7.27 Session Timer / MO Voice Call / UE is able to refresh the session / 5GS

34.229-53GPPInternet Protocol (IP) multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP)Part 5: Protocol conformance specification using 5G System (5GS)Release 16TSUser Equipment (UE) conformance specification

7.27.1 Test Purpose (TP)

(1)

with { UE being registered to IMS and being configured to use Session Timer and preconditions }

ensure that {

when { UE is being made to initiate a voice call }

then { UE sends INVITE for voice call }

}

(2)

with { UE having included Session-Expires in INVITE }

ensure that {

when { UE receives 100 Trying followed by 422 Session Interval Too Small with Min-SE value of 1860 }

then { UE sends ACK and new INVITE with Min-SE value and Session-Expires value being 1860 }

}

(3)

with { UE having send 2nd INVITE }

ensure that {

when { UE receives 100 Trying followed by 422 Session Interval Too Small with Min-SE value of 1920 }

then { UE sends ACK and new INVITE with Min-SE value and Session-Expires value being 1920 }

}

(4)

with { UE having sent 3rd INVITE }

ensure that {

when { UE receiving 100 Trying followed by 183 Session Progress }

then { UE concludes voice call set up procedure up until sending ACK, with Session-Expires having value 1920 and refresher being set to uac }

}

(5)

with { UE having been chosen as refresher for established voice call }

ensure that {

when { voice call has been going on for 960 seconds }

then { UE sends UPDATE to refresh the session }

}

(6)

with { UE having been chosen as refresher for established voice call }

ensure that {

when { voice call has been going on for another 960 seconds }

then { UE sends UPDATE to refresh the session }

}

7.27.2 Conformance Requirements

The conformance requirements covered in the present test case are, unless otherwise stated, Rel-15 requirements.

[TS 24.229 clause 5.1.2A.1.1]

A UE supporting RFC 4028 [58], when it receives a 422 (Session Interval Too Small) to an INVITE request where the response contains a Min-SE header field, shall retry the request in accordance with RFC 4028 [58] subclause 7.4.

[TS 24.229 clause 5.2.7.2]

When the P-CSCF receives from the UE an INVITE request, the P-CSCF may require the periodic refreshment of the session to avoid hung states in the P-CSCF. If the P-CSCF requires the session to be refreshed, then the P-CSCF shall apply the procedures described in RFC 4028 [58] clause 8.

NOTE 1: Requesting the session to be refreshed requires support by at least one of the UEs. This functionality cannot automatically be granted, i.e. at least one of the involved UEs needs to support it.

[TS 24.229 clause 5.2.7.3]

When the P-CSCF receives an INVITE request destined for the UE the P-CSCF may require the periodic refreshment of the session to avoid hung states in the P-CSCF. If the P-CSCF requires the session to be refreshed, then the P-CSCF shall apply the procedures described in RFC 4028 [58] clause 8.

NOTE 1: Requesting the session to be refreshed requires support by at least one of the UEs. This functionality cannot automatically be granted, i.e. at least one of the involved UEs needs to support it in order to make it work.

[TS 24.229 clause 5.4.5.3]

If the S-CSCF requested the session to be refreshed periodically, and the S-CSCF got the indication that the session will be refreshed, when the session timer expires, the S-CSCF shall delete all the stored information related to the dialog.

7.27.3 Test description

7.27.3.1 Pre-test conditions

System Simulator:

– 1 NR Cell connected to 5GC, default parameters.

UE:

– UE contains either ISIM and USIM applications or only USIM application on UICC.

– UE is configured to register for IMS after switch on.

– UE is configured to use Session Timer and preconditions.

Preamble:

– UE is in state 1N-A (TS 38.508-1 [21]) and registered to IMS.

7.27.3.2 Test procedure sequence

Table 7.27.3.2-1: Main Behaviour

St		Procedure		Message Sequence				TP		Verdict
				U – S		Message
1		UE is made to attempt an IMS voice call.		–		–
2-7		Steps 2-7 of generic procedure specified in Table 4.9.15.2.2-1 of TS 38.508-1 [21] are performed.		–		–
–		EXCEPTION: In parallel with Step 8, parallel behaviour defined in table 7.27.3.2-2 takes place		–		–		–		–
8		UE sends INVITE with either the Session-Expires value set to 1800 or no Session-Expires header.		–>		INVITE		1		P
–		EXCEPTION: Steps 9a0 to 9a7 describe behaviour that depends on UE capability: the "lower case letter" identifies a step sequence that takes place if the UE included Session-Expires in step 8		–		–
9a0		SS sends a 100 Trying response. (Step 2 of Annex A.4.1a)		<–		100 Trying
9a1		SS sends 422 Session Interval Too Small response with Min-SE value of 1860.		<–		422 Session Interval Too Small
9a2		UE sends ACK.		–>		ACK		2		P
9a3		UE sends INVITE with Min-SE value and Session-Expires value being 1860.		–>		INVITE		2		P
9a4		SS sends a 100 Trying response. (Step 2 of Annex A.4.1a)		<–		100 Trying
9a5		SS sends 422 Session Interval Too Small response with Min-SE value of 1920.		<–		422 Session Interval Too Small
9a6		UE sends ACK.		–>		ACK		3		P
9a7		UE sends INVITE with Min-SE value and Session-Expires value being 1920.		–>		INVITE		3		P
10-13		Steps 2-5 of Annex A.4.1a happen.		–		–
13A		Step 10 of generic procedure specified in Table 4.9.15.2.2-1 of TS 38.508-1 [21] is performed.		–		–		–		–
–		EXCEPTION: In parallel to steps 13B and 13C below, step 14 occurs.		–		–		–		–
13B-13C		Steps 11-12 of generic procedure specified in Table 4.9.15.2.2-1 of TS 38.508-1 [21] are performed.		–		–		–		–
14-18		Steps 6-10 of Annex A.4.1a happen.		–		–		–		–
19		SS sends 200 OK for INVITE with negotiated Session-Expires value set to 1920 and refresher value set to uac.		<–		200 OK		4		P
20		UE sends ACK.		–>		ACK		4		P
21		960 seconds after step 20, UE sends an UPDATE request to refresh the session.		–>		UPDATE		5		P
22		SS sends 200 OK for UPDATE.		<–		200 OK
23		960 seconds after step 22, UE sends an UPDATE request to refresh the session.		–>		UPDATE		6		P
24		SS sends 200 OK for UPDATE.		<–		200 OK
25-26		SS releases the call. (Steps 1-2 of Annex A.8)		–		–

