CN101321227B - IP fax and its work method - Google Patents

Abstract

An IP fax and working method thereof, referring to the technical field of utilizing IP technique to fax. This invention includes a mail sending/receiving module, a session initialization protocol fax device, opposite user agents, further includes an IP fax server; a control order port of the mail sending/receiving module is connected with the IP fax server; after receiving by IP fax server, the IP fax server will send a feedback information to the mail sending/receiving module; the first input end of the IP fax server is connected with an input end of the session initialization protocol fax device so as to realize the inter-conversion flowing from T.38 to the fax file form; the second input end of the IP fax server is connected with an input end of the opposite user agents so as to realize the encapsulation to the session initialization protocol stack. The target of this invention is to provide a target of source file fax transmission which has distinct gradation, simple protocol, powerful function, supports multi-path fax session, fax file distributing mailbox and plural file forms.

Description

A kind of Fax over IP device and method of work thereof

Technical field

The present invention relates to the technical field of utilizing the IP technology to fax.

Background technology

At present, PBX (private branch exchange system) finds broad application in office mechanism of enterprise, and important function has been played in the raising of enterprise's work efficiency.But what traditional PBX adopted is the special technology that lacks open and standard, not only costs an arm and a leg, and not enough to emerging CTI (computer and phone are integrated) and VOIP technical support.In recent years, along with the success of the popular of Internet and IP technology, P-PBX arises at the historic moment based on the IP protocol of I, is expected to solve the deficiency of conventional P BX.

The IP-PBX system has realized the functional unification of computer network and telephone exchange.Each telephone terminal adopts the IP mode to carry out data communication in the IP-PBX network system, can not only converse, and can also realize the transmission of text, data, image, and telephone network and computer network is unified in aggregates, realizes the teleworking in the local area network (LAN).Particularly in remote Collaborative Commerce, teleworking, will give full play to its powerful resources advantage, for business cooperation, that the work reorganization brings is convenient.

Control centre in the IP-PBX local area network (LAN) can manage computer network, telephone network as the case may be effectively, thereby reaches resource-sharing.By the Internet net, can realize cheap telecommunication, teleworking and ecommerce between the IP-PBX net of different regions.

IP-PBX systematic research exploitation receives many-sided concern, but industry is only finished based on the finished product exploitation of agreement H.323 at present.And the IP-PBX system based on Session Initiation Protocol (session initiation protocol), the multiple value-added service of support that the author participates in developing still belongs to new things at message area.Later development also can add functions such as present widely used instant note (Instant Message), multimedia service in the native system to, and final IP-PBX system will be subjected to many enterprise customers' favor, creates huge economic interests.

Industry IP-PBX system is based on H.323 consensus standard exploitation more at present.

Because it is H.323 standard is too complicated, too complicated or expensive for the product of calling out control between the network lock road of many needs basic " quick but imperfect ".And H.323 can not integrating, or the additional SS7 power that must provide with SS7 (Signaling System#7, Signaling System Number 7).

Summary of the invention

The object of the invention provide a kind of well arranged, agreement is simple, powerful, support the multichannel fax session, support fax paper to transmit mailbox, support the Fax over IP and the method for work thereof of the source file facsimile transmission of multiple file format.

The present invention adopts following technical scheme for achieving the above object:

The present invention includes mail transmission/receiver module, session initiation protocol facsimile equipment, back-to-back user agent, also comprise the Fax over IP server, the control command port of mail transmission/receiver module is connected with the Fax over IP server, and the Fax over IP server can send feedback information to mail transmission/receiver module after receiving; First output of Fax over IP server is connected with the input of session initiation protocol facsimile equipment, has realized T.38 flowing to the mutual conversion of fax paper form; Second output of Fax over IP server is connected with back-to-back user agent's input, has realized the encapsulation to SIP stack;

Described Fax over IP server comprises fax control module, medium process module, Call Control Block;

The fax control module comprises fax managing module and call state machine module, also obtains the FAX mode notification message when fax managing module realizes to the fax operation requests of the management of fax operation, the transmission/receiver module that handles postal matter, by interface control facsimile call process, is undertaken alternately by intermodule communication and mail transmission/receiver module; And the call state machine module is responsible for safeguarding facsimile call process status machine, is finished fax registration/cancellation, fax incoming call exhalation by interprocess communication;

Medium process module: realize T.38 flowing to the mutual conversion of fax paper form; And by interprocess communication, finish the mutual of the control of medium processing procedure and media session information between the call state machine module; The Real-time Transport Protocol destructing; The RTP passage is set up/is removed, the rtp streaming transmitting-receiving;

Call Control Block: realize the encapsulation of SIP stack, can finish the structure and the parsing of session initiation protocol, carry out the release that builds on of link with the opposite end of communicating by letter; And use interprocess communication between the call state machine module, finish call control procedure.

