Hari.
if you are talking of the #SS7 link from MSC to SMSC, then you calculate in terms of kbps.i.e. A complete SMS right from deposit to delivery consists an average of 4 MSU with 75octets/MSU.This comes out as 75*8*4=2.4kb.With 0.4 occupancy of a 64 kbps #ss7 channel no of SMS will be 64*0.4/2.4=11