Table 7.27.3.2-2: Parallel behaviour

St	Procedure	Message Sequence		TP	Verdict
		U – S	Message
1	The UE transmits an RRCReconfigurationComplete message.	–>	NR RRC: RRCReconfigurationComplete	–	–

7.27.3.3 Specific message contents

Table 7.27.3.3-1: INVITE (step 8, table 7.27.3.2-1)

Derivation Path: Annex A.4.1a, Step 1, with A26 as additional condition.
Header/param	Cond	Value/remark	Rel	Reference
Session-Expires		(if present)		RFC 4028 [37]
delta-seconds		1800
refresher		uac (if present)

Table 7.27.3.3-2: 422 Session Interval Too Small (step 9a1, table 7.27.3.2-1)

Derivation Path: TS 34.229-1 [2], Annex A.2.24
Header/param	Cond	Value/remark	Rel	Reference
Min-SE				RFC 4028 [37]
delta-seconds		1860

Table 7.27.3.3-3: INVITE (step 9a3, table 7.27.3.2-1)

Derivation Path: Annex A.4.1a, Step 1, with A26 as additional condition.
Header/param	Cond	Value/remark	Rel	Reference
Session-Expires				RFC 4028 [37]
delta-seconds		1860
Min-SE				RFC 4028 [37]
delta-seconds		1860

Table 7.27.3.3-4: 422 Session Interval Too Small (step 9a5, table 7.27.3.2-1)

Derivation Path: TS 34.229-1 [2], Annex A.2.24
Header/param	Cond	Value/remark	Rel	Reference
Min-SE				RFC 4028 [37]
delta-seconds		1920

Table 7.27.3.3-5: INVITE (step 9a7, table 7.27.3.2-1)

Derivation Path: Annex A.4.1a, Step 1, with A26 as additional condition.
Header/param	Cond	Value/remark	Rel	Reference
Session-Expires				RFC 4028 [37]
delta-seconds		1920
Min-SE				RFC 4028 [37]
delta-seconds		1920

Table 7.27.3.3-6: 183 Session Progress (step 11, table 7.27.3.2-1)

Derivation Path: TS 34.229-1 [2], Annex A.2.3, Conditions A1
Header/param	Cond	Value/remark	Rel	Reference
Allow		INVITE, UPDATE, PRACK, ACK, OPTIONS, CANCEL, BYE		RFC 4028 [37]

Table 7.27.3.3-7: 200 OK (step 19, table 7.27.3.2-1)

Derivation Path: TS 34.229-1 [2], Annex A.3.1, Conditions A1 and A10
Header/param	Cond	Value/remark	Rel	Reference
Allow		INVITE, UPDATE, PRACK, ACK, OPTIONS, CANCEL, BYE		RFC 4028 [37]
Require		timer		RFC 4028 [37]
Supported		timer		RFC 4028 [37]
Session-Expires				RFC 4028 [37]
delta-seconds		1920
refresher		uac
Min-SE				RFC 4028 [37]
delta-seconds		1920

Table 7.27.3.3-8: UPDATE (steps 21 and 23, table 7.27.3.2-1)

Derivation Path: TS 34.229-1 [2], Annex A.2.5, Conditions A1 and A6
Header/param	Cond	Value/remark	Rel	Reference
Supported		timer		RFC 4028 [37]
Session-Expires				RFC 4028 [37]
delta-seconds		1920
refresher		uac
Min-SE				RFC 4028 [37]
delta-seconds		1920
Content-Type		any value if present		RFC 4028 [37]

Table 7.27.3.3-9: 200 OK (steps 22 and 24, table 7.27.3.2-1)

Derivation Path: TS 34.229-1 [2], Annex A.3.1, Conditions A1 and A10
Header/param	Cond	Value/remark	Rel	Reference
Supported		timer		RFC 4028 [37]
Session-Expires				RFC 4028 [37]
delta-seconds		1920
refresher		uac
Min-SE				RFC 4028 [37]
delta-seconds		1920