Why NAS Message Security Required while Security is already Activated by PDCP Layer?
My understanding is that PDCP level security ends at eNB. But NAS messages need to reach till MME. So, without NAS level security, the path between MME and eNB is not end to end secured. That’s why we need need NAS level security on the top of PDCP level security.
Thanks a lot
NAS also used for mobility and connection between UE and core network.