Network Errors Interpretation

Network errors can be categorized by how they are measured: cumulative, absolute, and delta values.

Cumulative values increment over time and do not reset automatically unless explicitly cleared or the device is restarted. Examples: CRC errors and total input packets in Cisco's show interface output.

Absolute values reflect the current value and do not increment over time. Example: input and output rate in Cisco's show interface output.

Delta value is typically not found in any Cisco's CLI output but there is a way to calculate it. It can be very useful to interpret certain error stats. For example, if an interface has 500k CRC errors, we cannot take it at face value. Normally, cumulative values need to be interpreted with a time factor like "Last clearing counters". Example: My network health assessment report is able to generate delta values to interpret link error or traffic input/output.