L.1 Mapping of NAS procedure to RRC establishment cause(Iu mode only)

24.0083GPPCore network protocolsMobile radio interface Layer 3 specificationRelease 18Stage 3TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

When MM requests the establishment of an RR connection, the RRC establishment cause used by the MS shall be selected according to the CS NAS procedure as specified in table L.1.1.

Table L.1.1/3GPP TS 24.008: Mapping of CS NAS procedure to establishment cause

CS NAS procedure	RRC Establishment cause (according 3GPP TS 25.331 [23c])
Originating CS speech call	Originating Conversational Call
Originating CS data call	Originating Conversational Call
CS Emergency call	Emergency call
Call re-establishment	Call re-establishment
Location update	Registration
IMSI Detach	Detach
MO SMS via CS domain	Originating Low Priority Signalling
Supplementary Services	Originating High Priority Signalling
Answer to circuit switched paging	Set equal to the value of the paging cause used in the reception of paging in the RRC layer
Answer to paging for CS fallback	Terminating Conversational Call
Answer to paging for CS fallback	Terminating High Priority Signalling, if in the E-UTRAN, the RRC connection is released with cause CS Fallback High Priority.
SS part of Location services	Originating High Priority Signalling
Any CS NAS procedure where the initiating uplink signalling message has the Device properties IE with low priority indicator set to "MS is configured for NAS signalling low priority"	Delay tolerant

When MM requests the establishment of an RR connection, if the MS is configured for EAB (see the "ExtendedAccessBarring" leaf of the NAS configuration MO in 3GPP TS 24.368 [135] or 3GPP TS 31.102 [112]), the MS is not an MS configured to use AC11 – 15 in selected PLMN, the MS is not answering to paging and the RRC Establishment cause is not set to "Emergency call", then the MM shall indicate to the lower layer for the purpose of access control that EAB applies for this request.

NOTE 1: void.

NOTE 2: EAB override is not supported in the CS domain.

When GMM requests the establishment of a PS signalling connection, the RRC establishment cause used by the MS shall be selected according to the PS NAS procedure as specified in Table L.1.2.

Table L.1.2/3GPP TS 24.008: Mapping of PS NAS procedure to establishment cause

PS NAS procedure	RRC Establishment cause (according 3GPP TS 25.331 [23c])
GPRS Attach	If the ATTACH REQUEST has Attach type not set to "Emergency attach", the RRC establishment cause shall be set to Registration except when the MS initiates attach procedure to establish emergency bearer services.
GPRS Attach	If the ATTACH REQUEST has Attach type set to "Emergency attach" or if the ATTACH REQUEST has Attach type not set to "Emergency attach" but the MS initiates the attach procedure on receiving request from upper layer to establish emergency bearer services, the RRC establishment cause shall be set to Emergency call. (See Note 2)
Routing Area Update – for the case of ‘Directed Signalling Connection Re-Establishment (see chapter 4.7.2.5.)	If the MS does not have a PDN connection established for emergency bearer services, the RRC establishment cause shall be set to Call Re-Establishment.
	If the MS has a PDN connection established for emergency bearer services, the RRC establishment cause shall be set to Emergency call. (See Note 2)
Routing area Update – all cases other than ‘Directed Signalling Connection Re-Establishment or answer to packet paging	If the MS does not have a PDN connection established for emergency bearer services, the RRC establishment cause shall be set to Registration.
	If the MS has a PDN connection established for emergency bearer services, or is initiating a PDP CONTEXT ACTIVATION that has request type set to "emergency", the RRC establishment cause shall be set to Emergency call. (See Note 2)
GPRS Detach	Detach
Request to re-establish RABs	If the request is not to re-establish RABs for emergency bearer services, the RRC establishment cause shall be set to either ‘Originating Conversational Call’ or ‘Originating Streaming Call’ or ‘Originating Interactive Call’ or ‘Originating Background Call ‘ – depending on the Traffic Class in QoS of the "most demanding" Traffic Class, considering all active PDP contexts. (see Note 1)
Request to re-establish RABs	If the request is to re-establish RABs for emergency bearer services, the RRC establishment cause shall be set to Emergency call. (See Note 2)
Request to establish a PS signalling connection for MBMS	MBMS reception or MBMS p-t-p RB request
Activate PDP Context	If the ACTIVATE PDP CONTEXT REQUEST has the Request Type not set to "emergency", the RRC establishment cause shall be set to either ‘Originating Conversational Call’ or ‘Originating Streaming Call’ or ‘Originating Interactive Call’ or ‘Originating Background Call ‘ – depending on the Traffic Class in QoS of the "most demanding" Traffic Class, considering all active PDP contexts together with the PDP context to be activated. (see Note 1) – If Traffic Class in QoS is not ‘Conversational Class’ or ‘Streaming Class’ or ‘Interactive Class’ or ‘Background Class’ but is ‘Subscribed Traffic Class’, then ‘Originating Subscribed traffic Call’ shall be used.
Activate PDP Context	If the ACTIVATE PDP CONTEXT REQUEST has the Request Type set to "emergency", the RRC establishment cause shall be set to Emergency call. (See Note 2)
Modify PDP Context	Originating High Priority Signalling
Deactivate PDP Context	Originating High Priority Signalling
MO SMS via PS domain	Originating Low Priority Signalling
SS part of Location services	Originating High Priority Signalling
Answer to packet paging or receipt of a "call-pull-initiated" indication from the upper layer (see 3GPP TS 24.174 [185])	If the MS does not have a PDN connection established for emergency bearer services, the RRC establishment cause shall be set equal to the value of the paging cause used in the reception of paging in the RRC layer.
	If the MS has a PDN connection established for emergency bearer services, the RRC establishment cause shall be set to Emergency call. (See Note 2)
Any PS NAS procedure where the initiating uplink signalling message has the Device propertiesIE with low priority indicator set to "MS is configured for NAS signalling low priority"	Delay tolerant
NOTE 1: For classification of "most demanding" Traffic Class the following ranking order applies: "Conversational" followed by "Streaming" followed by "Interactive" followed by "Background", where "Conversational" is the most demanding Traffic class in terms of being delay sensitive. NOTE 2: The emergency bearer services are only supported in UTRAN Iu mode.

