METHOD OF CALLING BETWEEN TERMINALS IN PACKET-BASED MULTIMEDIA COMMUNICATION SYSTEM

摘要

THE PRESENT INVENTION RELATES TO THE COMMUNICATION FIELD, DISCLOSING A METHOD OF CALLING BETWEEN TERMINALS IN A PACKET-BASED MULTIMEDIA COMMUNICATION SYSTEM. BY WHICH AN H.323 NORMAL-START TERMINAL CAN CALL AN H.323 TERMINAL THROUGH AN SIP RELAY.IN THE PRESENT INVENTION, VIRTUAL SDP INFORMATION IS CONSTRUCTED AND ADDED IN AN SIP 200 OK NIESSAGE SO THAT THE SIP RELAY MAY BE CONTINUED. AN H.245 INTERACTION PROCESS IS DIVIDED SO THAT INFORMATION SUCH AS CAPABILITIES, AN ADDRESS, A PORT NUMBER OR THE LIKE OF AN H. 323 TERMINAL MAY BE OBTAINED. THEN BOTH PARTIES MAY HAVE THE KNOWLEDGE OF EACH OTHER THROUGH A MEDIA REDIRECTION, AND A NORMAL CALL CAN THUS BE ESTABLISHED. ALTERNATIVELY, THE SPECIFIC SDP INFORMATION FOR CARRYING H.245 ADDRESS INFORMATION OF THE CALLED H. 323 TERMIINAL IS IDENTIFIED BY SPECIFIC CODING/DECODING INFORMATION, AND SENT TO THE CALLING H. 323 TENNINAL THROUGH THE SIP RELAY. BOTH OF THE PARTIES CAN ESTABLISH A MEDIA COMMUNIICATION THROUGH A NEGOTIATION.