Dear All, I’m facing difficulty in understanding the below scenario especially to determine what should be the media direction in M19 and M22. Kindly help me.
Party-A and Party-B: User Agents Proxy: B2BUA 1. Party-A sends INVITE with media direction “sendrecv” 2. Party-B answers the call with the media direction “sendrecv”. Call got successfully established 3. Party-A has initiated Call Hold, so it’s sending re-INVITE with media direction as “sendonly” (as per 24.610 <https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1124> ) 4. Party-B has received re-INVITE with media direction as “sendonly”, so it’s responding with “recvonly” (as per 24.610 <https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1124>). Call hold is successful. 5. Server is sending re-INVITE without SDP to Party-A. As per rfc6337 <https://tools.ietf.org/html/rfc6337#section-5.1>, since the “Desired State” of Party-A is “Hold” i.e “sendonly” so Party-A is sending an offer with the media direction as “sendonly” in 200OK 6. Server is receiving an offer in 200OK with media direction as “sendonly” and responding back with “recvonly” (Proxy’s previously negotiated media direction is “recvonly” towards Party-A) 7. Server is sending re-INVITE without SDP to Party-B. As per rfc6337 <https://tools.ietf.org/html/rfc6337#section-5.1>, since the “Desired State” of Party-B is “ACTIVE” i.e “sendrecv” so Party-B is sending an offer with the media direction as “sendrecv” in 200OK 8. Server is receiving an offer in 200OK with media direction as “sendrecv” and responding back with “sendonly” (Proxy’s previously negotiated media direction is “sendonly” towards Party-B) 9. Party-B also has initiated Call Hold, so it’s sending re-INVITE with media direction as “inactive” (as per 24.610 <https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1124> ) 10. Party-A has received re-INVITE with media direction as “inactive”, so it’s responding with “inactive” (as per 24.610 <https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1124>). Call hold is successful. 11. Server is sending re-INVITE without SDP to Party-A. As per rfc6337 <https://tools.ietf.org/html/rfc6337#section-5.1>, since the “Desired State” of Party-A is “Hold” i.e “sendonly” so Party-A is sending an offer with the media direction as “sendonly” in 200OK 12. Server is receiving an offer in 200OK with media direction as “sendonly” and responding back with “inactive” (Proxy’s previously negotiated media direction is “inactive” towards Party-A). *Is this correct?* 13. Server is sending re-INVITE without SDP to Party-B. As per rfc6337 <https://tools.ietf.org/html/rfc6337#section-5.1>, since the “Desired State” of Party-B is “HOLD” i.e “sendonly” so Party-B is sending an offer with the media direction as “sendonly” in 200OK. *Is this correct?* 14. Server is receiving an offer in 200OK with media direction as “sendonly” and responding back with “inactive” (Proxy’s previously negotiated media direction is “inactive” towards Party-B) *References:* https://portal.3gpp.org/desktopmodules/Specifications/ SpecificationDetails.aspx?specificationId=1124 4.5.2 Invocation and operation 4.5.2.1 Actions at the invoking UE In addition to the application of procedures according to 3GPP TS 24.229 [1], the following procedures shall be applied at the invoking UE in accordance with RFC 3264 [4]. If not all the media streams are affected, the invoking UE shall generate a new SDP offer where: 1) for each media stream that is to be held, the SDP offer contains: - an "inactive" SDP attribute if the stream was previously set to "recvonly"; or - a "sendonly" SDP attribute if the stream was previously set to "sendrecv"; https://tools.ietf.org/html/rfc6337 Below sections: 5.1. General Principle for Constructing Offers and Answers 5.3. Hold and Resume of Media I’m not sure whether the same issue is already discussed before on this thread. Unfortunately could not able to locate anything related to this. Please help me in figuring out an ideal media direction in the above scenario. Regards, Bharath Ph: +91-914 897 8095 "*Confidentiality Warning*: This message and any attachments are intended only for the use of the intended recipient(s), are confidential and may be privileged. If you are not the intended recipient, you are hereby notified that any review, re-transmission, conversion to hard copy, copying, circulation or other use of this message and any attachments is strictly prohibited. If you are not the intended recipient, please notify the sender immediately by return email and delete this message and any attachments from your system. *Virus Warning:* Although the company has taken reasonable precautions to ensure no viruses are present in this email. The company cannot accept responsibility for any loss or damage arising from the use of this email or attachment."
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