9.1.7 Service request

38.523-13GPP5GSPart 1: ProtocolRelease 17TSUser Equipment (UE) conformance specification

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

9.1.7.1 Service request / Idle mode uplink user data transport / Rejected / Restricted service area, abnormal / T3517, T3525

9.1.7.1.1 Test Purpose (TP)

(1)

with { the UE is in 5GMM-REGISTERED state and 5GMM-IDLE mode over 3GPP access }

ensure that {

when { UE has uplink user data pending }

then { the UE sends a SERVICE REQUEST message }

}

(2)

with { the UE sent a SERVICE REQUEST message }

ensure that {

when { UE receives a SERVICE REJECT message including an appropriate 5GMM cause value #28(Restricted service area) }

then { the UE performs the mobility registration update procedure }

}

(3)

with { the UE is in 5GMM-REGISTERED state and the UE has triggered the SERVICE REQUEST in 5GMM-IDLE mode }

ensure that {

when { T3517 expired}

then { the UE increases the service request attempt counter, aborts the procedure and release locally any resources allocated for the service request procedure }

}

(4)

with { the UE is in 5GMM-REGISTERED state and 5GMM-IDLE mode }

ensure that {

when { the service request attempt counter is equal to 5}

then { the UE starts timer T3525 and not attempts service request until expiry of T3525}

}

9.1.7.1.2 Conformance requirements

References: The conformance requirements covered in the current TC are specified in: TS 24.501, clause 5.6.1.1, 5.6.1.5 and 5.6.1.7. Unless otherwise stated these are Rel-15 requirements.

[TS 24.501, clause 5.6.1.1]

The purpose of the service request procedure is to change the 5GMM mode from 5GMM-IDLE to 5GMM-CONNECTED mode, and/or to request the establishment of user-plane resources for PDU sessions which are established without user-plane resources. In latter case, the 5GMM mode can be the 5GMM-IDLE mode or the 5GMM-CONNECTED mode if the UE requires to establish user-plane resources for PDU sessions.

…

The UE shall invoke the service request procedure when:

…

d) the UE, in 5GMM-IDLE mode over 3GPP access, has uplink user data pending;

…

If one of the above criteria to invoke the service request procedure is fulfilled, then the service request procedure shall only be initiated by the UE when the following conditions are fulfilled:

– its 5GS update status is 5U1 UPDATED, and the TAI of the current serving cell is included in the TAI list; and

– no 5GMM specific procedure is ongoing.

The UE shall not invoke the service request procedure when the UE is in the state 5GMM-SERVICE-REQUEST-INITIATED.

Figure 5.6.1.1.1: Service Request procedure

[TS 24.501, clause 5.6.1.5]

If the service request cannot be accepted, the network shall return a SERVICE REJECT message to the UE including an appropriate 5GMM cause value and stop timer T3517.

…

If the AMF determines that the UE is in a non-allowed area or is not in an allowed area as specified in subclause 5.3.5, then:

a) if the service type IE in the SERVICE REQUEST message is set to "signalling" or "data", the AMF shall send a SERVICE REJECT message with the 5GMM cause value set to #28 "Restricted service area";

…

The UE shall take the following actions depending on the 5GMM cause value received in the SERVICE REJECT message.

#28 (Restricted service area).

The UE shall enter the state 5GMM-REGISTERED.NON-ALLOWED-SERVICE, and perform the registration procedure for mobility and periodic registration update unless the service type IE in the SERVICE REQUEST message was set to "elevated signalling" (see subclause 5.3.5 and 5.5.1.3).

If the service type IE in the SERVICE REQUEST message was set to "elevated signalling", the UE shall not re-initiate service request procedure until the UE enters an allowed area or leaves a non-allowed area, except for emergency services, high priority access or responding to paging or notification.

[TS 24.501, clause 5.6.1.7]

The following abnormal cases can be identified:

a) T3517 expired.

The UE shall enter the state 5GMM-REGISTERED.

