Session link system, session liaison, liaison manager, session link method and program storage medium storing program thereof

摘要

Information of PoC sessions is registered in a session information storage. The liaison manager refers to the session information storage, and requests a link PoC server to establish a link PoC session while specifying PoC sessions. The liaison manager requests session liaisons to attend the respective PoC sessions and the link PoC session. The multicast terminal requests the link PoC server for acquisition of talk right. The session liaisons request the respective PoC servers for forcible acquisition of talk right. The multicast terminal transmits voice data to the link PoC server. The link PoC server multicasts the voice data to the session liaisons. The session liaisons transfer the voice data to the respective PoC servers. The PoC servers multicast the voice data to PoC terminals. Thus, extended multicast in a plurality of sessions is effectively achieved.