CN101902506A - SIP call-based traversal network address translation method and system - Google Patents
SIP call-based traversal network address translation method and system Download PDFInfo
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Abstract
The invention discloses an SIP call-based traversal network address translation method and an SIP call-based traversal network address translation. The method comprises the following steps that: a private network user performs the SIP call, and signalling proxy equipment, to which the private network user belongs, performs application layer SIP protocol analysis of an SIP message, judges whether media channel information of the application layer SIP protocol of the SIP message is needed to be modified or not according to the analyzed result, if so, modifies the media channel information into media addresses and ports which are distributed by the network and perform communication with opposite terminal network elements on media proxy equipment, and sends the modified message; and the private network user establishes media connections with an opposite terminal user through the media addresses and the ports. Through the method and the system, the SIP call-based NAT traversal is realized, without upgrading terminals and NAT equipment and increasing the loads of the NAT equipment.
Description
Technical field
The present invention relates to the communications field, relate in particular to a kind of method and system of SIP call-based traversal network address conversion equipment.
Background technology
The reason such as in short supply and safety owing to the IP address resource, a large amount of enterprise network and residence network adopt the network address translation (nat) equipment of private IP address by outlet are inserted public network.NAT device is in fact only made amendment to UDP or TCP heading domain addresses information, and the source address of internal network is become the outside network address of NAT device oneself, and the content of application layer is not made an amendment.The content of this application layer comprises session initiation protocol (SIP) message, and the NAT of SIP signaling passed through when NAT device was used for finishing session.Because Session Initiation Protocol belongs to application layer protocol, sip message carries control channel and media channel information (IP address and port), support the network element of Session Initiation Protocol to use this information to carry out the mutual of signaling and medium aspect, but the address that Session Initiation Protocol carries is a private net address, when calling out a side at least for private user, as not revising the address information that Session Initiation Protocol itself carries, then can't utilize control channel and media channel information and calling opposite end mutual, calling can not be set up.At present SIP is called out the method for carrying out network address translation, the solution of industry has following several:
1, ALG (ALG, Application Layer Gateway) mode
NAT device is also resolved the Session Initiation Protocol message of application layer except revising UDP or TCP heading domain addresses, revises the address information that sip message itself carries.Use this mode to support the NAT device of Session Initiation Protocol to need upgrading, and because all bags are monitored and resolved, the load of NAT device is very big.
2, middlebox communications (MIDCOM, Middlebox Communication) mode
The basic framework of MIDCOM mode is to adopt believable third party middle-agent (MIDCOM Agent) that middleboxes (Middlebox) is controlled, middleboxes receives sip message, revise UDP or TCP heading domain addresses, and between network and MIDCOM Agent, carry out transparent forwarding using layer data.The identification of application layer protocol be can't help middleboxes and is finished, but is finished by the MIDCOM Agent of outside, by the Session Initiation Protocol message that MIDCOM Agent resolves application layer, revises the address information that sip message itself carries.Therefore Session Initiation Protocol is transparent to middleboxes, only needs to support that the MIDCOM agreement gets final product.Use the NAT device of this mode to need upgrading, to support the MIDCOM agreement.
3, the UDP simple traversal mode of NAT (STUN, Simple Traversal of UDP over NATS)
Private network accesses terminal and obtains its address correspondence in advance in the external address of outlet on the NAT by certain mechanism, directly the address of the sip message of application layer is extended this as this external address on the outlet NAT, rather than the private IP address of private net terminal.The content of message application layer need not to revise through NAT the time like this, only needs to get final product by the IP address of common NAT flow process conversion heading, and the address in application layer load this moment is consistent with UDP or TCP heading domain addresses.Simple Traversal of UDP Through Network Address Translators solves the problem of application layer address conversion based on this thinking.This mode needs upgrading terminals to support the STUN client functionality, and this mode is not supported passing through of symmetrical NAT type simultaneously.
4, by trunking scheme passing through NAT (TURN, Traversal Using Relay NAT)
Thinking and STUN mode that the TURN mode solves the network address translation crossing problem that SIP calls out are similar, private network accesses terminal and obtains the public network address of its privately owned address correspondence in advance by certain mechanism (address that the STUN mode obtains is the address of outlet on the NAT device, the address that the TURN mode obtains is the address on the TURNServer), then the address in the application layer load of message is extended this as this public network address.This mode also needs upgrading terminals, to support the TURN client functionality, need provide the TURN server apparatus simultaneously, and all messages must pass through the TURN server forwards, has increased the delay of bag and the possibility of packet loss.
More than several solutions owing to needs are resolved Session Initiation Protocol, reasons such as upgrading NAT device or terminal, in performance, extensibility and aspect the existing network transformation, all have certain defective, therefore need a kind of performance more excellent and need not the method for upgrading terminals and NAT device, solve the NAT crossing problem of Session Initiation Protocol.
Summary of the invention
The technical problem to be solved in the present invention provides the method for another kind of SIP call-based traversal network address conversion, need not upgrading terminals and NAT device.
In order to address the above problem, the invention provides the method for a kind of session initiation protocol (SIP) call-based traversal network address conversion, comprising:
Private user carries out SIP to be called out, and the Xin Lingdaili equipment of this private user ownership carries out the application layer Session Initiation Protocol to this sip message and resolves;
The result that this Xin Lingdaili equipment obtains according to parsing, judge whether to need to revise the media channel information of this sip message application layer Session Initiation Protocol, be, then media channel information is revised as the media address and the port that communicate with the opposite end network element on the media agent device of network allocation, and sends amended message;
This private user by described media address and port with end subscriber set up medium be connected.
Further, the result that this Xin Lingdaili equipment obtains according to parsing as judging the media channel information that need not revise this sip message application layer Session Initiation Protocol, then directly transmits this sip message;
The Xin Lingdaili devices communicating that this private user terminal also belongs to by network address translation (nat) equipment and this private user, this NAT device carries out network layer address and transport layer port conversion to the sip message of this calling, this private user also utilize this NAT device by described media address and port with end subscriber set up medium be connected.
Further, the media channel information of this sip message application layer Session Initiation Protocol of this Xin Lingdaili apparatus modifications comprises:
As this sip message is request message, then the media channel information of this sip message application layer Session Initiation Protocol is revised as the network address and the port that media agent device and opposite end network element communicate, while increased the address and the port of this Xin Lingdaili equipment before the first row information of the original control channel information Via header field of this message, also in the row of this increase, add medium additional parameter, the network address and port that this media agent device that this medium additional parameter is a network allocation and opposite end network element communicate;
As this sip message is response message, then replace the media address and the port of the media channel information that this response message carries, and delete first row of this Via header field with media address and port in the medium additional parameter of the first row information of Via header field in this messages application layer control channel information.
Further, the result that this Xin Lingdaili equipment obtains according to parsing judges whether need to revise the media channel information of this sip message application layer Session Initiation Protocol in the following manner:
This Xin Lingdaili equipment is inconsistent as the address and the port of the control channel information Via header field first row information of judging this news network layer source address and transport layer source port and application layer Session Initiation Protocol, or the called subscriber belongs to the private user of this Xin Lingdaili equipment and media channel information that this sip message carries does not change, and then needs to revise the media channel information of this sip message application layer Session Initiation Protocol.
