22 Session Timer

34.229-13GPPInternet Protocol (IP) multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP)Part 1: Protocol conformance specificationRelease 16TSUser Equipment (UE) conformance specification

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

22.1 MO Call – UE is able to refresh the session

22.1.1 Definition

Test to verify that a UE supporting and using Session timer as described in RFC 4028 [146], and configured to be the refresher and triggered to perform an IMS mobile originated voice call when using IMS Multimedia Telephony with preconditions, correctly negotiates the Session-Expires header, processes received 422 Session Interval Too Small responses, and keeps the session alive as negotiated. This process is described in IR.92 [133] clause 2.2.8, RFC 4028 [146] sections 7.1-7.4 and 3GPP TS 24.229 [10], clause 5.1.2A.1.1.

22.1.2 Conformance requirement

[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.

[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.

Reference(s)

3GPP TS 24.229 [10], clauses 5.1.2A.1.1, 5.2.7.2, 5.2.7.3, and 5.4.5.3.

22.1.3 Test purpose

1) To verify that, when setting up an MO call, the UE performs correct exchange of SIP protocol signalling messages for Session Timer extension; and

2) To verify that within SIP signalling the UE is able to handle 422 Session Interval Too Small responses by retrying the initial INVITE request (as described by RFC 4028 [10], section 7.4); and

3) To verify that the UE is able to refresh the session using UPDATE based on the session expiration value negotiated in SIP signalling during session set up; and

4) To verify that the UE is able to keep the session active during session refreshes until released; and

5) To verify that the UE does not change the role of refresher during session refreshes.

22.1.4 Method of test

Initial conditions

UE contains either ISIM and USIM applications or only USIM application on UICC. UE has discovered P-CSCF and registered to IMS services, by executing the generic test procedure in Annex C.2 up to the last step.

SS is configured with the shared secret key of IMS AKA algorithm, related to the IMS private user identity (IMPI) configured on the UICC card equipped into the UE. SS has performed AKAv1-MD5 authentication with the UE and accepted the registration (IMS security).

Test procedure applicable for a UE with E-UTRA support (TS 34.229-2 [5] A.18/1)

Expected sequence

NOTE: Only the IMS procedure relevant to the test purpose is described below.

Step	Direction		Message	Comment
	UE	SS
1			Make the UE attempt an IMS speech call	MTSI MO speech call. Referred from 36.508 [94] table 4.5A.6.3-1 for a UE with E-UTRA support.
2	🡪		INVITE	UE sends INVITE as described in C.21, step 2, with either the Session-Expires value set to 1800 or no Session-Expires header.
3
–			EXCEPTION: Steps 4a0 to 4a7 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 2
4a0	🡨		100 Trying	SS sends 100 Trying response.
4a1	🡨		422 Session Interval Too Small	SS sends 422 Session Interval Too Small response with Min-SE value of 1860.
4a2	🡪		ACK	UE sends ACK.
4a3	🡪		INVITE	UE sends INVITE with Min-SE value and Session-Expires value being 1860.
4a4	🡨		100 Trying	SS sends 100 Trying response.
4a5	🡨		422 Session Interval Too Small	SS sends 422 Session Interval Too Small response with Min-SE value of 1920.
4a6	🡪		ACK	UE sends ACK.
4a7	🡪		INVITE	UE sends INVITE with Min-SE value and Session-Expires value being 1920.
5-13			Steps 3-11 defined in annex C.21
14	🡨		200 OK	SS sends 200 OK for INVITE with negotiated Session-Expires value set to 1920 and refresher value set to uac.
15	🡪		ACK	UE sends ACK.
16	🡪		UPDATE	960 seconds after step 15, UE sends an UPDATE request to refresh the session.
17	🡨		200 OK	SS sends 200 OK for UPDATE.
18	🡪		UPDATE	960 seconds after step 17, UE sends an UPDATE request to refresh the session.
19	🡨		200 OK	SS sends 200 OK for UPDATE.
20-23			Steps defined in annex C.33	SS releases the call.

