Hi Sofiane,
Historically, Telecommunications Networks (e.g. Wireline) were dimensioned based on forecasted traffic volume.
This was based on the Erlang. This helped operators to understand the number of circuits (e.g. E1.0s) that will be required. Additional software features could be procured or the license could be increased.
Erlang is the main unit that is used for Voice. It is key for GSM/3G/4G for Voice based telephony services.
As Mobile Broadband is now a part of the landscape the MB figure has to be used.
As most Networks now have a “convergent” BSS in place you can obtain Traffic information/statistics
from the SCP (Control) node. This will handle Voice (CAMEL) and Data (Diameter) traffic.
VBR/ Wallis Dudhnath