Calling method between packet multimedia communication system terminals

Abstract

The method makes H.323 slow starting terminal possible to pass through SIP relay to call H.323 terminal. In the invention, using virtual constructed SDP information to fill in SIP 200OK message makes SIP relay carry on. Parsing H.245 interactive procedure obtains information including capability, address, port number etc., and using direction change makes both parties known each other in order to establish normal call finally. Or, using specific encoding and decoding information identifies specific SDP information, which is in use for carrying H.245 address information of called H.323 terminal. Through SIP relay, the H.245 address information is transferred to calling H.323 terminal. Through negotiation, the two parties establish media communication finally.

Description

technical field [0001] The invention relates to the communication field, in particular to the intercommunication technology between the packet multimedia communication system (H.323) and the session initiation protocol (SIP). Background technique [0002] Today, with the rapid development of the Internet, packet data services are becoming more and more important. Many traditional voice services will be gradually replaced by packet services or integrated into one, becoming the development direction of the NextGeneration Network ("NGN" for short). For example, the use of Internet Protocol (Internet Protocol, "IP" for short) to transmit IP telephony is to perform traditional voice services on the basis of Internet packet transmission. [0003] In the traditional telephone system, a call requires certain signaling to cooperate from establishing a system connection to disconnecting the connection. Similarly, in IP telephony, how to find the called party, how to establish a resp...

AI Technical Summary

Problems solved by technology

However, since there is no logical channel information in the Connect message, the 200 OK message mapped to SIP has no SDP information, which is contrary to the provisions of the SIP protocol. Therefore, the call is released by softswitch 2

The entire call could not succeed

[0014] In practical application, the above solution has the following problems: when an H.323 slow-start terminal calls an H.323 terminal, because the media information is not provided, the SIP interaction does not meet the standard and is released, resulting in an unsuccessful call

[0015] The main reason for this situation is that when an H.323 slow-start terminal initiates a call, it does not carry logical channel information, and the softswitch cannot construct an SDP message. Therefore, the softswitch on the called side returns a 200 OK SIP message to the softswitch on the calling side. The SDP message is not carried in the signaling, which does not conform to the SIP standard

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