Specific Message Contents

INVITE (Step 2)

Use the default Message "INVITE" in Annex C.21 with conditions A1, A3, A4 and A26 and the following exceptions:

Header/param	Value/remark
Session-Expires	(if present)
delta-seconds	1800
refresher	uac (if present)

422 Session Interval Too Small (Step 4a1)

Use the default Message "422 Session Interval Too Small" in Annex A.2.24 with the following exceptions:

Header/param	Value/remark
Min-SE
delta-seconds	1860

INVITE (Step 4a3)

Use the default Message "INVITE" in Annex C.21 with conditions A1, A3, A4 and A26 and the following exceptions:

Header/param	Value/remark
Session-Expires
delta-seconds	1860
Min-SE
delta-seconds	1860

422 Session Interval Too Small (Step 4a5)

Use the default Message 422 Session Interval Too Small in Annex A.2.24 with the following exceptions:

Header/param	Value/remark
Min-SE
delta-seconds	1920

INVITE (Step 4a7)

Use the default Message "INVITE" in Annex A.2.1 with conditions A1, A3, A4 and A26 and the following exceptions:

Header/param	Value/remark
Call-ID
Session-Expires
delta-seconds	1920
Min-SE
delta-seconds	1920

183 Session Progress (Step 6)

Use the default Message "183 Session Progress for INVITE" in Annex A.2.3 with condition A1 and the following exceptions:

Header/param	Value/remark
Allow	INVITE, UPDATE, PRACK, ACK, OPTIONS, CANCEL, BYE

200 OK (Step 14)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A1 and A10 and the following exceptions:

Header/param	Value/remark
Allow	INVITE, UPDATE, PRACK, ACK, OPTIONS, CANCEL, BYE
Require	timer
Supported	timer
Session-Expires
delta-seconds	1920
refresher	uac
Min-SE
delta-seconds	1920

UPDATE (Steps 16 and 18)

Use the default Message "UPDATE" in Annex A.2.5 with condition A1 and the following exceptions:

Header/param	Value/remark
Supported	timer
Session-Expires
delta-seconds	1920
refresher	uac
Min-SE
delta-seconds	1920
Content-Type	any value if present

200 OK (Steps 17 and 19)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A1 and A10 and the following exceptions:

Header/param	Value/remark
Supported	timer
Session-Expires
delta-seconds	1920
refresher	uac
Min-SE
delta-seconds	1920

22.2 MO Call – Remote end is refresher

22.2.1 Definition

Test to verify that a UE supporting and using Session timer as described in RFC 4028 [146], and configured to not ask to be the refresher and triggered to perform an IMS mobile originated voice call when using IMS Multimedia Telephony with preconditions, accepts the Session-Expires header provided by the remote UE, accepts keep alive requests, and terminates the session upon time. This process is described in TS 24.229 [10], IR.92 [133] clause 2.2.8 and RFC 4028 [146] sections 7.1-7.4.

22.2.2 Conformance requirement

[TS 24.229 clause 5.1.2A.1.1]

[TS 24.229 clause 5.2.7.2]

[TS 24.229 clause 5.2.7.3]

[TS 24.229 clause 5.4.5.3]

Reference(s)

3GPP TS 24.229 [10], clauses 5.1.2A.1.1, 5.2.7.2, 5.2.7.3, and 5.4.5.3.

22.2.3 Test purpose

1) To verify that, when setting up an MO call, the UE performs correct exchange of SIP protocol signalling messages for Session Timer extension; and

2) To verify that within SIP signalling the UE is able to handle incoming UPDATE requests that are intended to keep the session alive (as described by RFC 4028 [10], section 10) and respond accordingly; and

3) To verify that the UE does not change the role of refresher during session refreshes; and

4) To verify that the UE will end the call upon session expiration.

22.2.4 Method of test

Initial conditions

Test procedure applicable for a UE with E-UTRA support (TS 34.229-2 [5] A.18/1)

Expected sequence

NOTE: Only the IMS procedure relevant to the test purpose is described below.