NOTE 3: The RRC establishment cause can be used by the network to prioritise the connection establishment request from the MS at high load situations in the network.

When GMM requests the establishment of a PS signalling connection, if the MS is configured for EAB (see the "ExtendedAccessBarring" leaf of the NAS configuration MO as specified in 3GPP TS 24.368 [135] or 3GPP TS 31.102 [112]), the GMM shall indicate to the lower layer for the purpose of access control that EAB applies for this request except for the following cases:

– the MS is an MS configured to use AC11 – 15 in selected PLMN;

– the MS is answering to paging or a "call-pull-initiated" indication is received from the upper layer (see 3GPP TS 24.174 [185]);

– the RRC Establishment cause is set to "Emergency call";

– the MS is configured to allow overriding EAB (see the "Override_ExtendedAccessBarring" leaf of the NAS configuration MO as specified in 3GPP TS 24.368 [135] or 3GPP TS 31.102 [112]) and receives an indication from the upper layers to override EAB; or

– the MS is configured to allow overriding EAB (see the "Override_ExtendedAccessBarring" leaf of the NAS configuration MO as specified in 3GPP TS 24.368 [135] or 3GPP TS 31.102 [112]) and already has a PDN connection that was established with EAB override.

NOTE 4: void.

Annex M (normative):
Additional Requirements for backward compatibility with PCS 1900 for NA revision 0 ME

This annex provides additional requirements to support network mechanisms for backward compatibility with PCS 1900 for NA revision 0 mobile equipments (applicable until July 1, 1998).

PCS 1900 for NA revision 0 mobile equipments are defined to understand Mobile Network Codes made of up to 2 digits. However federal regulation mandates that a 3-digit MNC shall be allocated by each administration to network operators. Therefore each network operator is identified by a 3-digit Mobile Country Code and a 3-digit Mobile Network Code. An operator whose network code complies to the allocation principle specified for PCS 1900 for NA and wants to achieve for a transition period of time the backward compatibility with PCS 1900 for NA revision 0 mobile equipments shall apply the following:

– The network shall send over the air interface the 3-digit Mobile Country Code and only the two most significant digits of the Mobile Network Code (the value of the "digit" sent instead of the 3rd digit ^is specified in 3GPP TS 24.008, subclause 10.5.1.3) (see note).

When a PCS 1900 for NA (revision greater than 0) mobile equipment recognizes over the air the Mobile Country Code and the two most significant digits of the Mobile Network Code as being the HPLMN codes of the current IMSI, the mobile equipment shall take into account the value of the sixth IMSI digit read from the SIM/USIM. If this value matches to a value contained in the limited set of values for the least significant MNC digit assigned by the number administration bodies for PCS 1900 for NA then the following applies for the mobile equipment:

– The value sent over the air instead of the 3rd MNC di^git in the Location Area Identification (for coding see 3GPP TS 24.008, subclause 10.5.1.3) shall be interpreted as the value of the sixth IMSI digit read from the SIM/USIM.

