ATM vs. DS3

I've used 20% as the general ATM overhead now for almost two years, and have
been poo-pooed by lots of people claiming that it wasn't anywhere near that

Our inhouse figure is 23%. That was an empirical test of a traffic
generator comparing performance to Cicso HDLC. This might be slightly
pessimistic as Cisco traffic shaping (yes, even though you can't
see it, it is there working) is really very aggressive and with bursty
traffic it tends to prefer underfilling the line to overfilling it.

Alex Bligh
Xara Networks

I'm not sure if this is pessimistic. When we ran calculations based on
packet size distribution of CICNet, we got 23% as well, and I believe Peter's
calculations based on ICM traffic agreed with this also.