| 摘要 |
FIELD: information technology. ^ SUBSTANCE: message is received (3) at a server (S) from a second terminal (B), which invites a first terminal (A) to establish a half-duplex communication type session. The message contains a list of media types which the second terminal (B) can send to the first terminal (A) during the session. Before that, the first terminal (A) notifies (1) the server (S) on information indicating, for one or each type from at least one of the media types, under which condition, if any, the first terminal (A) will receive that media type during the half-duplex communication type session. In response to receiving the invitation message and based on the information, the server (S) revises the list of media types so that it includes all media types which the first terminal (A) will not receive from the second terminal (B). If at least one media type remains on the list, an invitation message with the revised list is sent (5) to the first terminal. In one version, the invitation message is a session initiation protocol (SIP) invite message and session description protocol (SDP) parameters are used to indicate the list of media types. The half-duplex communication type service can be a Push-To-Talk over Cellular (PoC) half-duplex communication type service. The half-duplex communication type service can be a conference call service. ^ EFFECT: improved management of transmission and reception of media data. ^ 21 cl, 2 dwg |
