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EPS security context is invalid?
Posted on 04. Aug, 2012 by r96942124
in LteWorld Forum
In TS24.301 P32(4.4.2.1), it said:
The UEi shall mark the EPSi security context on the USIMi or in the non-volatile memory as invalid when the UE initiates an attach procedure as described in subclause 5.5.1 or when the UE leaves state EMM-DEREGISTERED for any other state except EMM-NULL.
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I cannot understand why the EPS security context is invalid when UE leaves state EMM-DEREGISTERED for any other state except EMM-NULL.
I think UE can leave state EMM-DEREGISTERED because the attach procedure successes. It means the security activation success. Hence I think EPS security context is valid. However, the spec said it is invalid.
Why?
With new successful attach
With new successful attach procedure, UEi will establish a valid context again ..at the time of initiation of attach procedure ..UE needs to mark existing one invalid ..to handle the cases if attach fails/rejected ..