CN1208932C - Transmission calling method for multimedia communication - Google Patents
Transmission calling method for multimedia communication Download PDFInfo
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- CN1208932C CN1208932C CN 02124648 CN02124648A CN1208932C CN 1208932 C CN1208932 C CN 1208932C CN 02124648 CN02124648 CN 02124648 CN 02124648 A CN02124648 A CN 02124648A CN 1208932 C CN1208932 C CN 1208932C
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Abstract
The present invention relates to a transmission calling method for multimedia communication, which comprises the following steps: a, whether a private network terminal calls through an alias or not, if true, then registration is carried out on a gate keeper (GK) of a public network, else calling is directly started; b, the calling is established between the private network terminal and the public network terminal. The present invention can not only solve the problem of communications failure after communication protocols pass through an NAT (Network Address translator) device, but can save IP address resources of the public network through a multiplexing mode.
Description
Technical field
The present invention relates to the multi-medium data transmission, refer in particular to a kind of transmission calling method that is applied in the multi-media communication.
Technical background
In multi-media communication, all can relate to the multi-media communication agreement, and all can relate to the transmission of Media Stream (video/audio stream) in the multi-media communication agreement.
In the existing multi-media communication agreement, consider when utilizing IP network to carry out media flow transmission, all use basically in the prior art UDP (User Data Protocol: User Datagram Protoco (UDP)) come carrying media stream, so present most multi-media communication agreement use all come carrying media stream with UDP.But, because UDP is a kind of towards connectionless transport layer protocol, therefore NAT (Net Address Translation: network address translation) can't discern into to (from the public network to the private network by equipment, as: from the internet to the enterprise network) which terminal UDP bag should be forwarded in the private network on, and then cause into to UDP bag refused by NAT device, finally make the multi-media communication failure.
At the problem of above-mentioned appearance, technical scheme commonly used in the prior art has following two kinds:
One, static NAT conversion, its principle is: the private network IP address static mappings of on NAT device needs being carried out the terminal of multi-media communication becomes public network IP address, and promptly NAT device has been left public network IP address in the private network multimedia terminal in advance.
Two, pooled NAT conversion, its principle is: (discern by well-known port when multi-media communication, as: H.323 the calling well-known port of agreement is 1720), NAT device is dynamically distributed to the terminal of carrying out multi-media communication in the private network to certain public network IP address, finishes up to multi-media communication.
But, above-mentioned two kinds of technical schemes all can't be accomplished public network IP address of a plurality of multi-media communication terminal multiplexings in the private network, after that is: in case certain public network IP address is fixed and distributes to certain private network terminal, before the multi-media communication of this terminal finished, other-end all can not use this public network IP address.This just makes can cause the waste of public network IP address resources under a lot of situation of terminal in private network (or other H.323 node).
In addition, at NAPT (Net Address Port Translation: the network address port conversion) under the mode, still do not have at present to solve the technical scheme of being refused to make the multi-media communication failure problem because of the UDP bag by NAT device.
Summary of the invention
At the shortcoming of prior art, the invention provides a kind of transmission calling method that is applied in the multi-media communication, comprise following step:
(Net Address Translation: network address translation) equipment judges whether the private network terminal calls out the public network terminal by another name for A, NAT, if, NAT (Net AddressTranslation: network address translation) GK (the Gate Keeper: gatekeeper) for described private network terminal register of equipment to the public network then, call out then, otherwise described private network terminal directly begins to call out described public network terminal;
B, the calling private network terminal and the public network terminal room that pass through in the steps A are set up calling.
Registration described in the steps A comprises the steps:
(Net Address Translation: network address translation) equipment sends the register requirement signaling to NAT for A1, private network terminal;
(Net Address Translation: network address translation) equipment all is modified as the RAS address in the register requirement signaling (RasAddress:Ras address) and private network call signaling address to the visible public network call signaling of public network address, and amended register requirement signaling is sent to GK (Gate Keeper: the gatekeeper) on the public network for A2, NAT;
A3, GK (Gate Keeper: the gatekeeper) send registration and allow signaling to NAT device;
(Net Address Translation: network address translation) equipment will be registered the private network call signaling address that the call signaling address that allows in the signaling is modified as terminal again for A4, NAT, and allow signaling to send to the private network terminal the amended registration, so far, the private network terminal is finished registration.