Step	Direction		Message	Comment
	UE	SS
1			Make the UE attempt an IMS speech call	MTSI MO speech call. Referred from 36.508 [94] table 4.5A.6.3-1 for a UE with E-UTRA support.
2	🡪		INVITE	UE sends INVITE as described in C.21, step 2.
3-11			Steps 3-11 defined in annex C.21
12	🡨		200 OK	SS sends 200 OK for INVITE with Session-Expires value set to 1800 and refresher value set to uas.
13	🡪		ACK	UE sends ACK.
14	🡨		UPDATE	900 seconds after step 12, SS sends an UPDATE request to refresh the session.
15	🡪		200 OK	UE sends 200 OK for UPDATE.
16-19			Steps 2-5 defined in annex C.32	1800 seconds after step 15, UE releases the call due to session expiring.

Specific Message Contents

INVITE (Step 2)

Use the default Message "INVITE" in Annex C.21 with conditions A1, A3, A4 and A26 and the following exceptions:

Header/param	Value/remark
Session-Expires	(if present)
delta-seconds	1800
refresher	not present

200 OK (Step 12)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A1 and A10 and the following exceptions:

Header/param	Value/remark
Require	timer
Supported	timer
Session-Expires
delta-seconds	1800
refresher	uas

UPDATE (Step 14)

Use the default Message "UPDATE" in Annex A.2.5 with condition A3 and the following exceptions:

Header/param	Value/remark
Supported	timer
Session-Expires
delta-seconds	1800
refresher	uac
Content-Type	not present

200 OK (Step 15)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A1 and A10 and the following exceptions:

Header/param	Value/remark
Require	timer
Session-Expires
delta-seconds	1800
refresher	uac

22.3 MO Call – Remote end does not support Session Timer

22.3.1 Definition

Test to verify that a UE supporting and using Session Timer as described in RFC 4028 [146], configured to use Session Timer for its purposes when remote end does not support Session Timer (and no proxies in between mandate its usage), during an IMS mobile originated voice call when using IMS Multimedia Telephony with preconditions, correctly sets the Session-Expires interval and chooses refresher when the remote UE does not support the Session Timer extension, becomes refresher of the session, generates periodic session refreshes and keeps the session alive until termination. This process is described in RFC 4028 [146] sections 7.1-7.4.

22.3.2 Conformance requirement

[TS 24.229 clause 5.1.2A.1.1]

[TS 24.229 clause 5.2.7.2]

[TS 24.229 clause 5.2.7.3]

[TS 24.229 clause 5.4.5.3]

Reference(s)

3GPP TS 24.229 [10], clauses 5.1.2A.1.1, 5.2.7.2, 5.2.7.3, and 5.4.5.3.

22.3.3 Test purpose

1) To verify that, when setting up an MO call, the UE performs correct exchange of SIP protocol signalling messages for Session Timer extension; and

2) To verify that, within SIP signalling, the UE correctly sets Session Expires Interval and becomes refresher when remote end does not indicate Session Timer Support in 200 OK response to initial INVITE (as described by RFC 4028 [10], section 7.2); and

3) To verify that the UE generates periodic session refreshes and is able to keep the session active until released; and

4) To verify that the UE does not change the role of refresher during session refreshes.

22.3.4 Method of test

Initial conditions

Test procedure applicable for a UE with E-UTRA support (TS 34.229-2 [5] A.18/1)

Expected sequence

NOTE: Only the IMS procedure relevant to the test purpose is described below.

Step	Direction		Message	Comment
	UE	SS
1			Make the UE attempt an IMS speech call	MTSI MO speech call. Referred from 36.508 [94] table 4.5A.6.3-1 for a UE with E-UTRA support.
2	🡪		INVITE	UE sends INVITE as described in C.21, step 2, indicating support for Session Timer, with either the Session-Expires value set to 1800 or no Session-Expires header
3-11			Steps 3-11 defined in annex C.21
12	🡨		200 OK	SS sends 200 OK for INVITE, without timer tag in Supported and Require headers and without Session-Expires header
13	🡪		ACK	UE sends ACK.
14	🡪		UPDATE	900 seconds after step 13, UE sends an UPDATE request to refresh the session.
15	🡨		200 OK	SS sends 200 OK for UPDATE, without timer tag in Supported and Require headers and without Session-Expires header
16	🡪		UPDATE	900 seconds after step 15, UE sends an UPDATE request to refresh the session.
17	🡨		200 OK	SS sends 200 OK for UPDATE, without timer tag in Supported and Require headers and without Session-Expires header
18-21			Steps defined in annex C.33	SS releases the call.