If the UE triggered the service request procedure in 5GMM-IDLE mode and the service type of the SERVICE REQUEST message was not set to "emergency services fallback", then the 5GMM sublayer shall increment the service request attempt counter, abort the procedure and release locally any resources allocated for the service request procedure. The service request attempt counter shall not be incremented, if:

1) the service request procedure is initiated to establish an emergency PDU session;

2) the UE has an emergency PDU session established;

3) the UE is a UE configured for high priority access in selected PLMN; or

4) the service request is initiated in response to paging or notification from the network.

If the service request attempt counter is greater than or equal to 5, the UE shall start timer T3525. Additionally, if the service request was initiated for an MO MMTEL voice call, a notification that the service request was not accepted due to the UE having started timer T3525 shall be provided to the upper layers.

NOTE 1: This can result in the upper layers requesting implementation specific mechanisms, e.g. the MMTEL voice call being attempted to another IP-CAN, or establishment of a CS voice call (if supported and not already attempted in the CS domain).

The UE shall not attempt service request until expiry of timer T3525 unless:

1) the service request is initiated in response to paging or notification from the network;

2 the UE is a UE configured for high priority access in selected PLMN;

3) the service request is initiated to establish an emergency PDU session;

4) the UE has an emergency PDU session established; or

5) the UE is registered in a new PLMN.

NOTE 2: The NAS signalling connection can also be released if the UE deems that the network has failed the authentication check as specified in subclause 5.4.1.3.7.

9.1.7.1.3 Test description

9.1.7.1.3.1 Pre-test conditions

System Simulator:

– NGC Cell A.

UE:

– None.

Preamble:

– The UE is in state 3N-A with UE test loop mode B active (T_delay_modeB = 5) according to TS 38.508-1 [4].