Described step B comprises the steps:
B1, public network terminal are to GK (Gate Keeper: the gatekeeper) send out calling and allow demand signalling, request call private network terminal, because the private network terminal is registered, so GK (Gate Keeper: the gatekeeper) by calling out the private network call signaling address that allows confirmation signaling to tell public network terminal private network terminal;
B2, public network terminal are initiated TCP (TransferControl Protocol: transmission control protocol) connect to the call signaling address of private network terminal, (Net AddressTranslation: network address translation) equipment is given to the private network terminal with the private network call signaling address of private network terminal, at private network terminal and public network terminal room foundation TCP (TransferControl Protocol: transmission control protocol) be connected H.225 by NAT;
B3, private network terminal are passed through TCP (Transfer Control Protocol: transmission control protocol) connect to public network terminal transmission connection signaling, and notify its private network call signaling address H.225; (Net Address Translation: network address translation) equipment is revised the H.245 address after former H.245 address is conversion to NAT when transmitting the connection signaling, and notes this mapping relations;
B4, public network terminal are after receiving the connection signaling, initiating TCP to private network call signaling address connects, (Net Address Translation: network address translation) equipment is given to the private network terminal with the former H.245 address of private network terminal, and the TCP that sets up H.245 at private network terminal and public network terminal room is connected by NAT;
(Net Address Translation: network address translation) equipment is in private network terminal and mutual, the principal and subordinate's decision and the irrelevant H.245 signaling in address of transmittability pellucidly of public network terminal room for B5, NAT;
(Net Address Translation: network address translation) equipment is set up the logical channel signaling in the public network terminal in forwarding for B6, NAT, (Real Time Protocol: RTP) the bag receiver address is former RTP (Real TimeProtocol: RTP) wrap receiver address, and note this mapping relations to revise RTP in the open logical channel signaling;
B7, public network terminal receive that the RTP bag receiver address after the conversion of private network terminal sends RTP (Real Time Protocol: stream RTP) after the open logical channel signaling, (Net Address Translation: (Real Time Protocol: RTP) the bag receiver address is to the private network terminal, and so far access success is set up to transmit former RTP according to the mapping relations among the step B6 after network address translation) equipment is received for NAT.
Since adopted above technical scheme, so the transmission calling method that is applied in the multi-media communication among the present invention has following advantage:
1, because in whole process, the modification of signaling is finished in NAT device, thus can with respect to user transparent finish call setup.
2, NAT device is by being fixed to the private network terminal the different UDP/TCP ports of same public network IP address, and correctly transmits RAS signaling that the public network side sends and signaling H.225.
3, can solve the problem of multi-media communication agreement, save public network IP address resources in multiplexing mode simultaneously through Communications failure behind the NAT device.
Description of drawings
Fig. 1 is system group network figure of the present invention.
Fig. 2 is this the transmission calling method flow chart in the multi-media communication of being applied to
Fig. 3 is the flow chart that the private network terminal in the inventive method is registered to GK of public network according.
Fig. 4 sets up call flow diagram for private network terminal and public network terminal room in the inventive method.
Embodiment
Be that example elaborates to the present invention with most widely used H.323 agreement in the multi-media communication agreement below.
Please refer to Fig. 1, be system group network figure of the present invention, comprise: the terminal PC of public network terminal T3, the GK that is used for public network terminal T3 is managed, the private network terminal T1, the T2 that meet agreement H.323, private network and be used to connect the NAT device of private network and public network, native system couples together public network and private network by NAT device, and then between public network terminal T3 and private network terminal T1, T2, set up communication channel, in the public network terminal during to the private network terminal call, NAT device guarantees call establishment by the modification to signaling.
Following constipation closes Fig. 2, Fig. 3 and Fig. 4 elaborates to the transmission calling method of inventing that is applied in the multi-media communication:
Please refer to Fig. 2, the transmission calling method that is applied in the multi-media communication of the present invention comprises the steps:
A, judge whether private network terminal T1 or T2 call out by another name, if, GK (the Gate Keeper: the gatekeeper) register, otherwise directly begin to call out to the public network then;
B, set up at private network terminal and public network terminal room and to call out.
