Jun 182009
UMTS protocols are divided into two different strata (See Fig):
1. NAS (non access stratum)
2. AS (access stratum)
UE (User Equipment) and CN (Core Network, MSC for circuit switched service, SGSN for packet switched service) need to talk!
NAS protocols support the talk between UE and CN.
It does not care below access method (could be UTRAN, GSM/GPRS).
Some examples [...]
