What is the main reason for introducing ciphering/integrity at NAS level (when the same is present at RRC level as in UMTS)?
Pls refer this http://tech.queryhome.com/6670/why-is-security-command-required-at-both-nas-and-rrc-levels
I am bit confused why the different order are used for integrity and ciphering of RRC and NAS message ? What if the same order (ciphering and then integrity) is used for RRC message ?