Wherein, the registration in the step 1 comprises the steps (is example with private network terminal T1) again, sees Fig. 3:
A1, private network terminal T1 send RRQ (Register Request: register requirement) signaling to NAT device;
A2, NAT device are with (RasAddress:Ras address) address of the RAS in the RRQ signaling and private network call signaling (Call Signal Address) address (ip_a, 1720) all be modified as the visible public network call signaling address (ip_A of public network, port_1), and with amended RRQ signaling send to GK on the public network; Simultaneously on amended address, monitor to (from the public network to the private network) RAS and call signaling Q.931, allow into to RAS and Q.931 call signaling pass through NAT smoothly, the final private network terminal T1 that arrives, also will set up the H.225/Q.931 address mapping relation of reflection private network call signaling address and public network call signaling address relationship in addition, specific as follows:
| NAT revises call signaling address, back | Former call signaling address | ||
| ip_A | ?port_1 | ?ip_a | ?1720 |
| ip_A | ?port_2 | ?ip_b | ?1720 |
As seen this moment private network terminal T1 and all multiplexing public network IP address IP_A of T2, but the two used UDP/TCP port is different, wherein, private network terminal T1 is: port_1, private network terminal T2 is; Port_2.
A3, GK send RCF (Register Confirm: registration allows) signaling to NAT device;
(ip_A port_1) is modified as the private network call signaling address (ip_a, 1720) of terminal again, and the RCF signaling sends to private network terminal T1 after will revising, and so far, private network terminal T1 finishes registration with the call signaling address among the RCF for A4, NAT device.
After the private network terminal T1 that calls out with another name finishes registration, just carry out step B, promptly between public network terminal T3 and private network terminal T1, to set up and call out, its concrete steps are as follows, see Fig. 4:
B1, public network terminal T3 send out the ARQ signaling to GK, and request call private network terminal T1 is owing to T1 registers, so GK tells the private network call signaling address (ip_a, 1720) of public network terminal T3 private network terminal T1 by the ACF signaling;
B2, public network terminal T3 are to the private network call signaling address (ip_a of private network terminal T1,1720) initiate TCP (Transfer Control Protocol: transmission control protocol) connect, the H.225/Q.931 address mapping table that utilization has been set up in registration process, NAT device is with the private network call signaling address (ip_a of private network terminal T1,1720) be given to private network terminal T1, and then the TCP that sets up H.225 is connected between private network terminal T1 and public network terminal T3;
B3, the private network terminal T1 TCP by H.225 connects to public network terminal T3 and sends the connect signaling, and notify its private network terminal T1 former H.245 address (ip_a, port_245); NAT device is revised former H.245 address when transmitting the connect signaling (ip_a, port_245) (ip_A port_3), and notes this mapping relations for the H.245 address after the conversion.H.245 address mapping relation is as follows for this:
| H.245 address after the conversion | Former H.245 address | ||
| ip_A | ?port_3 | ip_a | ?port_h245 |
B4, public network terminal T3 are after receiving the connect signaling, to former H.245 address (ip_a, port_245) TCP that initiates H.245 connects, utilize the H.245 address mapping relation of setting up among the step B3, NAT device is with the former H.245 address (ip_a of private network terminal T1, port_245) be given to private network terminal T1, the TCP that sets up H.245 between private network terminal T1 and public network terminal T2 is connected;
B5, NAT device be mutual, principal and subordinate's decision of transmittability etc. and the irrelevant H.245 signaling (H.245message) in address pellucidly between private network terminal T1 and public network terminal T3;
B6, NAT device are being transmitted OLC Ack signaling in the public network terminal T3, and modification OLC Ack Central Plains RTP bag receiver address (ip_a, port_rtp_a) (ip_A port_3), and notes this mapping relations for the RTP after the conversion wraps receiver address; These RTP bag receiver address mapping relations are as follows:
| RTP bag receiver address after the conversion | Former RTP bag receiver address | ||
| ip_A | ?port_3 | ip_a | ?port_rtp_a |
After B7, public network terminal T3 receive OLC Ack, RTP bag receiver address (ip_A after private network terminal T1 conversion, port_3) send rtp streaming (Rtp stream), NAT device receives that the back is according to the RTP receiver address mapping relations among the step B6, rtp streaming is forwarded to the former RTP bag of private network terminal receiver address (ip_a, port_rtp_a), so far access success is set up.