Specific Message Contents

INVITE (Step 2)

Use the default Message "INVITE" in Annex C.21 with conditions A1, A3, A4 and A26 and the following exceptions:

Header/param	Value/remark
Session-Expires	(if present)
delta-seconds	1800
refresher	uac (if present)

183 Session Progress (Step 4)

Use the default Message "183 Session Progress for INVITE" in Annex A.2.3 with condition A1 and the following exceptions:

Header/param	Value/remark
Allow	INVITE, UPDATE, PRACK, ACK, OPTIONS, CANCEL, BYE

200 OK (Step 12)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A1 and A10 and the following exceptions:

Header/param	Value/remark
Allow	INVITE, UPDATE, PRACK, ACK, OPTIONS, CANCEL, BYE

UPDATE (Steps 14 and 16)

Use the default Message "UPDATE" in Annex A.2.5 with condition A1 and the following exceptions:

Header/param	Value/remark
Supported	timer
Session-Expires
delta-seconds	1800
refresher	uac
Content-Type	any value if present

22.4 MO Call – Remote end supports but does not use Session Timer

22.4.1 Definition

Test to verify that a UE supporting and using Session Timer as described in RFC 4028 [146], configured to indicate Session Timer support, when remote end supports but does not want to use Session Timer (and no proxies in between mandate its usage), during an IMS mobile originated voice call when using IMS Multimedia Telephony with preconditions, turns-off the use of Session Timer for the session hence does not generate periodic session refresh and keeps the session alive until termination. This process is described in IR.92 [133] clause 2.2.8, RFC 4028 [146] sections 7.1-7.4.

22.4.2 Conformance requirement

[TS 24.229 clause 5.1.2A.1.1]

[TS 24.229 clause 5.2.7.2]

[TS 24.229 clause 5.2.7.3]

[TS 24.229 clause 5.4.5.3]

Reference(s)

3GPP TS 24.229 [10], clauses 5.1.2A.1.1, 5.2.7.2, 5.2.7.3, and 5.4.5.3.

22.4.3 Test purpose

1) To verify that, when setting up an MO call, the UE performs correct exchange of SIP protocol signalling messages for Session Timer extension; and

2) To verify that, within SIP signalling, the UE correctly indicates Session Timer support by including timer tag in Supported header (as described by RFC 4028 [10], section 7.2); and

3) To verify that the UE turns off the use of Session Timer extension for the session upon receiving 200 OK response from the remote end indicating Session Timer support with timer tag in Supported header but without Session-Expires header; and

4) To verify that the UE does not generate any periodic session refreshes and is able to keep the session active until released.

22.4.4 Method of test

Initial conditions

Test procedure applicable for a UE with E-UTRA support (TS 34.229-2 [5] A.18/1)

Expected sequence

NOTE: Only the IMS procedure relevant to the test purpose is described below.

Step	Direction		Message	Comment
	UE	SS
1			Make the UE attempt an IMS speech call using a Session-Expires	MTSI MO speech call. Referred from 36.508 [94] table 4.5A.6.3-1 for a UE with E-UTRA support.
2	🡪		INVITE	UE sends INVITE as described in C.21, step 2, indicating support for Session Timer, with either the Session-Expires value set to 1800 or no Session-Expires header
3-11			Steps 3-11 defined in annex C.21
12	🡨		200 OK	SS sends 200 OK for INVITE, with timer tag in Supported header but without Session-Expires header
13	🡪		ACK	UE sends ACK.
14-17			Steps defined in annex C.33	1860 seconds after step 13, SS releases the call.

