SNMP Polling MIB Group Change Detection

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Solution Overview

Problem

Conventional network management methods, such as SNMP-trap and RMON, are not reliable and efficient in monitoring changes in Management Information Base (MIB) objects, leading to excessive network traffic and resource utilization, especially when polling each MIB object individually.

Innovation Solution

Implementing a method that periodically polls Aggregate Change Identifiers (ACIs) of MIB groups instead of individual MIB objects, reducing the number of polled objects and minimizing network traffic by only polling changed groups, thereby optimizing SNMP polling and reducing the time taken to detect changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If SNMP polling is performed on each MIB object individually, then changes in MIB objects can be detected reliably, but a large amount of SNMP traffic is generated in the network

Engineering Contradiction:

Improvechange detection reliabilityVSAvoidSNMP traffic volume

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent segments MIB objects into hierarchical groups (e.g., ifTable, ipRouteTable, tcpConnectionTable) and implements polling at the group level rather than individual object level. Each MIB group is assigned a unique identifier, allowing the NMS to poll groups systematically and reduce the total number of polling operations while maintaining comprehensive monitoring coverage.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent merges multiple individual MIB object monitoring into unified MIB group monitoring. By combining related MIB objects into logical groups (such as grouping all interface objects, all routing objects, or all connection objects), the system reduces redundant polling operations and minimizes network traffic while preserving the ability to detect changes in individual objects within each group.

Inventive Principle:

Principle #5Merging (Combining)

2Loss of time

If SNMP polling is performed frequently to detect changes quickly, then detection time is reduced, but network traffic and device resource utilization increase

Engineering Contradiction:

Improvechange detection timeVSAvoidnetwork traffic

Core Design Contradiction:

Loss of timeVSQuantity of substance

Solution Approach 1:

The patent implements periodic polling of MIB groups at optimized intervals rather than continuous or overly frequent polling. The system determines appropriate polling periods for different MIB groups based on their volatility and importance, allowing timely detection of changes while avoiding unnecessary traffic during stable periods. This periodic approach balances responsiveness with resource conservation.

Inventive Principle:

Principle #19Periodic action

3Quantity of substance

If asynchronous monitoring using SNMP-trap mechanism is used, then network traffic is reduced, but reliability is compromised as traps may not be received by the NMS

Engineering Contradiction:

Improvenetwork trafficVSAvoidmonitoring reliability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces MIB group change identifiers as intermediaries between the network devices and the NMS. These identifiers act as condensed representations of the state of entire MIB groups, allowing the NMS to detect changes efficiently without requiring high-volume trap messages. The change identifiers serve as a reliable intermediary mechanism that reduces traffic while maintaining monitoring reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Productivity

If RMON is used to monitor MIB objects, then monitoring capability is enhanced, but large memory of network devices is required which is not suitable for huge lists of MIB objects

Engineering Contradiction:

Improvemonitoring capabilityVSAvoiddevice memory requirement

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts the complex monitoring functionality from the network devices themselves and relocates it to the NMS. Instead of requiring devices to maintain large local memory for RMON-style monitoring, the system extracts MIB group state information and change identifiers to the NMS, where the actual analysis and monitoring logic resides. This extraction eliminates the need for high memory requirements at network devices while preserving enhanced monitoring capabilities.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS9473348B2Method and system for detecting changes in a network using simple network management protocol polling

Publication Date: 2016.10.18 CISCO TECHNOLOGY INC

AI summary

In an embodiment, methods and systems have been provided for detecting changes in a network using improved Simple Network Management Protocol (SNMP) polling that reduces network traffic. Examples of changes in the network include, but are not limited to, configuration and behavioral changes in a network device, and response of network device to a network change. A Network Management Station (NMS) periodically polls Management Information Base (MIB) groups instead of periodically polling individual MIB object instances. The NMS receives the Aggregate Change Identifiers (ACIs) of MIB groups in response to polling, from a SNMP agent. The changes in the received ACIs represent the changes in the MIB groups. A change in an MIB group represents changes in the MIB object instances of the MIB group. The ACIs can be checksum, timestamp, and a combination of number of MIB object instances in a group and checksum of the MIB group.