Further, this Xin Lingdaili equipment judges in the following way whether the called subscriber is the private user that belongs to this Xin Lingdaili equipment:
Terminal is when this Xin Lingdaili facility registration, this Xin Lingdaili equipment is resolved the registration sip message of this terminal, address as the control channel information of the network layer source address of this message and application layer Session Initiation Protocol is inconsistent, then preserves Subscriber Number, network layer source IP address and the port of this terminal;
This Xin Lingdaili equipment is resolved the message that the user calls out, and obtains the called number in this message related to calls, checks whether this locality preserves this number, if any, then this called subscriber is the private user that belongs to this Xin Lingdaili equipment.
Further, this Xin Lingdaili equipment carries out the application layer Session Initiation Protocol to this sip message resolves, and judges in the following manner whether the media channel information that this sip message carries changes:
This Xin Lingdaili equipment is checked the type of this sip message earlier, as this sip message is request message, judge again in the first row information of Via header field in this request message application layer control channel information and whether comprise the medium additional parameter, in this way, then this request message media channel information of carrying changes, as not, then this request message media channel information of carrying does not change;
As this sip message is response message, then check in the information that Via header field first is gone in this response message application layer control channel information and whether comprise the medium additional parameter, in this way, then this response message media channel information of carrying does not change, as not, then this response message media channel information of carrying changes.
Further, this Xin Lingdaili equipment is inconsistent as the address and the port of the control channel information Via header field first row information of judging this sip message network layer source address and transport layer source port and application layer Session Initiation Protocol, also behind the Contact header field original information of this control channel information, increase this network layer address and transport layer port additional parameter as Contact header field, be used to represent direct mode by this address and this private user of port access, as this sip message is request message, also after the first row information of original control channel information Via header field, increase this transport layer port, be used for return response message as the port additional parameter.
In order to address this problem, the present invention also provides a kind of system of SIP call-based traversal network address conversion, it is characterized in that comprising: the terminal of private user, Xin Lingdaili equipment and media agent device, wherein:
The terminal of this private user is used for Xin Lingdaili equipment by its ownership and carries out SIP and call out, the media address that provides by this Xin Lingdaili equipment and port with end subscriber set up medium be connected;
This media agent device is used to provide the network side media channel, comprises media address and port;
This Xin Lingdaili equipment, be used to the sip message of receiving that this terminal is called out, this message is carried out the application layer Session Initiation Protocol resolves, the result who obtains according to parsing, judge whether to need to revise the media channel information of this sip message application layer Session Initiation Protocol, be that then the media channel information with this messages application layer Session Initiation Protocol is revised as media address and the port that communicates with the opposite end network element on this media agent device, and sends amended message.
Further, this system also comprises network address translation (nat) equipment, between this private user terminal and this Xin Lingdaili equipment, be used to transmit and pass through the mutual sip message of this Xin Lingdaili equipment between this terminal and the opposite end, and this sip message is carried out network layer address and transport layer port conversion;
The terminal of this private user also is used for carrying out SIP by this NAT device and calls out, and utilizes media address that this NAT device provides by this Xin Lingdaili equipment and port and end subscriber is set up medium is connected;
This Xin Lingdaili equipment also is used for the result that obtains according to parsing, as judging the media channel information that need not revise this sip message application layer Session Initiation Protocol, then directly transmits this sip message.
Further, this Xin Lingdaili equipment, also be used to receive sip message, this sip message is resolved, obtaining this sip message as parsing is request message, the media channel information of this sip message application layer Session Initiation Protocol is revised as the network address and the port that media agent device and opposite end network element communicate, after increasing the address and port of this Xin Lingdaili equipment before the first row information of the original control channel information Via header field of this message, also in the row of this increase, add medium additional parameter, the network address and port that this media agent device that this medium additional parameter is a network allocation and opposite end network element communicate; Obtaining this sip message as parsing is response message, then replace the media address and the port of the media channel information that this response message carries, and delete first row of this Via header field with the media address of the medium additional parameter of Via header field in this response message application layer control channel information first row information and port.
Further, this Xin Lingdaili equipment judges whether to need to revise the media channel information of this sip message application layer Session Initiation Protocol according to the result who arrives who resolves, and comprising:
This Xin Lingdaili equipment, the address and the port of control channel information Via header field first row information of judging this news network layer source address and transport layer source port and application layer Session Initiation Protocol is inconsistent, or the called subscriber belongs to the private user of this Xin Lingdaili equipment and media channel information that this sip message carries does not change, and then needs to revise the media channel information of this sip message application layer Session Initiation Protocol.
Further, this Xin Lingdaili equipment, the register requirement that also is used for receiving terminal, registration sip message to this terminal is resolved, inspection also judges whether the network layer source address of this message is consistent with the address of the control channel information of application layer Session Initiation Protocol, as inconsistent, then preserve Subscriber Number, network layer source IP address and the port of this terminal; The message that the user calls out is resolved, obtain the called number in this message related to calls, check whether this locality preserves this number, if any, think that then this called subscriber is the private user that belongs to this Xin Lingdaili equipment.
Further, this Xin Lingdaili equipment, also be used to receive the sip message of this customer call, checking the type of this sip message, is request message as this sip message, judges in the first row information of Via header field in this request message application layer control channel information whether comprise the medium additional parameter again, in this way, think that then the media channel information that this request message carries changes, as not, then this request message media channel information of carrying does not change; As this sip message is response message, then check in the first row information of Via header field in this response message application layer control channel information and whether comprise the medium additional parameter, in this way, think that then the media channel information that this response message carries does not change, as not, then this response message media channel information of carrying changes.
Further, this Xin Lingdaili equipment, the address and the port of the control channel information Via header field first row information that also is used to judge this sip message network layer source address and transport layer source port and application layer Session Initiation Protocol is inconsistent, behind the Contact header field original information of this control channel information, increase this network layer address and transport layer port additional parameter as Contact header field, be used to represent direct mode by this address and this private user of port access, as this sip message is request message, also after the first row information of original control channel information Via header field, increase this transport layer port, be used for return response message as the port additional parameter.
Further, the function of this Xin Lingdaili equipment can be realized that the function of this media agent device can be realized by the media resource apparatus of IP multimedia system by the Proxy Call Session Control Function equipment of IP multimedia system (IMS).
The present invention carries out the application layer Session Initiation Protocol by Xin Lingdaili equipment to sip message and resolves, revising media channel information is the media address and the port of media agent device, this media channel information is sent to relevant terminal, make terminal utilize this media channel information to communicate by NAT device, realized that the NAT that SIP calls out passes through, need not upgrading terminals and NAT device, also can not increase the burden of NAT device.
The function of this Xin Lingdaili equipment of the present invention can be realized that the function of this media agent device can be realized by the media resource apparatus MRFP of IMS network, do not need to increase extra equipment by the Proxy Call Session Control Function equipment P-CSCF of IMS network.