Specific Message Contents

INVITE (Step 2)

Use the default Message "INVITE" in Annex C.21 with conditions A1, A3, A4 and A26 and the following exceptions:

Header/param	Value/remark
Session-Expires	(if present)
delta-seconds	1800
refresher	uac (if present)

200 OK (Step 12)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A1 and A10 and the following exceptions:

Header/param	Value/remark
Supported	timer

22.5 MT Call – Remote end supports but does not send Session-Expires

22.5.1 Definition

Test to verify that a UE supporting and using Session timer as described in RFC 4028 [146], during mobile terminated speech call setup when using IMS Multimedia Telephony, correctly responds to MT INVITE not having Session-Expires header, chooses remote end as refresher, responds to periodic refreshes, keeps session active until refresh requests are received from remote end, and terminates session upon not receiving session refresh request after session expiration interval. This process is described in IR.92 [133] clause 2.2.8 and RFC 4028 [146] sections 9.

22.5.2 Conformance requirement

[TS 24.229 clause 5.1.2A.1.1]

[TS 24.229 clause 5.2.7.2]

[TS 24.229 clause 5.2.7.3]

[TS 24.229 clause 5.4.5.3]

Reference(s)

3GPP TS 24.229 [10], clauses 5.1.2A.1.1, 5.2.7.2, 5.2.7.3, and 5.4.5.3.

22.5.3 Test purpose

1) To verify that, during an MT call setup, the UE performs correct exchange of SIP protocol signalling messages for Session Timer extension; and

2) To verify that within SIP signalling the UE correctly selects the remote end as refresher for the session where remote end indicates support with “timer” tag in Supported header but does not include Session-Expires header in INVITE request; and

3) To verify that the UE keeps the session active during session refreshes from remote end and is able to respond to periodic refresh UPDATE requests; and

4) To verify that the UE is able to terminate the session upon not receiving periodic session refresh request from remote end.

22.5.4 Method of test

Initial conditions

SS is configured with the shared secret key of IMS AKA algorithm, related to the IMS private user identity (IMPI) configured on the UICC card equipp5ed into the UE. SS has performed AKAv1-MD5 authentication with the UE and accepted the registration (IMS security).

Test procedure applicable for a UE with E-UTRA support (TS 34.229-2 [5] A.18/1)

1-26) UE executes the procedures described in TS 36.508 [94] table 4.5A.7.3-1 steps 1 to 26.

Expected sequence

NOTE: Only the IMS procedure relevant to the test purpose is described below.

Step	Direction		Message	Comment
	UE	SS
1	🡨		INVITE	SS sends INVITE as described in C.11, step 1.
2-11			Steps 3-11A defined in annex C.11
12	🡪		200 OK	UE sends 200 OK for INVITE with Session-Expires value set to 1800 and refresher value set to uac.
13	🡨		ACK	SS sends ACK.
14	🡨		UPDATE	900 seconds after step 12, SS sends an UPDATE request to refresh the session.
15	🡪		200 OK	UE sends 200 OK for UPDATE.
16-19			Steps 2-5 defined in annex C.32	1800 seconds after step 15, UE releases the call due to session expiry.

Specific Message Contents

INVITE (Step 1)

Use the default message “INVITE for MT Call” in annex A.2.9 with conditions A1, A3, and A4.

200 OK (Step 12)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A2 and A11 and the following exceptions:

Header/param	Value/remark
Require	timer
Session-Expires
delta-seconds	1800
refresher	uac

UPDATE (Step 14)

Use the default Message "UPDATE" in Annex A.2.5 with condition A3 and the following exceptions:

Header/param	Value/remark
Supported	timer
Session-Expires
delta-seconds	1800
refresher	uac
Content-Type	not present

200 OK (Steps 15)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A2 and A11 and the following exceptions:

Header/param	Value/remark
Supported	timer
Session-Expires
delta-seconds	1800
refresher	uac

22.6 MT Call – Remote end sends Session-Expires but does not choose refresher

22.6.1 Definition

Test to verify that a UE supporting and using Session timer as described in RFC 4028 [146], during mobile terminated speech call setup when using IMS Multimedia Telephony, chooses remote end as refresher, responds to periodic refreshes and keeps session active until refresh requests are received from remote end. This process is described in IR.92 [133] clause 2.2.8 and RFC 4028 [146] section 9.

