Hi,
working on a diagnostic interface, I also ran into the lack of a gsmtap type for LTE NAS
plain messages.
So I am supporting Shinzo's request for a new GSMTAP_TYPE_LTE_NAS (or
GSMTAP_TYPE_LTE_UU) type in packet-gsmtap.h.
This type would play a similar role to that of GSMTAP_TYPE_UM for GSM, if my understanding
is correct.
Best regards,
Martin
Unlike GSM and UMTS, LTE introduced separate layer for
encryption of NAS and
RRC. As a result, while NAS messages are piggybacked to LTE RRC, but after NAS
security had been activated only encrypted NAS messages are available at RRC
layer. This is reflected into the baseband diagnostics of various makers:
Qualcomm provides separate diagnostic item for LTE NAS (both encrypted and
plain) and RRC. Separate payload type for LTE RRC and LTE NAS will solve this
issue. I can submit a patch if this looks positive.