9.1.7.1.3.2 Test procedure sequence

Table 9.1.7.1.3.2-1: Main behaviour

St	Procedure	Message Sequence		TP	Verdict
		U – S	Message
1	The SS configures: – NGC Cell A as the "Serving cell".	–	–	–	–
2	The SS transmits one IP Packet to the UE.	<–	IP packet	–	–
3	The SS waits 1 second after the IP packet has been transmitted in step 2 and then transmits an RRCRelease message. (Note 1)	–	–	–	–
4	Check: Does UE transmit a SERVICE REQUEST message with Service type IE set to ‘data’? (Note 2)	–>	SERVICE REQUEST	1	P
5	The SS transmits a SERVICE REJECT message with 5GMM cause = "Restricted service area".	<–	SERVICE REJECT	–	–
6-7	Void	–	–	–	–
7AA	The SS starts timer 5 sec. Note: An arbitraty chosen timer to avoid message crossing.	–	–	–	–
	EXCEPTION: Steps 7ABa1 to 7ABb3 describe behaviour that depends on the UE implementation; the "lower case letter" identifies a step sequence that take place if the UE is implemented in a certain way.	–	–	–	–
7ABa1	UE transmit REGISTRATION REQUEST message. NOTE: Allowed for Rel-15 UEs.	–>	REGISTRATION REQUEST	2	P
7ABa2	Stop timer 5 sec.	–	–	–	–
7ABb1	Timer 5 sec expires.	–	–	–	–
7ABb2	The SS releases the RRC connection.	–	–	–	–
7ABb3	Check: Does the UE transmit REGISTRATION REQUEST over a new signalling connection?	–>	REGISTRATION REQUEST	2	P
7AC-7B	Void
8A	SS stops transmitting UL grant.	–	–	–	–
8B	The SS sends a REGISTRATION ACCEPT message	<–	REGISTRATION ACCEPT	–	–
8C	SS trasnmits one UL grant, for the UE to transmit the REGISTRATION COMPLETE message at step 8D.	–	–	–	–
8D	The UE sends a REGISTRATION COMPLETE.	–>	REGISTRATION COMPLETE	–	–
8E	The SS releases the RRC connection.	–	–	–	–
8F	The SS resumes UL grant transmission.	–	–	–	–
8G	The UE transmits a SERVICE REQUEST message over a new signalling connection.	–>	SERVICE REQUEST	–	–
8H	The SS does not respond to SERVICE REQUEST message. Note: The UE locally releases the signalling connection after T3517 expiry.	–	–	–	–
–	EXCEPTION: Steps 9 to 10 are repeated for 4 times.	–	–	–	–
9	Check: Does the UE transmits a SERVICE REQUEST message after T3517 expiry but before 60s over a new signalling connection?	–>	SERVICE REQUEST	3	P
10	The SS does not respond to SERVICE REQUEST message. Note: The UE locally releases the signalling connection after T3517 expiry.	–	–	–	–
11	Check: Does the UE transmits a SERVICE REQUEST message within 60 seconds (minimum value of T3525) over a new signalling connection?	–>	SERVICE REQUEST	3,4	F
12A	The SS starts timer 10 sec after Step 11 to see if UE performs the optional Steps listed below.	–	–	–	–
	EXCEPTION: Steps 12Aa1 to 12Aa6 describe behaviour that depends on the UE implementation; the "lower case letter" identifies a step sequence that take place if the UE is implemented in a certain way.	–	–	–	–
12Aa1	The UE transmits a SERVICE REQUEST message after T3525 expiry over a new signalling connection.	–>	SERVICE REQUEST	–	–
12Aa2-12Aa4	Steps 5 to 7 of the NR RRC_CONNECTED procedure in TS 38.508-1 [4] Table 4.5.4.2-3 are executed.	–	–	–	–
–	EXCEPTION: Steps 12Aa5 and 12Aa6 can occur in any order.	–	–	–	–
12Aa5	The UE transmits an RRCReconfigurationComplete message.	–>	NR RRC: RRCReconfigurationComplete	–	–
12Aa6	The UE loop backs the IP packet received in step 2 on the DRB associated with the default PDU session.	–	–	–	–
Note 1: The 1 second delay is used to secure that the UE have received and forwarded the IP Packet transmitted by the SS in step 2 to the UE test loop function before the RRCRelease message is sent by the SS in step 3. Note 2: Triggered when timer T_delay_modeB (IP PDU delay time) expires and pending uplink data exist in buffered PDCP SDUs according to TS 38.509 [6] clause 5.3.4.2.3 and TS 36.509 [8] clause 5.4.4.3.

9.1.7.1.3.3 Specific message contents

Table 9.1.7.1.3.3-1: ACTIVATE TEST MODE (preamble)

Derivation Path: TS 38.508-1 [4]
Information Element	Value/remark	Comment	Condition
Protocol discriminator	1 1 1 1
Skip indicator	0 0 0 0
Message type	1 0 0 0 0 1 0 0
UE test loop mode	0 0 0 0 0 0 0 1	UE test loop mode B	UE TEST LOOP MODE B

Table 9.1.7.1.3.3-2: CLOSE UE TEST LOOP (preamble)

Derivation Path: TS 38.508-1 [4]
Information Element	Value/remark	Comment	Condition
Protocol discriminator	1 1 1 1
Skip indicator	0 0 0 0
Message type	1 0 0 0 0 0 0 0
UE test loop mode	0 0 0 0 0 0 0 1	UE test loop mode B	UE TEST LOOP MODE B
UE test loop mode B LB setup
IP PDU delay	0 0 0 0 0 1 0 1	5 seconds

Table 9.1.7.1.3.3-3: SERVICE REQUEST (steps 4, 8G and 9, Table 9.1.7.1.3.2-1)

Derivation Path: TS 38.508-1 [4] Table 4.7.1-16
Information Element	Value/remark	Comment	Condition
Service type
Service type value	‘0001’B	data
Uplink data status		Indicates data present for the PDU session with the DL IP packet looped back. The other bits are not checked.	Not allowed to be sent in cleartext and shall only be included in the complete SERVICE REQUEST message in the NAS message container IE.

