10 Subscription

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

10.1 Invalid Behaviour – 503 Service Unavailable

10.1.1 Definition

Test to verify that when the UE receives a 503 (Service Unavailable) response to a SUBSCRIBE request containing a Retry-After header, then the UE shall not automatically reattempt the request until after the period indicated by the Retry-After header contents. This can happen when the server is temporarily unable to process the request due to a temporary overloading or maintenance of the server.

10.1.2 Conformance requirement

[TS 24.229, clause 5.1.2.2]

If the UA receives a 503 (Service Unavailable) response to an initial SUBSCRIBE request containing a Retry-After header, then the UE shall not automatically reattempt the request until after the period indicated by the Retry-After header contents.

Reference(s)

3GPP TS 24.229 [10], clause 5.1.2.2.

10.1.3 Test purpose

To verify that after receiving a 503 (Service Unavailable) response to a SUBSCRIBE request, containing a Retry-After header, the UE shall not automatically reattempt the request until after the period indicated by the Retry-After header contents. This can happen when the server is temporarily unable to process the request due to a temporary overloading or maintenance of the server.

10.1.4 Method of test

Initial conditions

UE contains either ISIM and USIM applications or only USIM application on UICC. UE has activated a PDP context, discovered P-CSCF and registered to IMS services, by executing the generic test procedure in Annex C.2 up to step 7 or C.2a (GIBA only) up to step 5.

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

1) The UE sends a SUBSCRIBE request over the established security associations.

2) The SS responds to the SUBSCRIBE request with a 503 (Service Unavailable) response with the Retry-After header with period set to T, indicating how long the service is expected to be unavailable to the requesting client.

3) The SS waits for the period of time T defined in the Retry-After header, to check that the UE does not try to SUBSCRIBE for the registration event during this period.

4) The UE sends a new SUBSCRIBE request.

5) Continue test execution with the Generic test procedure in Annex C.2 or C.2a (GIBA only), step 9.

Expected sequence

Step	Direction		Message	Comment
	UE	SS
1	🡪		SUBSCRIBE	UE subscribes to its registration event package.
2	🡨		503 Service Unavailable	The SS responds with 503 response containing a Retry-After header with period set to T.
3				SS waits for Time T to check that the UE does not re-attempt the request.
4	🡪		SUBSCRIBE	UE reattempts to subscribe to its registration event package.
5	🡨🡪		Continue with Annex C.2 step 9	Execute the Generic test procedure Annex C.2 steps 9-11 in order to get the UE in a stable registered state.

NOTE: The default messages contents in annex A are used with condition “IMS security “ or “GIBA” when applicable

Specific Message Contents

SUBSCRIBE (Step 1)

Use the default message “SUBSCRIBE for reg-event package” in annex A.1.4.

503 Service Unavailable response (Step 2)

Use the default message “503 Service Unavailable” in annex A.4.2.

SUBSCRIBE (Step 4)

Use the default message “SUBSCRIBE for reg-event package” in annex A.1.4 with the following exception:

Header/param	Value/remark
Call-ID
callid	value different from the previous SUBSCRIBE request

10.1.5 Test requirements

Step 3: The UE shall not automatically reattempt the request during the period duration T.

Step 4: The UE reattempts to send a SUBSCRIBE request for registration event package.