Description of drawings
Fig. 1 is embodiment one private user registration sip signaling process figure;
Fig. 2 is the schematic network structure that embodiment two private users are called out public network user;
Fig. 3 is the SIP signaling process figure that embodiment two private users are called out public network user;
Fig. 4 is the media channel information schematic diagram that embodiment two private users are called out public network user;
Fig. 5 is the schematic network structure that embodiment three public network users are called out private user;
Fig. 6 is the SIP signaling process figure that embodiment three public network users are called out private user;
Fig. 7 is the media channel information schematic diagram that embodiment three public network users are called out private user;
Fig. 8 is the schematic network structure that embodiment four private users are called out private user;
Fig. 9 is the SIP signaling process figure that embodiment four private users are called out private user;
Figure 10 is the media channel information schematic diagram that embodiment four private users are called out private user.
Embodiment
Also the present invention is described in further detail in conjunction with the accompanying drawings below by specific embodiment.
Increase the equipment of supporting Xin Lingdaili (PROXY) function in the embodiment of the invention, application layer SIP signaling is revised and transmitted; Transmit media data by media agent device.Xin Lingdaili equipment (abbreviation network agent) is used for safeguarding the media information (media channel information that is used to carry) of sip message, also supports expansion Session Initiation Protocol parameter, and this expansion Session Initiation Protocol parameter comprises the routing iinformation of Session Initiation Protocol.Signaling between the calling and called terminal is mutual by NAT, caller Xin Lingdaili and called Xin Lingdaili; Voice between caller and the terminal called and business datum are handled (MRFP) device transmission by NAT and media resource.
This Xin Lingdaili equipment can be independent equipment, also can increase this Xin Lingdaili function on existing equipment.For IP Multimedia System (IMS) network, this function can realize that the Media proxy function can be realized by media resource processing arrangements (MRFP) by agent call session control equipment (P-CSCF).
Network layer source address and transport layer source port when Xin Lingdaili equipment is preserved the private net terminal registration, and with this termination number binding.When private user is called out by the Xin Lingdaili equipment of NAT device and this private user ownership, this NAT device carries out network layer address and transport layer port conversion to message related to calls, this Xin Lingdaili equipment is resolved using layer protocol, the result who obtains according to parsing, judge whether to need to revise the media channel information of this sip message application layer Session Initiation Protocol, be, then media channel information is revised as the media address and the port that communicate with the opposite end network element on the media agent device of network allocation, as this message related to calls is the request message that NAT device is transmitted, then the address of this Xin Lingdaili of increase equipment and port and this media address and port increase the transport layer port of this message as the port additional parameter as the medium additional parameter after the former Via header field first row information before the original control channel information Via header field first row information of this message; INVITE request message and 200 response messages for NAT device is transmitted also increase this news network layer IP address and the port additional parameter as the Contact territory after Contact header field information; Then amended message is sent to corresponding network element.The processing that this method is called out public network user, public network user calling private user and private user calling private user to private user registration, private user is described in detail respectively below.
The registration of embodiment one private user
Terminal is when Xin Lingdaili carries out the SIP registration in the present embodiment, Xin Lingdaili is received the registration sip message of this terminal, as judge in this registration sip message that control channel (Via header field) address is inconsistent in the network layer source IP address and application layer sip message, then preserve network layer source IP address and transport layer source port, and bind with this termination number.As shown in Figure 1, the address of this terminal is 10.1.1.2, and the public network address of NAT is 20.0.0.1, and the address of this Xin Lingdaili is 20.0.0.3, and the processing of this terminal initiation SIP registration may further comprise the steps in the present embodiment:
Step S101: terminal is initiated the SIP registration, sends registration (Register) sip message to NAT, carries the control channel information of this terminal;
The network layer source IP address of this registration message is that terminal private net address, transport layer source port are the terminal signaling port; Network layer purpose IP address is that address, the transport layer destination interface of Xin Lingdaili is the port of Xin Lingdaili.
The control channel information that this registration message application layer is carried is:
Via:SIP/2.0/UDP 10.1.1.2 // terminal address is private net address, is used to receive registration reply message.
Contact:＜sip:10.1.1.2〉// terminal address, be private net address, be used to receive SIP request or updating message.
The registration message that step S102:NAT receiving terminal sends is revised network layer address and transmit port in this message, sends to Xin Lingdaili;
NAT is revised as the public network address 20.0.0.1 of NAT self with network layer source IP address 10.1.1.2 in this message, and the transport layer source port is revised as the port of NAT self, and other remains unchanged, and amended registration sip message is sent to Xin Lingdaili.
Step S103: Xin Lingdaili receives the registration message that NAT sends, finish location registration process after, return 200 response messages;
This Xin Lingdaili is received the registration message that NAT sends, judge whether the network layer source IP address is consistent with the network address of application layer SIP control channel (Via header field) in this message, as denying, then preserve network layer source IP address 20.0.0.1 and transport layer source port in this message, and bind with this termination number.
Xin Lingdaili returns 200 response messages to this NAT, and the network layer purpose IP address of this 200 response message is that address 20.0.0.1, the transport layer destination interface of NAT is the port of NAT; The network layer source IP address is that address 20.0.0.3, the transport layer source port of this Xin Lingdaili is the port of Xin Lingdaili.
Step S104:NAT receives 200 response messages that Xin Lingdaili sends, and revises network layer address and transmit port in this message, sends to terminal.
NAT is with network layer purpose IP is revised as terminal private net address 10.1.1.2 in the address in this 200 message, the transport layer destination interface is a terminal prot, and other remains unchanged, and sends 200 response messages to terminal.
Embodiment two private users are called out public network user
Network as shown in Figure 2, private user is called out public network user, private user carries out address transition by NAT, utilize the Xin Lingdaili of caller to revise application layer is carried in the message of this calling control channel and media channel information, by called Xin Lingdaili directly transmit and this public network user between message.When this NAT carries out address transition, network layer address and port are revised as public network address and the port of NAT respectively.The Xin Lingdaili of caller is received the message that NAT sends, keep original control channel (Contact and Via header field) information, and add this NAT net element information on this basis, revising media channel information simultaneously is address and the port of Media proxy network element (media resource apparatus MRFP).The IP address and the port of each network element is as shown in table 1 among Fig. 2:
| Calling terminal | NAT | The caller Xin Lingdaili | Media relays equipment | Called Xin Lingdaili | Terminal called | |
| The IP address | 10.1.1.1 | 20.0.0.1 | 20.0.0.2 | 20.0.0.9 | 20.0.0.3 | 20.0.0.100 |
| |
49170 | 9988 | 4000 | 50100 |
Table 1
The processing method that the Session Initiation Protocol NAT of this calling passes through may further comprise the steps as shown in Figure 3:
Step S301: calling terminal makes a call, and sends initial INVITE message to NAT;
The network layer source IP address of this INVITE and port are calling terminal private net address and signaling port 10.1.1.1:49170; Network layer purpose IP address is that caller Xin Lingdaili address 20.0.0.2, transport layer destination interface are caller Xin Lingdaili port.
