I am trying to calculate how much bandwidth should put in the priority queue in the Frame Relay WAN for 8xG.729 calls.
I understand that the bandwidth for each call is (payload size+L2 overhead)*packets/s. For the G.729, by default it has 20 bytes payload and 50 packets per second.
But I am confused about the overhead.
In the QoS SRND3.3 page 1-15, it says MLP overhead is 13bytes, and FRF.12 has 8 bytes.
But from http://www.cisco.com/warp/public/788/pkt-voice-general/bwidth_consume.htm,
it says both MLPPP and FRF.12 have 6 bytes of overhead. In voice bandwidth calculator, it also says 6 bytes overhead for both MLPPP and RF.12.
So which one I should trust, the SRND or cisco web site?
Also for cRTP, all documents says the overhead is 2 bytes or 4 bytes. Then should I use 2 or 4?
Thanks!