The present invention uses the method that the above-mentioned IP picture unit sends fax:

The first step, mail transmission/receiver module sends information to the fax control module, after receiving information, the fax control module sends a confirmation to mail transmission/receiver module, require mail transmission/receiver module that the form of concrete deposit data position with pathname provided simultaneously, the fax control module just sends a fax acknowledge message and shows the facsimile signal that begins to handle and send required transmission to mail transmission/receiver module;

In second step, the fax control module judges whether to carry out facsimile transmission, if the judgment is No, be that the call state machine module is operated at full capacity, then send failure, the fax control module will circular mail transmission/receiver module, allows mail transmission/receiver module do repeating transmission; If the judgment is Yes, then its interface function that can call the call state machine module produces one tunnel new fax session, and with the I address of opposite end with the facsimile data path of client information and required transmission etc. is all carried out record;

The 3rd step, Call Control Block sends conversation initiating protocol message to the fax session callee, whether both sides carry out link and connect, and finish T.38 protocol version, whether shift out or insert filling bit when transmitting T.38 data among peak transfer rate, the process C, carrying out the ability conversion between linear format and the MMR form, carry out format conversion between linear format and JBIG form, be locally to produce information reconciliation such as training signal and send the mutual of information such as training signal, identify label.After receiving the confirmation of receipt that the callee sends, can switch on the process of transmission medium; At this moment, the fax control module just sends by medium process module passes through T.38 finished fax signaling of agreement and facsimile signal, and the callee communicates with fax session, and cuts off link behind end of transmission; In this process, if make a mistake, the fax control module will finish this transmission, and to the reason of mail transmission/receiver module reporting errors; If do not send mistake, the fax managing module can send to mail/and the receiver module report this time sends successfully.

Reasonablely be: the concrete work of fax managing module of the present invention is as follows:

The 1st step: the fax managing module is blocked on the message queue,

The 2nd step: the fax managing module is cancelled breath from message queue,

The 3rd step: the fax managing module judges whether message is effective, as if being judged as is, the fax managing module passes to the call state machine module by the function of the driving condition machine that calls the call state machine module and provide with message; If be judged as not, then abandon message and got back to for the 1st step;

The 4th step: the fax managing module obtains function return value, and sends a message to corresponding module according to function return value, returns for the 1st step.

Reasonablely be: the concrete method of work of medium process module of the present invention is as follows:

The 1st) step: Select is a function, management multichannel message, i.e. a massage set; Select calls obstruction, in case the message of having detected, process obtains to carry out;

The 2nd) step: medium process module obtains a piece of news, and the validity of message is judged, if be judged as is, then sends Target id according to message and finds corresponding session; If be judged as not, then return the 1st) step; Judge simultaneously whether the message obtained is establishment information, being judged as is to create or discharge a dialogue, is judged as otherwise returns the 1st) step;

The 3rd) step: medium process module is judged the validity of message under read states, is judged as to be, then calls the interface function of corresponding module, if be judged as not, then returns the 1st) step;

The 4th) step: medium process module judges whether to need to send message, if be judged as is, then sends a message to fax control module (41), returns the 1st) step; If be judged as otherwise directly return the 1st) step.

The present invention adopts technique scheme, compared with prior art has following advantage: well arranged, agreement is simple, powerful, support the multichannel fax session, support fax paper to transmit mailbox, support the characteristics such as source file facsimile transmission of multiple file format.

1, the present invention is based on Session Initiation Protocol, have characteristics such as flexibility, the extensibility of Session Initiation Protocol be strong, and agreement is simple.