The control channel information that application layer is carried in this INVITE is:
Via:SIP/2.0/UDP 10.1.1.1 // calling terminal address is private net address, is used to receive sip response message.
Contact:＜sip:10.1.1.1〉// the calling terminal address, be private net address, be used to receive SIP request or updating message.
The media channel information that application layer is carried in this INVITE is:
C=IN IP4 10.1.1.1 // calling terminal media channel IP address
The media channel port of m=audio 49170 RTP/AVP 0 // calling terminal
Step S302:NAT receives the initial INVITE message that calling terminal sends, and revises network layer address and port in this message, amended message is sent to the Xin Lingdaili of caller;
NAT is self public network address and port 20.0.0.1:9988 with network layer source IP address and port modifications in this message, and out of Memory remains unchanged, and as control channel and media channel information, then amended message is sent to the caller Xin Lingdaili.
Step S303: the caller Xin Lingdaili is received the INVITE that NAT sends, and resolves the content of this messages application layer sip message, and makes amendment;
The caller Xin Lingdaili judges that the address and the port of control channel information Via header field first row information of this sip message network layer source address and transport layer source port and application layer Session Initiation Protocol is inconsistent, and this sip message is a request message, except that the control channel information of revising this messages application layer Session Initiation Protocol according to prior art increased the address and port of this Xin Lingdaili equipment before the first row information of the original control channel information Via header field of this message, also in the row of this increase, add medium additional parameter, the network address and port that this media agent device that this medium additional parameter is a network allocation and opposite end network element communicate; Behind the Contact header field original information of this control channel information, increase the network layer address of this sip message and transport layer port (being the address and the port of NAT device) as the additional parameter of Contact header field, be used to represent direct mode by this address and this private user of port access; After the first row information of original control channel information Via header field, increase this transport layer port, be used for return response message as the port additional parameter.Revise this media channel information simultaneously, the media channel information of this messages application layer Session Initiation Protocol is revised as media address and the port that communicates with the opposite end network element on this media agent device, then amended message is sent to terminal called by corresponding network element.
Particularly, this caller Xin Lingdaili comprises the modification of this INVITE:
A. the original control channel information (Contact and Via header field) that keeps the INVITE of calling terminal transmission;
B. in former control channel information (Via is capable and Contact is capable), add the NAT net element information as additional parameter;
C. obtain the forwarding address and the port of the Media proxy (media relays equipment) of IMS network allocation, revise address and the port of media channel information in this sip message for this Media proxy;
D. before original control channel information, add new control channel information (Via header field), content is the address of this caller Xin Lingdaili self, be used for return address as this sip message corresponding response message, and in the control channel information of this interpolation, carry additional parameter, this additional parameter comprises this Media proxy address and port, is used for when NAT returns response message, fills in the media channel information of this response message application layer according to the content of this additional parameter;
E. add control channel information (Record-Route header field), content is the address of caller Xin Lingdaili self, and the caller Xin Lingdaili receives the follow-up sip message of this calling;
F. keep other control channel content.
The caller Xin Lingdaili is revised control channel information and the media channel information that application layer is carried in this INVITE:
// caller Xin Lingdaili adds self address, and the address as receiving this INVITE corresponding response message increases additional parameter simultaneously, comprises the media channel information (IP address and port numbers) of the media agent device of IMS network allocation
Via：SIP/2.0/UDP?20.0.0.2；relaymedia＝20.0.0.9：4000
// caller Xin Lingdaili keeps the original control channel information of the INVITE of calling terminal transmission, increases IP address and the port of NAT, is used for the caller Xin Lingdaili and returns sip response message by NAT to calling terminal along this path
Via：SIP/2.0/UDP?10.1.1.1；received＝20.0.0.1；rport＝9988
// keep the original control channel information of the INVITE of calling terminal transmission, increase address and the port of NAT, be used for the caller Xin Lingdaili and send follow-up sip request message by NAT to calling terminal along this path
Contact：<sip:10.1.1.1；nataddr＝20.0.0.1：9988>
// caller Xin Lingdaili adds self address, calls out the address of follow-up sip message as receiving this
Record-Route：<sip:20.0.0.2>
// modification media channel information is the media channel information (IP address and port) of the Media proxy (as media resource apparatus MRFP) of IMS network allocation
C＝IN?IP4?20.0.0.9
m＝audio?4000?RTP/AVP?0
Step 304: called Xin Lingdaili is received the INVITE that this caller Xin Lingdaili sends, the binding information of preserving when registering according to the called number inquiry terminal in this message, judge this called whether be private user, as denying, then transmit this INVITE to terminal called according to prior art, after receiving 200 response messages that this terminal called returns, return 200 response messages to the caller Xin Lingdaili;
In the application layer message that 200 response messages that called Xin Lingdaili returns carry, fill in the control corresponding channel information according to prior art, keep the application layer control channel information that this INVITE carries simultaneously, and interpolation control channel information (Record-Route header field), content is the address of this called Xin Lingdaili self, this calling subscriber's of expression visit direct mode.This media channel information is revised as the media information of terminal called.
The crucial control channel information that application layer is carried in this response message is:
Via:SIP/2.0/UDP 20.0.0.2; The address of relaymedia=20.0.0.9:4000 // caller Xin Lingdaili and Media proxy address
Via:SIP/2.0/UDP 10.1.1.1; Received=20.0.0.1; The address of rport=9988 // calling terminal and NAT address
Contact:＜sip:20.0.0.100〉// the terminal called address, be used to receive follow-up sip request message, be public network address
Record-Route:＜sip:20.0.0.2〉// caller Xin Lingdaili address.
Record-Route:＜sip:20.0.0.3〉// called Xin Lingdaili address.
The media channel information that application layer is carried in this response message is:
C=IN IP4 20.0.0.100 // terminal called media channel IP address
The media channel port of m=audio 50100 RTP/AVP 0 // terminal called
Step 305: the caller Xin Lingdaili receives 200 response messages of called Xin Lingdaili, resolves the content of this messages application layer sip message, and revises the control channel information and the media channel information of 200 response messages, sends to NAT then;
The caller Xin Lingdaili judges that this 200 response message network layer source address is consistent with the address and the port of the control channel information Via header field first row information of application layer Session Initiation Protocol with the transport layer source port, but the called subscriber is the private user that belongs to this Xin Lingdaili equipment, check then in the first row information of Via header field in this response message application layer control channel information and whether comprise the medium additional parameter, in this way, then this response message media channel information of carrying does not change, then revise the control channel information and the media channel information of this 200 response message, replace the media address and the port of the media channel information that this response message carries with media address in the medium additional parameter of the first row information of this Via header field after the deletion and port, delete first row of this Via header field then.
The caller Xin Lingdaili comprises the modification of this 200 response message:
Modification to network layer address and transport layer port:
The caller Xin Lingdaili with the network layer purpose IP address of this 200 response message be revised as the NAT address, the transport layer destination interface is revised as nat port; The network layer source IP address is revised as caller Xin Lingdaili address, the transport layer source port is revised as caller Xin Lingdaili port.
Modification to application layer control channel and media channel information:
A. the spreading parameter content (Media proxy address, port) of carrying according to control channel (first Via header field) is replaced media channel information, and deletes this control channel.
