ed codec. 5) to 14) Upon receipt of the 200 OK response, the P-CSCF entity initiates the establishment of dedicated bearer for the video stream. 15), 16) The P-CSCF entity forwards the 200 OK response to the domain homeA net (or homeB net). 3.8. Termination of ViLTE session The procedure for clearing the ViLTE session is identical to that described for the VoLTE session if the two streams, audio and video, need to be released. The release of the ViLTE session may be limited to the removal of the video stream, the audio stream being retained. The procedure of the removal of the video stream, at the initiated side, is described in Figure 3.11. 1), 2), 3) Alice's UA entity (or Bob's) takes the initiative in removing the video flow by sending the UPDATE message to the domain homeB net (or homeA. net). The deletion of the video flow is indicated in the SDP message, which contains the port number of the video stream set to ZERO. 4) to 7) As described earlier, these messages are used to trigger the release of the dedicated bearer for the video stream. 8), 9), 10) Bob's UA entity (or Alice's) sends the 200 OK response to the UPDATE request to the domain homeA. net (or homeB.net) The deletion of the video flow is indicated in the SDP message, which contains the port number of the video stream set to ZERO. 11) to 16) As described earlier, these messages are used to remove the dedicated bearer for the video stream. Basic Procedures P-CSCF S-CSCF SIP UPDATE Homes SIP UPDATE SIP UPDATE DIAMETER STR DIAMETER RAR DIAMETER RAA DIAMETER STA SIP 200 OK SIP 200 OK SIP 200 OK GTPv2-C DELETE BEARER REQUEST GTPv2-C DELETE BEARER REQUEST ESM DEACTIVATE DEDICATED EPS BEARER CONTEXT REQUEST S1-APE-RAB RELEASE COMMAND RRC ConnectionReconfiguration ESM DEACTIVATE DEDICATED EPS BEARER CONTEXT ACCEPT RRC ConnectionReconfigurationComplete S1-AP E-RAB RELEASE RESPONSE GTPv2-C DELETE BEARER RESPONSE GTPv2-C DELETE BEARER RESPONSE Figure 3.11. Removing a video stream: initiated side The procedure of the removal of the video stream, at the receiv