Question: When an eP-CSCF (IMS-ALG) receives an SDP offer from the WebRTC access network releasing a particular WebRTC data channel while maintaining the SCTP Association, what action(s) should the eP-CSCF (IMS-ALG) take regarding the IMS core network?
Option 1: Immediately release all H.248 Stream endpoints towards both the WebRTC access network and the IMS core network.
Option 2: Forward the SDP offer to the IMS core network with the media line corresponding to the media stream in the data channel disabled by port zero, and then provide Send SCTP Stream Reset Requests Indicator information to the eIMS-AGW.
Option 3: Only notify the eIMS-AGW about the release without forwarding any SDP offer or answer to the IMS core network.
Option 4: Wait for an explicit notification from the eIMS-AGW that the peer has reset the corresponding incoming SCTP Stream before taking any action.
Explanation: According to procedures for releasing a WebRTC data channel, when the eP-CSCF (IMS-ALG) receives an SDP offer from the WebRTC access network releasing a data channel while maintaining the SCTP Association, it should forward this SDP offer to the IMS core network with adjustments (disabling the media line by port zero for the released data channel) and initiate the SCTP Stream reset process by sending the Send SCTP Stream Reset Requests Indicator to the eIMS-AGW. This ensures both signaling and transport layers are updated correctly in response to the data channel release.