SNMP

http://en.wikipedia.org/wiki/Snmp

Standard tools: snmpwalk, snmpget/set

mrtg

Maybe also:

Nagios

http://www.zenoss.com/

general

Rack

We are using SNMP to read out datas from - and configure - control units and switches for the racks.

RMC-Compact

The RMC is a product from Sinetica and has the vendor number 3711. It is able to receive its IP address during the boot process from a DHCP server.

not possible using SNMP

It is not possible to manipulate any IP address via SNMP nor the community string. For this purpose one has to use other methods, e.g.telnet.

read out

The status of sensors:

  • temperature
  • humidity

set and read out

- the warning and the critical upper and lower values for the temperature

input

  • temperature sensors
  • humidity sensors
  • fan status (on/off)
  • door status (close/open)
  • other sensors

output

- 3 switches

programing

A potential free switch can be used to control e.g. a relay. The switch is controls via a logical programming. Sensor inputs can be used and combined with "AND" or "OR" flags.

If the input is true the switch is on. For the first two switches the used sensors are stored in a string type value with the OIDs
  • .1.3.6.1.4.1.3711.15.1.1.3.7.1.0
and
  • .1.3.6.1.4.1.3711.15.1.1.3.7.2.0

Possible entries are
  • "9": The temperature is the lower the the critical lower level.
  • "10": The temperature is the lower the the warning lower level.
  • "11": The temperature is the lower the the warning upper level.
  • "12": The temperature is the lower the the critical upper level.

Since our rack shall be protects with a relay which is "ON" if it is connected, we have to invert the logic. We put e.g. value for the critical lower temperature to our maximal allowed temperature and compare it with the current temperature. Since we are always in the non normal modus the switch ins closed and the relay is on. If we reach the critical lower temperature we enter the normal modus and switch changes to status "off". The relay cuts the power supply for the rack and all nodes are down.

One has to assure that - if the temperature drops below our maximal allowed temperature (the lower critical temperature) - the relay has to keep staying in the "OFF" positions. This can be assured if the control power for relay is connected to power, the relay is cutting. Once the relay is "OFF" there is no way to bring it back to the "ON" modus. To switch it on initially we have to provide the relay with a separate power source. This extern power source can be controlled by a second switch in the control unit, accessible via SNMP.

ProCurve 2900

Pro Curve 2900 family switch

All configuration can be done using SNMP.

see also

SNMPTRAP

This topic: ATLAS > SNMP
Topic revision: 23 Jun 2009, JenniferSchenke
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