| 摘要 |
<p>Multimedia multipoint conferencing and distance learning sessions utilizing the ATM network (140) use multimedia conferencing equipment at remote sites coupled to the ATM network via ATM network interface switches (160NIb-e). All ATM switches (160) are coupled to, and receive control information from a network manager NM (130). An application server AS (120) is coupled to the NM, and is also coupled to conferencing equipment via an out-of-band connection such as ETHERNET, to which the conferencing equipment is also connected. To establish multimedia multipoint conference, the AS sends information regarding the participants to the NM. At conference time, the NM establishes a plurality of SPVC multicast trees from each participating site to all other participating sites in the conference, and activates one multicast tree and deactivates all others. An application running on a computer system at a main site (110a) tracks requests from remote sites (110b, c, d) for recognition. A request is recognized via a command sent from the main site to the AS which causes the NM to deactivate the previously activated multicast tree, and activate the already set up, but non-activated multicast tree from the recognized site to the main and other sites. Control is re-obtained by the main site by sending another command to the AS which causes the NM to deactivate the then active multicast tree and to reactivate the previous multicast tree from the main site to all remotes sites.</p> |