22.6.2 Conformance requirement

[TS 24.229 clause 5.1.2A.1.1]

[TS 24.229 clause 5.2.7.2]

[TS 24.229 clause 5.2.7.3]

[TS 24.229 clause 5.4.5.3]

Reference(s)

3GPP TS 24.229 [10], clauses 5.1.2A.1.1, 5.2.7.2, 5.2.7.3, and 5.4.5.3.

22.6.3 Test purpose

1) To verify that, during a MT call setup, the UE performs correct exchange of SIP protocol signalling messages for Session Timer extension; and

2) To verify that the UE correctly responds with 200 OK with Session-Expires value received in MT INVITE and correctly selects the remote end as refresher for the session; and

3) To verify that the UE keeps the session active during session refreshes from remote end and able to respond to periodic refresh UPDATE requests.

22.6.4 Method of test

Initial conditions

Test procedure applicable for a UE with E-UTRA support (TS 34.229-2 [5] A.18/1)

1-26) UE executes the procedures described in TS 36.508 [94] table 4.5A.7.3-1 steps 1 to 26.

Expected sequence

NOTE: Only the IMS procedure relevant to the test purpose is described below.

Step	Direction		Message	Comment
	UE	SS
1	🡨		INVITE	SS sends INVITE as described in C.11, step 2, with timer tag set in Supported header and Session-Expires value set to 1800.
2-11			Steps 3-11A defined in annex C.11
12	🡪		200 OK	UE sends 200 OK for INVITE with Session-Expires value set to 1800 and refresher value set to uac.
13	🡨		ACK	SS sends ACK.
14	🡨		UPDATE	900 seconds after step 17, SS sends an UPDATE request to refresh the session.
15	🡪		200 OK	UE sends 200 OK for UPDATE.
16-19			Steps defined in annex C.33	SS releases the call.

Specific Message Contents

INVITE (Step 1)

Use the default message “INVITE for MT Call” in annex A.2.9 with conditions A1, A3, A4 and following exceptions:

Header/param	Value/remark
Session-Expires
delta-seconds	1800

200 OK (Step 12)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A2 and A11 and the following exceptions:

Header/param	Value/remark
Require	timer
Session-Expires
delta-seconds	1800
refresher	uac

UPDATE (Step 14)

Use the default Message "UPDATE" in Annex A.2.5 with condition A3 and the following exceptions:

Header/param	Value/remark
Supported	timer
Session-Expires
delta-seconds	1800
Refresher	uac
Content-Type	not present

200 OK (Steps 15)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A2 and A11 and the following exceptions:

Header/param	Value/remark
Supported	timer
Session-Expires
delta-seconds	1800
refresher	uac

22.7 MT Call – Remote end chooses UE as refresher

22.7.1 Definition

Test to verify that a UE supporting and using Session timer as described in RFC 4028 [146], during mobile terminated speech call setup when using IMS Multimedia Telephony, correctly responds to MT INVITE with Session-Expires and refresher set as uas, becomes refresher of the session and does periodic refreshes and keeps session active during session refreshes. This process is described in IR.92 [133] clause 2.2.8 and RFC 4028 [146] section 9.

22.7.2 Conformance requirement

[TS 24.229 clause 5.1.2A.1.1]

[TS 24.229 clause 5.2.7.2]

[TS 24.229 clause 5.2.7.3]

[TS 24.229 clause 5.4.5.3]

Reference(s)

3GPP TS 24.229 [10], clauses 5.1.2A.1.1, 5.2.7.2, 5.2.7.3, and 5.4.5.3.

22.7.3 Test purpose

1) To verify that, during an MT call setup, the UE performs correct exchange of SIP protocol signalling messages for Session Timer extension; and

2) To verify that, within SIP signalling, the UE responds to MT INVITE correctly where remote end has indicated session timer support and chosen UE as refresher by setting refresher as uas in Session-Expires header; and

3) To verify that, the UE becomes refresher of the session and generate periodic session refresh with Re-INVITE requests since UPDATE method is not listed in Allow header of MT INVITE; and

4) To verify that, the UE keeps the session active during session refreshes.