Table 9.1.7.1.3.3-4: SERVICE REJECT (step 5, Table 9.1.7.1.3.2-1)

Derivation Path: TS 38.508-1 [4] Table 4.7.1-18
Information Element	Value/remark	Comment	Condition
5GMM cause	‘0001 1100’B	Restricted service area

Table 9.1.7.1.3.3-5: REGISTRATION REQUEST (steps 7ABa1 and 7ABb3, Table 9.1.7.1.3.2-1)

Derivation Path: TS 38.508-1 [4] Table 4.7.1-6
Information Element	Value/remark	Comment	Condition
5GS registration type	‘010’B	mobility registration updating

9.1.7.2 Service request / Connected mode user data transport / Abnormal / T3517

9.1.7.2.1 Test Purpose (TP)

(1)

with { the UE is in 5GMM-REGISTERED state and 5GMM-CONNECTED mode over 3GPP access }

ensure that {

when { the UE has user data pending due to no user-plane resources established for PDU session(s) used for user data transport }

then { the UE sends a SERVICE REQUEST message }

}

(2)

with { the UE sends a SERVICE REQUEST message in 5GMM-CONNECTED mode }

ensure that {

when { T3517 expired }

then { the UE stays in 5GMM-CONNECTED mode }

}

9.1.7.2.2 Conformance requirements

References: The conformance requirements covered in the current TC are specified in: TS 24.501 clauses 5.6.1.1, 5.6.1.2 and 5.6.1.7. Unless otherwise stated these are Rel-15 requirements.

[TS 24.501, clause 5.6.1.1]

NOTE 1: The lower layer indicates when the user-plane resources for PDU sessions are successfully established or released.

This procedure is used when:

…

– the UE has user data pending over 3GPP access and the UE is in 5GMM-IDLE or 5GMM-CONNECTED mode over 3GPP access;

The UE shall invoke the service request procedure when:

…

e) the UE, in 5GMM-CONNECTED mode or in 5GMM-CONNECTED mode with RRC inactive indication, has user data pending due to no user-plane resources established for PDU session(s) used for user data transport;

Figure 5.6.1.1.1: Service Request procedure

[TS 24.501, clause 5.6.1.2]

The UE initiates the service request procedure by sending a SERVICE REQUEST message to the AMF and starts timer T3517.

…

For cases d) and e) in subclause 5.6.1.1, the Uplink data status IE shall be included in the SERVICE REQUEST message to indicate the PDU session(s) the UE has pending user data to be sent. If the UE is not a UE configured for high priority access in selected PLMN:

a) if there exists an emergency PDU session which is indicated in the Uplink data status IE the service type IE in the SERVICE REQUEST message shall be set to "emergency services"; or

b) otherwise, the service type IE in the SERVICE REQUEST message shall be set to "data".

…

The Uplink data status IE may be included in the SERVICE REQUEST message to indicate which PDU session(s) associated with the access type the SERVICE REQUEST message is sent over have pending user data to be sent.

…

[TS 24.501, clause 5.6.1.7]

The following abnormal cases can be identified:

a) T3517 expired.

The UE shall enter the state 5GMM-REGISTERED.

1) the service request procedure is initiated to establish an emergency PDU session;

2) the UE has an emergency PDU session established;

3) the UE is a UE configured for high priority access in selected PLMN; or

4) the service request is initiated in response to paging or notification from the network.

The UE shall not attempt service request until expiry of timer T3525 unless:

1) the service request is initiated in response to paging or notification from the network;

2) the UE is a UE configured for high priority access in selected PLMN;

3) the service request is initiated to establish an emergency PDU session;

4) the UE has an emergency PDU session established; or

5) the UE is registered in a new PLMN.

NOTE 2: The NAS signalling connection can also be released if the UE deems that the network has failed the authentication check as specified in subclause 5.4.1.3.7.

…

9.1.7.2.3 Test description

9.1.7.2.3.1 Pre-test conditions

System Simulator:

– NGC Cell A

UE:

– None.