B. the content of parameter (NAT address, port) of carrying according to control channel (second Via header field) destination of message is in response deleted content of parameter then.
C. keep other control channel content, as Contact header field.
The caller Xin Lingdaili is revised control channel information and the media channel information that application layer is carried in this 200 response message:
Via:SIP/2.0/UDP 10.1.1.1 // remove first Via header field keeps second Via header field, and removes NAT information
Contact:＜sip:20.0.0.100〉// the reservation Contact header field
C=IN IP4 20.0.09 // media channel replaces with the Media proxy address
M=audio 4000 RTP/AVP 0 // media channel replaces with the Media proxy port
Step 306:NAT receives 200 response messages that the caller Xin Lingdaili sends, and network layer purpose IP address is that calling terminal address, transport layer destination interface are calling terminal control channel port in the modification message, and other remains unchanged, and sends a message to calling terminal.
Application layer is carried in 200 response messages that calling terminal receives control channel information and media channel information are:
Via:SIP/2.0/UDP 10.1.1.1 // calling terminal self address
Contact:＜sip:20.0.0.100〉// the terminal called address
Record-Route:＜sip:20.0.0.2〉// caller Xin Lingdaili address
Record-Route:＜sip:20.0.0.3〉// called Xin Lingdaili address
C=IN IP4 20.0.0.9 // Media proxy address
M=audio 4000 RTP/AVP 0 // Media proxy port
Step 307: calling terminal returns the affirmation ACK message of 200 response messages;
The network layer source IP address of this ACK message is that calling terminal private net address, transport layer source port are calling terminal signaling port; Network layer purpose IP address is that caller Xin Lingdaili address, transport layer destination interface are caller Xin Lingdaili port.
This ACK messages application layer does not carry media channel information, and the control channel information of carrying is:
Ack sip:20.0.0.100 // terminal called address
Route:＜sip:20.0.0.2〉// caller Xin Lingdaili address
Route:＜sip:20.0.0.3〉// called Xin Lingdaili address
Step 308:NAT receives the ACK message that calling terminal sends;
The network layer source IP address is that public network address, the modification transport layer source port of NAT self are the port of NAT self in the NAT modification message, and other remains unchanged, and amended message is sent to the caller Xin Lingdaili.
Step 309: the caller Xin Lingdaili is received the ACK message that NAT sends, resolve the content of this messages application layer sip message, first Route header field of self content represent in deletion,, sends ACK message and arrives called Xin Lingdaili as the message destination according to second Route header field address.
This key control channel information is:
Ack sip:20.0.0.100 // terminal called address
Route:＜sip:20.0.0.3〉// called Xin Lingdaili address
Calling terminal and terminal called utilize this media channel information to carry out voice or data communication by caller NAT device and media agent device.Shown in Figure 4 is the media data flow process of media channel transmission, and the data of calling terminal send to terminal called by caller NAT device and media agent device, and the data of terminal called are given calling terminal along this path back transfer.
Embodiment three public network users are called out private user
Network as shown in Figure 5, public network user is called out private user, and the calling and called terminal room carries out signaling by caller Xin Lingdaili, called Xin Lingdaili and NAT device communicates by letter, and carries out media communication by Media proxy and NAT device.NAT device is used for network address translation, with the network layer address of the message of called transmission and public network address and the port that port is revised as NAT respectively.Called Xin Lingdaili is received the message that the caller Xin Lingdaili sends, the binding relationship of preserving when searching registration according to called number, obtain corresponding NAT information, judge whether terminal called is private user, in this way, then keep original control channel (Contact and Via header field) information, and add this NAT net element information (network layer address of this message and transport layer port) on this basis, revising media channel information simultaneously is address and the port of Media proxy network element (media resource apparatus MRFP).The IP address and the port of each network element is as shown in table 2 among Fig. 5:
| Calling terminal | The caller Xin Lingdaili | Media relays equipment | Called Xin Lingdaili | NAT | Terminal called | |
| The IP address | 20.0.0.100 | 20.0.0.2 | 20.0.0.9 | 20.0.0.3 | 20.0.0.1 | 10.1.1.2 |
| |
50100 | 4000 | 9988 | 47100 |
Table 2
The processing method that the Session Initiation Protocol NAT of this calling passes through may further comprise the steps as shown in Figure 6:
Step S601: the caller Xin Lingdaili is received the call request of calling terminal, sends initial INVITE message to called Xin Lingdaili;
The caller Xin Lingdaili encapsulates this initial INVITE message according to the method for prior art, and the control channel information that application layer is carried in this INVITE is:
Via:SIP/2.0/UDP 20.0.0.2 // caller Xin Lingdaili address.
Via:SIP/2.0/UDP 20.0.0.100 // calling terminal address is public network address.
Contact:＜sip:20.0.0.100〉// the calling terminal address, be public network address.
The media channel information that application layer is carried in this INVITE is:
C=IN IP4 20.0.0.100 // calling terminal media channel IP address
The media channel port of m=audio 50100 RTP/AVP 1 // calling terminal
Step S602: called Xin Lingdaili is received the initial INVITE message that the caller Xin Lingdaili sends, and resolves the content of this messages application layer Session Initiation Protocol, revises the control channel information and the media channel information of this sip message;
The network layer purpose IP address of this INVITE is that NAT address, transport layer destination interface are nat port; The network layer source IP address is that called Xin Lingdaili address, transport layer source port are called Xin Lingdaili port.
This called Xin Lingdaili equipment judges that this news network layer source address is consistent with the address and the port of the control channel information Via header field first row information of application layer Session Initiation Protocol with the transport layer source port, the binding information of preserving when searching endpoint registration according to the called number in the initial INVITE message of caller Xin Lingdaili transmission then, judge that this is called for belonging to the private user of this Xin Lingdaili equipment, obtain corresponding NAT information then, also judge in the first row information of Via header field in this request message application layer control channel information and whether comprise the medium additional parameter, in this way, think that then the media channel information that this request message carries changes; Not, then revise this INVITE, send amended INVITE to this NAT device.Called Xin Lingdaili comprises the modification of this INVITE application layer:
A. keep original control channel information (Contact and Via header field) in the INVITE that the caller Xin Lingdaili sends;
B. obtain the forwarding address and the port of the Media proxy (media relays equipment) of IMS network allocation, revise media channel information in the sip message, be replaced by this Media proxy address and port;
C. before original control channel information, add control channel information (Via header field), content is the address of called Xin Lingdaili self, the receiving terminal NAT device that is used for this INVITE returns sip response message according to this address, this called Xin Lingdaili also carries the medium additional parameter in the control channel information of this interpolation, this medium additional parameter comprises this Media proxy address and port, be used for when the caller Xin Lingdaili returns sip response message, revise media channel information according to this medium additional parameter;
D. add control channel information (Record-Route header field), content is the address of called Xin Lingdaili self, is used to receive follow-up sip message;
E. keep other control channel content.
Called Xin Lingdaili is revised control channel information and the media channel information that application layer is carried in this INVITE:
// called Xin Lingdaili adds self address, as the return address of the sip response message of this INVITE correspondence; Carry additional parameter, comprise the media channel information (IP address and port numbers) of the media agent device of IMS network allocation
Via：SIP/2.0/UDP?20.0.0.3；relaymedia＝20.0.0.9：4000
The original control channel information of // reservation
Via:SIP/2.0/UDP 20.0.0.2 // caller Xin Lingdaili address.
