Maximum value of the graph |
If you set both these values to 0, the y-axis of a given graph will automatically be adjusted to reflect the measured values. Thus, for example, if CPU load hovers around 50 %, the minimum value of a given graph will be 40 % and the maximum value 60 %. If you set the minimum value to 0 % and the maximum value to 100 %, the resultant graph will be clearer. |
| OID |
The SNMP OID of what is being measured Here you can set in detail each measured characteristic. You can add up to 32 measured values (for example: 1.3.6.1.2.1.2.2.1.10.1 - the total number of octets received on the interface, including framing characters). You can retrieve these values from MIB (Management Information Base) tables of a given device. You have to enter an SNMP OID in numerical unshortened form. |
| Description |
The description of the data measured (for example, CPU load and Temperature) This description will be displayed on a graph. |
| Graph |
If this box is checked, a graph of the data measured will be plotted. If not, a graph will not be plotted, but the system will still gather data from a given device and it will be possible to have a look at them later. |
| Group |
Individual values can be grouped. Here a group means a set of values that are displayed on a single graph. For example, if you assign three values to group 1 and further two to group 2, two graphs will be plotted for a given device. There will be three values on the first graph and two on the second one. |
| Operator |
Here it is possible to convert values to the appropriate unit. For example, the system returns 1245 (instead of 12,45) as the battery voltage value. This value must be converted to the appropriate form by dividing it by 100. |
| Ratio value |
The value that is used (along with a particular operator) to convert the value returned by the system to the desired form |
| Unit |
The unit displayed on a graph next to values (kbps, A, V, % ...) |
| Number of decimal places |
The number of decimal places displayed on a graph (0-3) |
| Absolute value |
When the system gathers data, for example, about temperature or voltage, absolute values (e.g. 12,45 V, 12,58 V) are used. That means that the used values are not incremental. In this case, it is necessary to check the box. However, if you want to plot graphs of transferred data (devices return incremental values - counters), it is necessary to always calculate the difference between the current measured value and the previous measured value and plot the result on a given graph. In this case, it is necessary to leave the box unchecked. |
| Color |
You can choose the colour that will be used for all the data point in the data series. |
| Type |
Here you can choose which type of graph you want: the LINE type (thickness 1-3) or the AREA type. The LINE type: a simple line (of a particular thickness). The AREA type: the shaded area of a graph. |
| OID key | It is an identifier and it has to remain unchanged for this specific purpose. |
Any changes made to an SNMP OID template will immediately be seen in the graph being plotted. That means that if you, for example, change a ratio value, the graph will be updated to reflect the change. Even values gathered earlier will be adjusted accordingly.
Debugging
SNMP walker - If you want to debug and work further with the SNMP protocol, you can make use of the snmpwalk utility, which is accessible directly from the OS Linux console:
snmpwalk -c public -v2c 192.168.1.1
With this command, you can log into the device with the IP address given. Password: public. Protocol version: v.2 = 2c, v.1 = 1. When you execute this command, a list of OIDs and their values will appear.
Connection test - By running this test, you can check whether communication with a given router works, whether communication through SNMP protocol works and whether the data gathered through a defined OID are correct.