well, could you please share the numerical values ?
you know that the PCU (equipment between the SGSN and the BSC) is segmenting the frames from the SGSN into RLC blocks.
The frames from the SGSN looks like :
Gn header + Gb header + user payload
n “RLC blocks” = n*[(Gn header + Gb header + user payload)/n]
Gn header = GTP header
Gb header = LLC hedaer
user payload = the whole IP datagram, including the IP header.
Well, just have a look to the protocol stacks of the GPRS, you’ll see all the headers 🙂