Via:SIP/2.0/UDP 20.0.0.100 // calling terminal address is public network address.
Contact:＜sip:20.0.0.100〉// the calling terminal address, be public network address.
// in the address that the Record-Route header field adds called Xin Lingdaili, as the address that receives sip message
Record-Route：<sip:20.0.0.3>
// modification media channel information is the media channel information (IP address and the port of such as media resource apparatus MRFP) of the Media proxy of IMS network allocation
C＝IN?IP4?20.0.0.9
m＝audio?4000?RTP/AVP?0
Step 603:NAT receives the INVITE that called Xin Lingdaili sends, and network layer purpose IP address is that terminal called private net address, transport layer destination interface are the terminal called port in the modification message, and other remains unchanged, and sends a message to terminal called;
Step 604: terminal called receipt of call INVITE sends 200 response messages to NAT;
Network layer purpose IP address is that called Xin Lingdaili address, transport layer destination interface are called Xin Lingdaili port in this response message; The network layer source IP address is that terminal called private net address, transport layer source port are terminal called Xin Lingdaili port.
This terminal called encapsulates the control channel and the media channel information of this response message according to prior art, and keeps the original control channel information in the INVITE that receives.The crucial control channel information that application layer is carried in this response message is:
Via:SIP/2.0/UDP 20.0.0.3; The address of relaymedia=20.0.0.9:4000 // called Xin Lingdaili and Media proxy address
The address of Via:SIP/2.0/UDP 20.0.0.2 // caller Xin Lingdaili
Via:SIP/2.0/UDP 20.0.0.100 // calling terminal address
Contact:＜sip:10.1.1.2〉//Contact header field is revised as the terminal called address, is private net address, is used to receive follow-up sip message
Record-Route:＜sip:20.0.0.3〉// called Xin Lingdaili address.
The media channel information that application layer is carried in this response message is:
C=IN IP4 10.1.1.2 // terminal called media channel IP address
M=audio 47100 RTP/AVP 1 // the cry media channel port of terminal
Step 605:NAT receives 200 message that terminal called sends, the network layer source IP address of revising this message is the public network address of NAT self, revising the transport layer source port is the port of NAT self, and other remains unchanged, and amended message is sent to called Xin Lingdaili;
Step 606: called Xin Lingdaili receives 200 response messages that NAT sends, and resolves this messages application layer content, and revises control channel information and media channel information, sends to the caller Xin Lingdaili then;
Called Xin Lingdaili judges that the address and the port of control channel information Via header field first row information of this sip message network layer source address and transport layer source port and application layer Session Initiation Protocol is inconsistent, check in the first row information of Via header field in this response message application layer control channel information and whether comprise the medium additional parameter, in this way, think that then the media channel information that this response message carries does not change, replace the media address and the port of the media channel information that this response message carries with media address and port in the medium additional parameter of the first row information of Via header field in this messages application layer control channel information, delete first row of this Via header field then.Also behind the Contact header field original information of this control channel information, increase this network layer address and transport layer port additional parameter, be used to represent direct mode by this address and this private user of port access as Contact header field.
Called Xin Lingdaili comprises the modification of this 200 response message:
Modification to network layer address and transport layer port:
The network layer source IP address of revising this ACK message is that called Xin Lingdaili address, transport layer source port are called Xin Lingdaili port; Revising network layer purpose IP address is that NAT address, transport layer destination interface are nat port.
Modification to application layer Session Initiation Protocol content:
A. the content (Media proxy address, port) of the additional parameter that carries according to control channel (first Via header field) is replaced media channel information, and deletes this Via header field;
B. keep original control channel (Contact header field) content, and the address of adding NAT on this basis, be used to represent that the caller Xin Lingdaili visits the direct mode of called Xin Lingdaili by NAT device;
C. keep other control channel content.
The caller Xin Lingdaili is revised control channel information and the media channel information that application layer is carried in this 200 response message:
// remove first Via header field, keep follow-up Via header field
Via：SIP/2.0/UDP?20.0.0.2
Via：SIP/2.0/UDP?20.0.0.100
//Contact header field adds NAT information
Contact：<sip:10.1.1.1；nataddr＝20.0.0.1：9988>
Route:＜sip:20.0.0.3〉// called Xin Lingdaili address
// media channel replaces with the Media proxy address
C＝IN?IP4?20.0.0.9
// media channel replaces with the Media proxy port
m＝audio?4000?RTP/AVP?0
Step 607: the caller Xin Lingdaili returns the affirmation ACK message of 200 response messages to called Xin Lingdaili, and this ACK messages application layer does not carry media channel information, only carries control channel information, and this control channel information is:
Ack sip:10.1.1.2; Nataddr=20.0.0.1:9988 // terminal called address and NAT address
Route:＜sip:20.0.0.3〉// called Xin Lingdaili address
Step 608: called Xin Lingdaili receives the ACK message that the caller Xin Lingdaili sends, and the control channel information of network layer address and port and application layer is made amendment;
Called Xin Lingdaili is identical with the processing of step 602 to the modification of this ACK news network layer address and port.Called Xin Lingdaili is resolved the content of this messages application layer sip message, revises the control channel information deletion and represents the Route header field of self, according to initial row Ack sip:10.1.1.2; Nataddr content of parameter among the nataddr=20.0.0.1:9988 (NAT information) is as the message destination, and deletion nataddr parameter sends a message to NAT.Amended control channel information is:
Ack sip:10.1.1.2 // terminal called address
Step 609:NAT receives the ACK message that called Xin Lingdaili sends, and network layer purpose IP address is that terminal called address, transport layer destination interface are terminal called control channel port in the modification message, and other remains unchanged, and sends a message to terminal called.
Calling terminal and terminal called utilize this media channel information to carry out voice or data communication by media agent device and called NAT device.Shown in Figure 7 is the media data flow process of media channel transmission, and the data of calling terminal send to terminal called by media agent device and called NAT device, and the data of terminal called are given calling terminal along this path back transfer.