NOTE: It is still a network operator option to apply this requirement after July 1, 1998. However, in this case the following shall be considered:

1. Network selection considerations for overlapping networks:

– Networks overlapping to the HPLMN, identified over the radio interface by an identical combination MCC1 MCC2 MCC3 MNC1 MNC2 (possible after July 1, 1998) may be selectable by PCS 1900 for NA mobile equipments revision 0 with the same priority as the HPLMN or presented to the user as the HPLMN.

2 Roaming considerations:

– Roamers (SIM/USIM) from networks identified by an identical combination MCC1 MCC2 MCC3 MNC1 MNC2 (possible after July 1, 1998) when roaming into the operator network with PCS 1900 for NA mobile equipments revision 0, may cause these equipments to exhibit an unpredictable behaviour (e.g. looping in the HPLMN selection and registration procedures).

– Home subscribers (SIM/USIM) roaming with PCS 1900 for NA mobile equipments revision 0 into networks identified by an identical combination MCC1 MCC2 MCC3 MNC1 MNC2 (possible after July 1, 1998), may consider being attached to the HPLMN.

Annex N (normative):
Ranking of reject causes for Location Registration (MM and GMM) in a shared network

This annex describes how the reject cause is determined:

– for a network sharing non-supporting MS in a shared network with multi-operator core network (MOCN) configuration; or

– for any MS in a multi-operator core network (MOCN) with common GERAN,

when a location registration request from the MS is redirected among CN operators via the shared RAN (see 3GPP TS 23.251 [109]) and is rejected by all core networks. In the following, the term ‘location registration’ is used for location area updating, GPRS attach, combined GPRS attach, routing area updating, and combined routing area updating.

i) If the location registration request was either:

1) accepted;

2) rejected with a reject cause different from #11, #12, #13, #14, #15, #17, and #25; or

3) rejected with a reject cause #17 when the MSC or the SGSN received an error not indicating "system failure", "data missing" or "unexpected data value" from the HLR (see 3GPP TS 29.002 [37] and 3GPP TS 29.010 [152]),

then one of the following actions is taken:

– in UTRAN Iu mode, the MSC or SGSN shall include the redirection completed information element in the RANAP DIRECT TRANSFER message transmitting the location registration accept message or location registration reject message to the RNC. According to 3GPP TS 25.413 [19c], the RNC will then forward the location registration accept message or the location registration reject message to the MS.

– in A/Gb mode, the MSC shall use DTAP message and SGSN shall use BSSGP DL-UNIDATA message to carry the location registration accept message or location registration reject message to the BSC. According to 3GPP TS 48.008 [85] and 3GPP TS 48.018 [86], the BSC will then forward the location registration accept message or location registration reject message to the MS.

ii) If the location registration request was either:

1) rejected with one of the reject causes #11, #12, #13, #14, #15, and #25; or

2) rejected with a reject cause #17 when the MSC or the SGSN received an error indicating "system failure", "data missing" or "unexpected data value" from the HLR (see 3GPP TS 29.002 [37] and 3GPP TS 29.010 [152]),

then one of the following actions is taken:

– in UTRAN Iu mode, the MSC or SGSN shall include a redirection indication in the RANAP DIRECT TRANSFER message transmitting the location registration reject message to the RNC. According to 3GPP TS 25.413 [19c], the RNC will then initiate the redirection procedure towards the next CN operator and treat the response from the core network according to (i) and (ii).

– in A/Gb mode, the MSC shall use BSSMAP Reroute Command message and SGSN shall use BSSGP DL-UNIDATA message to transmit the location registration reject message to the BSC with a redirection indication. According to 3GPP TS 48.008 [85] and 3GPP TS 48.018 [86], the BSC will then initiate the redirection procedure towards the next CN operator and treat the response from the core network according to (i), (ii) and (iii).

iii) If the location registration request was rejected including a redirection indication and with one of the reject causes #11, #12, #13, #14, #15, #17, and #25 by all CN operators taking part in a shared network, the RNC for UTRAN Iu mode or the BSC for A/Gb mode shall determine the reject cause with the highest rank from the received reject causes and send a location registration reject message containing this reject cause to the MS.

The ranking of the reject causes, from the lowest rank to the highest rank, is given by:

#11 < #12 < #13 < #14 < #15 < #25 < #17.

iv) If the location registration request was rejected with one of the reject causes #11, #12, #13, #14, and #15 by all CN operators taking part in a shared network in a specific location area, but there is at least one additional CN operator taking part in a shared network in another location area of the shared network defined by the same common PLMN identity, the RNC for UTRAN Iu mode or the BSC for A/Gb mode shall send a location registration reject message with the reject cause #15 to the MS.

Annex O (normative):
3GPP capability exchange protocol