Why It's Important To Understand MIBs

Why is the MIB important?

Because as far as many SNMP managers and agents are concerned, if a component of a network device isn't described in the MIB, it doesn't exist.

For example, let's say you have an SNMP RTU with a built-in temperature sensor. You think you'll get temperature alarms from this device - but you never do, no matter how hot it gets. Why not? You read the RTU's MIB file and find out that it only lists discrete points, and not the temperature sensor. Since the sensor isn't described in the MIB, the RTU can't send Traps with temperature data.

Some next-generation SNMP Managers like the DPS TMonLNX system, are not as dependant on the MIB for collecting information from SNMP Agents. Instead, the TMonLNX offers a translated data element where TRAP information can be accessed simply by referencing its index in the TRAP message. The index is easily identified from the TMonLNX process diagnostic logs without needing to worry about collecting and loading some specific MIB file or files.

Why do I need to understand the MIB?

As you can see, the MIB is your best guide to the real capabilities of an SNMP device. Just looking at the physical components of a device won't tell you what kind of Traps you can get from it. You might think it's strange that a manufacturer would add a component to a device and not describe it in the MIB. But the fact is, a lot of devices have sketchy MIBs that don't fully support all their functions.

The TMonLNX solution also compensates for these sketchy MIBs by providing a clear presentation of the translated data element. This eliminates concern about whether a MIB versioning or accuracy and allows telemetry information to be integrated directly from the TRAP message traffic.

When you're planning your SNMP monitoring and do not have next-generation SNMP Manager like the TMonLNX, you need to be able to read the MIB so you can have a realistic idea of what capabilities you have. You will also need to interact with the SNMP equipment vendor to collect and review the MIB file or files carefully before you purchase.

What Features Do I Need in an SNMP RTU?

Here are 5 essential features that your SNMP RTU must have:

  1. Discrete alarm inputs (also called digital inputs or contact closures): These are typically used to monitor equipment failures, intrusion alarms, beacons, and flood and fire detectors.
  2. Analog alarm inputs: Analog alarms measure continuously variable levels of voltage or current. Analog alarms monitor temperature, humidity and pressure, all of which can critically affect equipment performance.
  3. Ping alarms: An RTU that supports ping alarms will ping devices on your network at regular intervals. If a device fails to respond, the RTU will send an alarm as an SNMP Trap.
  4. Control relays: An RTU with control relay outputs will let you operate remote site equipment directly from your NOC.
  5. Terminal server function: Your RTU can also serve as a terminal server to remote-site serial devices. Your devices connect to the RTU's serial ports, giving you immediate Telnet access via LAN from your NOC at any time.

DPS Telecom offers SNMP RTUs that meet all these requirements - and offer stand-alone local visibility through any web browser, expandable alarm capacity, LAN access via dial-up connection and more.

NetGuardian 832A
The NetGuardian 832A monitors 32 discrete alarms and 8 analog alarms, pings 32 network elements, controls 8 relays, provides LAN reach through access to 8 serial ports, and reports via SNMP or DCPX, e-mail, or pagers.

To learn more about the NetGuardian and other DPS RTUs, request a live Web demo.