Part 3: Understanding the MIB (Management Information Base)

Each snmp element manages specific objects with each object having specific characteristics. Each object/characteristic has a unique object identifier (OID) consisting of numbers separated by decimal points (e.g., 1.3.6.1.4.1.2682.1). These object identifiers naturally form a tree as shown in the below illustration. The MIB associates each OID with a readable label (e.g., dpsRTUAState) and various other parameters related to the object. The MIB then serves as a data dictionary or codebook that is used to assemble and interpret SNMP messages.

SNMP MIB Tree
Figure 2. The branch of the MIB object identifier tree that represents managed elements used by DPS Telecom equipment.

When an SNMP manager wants to know the value of an object/characteristic, such as the state of an alarm point, the system name, or the element uptime, it will assemble a GET packet that includes the OID for each object/characteristic of interest. The element receives the request and looks up each OID in its code book (MIB). If the OID is found (the object is managed by the element), a response packet is assembled and sent with the current value of the object / characteristic included. If the OID is not found, a special error response is sent that identifies the unmanaged object.

When an element sends a Trap packet, it can include OID and value information (bindings) to clarify the event. DPS remote units send a comprehensive set of bindings with each Trap to maintain traditional telemetry event visibility. Well-designed SNMP managers can use the bindings to correlate and manage the events. SNMP managers will also generally display the readable labels to facilitate user understanding and decision-making.

Essential SNMP: What is the MIB?

The MIB lists the unique object identifier (OID) of each managed element in an SNMP network. Your SNMP manager can't monitor your devices unless it has compiled their MIB files. The MIB is also a guide to the capabilities of your SNMP devices. For example, if your device's MIB lists OIDs for Traps but not for GetResponse messages, you know it will report alarms, but will not respond to alarm polls. Learning to read MIBs is difficult, but it's worth the trouble.


Reality Check: How to Get Better Visibility of Your SNMP Alarms

Receiving Traps is Only the Beginning of Effective SNMP Monitoring.

There's a big difference between basic alarm monitoring and intelligent alarm management. Any basic system will give you some kind of notification of an alarm. But simple status reports don't provide effective full visibility of your network.

Automated Correction

Your staff can't hover around a screen watching for alarms with their full attention 24/7. A simple system cannot get alarm information to the people who can correct problems quick enough to make a difference. And some problems require immediate action far faster than any human being can respond.

Using a basic alarm monitoring system makes it more likely that faults will not be corrected, potentially resulting in serious damage to your network and your revenue.

Intelligent Notification

An intelligent alarm management system won't just tell personnel there's a problem; it will locate the problem, provide instructions for corrective action, route alarm information directly to the people who need it, and, if possible, correct the problem automatically. Advanced features like these can make the difference between a minor incident and major downtime, and that's a crucial edge to have in today's competitive telecom industry.

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