22.7.4 Method of test

Initial conditions

Test procedure applicable for a UE with E-UTRA support (TS 34.229-2 [5] A.18/1)

1-26) UE executes the procedures described in TS 36.508 [94] table 4.5A.7.3-1 steps 1 to 26.

Expected sequence

NOTE: Only the IMS procedure relevant to the test purpose is described below.

Step	Direction		Message	Comment
	UE	SS
1	🡨		INVITE	SS sends INVITE as described in C.11, step 1, with Session-Expires value set to 1800 and refresher set to uas.
2-11			Steps 3-11A defined in annex C.11
12	🡪		200 OK	UE sends 200 OK for INVITE with Session-Expires value set to 1800 and refresher value set to uas.
13	🡨		ACK	SS sends ACK.
14	🡪		INVITE	900 seconds after step 13, UE sends an INVITE request to refresh the session.
15	🡨		200 OK	SS sends 200 OK for INVITE.
16	🡪		ACK	UE sends ACK.
17	🡪		INVITE	900 seconds after step 16, UE sends an INVITE request to refresh the session.
18	🡨		200 OK	SS sends 200 OK for INVITE.
19	🡪		ACK	UE sends ACK.
20-23			Steps defined in annex C.33	SS releases the call.

Specific Message Contents

INVITE (Step 1)

Use the default message “INVITE for MT Call” in annex A.2.9 with conditions A1, A3, A4 and following exceptions:

Header/param	Value/remark
Allow	INVITE, ACK, OPTIONS, CANCEL, BYE
Session-Expires
delta-seconds	1800
refresher	uas

200 OK (Step 12)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A2 and A11 and the following exceptions:

Header/param	Value/remark
Supported	timer
Session-Expires
delta-seconds	1800
refresher	uas

INVITE (Step 14 and 17)

Use the default Message "INVITE" in Annex A.2.1 with conditions A32 and A26 and the following exceptions:

Header/param	Value/remark
Session-Expires
delta-seconds	1800
refresher	uac
Content-Type
media-type	application/sdp
Content-Length
value	length of message-body
Message-body	Same SDP message as the last SDP message sent by the UE in the 200 OK at step 7 (step 8 of C.11); the session version in the origin shall not be incremented

200 OK (Steps 15 and 18)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A2 and A11 and the following exceptions:

Header/param	Value/remark
Require	timer
Session-Expires
delta-seconds	1800
refresher	uac
Content-Type
media-type	application/sdp
Content-Length
value	length of message-body
Message-body	Same SDP message as the last SDP message sent by the SS in the UPDATE at step 6 (step 7 of C.11); the session version in the origin shall not be incremented

22.8 MT Call – Remote end does not support Session Timer

22.8.1 Definition

Test to verify that a UE supporting and using Session timer as described in RFC 4028 [146], when receiving INVITE without Session Timer will instrument and use a Session Timer for its own purpose. This process is described in RFC 4028 [146] sections 7.1-7.4.

22.8.2 Conformance requirement

[TS 24.229 clause 5.1.2A.1.1]

[TS 24.229 clause 5.2.7.2]

[TS 24.229 clause 5.2.7.3]

[TS 24.229 clause 5.4.5.3]

Reference(s)

3GPP TS 24.229 [10], clauses 5.1.2A.1.1, 5.2.7.2, 5.2.7.3, and 5.4.5.3.

22.8.3 Test purpose

1) To verify that, during an MT call setup, the UE performs correct exchange of SIP protocol signalling messages for Session Timer extension; and

2) To verify that, within SIP signalling, the UE responds to MT INVITE correctly where remote end has not indicated session timer support by setting refresher as uas in Session-Expires header; and

3) To verify that, the UE becomes refresher of the session and generates periodic session refresh UPDATE requests; and

4) To verify that, the UE keeps the session active during session refreshes.

