mean use time / time between request
for ex: calls = 60s average
in between = 2s
60/2 = 30 erlangs
ok, that’s a weird computation 🙂 but it works
if you want to know the variance, you need to know the duration of each call, or find a QoS indicator that measures the distribution of call duration. I believe you can find such data in the MSC/VLR, not in the BSS counters.