Preamble:

– the UE is in 5GS state 3N-A with at least one PDU session (with PDU session ID X where 1 <= X <= 15) active according to TS 38.508-1 [4], clause 4.4A.3 Table 4.4A.3-1. and using the message condition UE TEST LOOP MODE B prepared according to TS 38.508-1 [4]. DRB n is defined as default DRB for the PDU session X.

9.1.7.2.3.2 Test procedure sequence

Table 9.1.7.2.3.2-1: Main behaviour

St	Procedure	Message Sequence		TP	Verdict
		U – S	Message
1	Void.
1A	Cause the UE to request establishment of PDU session Y to the DN. (Note 1)	–	–	–	–
1B	The UE transmits a PDU SESSION ESTABLISHMENT REQUEST message. (Note 2)	–>	NR 5GSM: PDU SESSION ESTABLISHMENT REQUEST	–	–
1C	SS transmits a PDU SESSION ESTABLISHMENT ACCEPT message. (Note 2)	<–	NR 5GSM: PDU SESSION ESTABLISHMENT ACCEPT	–	–
1D	The SS transmits a CLOSE UE TEST LOOP message with IP PDU delay set to 1 second.	<–	CLOSE UE TEST LOOP	–	–
1E	The UE transmits a CLOSE UE TEST LOOP COMPLETE message.	–>	CLOSE UE TEST LOOP COMPLETE	–	–
1F	The SS transmits one IP PDU on PDU session X.	<–	–	–	–
2	The SS transmits an RRCReconfiguration message to release User-plane resources for the PDU session X.	<–	NR RRC: RRCReconfiguration	–	–
3	The UE transmits an RRCReconfigurationComplete message.	–>	NR RRC: RRCReconfigurationComplete	–	–
4	Check: Does the UE transmit a SERVICE REQUEST message?	–>	NR 5GMM: SERVICE REQUEST	1	P
5	The SS does not respond to the SERVICE REQUEST message.	–	–	–	–
6	Wait for T3517 seconds (Note 3).	–	–	–	–
7	The UE transmit a SERVICE REQUEST message.	–>	NR 5GMM: SERVICE REQUEST	–	–
8	The SS sends an IDENTITY REQUEST message.	<–	NR 5GMM: IDENTITY REQUEST	–	–
9	Check: Does the UE transmit an IDENTITY RESPONSE message?.	–>	NR 5GMM: IDENTITY RESPONSE	2	P
10	The SS transmits an RRCReconfiguration message Piggybacked with SERVICE ACCEPT message to setup User-plane resources for the PDU session X.	<–	NR RRC: RRCReconfiguration NR 5GMM: SERVICE ACCEPT
	EXCEPTION: Steps 11 and 13 can occur in any order	–	–	–	–
11	The UE transmits an RRCReconfigurationComplete message	–>	NR RRC: RRCReconfigurationComplete	–	–
12	Void.	–	–	–	–
13	The UE loop back the IP PDU on PDU session X.	–	–	–	–
Note 1: The request to establish a PDU session may be performed by MMI or AT command. Note 2: The reason to establish PDU session Y is to avoid that, after release user-plane resource for PDU session X in step 2-3, the UE can still be in 5GMM-CONNECTED mode as TP1 said. Otherwise, if the UE has only PDU session X, then according to TS 38.331 clause 5.3.1.1, UE has to release both SRB2 and DRB of PDU session X, then go to 5GMM-IDLE mode which violate TP1. Note 3: T3517 expires after 15 seconds.