Since adopted above technical scheme, so the inventive method has following advantage:
1, because in whole process, the modification of signaling is finished in NAT device, thus can with respect to user transparent finish call setup.
2, NAT device is by being fixed to the private network terminal the different UDP/TCP ports of same public network IP address, and correctly transmits RAS signaling that the public network side sends and signaling H.225.
3, can solve the multi-media communication agreement through the problem of Communications failure behind the NAT device, save public network IP address resources in multiplexing mode simultaneously.
In addition, for other multi-media protocols, the calling procedure of public network terminal and the private network terminal room also method with above-mentioned is similar, is that concrete signaling title and field name had any different, and just no longer elaborates at this.
Claims (10)
1, a kind of transmission calling method that is applied in the multi-media communication is characterized in that, this method comprises the steps:
(Net Address Translation: network address translation) equipment judges whether the private network terminal calls out the public network terminal by another name for A, NAT, if, NAT (Net AddressTranslation: network address translation) GK (the Gate Keeper: gatekeeper) for described private network terminal register of equipment to the public network then, call out then, otherwise described private network terminal directly begins to call out described public network terminal;
B, the calling private network terminal and the public network terminal room that pass through in the steps A are set up calling.
2, the transmission calling method that is applied in the multi-media communication as claimed in claim 1 is characterized in that, the registration described in the steps A comprises the steps:
(Net Address Translation: network address translation) equipment sends the register requirement signaling to NAT for A1, private network terminal;
(Net Address Translation: network address translation) equipment all is modified as the RAS address in the register requirement signaling (RasAddress:Ras address) and private network call signaling address to the visible public network call signaling of public network address, and amended register requirement signaling is sent to GK (Gate Keeper: the gatekeeper) on the public network for A2, NAT;
A3, GK (Gate Keeper: the gatekeeper) send registration and allow signaling to NAT device;
(Net Address Translation: network address translation) equipment will be registered the private network call signaling address that the call signaling address that allows in the signaling is modified as terminal again for A4, NAT, and allow signaling to send to the private network terminal the amended registration, so far, the private network terminal is finished registration.
3, the transmission calling method that is applied in the multi-media communication as claimed in claim 1 or 2 is characterized in that, described step B comprises the steps:
B1, public network terminal are to GK (Gate Keeper: the gatekeeper) send out calling and allow demand signalling, request call private network terminal, because the private network terminal is registered, so GK (Gate Keeper: the gatekeeper) by calling out the private network call signaling address that allows confirmation signaling to tell public network terminal private network terminal;
B2, public network terminal are initiated TCP (TransferControl Protocol: transmission control protocol) connect to the call signaling address of private network terminal, (Net AddressTranslation: network address translation) equipment is given to the private network terminal with the private network call signaling address of private network terminal, at private network terminal and public network terminal room foundation TCP (TransferControl Protocol: transmission control protocol) be connected H.225 by NAT;
B3, private network terminal are passed through TCP (Transfer Control Protocol: transmission control protocol) connect to public network terminal transmission connection signaling, and notify its private network call signaling address H.225; (Net Address Translation: network address translation) equipment is revised the H.245 address after former H.245 address is conversion to NAT when transmitting the connection signaling, and notes this mapping relations;
B4, public network terminal are after receiving the connection signaling, initiating TCP to private network call signaling address connects, (Net Address Translation: network address translation) equipment is given to the private network terminal with the former H.245 address of private network terminal, and the TCP that sets up H.245 at private network terminal and public network terminal room is connected by NAT;
(Net Address Translation: network address translation) equipment is in private network terminal and mutual, the principal and subordinate's decision and the irrelevant H.245 signaling in address of transmittability pellucidly of public network terminal room for B5, NAT;
(Net Address Translation: network address translation) equipment is set up the logical channel signaling in the public network terminal in forwarding for B6, NAT, (Real Time Protocol: RTP) the bag receiver address is former RTP (Real TimeProtocol: RTP) wrap receiver address, and note this mapping relations to revise RTP in the open logical channel signaling;
B7, public network terminal receive that the RTP bag receiver address after the conversion of private network terminal sends RTP (Real Time Protocol: stream RTP) after the open logical channel signaling, (Net Address Translation: (Real Time Protocol: RTP) the bag receiver address is to the private network terminal, and so far access success is set up to transmit former RTP according to the mapping relations among the step B6 after network address translation) equipment is received for NAT.
