SNMP Bitmap Change Detection for Managed Device Polling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current SNMP polling methods are inefficient, particularly in change detection, as they require polling all managed objects and comparing their values, which burdens networks and devices, especially during audits and performance monitoring, due to high bandwidth usage and resource consumption.
Innovation Solution
Implementing a bitmap-based change detection technique where the SNMP agent on managed devices identifies and stores changed objects within the MIB, allowing the NMS to poll only these changed objects, reducing the burden on devices and bandwidth by using a 'changedObjects' object to track changes and generate bitmaps that indicate altered objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If SNMP polling is used to collect inventory and configuration data, then change detection capability is improved, but network bandwidth consumption and device resource usage increase significantly
Solution Approach 1:
The patent extracts only the changed objects from the complete MIB database using a bitmap mechanism. Instead of polling all objects, the system identifies and retrieves only those objects whose values have changed since the last poll, significantly reducing network bandwidth consumption while maintaining change detection capability
Solution Approach 2:
The patent introduces a bitmap parameter that changes state (from 0 to 1) only when an object value changes. This parameter change mechanism allows the system to track modifications without polling all objects, reducing the effective polling load from O(n) to O(m) where m is the number of changed objects
2Reliability
If all MIB objects are polled periodically to detect changes, then complete monitoring coverage is achieved, but device processing time and computational resources increase
Solution Approach 1:
The patent segments the MIB database into individual objects, each with its own change indicator in the bitmap. This segmentation allows the system to process only the relevant subset of objects (those with changed values) rather than the entire database, reducing processing time while maintaining complete monitoring coverage
Solution Approach 2:
The patent applies partial action by polling only the necessary portion of the MIB database (changed objects identified via bitmap) rather than performing excessive action of polling all objects. This selective approach reduces device processing time while achieving the required monitoring coverage
3Speed
If high-frequency polling is implemented to detect changes rapidly, then change detection speed is improved, but network load and device resource consumption increase
Solution Approach 1:
The patent implements preliminary action by pre-calculating and storing the bitmap of changed objects at the managed device before the NMS polls. This preliminary preparation allows the NMS to quickly retrieve only the changed objects without performing extensive comparisons, achieving rapid change detection while reducing network load
Data Source
AI summary
Techniques for detecting device changes using SNMP polling are described. In response to determining that an MIB of a managed device has changed, the device's SNMP agent identifies the altered objects in the device's MIB. In response to detecting such a change, the SNMP agent generates a bitmap. This bitmap identifies all the MIB's objects that have changed. The NMS may access and use this bitmap to take further action. For example, the NMS may use the bitmap to poll only the changed objects in the MIB, rather than all of the objects in the MIB (including the unchanged objects). Because fewer than all of the MIB's objects need to be polled in order to identify changes to the managed device, both the burden on the device and the bandwidth required for the polling is significantly reduced.