9.1.7.2.3.3 Specific message contents

Table 9.1.7.2.3.3-0: PDU SESSION ESTABLISHMENT ACCEPT (step 1C, Table 9.1.7.2.3.2-1)

Derivation path: TS 38.508-1 [4], Table 4.7.2-2
Information Element	Value/remark	Comment	Condition
Authorized QoS rules	5GC QoS rule of the Config#1 in Table 4.8.4-1
Mapped EPS bearer contexts
Mapped EPS bearer context
Mapped EPS QoS parameters	EPC default bearer context of the Config#1 in Table 4.8.4-1
DNN	The same DNN value as sent in the UL NAS TRANSPORT message at step 1B

Table 9.1.7.2.3.3-1: RRCReconfiguration (step 2, Table 9.1.7.2.3.2-1)

Derivation Path: TS 38.508-1 [4], Table 4.6.1-13
Information Element	Value/remark	Comment	Condition
RRCReconfiguration ::= SEQUENCE {
criticalExtensions CHOICE {
rrcReconfiguration SEQUENCE {
radioBearerConfig	RadioBearerConfig
masterCellGroup	MasterCellGroup
}
}
}

Table 9.1.7.2.3.3-2a: RadioBearerConfig (Table 9.1.7.2.3.3-1)

Derivation Path: TS 38.508-1 [4], Table 4.6.3-132
Information Element	Value/remark	Comment	Condition
RadioBearerConfig ::= SEQUENCE {
drb-ToReleaseList SEQUENCE (SIZE (1..maxDRB)) OF DRB-Identity {	1 entry
DRB-Identity[1]	DRB configured in the preamble	entry 1
}
}

Table 9.1.7.2.3.3-2b: MasterCellGroup (Table 9.1.7.2.3.3-1)

Derivation path: TS 38.508-1 [4], Table 4.6.3-19
Information Element	Value/remark	Comment	Condition
CellGroupConfig ::= SEQUENCE {
rlc-BearerToAddModList	Not present
rlc-BearerToReleaseList SEQUENCE (SIZE(1..maxLC-ID)) OF LogicalChannelIdentity {	1 entry
logicalChannelIdentity[1]	Logical channel identity corresponding to DRB configured in the preamble	entry 1
}
mac-CellGroupConfig	Not present
physicalCellGroupConfig	Not present
spCellConfig	Not present
}

Table 9.1.7.2.3.3-3: SERVICE REQUEST (step 4, 7, Table 9.1.7.2.3.2-1)

Derivation path: TS 38.508-1 [4], table 4.7.1-16
Information Element	Value/Remark	Comment	Condition
Service type	‘0001’B	data
Uplink data status
PSI(X)	‘1’B	PSI(X) is set to 1 indicates that uplink data are pending for the PDU session X activated in preamble.

Table 9.1.7.2.3.3-4: IDENTITY REQUEST (step 8, Table 9.1.7.2.3.2-1)

Derivation Path: TS 38.508-1 [4] table 4.7.1-21
Information Element	Value/remark	Comment	Condition
Identity type	‘0010’B	5G-GUTI

Table 9.1.7.2.3.3-5: IDENTITY RESPONSE (step 9, Table 9.1.7.2.3.2-1)

Derivation Path: TS 38.508-1 [4] table 4.7.1-22
Information Element	Value/remark	Comment	Condition
Mobile identity	5G-GUTI

Table 9.1.7.2.3.3-6: RRCReconfiguration (step 10, Table 9.1.7.2.3.2-1)

Derivation Path: TS 38.508-1 [4], Table 4.6.1-13
Information Element	Value/remark	Comment	Condition
RRCReconfiguration ::= SEQUENCE {
criticalExtensions CHOICE {
rrcReconfiguration SEQUENCE {
radioBearerConfig	RadioBearerConfig with conditions DRB configured in the preamble
nonCriticalExtension SEQUENCE {
masterCellGroup	CellGroupConfig with condition DRB configured in the preamble	OCTET STRING (CONTAINING CellGroupConfig)
}
}
}
}

Table 9.1.7.2.3.3-7: SERVICE ACCEPT (step 10, Table 9.1.7.2.3.2-1)

Derivation path: TS 38.508-1 [4], table 4.7.1-17
Information Element	Value/Remark	Comment	Condition
PDU session reactivation result
PSI(X)	‘0’B	PSI(X) is set to 0 indicates that establishment of user-plane resource of the PDU session X activated in preamble is successful.