Content for TS 24.186 Word version: 19.0.0

1… 4… 9… 9.3… 9.3.3… 9.4… 10… 10.11… A… A.1.2… A.1.2.2… A.1.3… A.1.3.2… A.1.3.3… B… C…

9.4 Abnormal cases 9.4.1 General 9.4.2 No response on DC2 interface 9.4.3 Insufficient data channel resource 9.4.4 No response or failure response on DC1 interface 9.4.5 QoS parameters not received 9.4.6 Re-INVITE request collision
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9.4 Abnormal cases p. 24

9.4.1 General p. 24

Abnormal cases on IMS data channel include the following:

The IMS AS has sent a data channel resource reservation/update request and does not receive a response to that request.
The IMS AS has sent a data channel resource reservation/update request, and receives an error response to that request due to no sufficient data channel resource.
The IMS AS hasn't received QoS parameters when generating SDP offer or answer for the application data channel media.
The IMS AS has notified a session event to the DCSF and does not receive a response or receives a failure.
The re-INVITE request collision in the IMS AS during IMS data channel establishment and closing.

The failures during IMS data channel establishment and maintenance shall not impact any other ongoing media which are associated with the same IMS session (e.g. audio, video, etc.).

9.4.2 No response on DC2 interface p. 24

9.4.2.1 Actions at the IMS AS p. 24

If the IMS AS does not receive a response to a bootstrap data channel resource reservation/update request, the IMS AS shall:

remove the data channel media description from the SDP offer for the INVITE/re-INVITE request; and
set the port number of the "m=" lines for data channel as zero in the SDP answer of the response to the INVITE/re-INVITE request.

If the IMS AS does not receive a response to an application data channel resource reservation/update request, the IMS AS shall:

remove from the SDP offer for the re-INVITE request:
1. the "a=dcmap" line associated to this requested application data channel; or
2. the data channel media description containing this requested application data channel if no other "a=dcmap" attribute line existed in this media description; and
set the port number of the "m=" lines for the data channel media description containing this requested application data channel as zero in the SDP answer of the response to the re-INVITE request in the case 2).

9.4.3 Insufficient data channel resource p. 25

9.4.3.1 Actions at the IMS AS p. 25

If the IMS AS receives an error response message to a bootstrap data channel resource reservation/update request, the IMS AS shall:

remove the data channel media description from the SDP offer for the INVITE/re-INVITE request;
continue the ongoing session procedure; and
set the port number of the "m=" lines for data channel as zero in the SDP answer of the response to the INVITE/re-INVITE request.

If the IMS AS receives an error response message to an application data channel resource reservation/update request, the IMS AS shall:

remove from the SDP offer for the re-INVITE request:
1. the "a=dcmap" line associated to this requested application data channel; or
2. the data channel media description containing this requested application data channel if no other "a=dcmap" attribute line existed in this media description; and
set the port number of the "m=" lines for the data channel media description containing this requested application data channel as zero in the SDP answer of the response to the re-INVITE request in the case 2).

9.4.4 No response or failure response on DC1 interface p. 25

9.4.4.1 Actions at the IMS AS p. 25

If the IMS AS does not receive a response to a session event notification or receives a failure response to a session event notification, the IMS AS shall:

in the case of notifying IMS data channel session establishment request or media change request on bootstrap data channel setup, remove the IMS data channel SDP media description from the SDP offer for the INVITE/re-INVITE request and continue the ongoing session procedure;
in the case of notifying media change request on application data channel setup,
- remove from the SDP offer for the re-INVITE request:
  1. the "a=dcmap" line associated to this requested application data channel; or
  2. the data channel media description containing this requested application data channel if no other "a=dcmap" attribute line existed in this media description; and
- continue the ongoing session procedure;
- set the port number of the "m=" lines for IMS data channel as zero in the SDP answer of the response to the INVITE/re-INVITE request; and
in the case of notifying IMS data channel session establishment failure, media change failure, and session termination request, continue the ongoing session procedure

9.4.5 QoS parameters not received p. 26

9.4.5.1 Actions at the IMS AS p. 26

If new SDP offer generated by the UE includes the application data channel media description containing "a=3gpp-req-app" attribute with "endpoint" parameter set to "server" and:

"a=3gpp-qos-hint" attribute but no QoS parameters received in the media instruction from the DCSF, the IMS AS of the served UE shall generate "a=3gpp-qos-hint" attribute with the default values based on the configuration, if available; or
updated "a=3gpp-qos-hint" attribute but no QoS parameters received in the media instruction from the DCSF, the IMS AS of the served UE shall generate "a=3gpp-qos-hint" attribute with the values previously negotiated within SDP offer and SDP answer;

for the corresponding application data channel media description before forwarding the SDP offer and the associated SDP answer.

9.4.6 Re-INVITE request collision |R19| p. 26

9.4.6.1 Actions at the IMS AS p. 26

The IMS AS shall handle re-INVITE request collisions as specified in TS 24.229 with the clarification in this subclause.

When a re-INVITE request including an SDP offer containing IMS data channel media description is received while a re-INVITE is progressing as per clauses 9.3.2.2.2 and 9.3.3.2.2, or while a re-INVITE has already been sent out, the IMS AS shall not notify the DCSF about the media change request including the information of the received re-INVITE request and shall return 491 (Request Pending) response to the received re-INVITE request.