Embodiment four calling and called are the scene of private user
Network as shown in Figure 8, private user is called out private user, the calling and called terminal room carries out signaling by caller NAT device, caller Xin Lingdaili, called Xin Lingdaili and called NAT device communicates by letter, and carries out media communication by caller NAT device, media agent device and called NAT device.Identical with embodiment one with embodiment two, NAT device is used for network address translation, the network layer address of the message that terminal is sent and public network address and the port that port is revised as NAT respectively, the network layer address and the port of the message that Xin Lingdaili equipment is sent are revised as private net address and port respectively.As shown in Figure 9, behavior of caller Xin Lingdaili and embodiment two scenes (private user calling public network user) are just the same, all need revise application layer control channel and media channel information.Called Xin Lingdaili behavior is compared with the scene (public network user calling private user) of embodiment three, does not need to revise the application-layer media channel information, only needs to revise application layer control channel information.Concrete, because the caller Xin Lingdaili has been revised media information and the control channel information of calling terminal in the INVITE that NAT device is transmitted, and amended message sent to called Xin Lingdaili, this called Xin Lingdaili is received this INVITE, this sip message is resolved, check in the first row information of Via header field in this messages application layer control channel information and comprised additional parameter, think that then the media channel information that this message is carried changes, this called Xin Lingdaili equipment is according to prior art, in original control channel information Via header field, increase the address of this Xin Lingdaili before the first row information, the address of adding this Xin Lingdaili in Record-Route territory the last item record back sends to terminal called by called NAT device with amended INVITE then simultaneously.This called Xin Lingdaili is received 200 response messages that terminal is returned, delete first row (address of this Xin Lingdaili) of this messages application layer control channel information Via header field, whether comprise described additional parameter in the first row information of this Via header field after the inspection deletion, because this 200 response message has kept control channel and media channel information in should the INVITE of called Xin Lingdaili transmission, therefore, comprised this additional parameter in the first row information of current this Via header field, this called Xin Lingdaili is directly transmitted this response message to the caller Xin Lingdaili, this caller Xin Lingdaili is according to handling with the same mode of embodiment one, and calling terminal and terminal called utilize this media channel information to carry out voice or data communication by calling and called NAT device and media agent device.Shown in Figure 10 is the media data flow process of media channel transmission, and the data of calling terminal send to terminal called by caller NAT device, media agent device and called NAT device, and the data of terminal called are given calling terminal along this path back transfer.
Claims (15)
1. the method for a session initiation protocol (SIP) call-based traversal network address conversion is characterized in that:
Private user carries out SIP to be called out, and the Xin Lingdaili equipment of this private user ownership carries out the application layer Session Initiation Protocol to this sip message and resolves;
The result that this Xin Lingdaili equipment obtains according to parsing, judge whether to need to revise the media channel information of this sip message application layer Session Initiation Protocol, be, then media channel information is revised as the media address and the port that communicate with the opposite end network element on the media agent device of network allocation, and sends amended message;
This private user by described media address and port with end subscriber set up medium be connected.
2. the method for claim 1 is characterized in that:
The result that this Xin Lingdaili equipment obtains according to parsing as judging the media channel information that need not revise this sip message application layer Session Initiation Protocol, then directly transmits this sip message;
The Xin Lingdaili devices communicating that this private user terminal also belongs to by network address translation (nat) equipment and this private user, this NAT device carries out network layer address and transport layer port conversion to the sip message of this calling, this private user also utilize this NAT device by described media address and port with end subscriber set up medium be connected.
3. the method for claim 1 is characterized in that comprising the media channel information of this sip message application layer Session Initiation Protocol of this Xin Lingdaili apparatus modifications:
As this sip message is request message, then the media channel information of this sip message application layer Session Initiation Protocol is revised as the network address and the port that media agent device and opposite end network element communicate, while increased the address and the port of this Xin Lingdaili equipment before the first row information of the original control channel information Via header field of this message, also in the row of this increase, add medium additional parameter, the network address and port that this media agent device that this medium additional parameter is a network allocation and opposite end network element communicate;
As this sip message is response message, then replace the media address and the port of the media channel information that this response message carries, and delete first row of this Via header field with media address and port in the medium additional parameter of the first row information of Via header field in this messages application layer control channel information.
4. the method for claim 1 is characterized in that the result that this Xin Lingdaili equipment obtains according to parsing, judges whether to need to revise the media channel information of this sip message application layer Session Initiation Protocol in the following manner:
This Xin Lingdaili equipment is inconsistent as the address and the port of the control channel information Via header field first row information of judging this news network layer source address and transport layer source port and application layer Session Initiation Protocol, or the called subscriber belongs to the private user of this Xin Lingdaili equipment and media channel information that this sip message carries does not change, and then needs to revise the media channel information of this sip message application layer Session Initiation Protocol.
5. method as claimed in claim 4 is characterized in that this Xin Lingdaili equipment judges in the following way whether the called subscriber is the private user that belongs to this Xin Lingdaili equipment:
Terminal is when this Xin Lingdaili facility registration, this Xin Lingdaili equipment is resolved the registration sip message of this terminal, address as the control channel information of the network layer source address of this message and application layer Session Initiation Protocol is inconsistent, then preserves Subscriber Number, network layer source IP address and the port of this terminal;
This Xin Lingdaili equipment is resolved the message that the user calls out, and obtains the called number in this message related to calls, checks whether this locality preserves this number, if any, then this called subscriber is the private user that belongs to this Xin Lingdaili equipment.
6. method as claimed in claim 4 is characterized in that this Xin Lingdaili equipment carries out the application layer Session Initiation Protocol to this sip message and resolves, and judges in the following manner whether the media channel information that this sip message carries changes:
This Xin Lingdaili equipment is checked the type of this sip message earlier, as this sip message is request message, judge again in the first row information of Via header field in this request message application layer control channel information and whether comprise the medium additional parameter, in this way, then this request message media channel information of carrying changes, as not, then this request message media channel information of carrying does not change;
As this sip message is response message, then check in the information that Via header field first is gone in this response message application layer control channel information and whether comprise the medium additional parameter, in this way, then this response message media channel information of carrying does not change, as not, then this response message media channel information of carrying changes.
7. as claim 3 or 4 described methods, it is characterized in that:
This Xin Lingdaili equipment is inconsistent as the address and the port of the control channel information Via header field first row information of judging this sip message network layer source address and transport layer source port and application layer Session Initiation Protocol, also behind the Contact header field original information of this control channel information, increase this network layer address and transport layer port additional parameter as Contact header field, be used to represent direct mode by this address and this private user of port access, as this sip message is request message, also after the first row information of original control channel information Via header field, increase this transport layer port, be used for return response message as the port additional parameter.
8. the system of SIP call-based traversal network address conversion is characterized in that comprising: the terminal of private user, Xin Lingdaili equipment and media agent device, wherein:
The terminal of this private user is used for Xin Lingdaili equipment by its ownership and carries out SIP and call out, the media address that provides by this Xin Lingdaili equipment and port with end subscriber set up medium be connected;
This media agent device is used to provide the network side media channel, comprises media address and port;
This Xin Lingdaili equipment, be used to the sip message of receiving that this terminal is called out, this message is carried out the application layer Session Initiation Protocol resolves, the result who obtains according to parsing, judge whether to need to revise the media channel information of this sip message application layer Session Initiation Protocol, be that then the media channel information with this messages application layer Session Initiation Protocol is revised as media address and the port that communicates with the opposite end network element on this media agent device, and sends amended message.
