KBI 311186 Issue Addressed: Negative Bandwidth Usage Mbps Returned By DeviceMagic
Version
Argent for SNMP 3.1A-1501-C and earlier
Date
Thursday, 26 March 2015
Summary
The bandwidth usage (Mbps) collected by DeviceMagic may show negative number occasionally
It is more likely to happen for very busy switches
The issue has been addressed in Argent for SNMP 3.1A-1501-T4
Technical Background
DeviceMagic calculates switch bandwidth usage by calculating the Delta value of IN/OUT octets of switch ports
The IN/OUT octets are stored in switch as 32-bit counter
As a result, the number is reset after 232
If the number happens to be reset between two consecutive poll, the Delta value will be negative as well as the calculated Mbps
The number should be adjusted by adding 232
Resolution
Upgrade to Argent AT 3.1A-1501-T4 or later