4, the transmission calling method that is applied in the multi-media communication as claimed in claim 2, it is characterized in that, described steps A 2 all is being modified as the RAS address in the register requirement signaling (RasAddress:Ras address) and private network call signaling address to public network behind the visible public network call signaling address, also monitors to RAS (RasAddress:Ras address) and 1 call signaling Q.93.
5, the transmission calling method that is applied in the multi-media communication as claimed in claim 2, it is characterized in that, RAS address (RasAddress:Ras address) and the private network call signaling address of described steps A 2 in register requirement signaling just all is modified as public network behind the visible public network call signaling address, also can set up the mapping relations of a private network call signaling address and public network call signaling address, specifically in agreement H.323, be H.225/Q.931 address mapping relation.
6, the transmission calling method that is applied in the multi-media communication as claimed in claim 5, it is characterized in that, (Net Address Translation: network address translation) equipment is given to the private network terminal with the private network call signaling address of private network terminal to NAT described in the step B2, utilize mapping relations foundation TCP (the Transfer Control Protocol: transmission control protocol) be connected H.225 of private network call signaling address at private network terminal and public network terminal room, in agreement H.323, promptly be to have utilized H.225/Q.931 address mapping relation specifically.
7, the transmission calling method that is applied in the multi-media communication as claimed in claim 3, it is characterized in that, (Net Address Translation: network address translation) equipment is given to the private network terminal with the former H.245 address of private network terminal to the described NAT of step B4, sets up H.245 TCP (Transfer Control Protocol: transmission control protocol) be connected and utilized the mapping relations described in the step B3 at private network terminal and public network terminal room.
8, the transmission calling method that is applied in the multi-media communication as claimed in claim 7 is characterized in that, described mapping relations are H.245 address mapping relation in agreement H.323.
9, the transmission calling method that is applied in the multi-media communication as claimed in claim 6 is characterized in that, for private network terminal T1 and T2, described H.225/Q.931 address mapping relation is specially:
NAT revises call signaling address, back Former call signaling address
ip_A ?port_1 ?ip_a ?1720
ip_A ?port_2 ?ip_b ?1720
10, the transmission calling method that is applied in the multi-media communication as claimed in claim 8 is characterized in that, for private network terminal T1, H.245 address mapping relation is specially:
H.245 address after the conversion Former H.245 address
ip_A ?port_3 ?ip_a ?port_h245
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02124648 CN1208932C (en) | 2002-06-19 | 2002-06-19 | Transmission calling method for multimedia communication |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 02124648 CN1208932C (en) | 2002-06-19 | 2002-06-19 | Transmission calling method for multimedia communication |
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| CN1464721A CN1464721A (en) | 2003-12-31 |
| CN1208932C true CN1208932C (en) | 2005-06-29 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 02124648 Expired - Lifetime CN1208932C (en) | 2002-06-19 | 2002-06-19 | Transmission calling method for multimedia communication |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100525202C (en) * | 2004-05-28 | 2009-08-05 | 中兴通讯股份有限公司 | A method of registration for the private network terminal to the gatekeeper based on the H.323 protocol |
| CN1299476C (en) * | 2004-05-28 | 2007-02-07 | 中兴通讯股份有限公司 | Method for H.323 agent server to register on gatekeeper from terminals after being agent of NAT |
| JP4377786B2 (en) * | 2004-09-22 | 2009-12-02 | パナソニック株式会社 | ELECTRIC DEVICE, SERVER DEVICE, PORTABLE TERMINAL, COMMUNICATION SYSTEM, COMMUNICATION METHOD, AND PROGRAM |
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