9. system as claimed in claim 8, it is characterized in that this system also comprises network address translation (nat) equipment, between this private user terminal and this Xin Lingdaili equipment, be used to transmit and pass through the mutual sip message of this Xin Lingdaili equipment between this terminal and the opposite end, and this sip message is carried out network layer address and transport layer port conversion;
The terminal of this private user also is used for carrying out SIP by this NAT device and calls out, and utilizes media address that this NAT device provides by this Xin Lingdaili equipment and port and end subscriber is set up medium is connected;
This Xin Lingdaili equipment also is used for the result that obtains according to parsing, as judging the media channel information that need not revise this sip message application layer Session Initiation Protocol, then directly transmits this sip message.
10. system as claimed in claim 8 is characterized in that:
This Xin Lingdaili equipment, also be used to receive sip message, this sip message is resolved, obtaining this sip message as parsing is request message, the media channel information of this sip message application layer Session Initiation Protocol is revised as the network address and the port that media agent device and opposite end network element communicate, after increasing the address and port of this Xin Lingdaili equipment before the first row information of the original control channel information Via header field of this message, also in the row of this increase, add medium additional parameter, the network address and port that this media agent device that this medium additional parameter is a network allocation and opposite end network element communicate; Obtaining this sip message as parsing is response message, then replace the media address and the port of the media channel information that this response message carries, and delete first row of this Via header field with the media address of the medium additional parameter of Via header field in this response message application layer control channel information first row information and port.
11. system as claimed in claim 8 is characterized in that this Xin Lingdaili equipment according to the result who arrives who resolves, judges whether to need to revise the media channel information of this sip message application layer Session Initiation Protocol, comprising:
This Xin Lingdaili equipment, the address and the port of control channel information Via header field first row information of judging this news network layer source address and transport layer source port and application layer Session Initiation Protocol is inconsistent, or the called subscriber belongs to the private user of this Xin Lingdaili equipment and media channel information that this sip message carries does not change, and then needs to revise the media channel information of this sip message application layer Session Initiation Protocol.
12. system as claimed in claim 11 is characterized in that:
This Xin Lingdaili equipment, the register requirement that also is used for receiving terminal, registration sip message to this terminal is resolved, inspection also judges whether the network layer source address of this message is consistent with the address of the control channel information of application layer Session Initiation Protocol, as inconsistent, then preserve Subscriber Number, network layer source IP address and the port of this terminal; The message that the user calls out is resolved, obtain the called number in this message related to calls, check whether this locality preserves this number, if any, think that then this called subscriber is the private user that belongs to this Xin Lingdaili equipment.
13. system as claimed in claim 11 is characterized in that:
This Xin Lingdaili equipment, also be used to receive the sip message of this customer call, check the type of this sip message, as this sip message is request message, judge in the first row information of Via header field in this request message application layer control channel information whether comprise the medium additional parameter again, in this way, think that then the media channel information that this request message carries changes, as not, then this request message media channel information of carrying does not change; As this sip message is response message, then check in the first row information of Via header field in this response message application layer control channel information and whether comprise the medium additional parameter, in this way, think that then the media channel information that this response message carries does not change, as not, then this response message media channel information of carrying changes.
14. system as claimed in claim 11 is characterized in that:
This Xin Lingdaili equipment, the address and the port of the control channel information Via header field first row information that also is used to judge this sip message network layer source address and transport layer source port and application layer Session Initiation Protocol is inconsistent, behind the Contact header field original information of this control channel information, increase this network layer address and transport layer port additional parameter as Contact header field, be used to represent direct mode by this address and this private user of port access, as this sip message is request message, also after the first row information of original control channel information Via header field, increase this transport layer port, be used for return response message as the port additional parameter.
15. system as claimed in claim 11 is characterized in that:
The function of this Xin Lingdaili equipment can be realized that the function of this media agent device can be realized by the media resource apparatus of IP multimedia system by the Proxy Call Session Control Function equipment of IP multimedia system (IMS).
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| CN102546644A (en) * | 2012-01-17 | 2012-07-04 | 华为技术有限公司 | Method, equipment and system for implementing SIP (Session Initiation Protocol) calling |
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Cited By (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102651778A (en) * | 2011-02-24 | 2012-08-29 | 中兴通讯股份有限公司 | Method and system for implementing NAT (Network Address Translator) traversal by FCC (Fast Channel Change) system |
| CN102420835A (en) * | 2012-01-10 | 2012-04-18 | 广东佳和通信技术有限公司 | Method for realizing real-time transport protocol (RTP) media stream agent in unified communication system |
| CN102420835B (en) * | 2012-01-10 | 2014-07-16 | 广东佳和通信技术有限公司 | Method for realizing real-time transport protocol (RTP) media stream agent in unified communication system |
| CN102546644A (en) * | 2012-01-17 | 2012-07-04 | 华为技术有限公司 | Method, equipment and system for implementing SIP (Session Initiation Protocol) calling |
| CN102546644B (en) * | 2012-01-17 | 2015-03-25 | 华为技术有限公司 | Method, equipment and system for implementing SIP (Session Initiation Protocol) calling |
| CN104753928A (en) * | 2015-03-16 | 2015-07-01 | 苏州科达科技股份有限公司 | Code stream forwarding method and system |
| CN104753928B (en) * | 2015-03-16 | 2018-08-17 | 苏州科达科技股份有限公司 | A kind of code stream retransmission method and system |
| CN105049545B (en) * | 2015-06-17 | 2018-02-02 | 广州云积软件技术有限公司 | Based on the Streaming Media NAT through method under the online inspection system video standard of the national education examinations |
| CN105049545A (en) * | 2015-06-17 | 2015-11-11 | 广州云积软件技术有限公司 | Streaming media NAT traverse method based on national education examination online patrol system video standard |
| CN104980528A (en) * | 2015-06-26 | 2015-10-14 | 广州华多网络科技有限公司 | Method, system and apparatus for realizing communication between nodes |
| CN111131747A (en) * | 2019-12-06 | 2020-05-08 | 视联动力信息技术股份有限公司 | Method and device for determining data channel state, electronic equipment and storage medium |
| CN111131315A (en) * | 2019-12-31 | 2020-05-08 | 西安抱朴通信科技有限公司 | Session connection method, device, equipment and medium |
| CN111835885A (en) * | 2020-07-15 | 2020-10-27 | 杭州迪普科技股份有限公司 | Network address translation method, device and equipment |
| CN111835885B (en) * | 2020-07-15 | 2023-04-07 | 杭州迪普科技股份有限公司 | Network address translation method, device and equipment |
| CN114500166A (en) * | 2021-12-24 | 2022-05-13 | 广州爱浦路网络技术有限公司 | IMS communication method based on public network and private network superposition |
| CN114500166B (en) * | 2021-12-24 | 2023-06-16 | 广州爱浦路网络技术有限公司 | IMS communication method based on public network and private network superposition |
| CN115484311A (en) * | 2022-08-19 | 2022-12-16 | 重庆长安汽车股份有限公司 | Signaling interaction method, device and server of national standard signaling edge proxy system |
| CN116566955A (en) * | 2023-07-07 | 2023-08-08 | 杭州英旭智能科技有限公司 | Digital voice call method, device and application based on mqtt |
| CN116566955B (en) * | 2023-07-07 | 2023-09-19 | 杭州英旭智能科技有限公司 | Digital voice call method, device and application based on mqtt |
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