C.43 Generic Test Procedure for UE receiving SIP REFER request for transfer of additional CS to PS call – EPS

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

Test procedure:

1. The UE waits for the SS to send a REFER request in dialog of INVITE to STI-rSR for transfer of 2nd call

2. The UE responds to the REFER with a 200 OK response

3. The UE sends INVITE request for transfer of additional call

4. The SS responds to the INVITE with a 200 OK response

5. The UE sends ACK for receipt of 200 OK

Expected sequence:

Step

Direction

Message

Comment

UE

SS

1

🡨

REFER

The SS sends REFER request

2

🡪

200 OK

The UE responds with 200 OK.

3

🡪

INVITE

The UE sends INVITE for transfer of additional call

4

🡨

200 OK

The SS responds with 200 OK.

5

🡪

ACK

UE acknowledges the receipt of 200 OK for INVITE

Specific message contents:

REFER (Step 1)

Use the default message "MT REFER" in annex A.2.12 with the following exceptions:

Header/param

Value/remark

Request-URI

SS sends REFER request in the dialog of the INVITE to STI-rSR for transfer of second call

Refer-To

addr-spec

SIP or Tel URI of the transfer target

To

addr-spec

SIP URI of the UE which shall be the same URI as used for UE in the earlier requests within the dialog created by the INVITE sent by the UE when initiating the call to be transferred

tag

no tag given

CSeq

value

any value

200 OK for REFER (Step 2)

Use the default message “200 OK for other requests than REGISTER or SUBSCRIBE” in annex A.3.1 with the following exceptions:

Header/param

Value/remark

Refer-Sub

referSubValue

false

INVITE (Step 3)

Use the default message "INVITE for MO Call" in annex A.2.1, with the following exceptions:

Header/param

Value/remark

Supported

option-tag

precondition

Message-body

The following SDP types and values shall be present.

Session description:

  • v=0
  • o=(username) (sess-id) (sess-version) IN (addrtype) (unicast-address for UE)
  • c=IN (addrtype) (connection-address for UE) [Note 1]
  • s=(session name)
  • b=AS: (bandwidth-value)

Time description:

  • t=(start-time) (stop-time)

Media description:

  • m=audio (transport port) RTP/AVP (fmt)
  • c=IN (addrtype) (connection-address for UE) [Note 1]
  • b=AS: (bandwidth-value)
  • b=RS: (bandwidth-value) [Note 6]
  • b=RR: (bandwidth-value) [Note 6]

Attributes for media:

  • a=rtpmap:(payload type) AMR-WB/16000 [Note 3]
  • a=fmtp: (format) mode-change-capability=2; max-red= (att-field) [Note 4]
  • a=rtpmap: (payload type) telephone-event/16000
  • a=fmtp:(format)

Attributes for preconditions:

  • a=curr:qos local sendonly
  • a=curr:qos remote none
  • a=des:qos mandatory local sendonly
  • a=des:qos optional remote sendonly

Note 1: At least one "c=" field shall be present.

Note 2: Void

Note 3: The AMR channel number shall be “/1” or omitted.

Note 4: Values from 0 to 220 are allowed

Note 5: A rate may be added to the “telephone-event” separated by “/” (e.g. "telephone-event/8000")

Note 6: The RR value must be greater than 0. The RS value can be any value.

200 OK for INVITE (Step 4)

Use the default message "200 OK for other requests than REGISTER or SUBSCRIBE" in annex A.3.1 with the following exceptions:

Header/param

Value/remark

Message-body

SDP body of the 200 OK response copied from the received INVITE but modified as follows:

– "o=" line identical to previous SDP sent by SS except that sess-version is incremented by one

– IP address on "c=" line and transport port on "m=" lines changed to indicate to which IP address and port the UE should send the media; and

In case of Call Hold:

– "sendonly" direction attribute inverted to "recvonly".

Note that this applies to “a=sendonly” direction attributes only, not to the direction tags found in preconditions.