The SBC calculates the packet loss rate as (number of packets lost/number of packets expected) x 100.
For every incoming call leg:
The SBC periodically (approximately after every 512 expected packets) calculates the packet loss rate.
The SBC also periodically (approximately after every 10 seconds) checks if the packet loss rate of the call is above the configured value for the parameter Packet Loss Threshold.
If the SBC detects that the loss rate has exceeded the threshold, it reports the difference to higher layer of services within the software stack.