22.8.4 Method of test

Initial conditions

Test procedure applicable for a UE with E-UTRA support (TS 34.229-2 [5] A.18/1)

1-26) UE executes the procedures described in TS 36.508 [94] table 4.5A.7.3-1 steps 1 to 26.

Expected sequence

NOTE: Only the IMS procedure relevant to the test purpose is described below.

Step	Direction		Message	Comment
	UE	SS
1	🡨		INVITE	SS sends INVITE as described in C.11, step 1, without support for Session-Timer.
2-11			Steps 3-11A defined in annex C.11
12	🡪		200 OK	UE sends 200 OK for INVITE with Session-Expires value set to 1800 and refresher value set to uas.
13	🡨		ACK	SS sends ACK.
14	🡪		UPDATE	900 seconds after step 13, UE sends an UPDATE request to refresh the session.
15	🡨		200 OK	SS sends 200 OK for UPDATE.
16-19			Steps 1-4 defined in annex C.33	SS ends the call.

Specific Message Contents

INVITE (Step 1)

Use the default Message "INVITE" in Annex C.11 with conditions A1, A3, A4 and A7 and the following exceptions:

Header/param	Value/remark
Allow	INVITE, UPDATE, PRACK, ACK, OPTIONS, CANCEL, BYE

200 OK (Step 12)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A2 and A11 and the following exceptions:

Header/param	Value/remark
Session-Expires
delta-seconds	1800
refresher	uas

UPDATE (Step 14)

Use the default Message "UPDATE" in Annex A.2.5 with condition A3 and the following exceptions:

Header/param	Value/remark
Supported	timer
Session-Expires
delta-seconds	1800
refresher	uac
Content-Type	any value if present

200 OK (Steps 15)

Use the default Message "200 OK for other requests than REGISTER or SUBSCRIBE" in Annex A.3.1 with conditions A1 and A10.

Annex A (normative):
Default Messages

For all the message definitions below, the acceptable order and syntax of headers and fields within these headers must be according to IETF RFCs where those headers have been defined. Typically the order of headers is not significant, but there are well defined exceptions (like Via, Route, Record-Route headers, and SDP lines) where the order is important.

The contents of the messages described in the present Annex is not complete – only the fields, headers, and SDP lines required to be checked or generated by SS are listed here. The messages sent by the UE may contain additional parameters, fields, headers, and SDP lines which are not checked and must thus be ignored by SS.

Values prefixed with px_ will be implemented in the TTCN with a PIXIT.

Values shown in italics shall be used in the messages as such.

Conditions listed in the “Cond” column in the tables of the present Annex have different purposes.

– When a condition is listed on the same line as the name of header, the presence of this header is:

– optional when this condition applies and the condition is appended by the (o) tag: e.g. ‘A2(o)’.

– mandatory when this condition applies and the condition is not appended: e.g. ‘A2’.

NOTE 1: This includes negative Boolean expressions, i.e. a “NOT expression” mandates presence of the header whenever the condition does not apply. Still the UE is allowed to include the header under such negative Boolean expression – it is just not required to do so.

– The absence of a header or parameter is checked under a condition listed on the same line as the name of the header/parameter when the Value/remark column carries the explicit phrase “not present”.

– When no condition is listed on the same line as the name of a header, presence or absence of the header is regulated under all conditions, i.e., when the Value/remark column states absence of the header it is absent under all conditions. Otherwise it is present under all conditions.

– When a condition is listed on the same line as an indented subentry of a header, i.e., a parameter, the corresponding entry in the “Value/remark” column imposes a requirement on the value of this parameter when this condition applies.

– When no condition is listed on the same line as a parameter and there are line(s) for the same parameter carrying condition(s), the meaning is that the former line constitutes a default and the latter line(s) constitute special regulations under the specific condition(s).

NOTE 2: In above bullet points, “header” is used for the boldface entries in the Header/param columns starting a sub table, e.g., Request-Line, Route, and Message-body, even though not all these terms technically represent SIP headers. Similarly, we use the generic term “parameter” to denote subentries of such “headers”.