LTE Combined Attach

Question

During a combined attache, a UE can receive an ATTACH-REJECT if for the specific PLMN the EPS service are not allowed.
In this case, the EMM cause value received in the ATTACH REJECT message should be 14.
The 124.301 ETSI standard tells that in this situation, if the UE operates in CS/PS mode 1, it may select GERAN or UTRAN
radio access technology instead of LTE for the same PLMN.
The standards doesn't tell anything about UE's operating in CS/PS mode 2: must they choose another PLMN?

Answer 1

Hi Giorgio,

In 24.301 spec, following statement is mentioned for the attach reject with the cause value #14 i.e (EPS services not allowed in this PLMN).
"A UE operating in CS/PS mode 1 of operation and supporting S1 mode only, or operating in CS/PS mode 2 of operation shall delete the list of equivalent PLMNs and shall perform a PLMN selection according to 3GPP TS 23.122 [6]."

If I understood your query then I think this is the answer.