2, the present invention can manage the multichannel fax, supports the fax paper of receiving (Tiff form) is forwarded to the function of subscriber mailbox, and is with better function.

3, the present invention is with virtual driving at PC end, supports word, pdf, bmp formatted file to change into behind the Tiff form as facsimile transmission.

4, the present invention can support the source file facsimile transmission of multiple file format.

Description of drawings

Fig. 1 is the structural representation of Fax Server module of the present invention.

Fig. 2 is the schematic diagram that Fax Server module of the present invention sends the step 1 of fax.

Fig. 3 is the schematic diagram that Fax Server module of the present invention sends the step 2 of fax.

Fig. 4 is the schematic diagram that Fax Server module of the present invention sends the step 3 of fax.

Fig. 5 is the message format of interprocess communication of the present invention.

Fig. 6 is the form of function call pass-along message of the present invention.

Fig. 7 is the schematic flow sheet of Fax Server module fax managing module of the present invention.

Fig. 8 is the schematic flow sheet of Fax Server module medium process module of the present invention

Fig. 9 is the software architecture schematic diagram of Fax Server module of the present invention.

Embodiment

Below in conjunction with accompanying drawing technical scheme of the present invention is elaborated, as shown in Figure 1, the present invention includes mail transmission/receiver module 1, session initiation protocol facsimile equipment 2, back-to-back user agent 3, also comprise Fax over IP server 4, the control command port of mail transmission/receiver module 1 is connected with Fax over IP server 4, can send feedback information to mail transmission/receiver module 1 after Fax over IP server 4 receives; First output of Fax over IP server 4 is connected with the input of session initiation protocol facsimile equipment 2, has realized T.38 flowing to the mutual conversion of fax paper form; Second output of Fax over IP server 4 is connected with back-to-back user agent's 3 input, has realized the encapsulation to SIP stack;

Described Fax over IP server 4 comprises fax control module 41, medium process module 42, Call Control Block 43;

Fax control module 41 comprises fax managing module 411 and call state machine module 412, also obtains the FAX mode notification message when fax managing module 411 realizes to the fax operation requests of the fax management of operation, the transmission/receiver module 1 that handles postal matter, by interface control facsimile call process, is undertaken alternately by intermodule communication and mail transmission/receiver module 1; And call state machine module 412 is responsible for safeguarding facsimile call process status machine, is finished fax registration/cancellation, fax incoming call exhalation by interprocess communication;

Medium process module 42: realize T.38 flowing to the mutual conversion of fax paper form; And by interprocess communication, finish the mutual of the control of medium processing procedure and media session information between the call state machine module 412; The Real-time Transport Protocol destructing; The RTP passage is set up/is removed, the rtp streaming transmitting-receiving;

Call Control Block 43: realize the encapsulation of SIP stack, can finish the structure and the parsing of session initiation protocol, carry out the release that builds on of link with the opposite end of communicating by letter; And use interprocess communication between the call state machine module 412, finish call control procedure.

Fax over IP server 4 is cores that entire I P fax is realized, fax control module 41 is managed the operation of whole module as main control module, and carries out alternately with other modules in the IP-PBX system.Secondly Call Control Block 43 is used to manage the process that makes a call and connect, be implemented in the dialing of controlling by Session Initiation Protocol under the IP world, initiate processes such as connections, a road each line state that the point-to-point Fax over IP of multichannel is transmitted of supporting in the management Fax Server module.At last, T.30 will be implemented in, form a media management module, carry the signaling and the view data that will send in the Fax over IP with agreement T.38.

Mail transmission/receiver module can be realized the function of mail transmission/reception and fax transmitting-receiving, management as an external interface of Fax Server 4.Major function is: to outside fax sending and receiving processing of request, send the fax request to Fax Server, and according to Fax Server to fax processing of request situation external reporting result.And be provided at the function that is sent to subscriber mailbox after fax receives.

Below be that mail transmission/receiver module sends a request to Fax Server by IP-PBX internal system agreement, thereby realize sending the process of fax.

The first step, as shown in Figure 2, the message that transmission/receiver module 1 sends of being responsible for handling postal matter of the fax control module 41 in the Fax Server module 4.Fax control module 41 at first can respond the request of mail transmission/receiver module 1, and beam back a confirmation, and require mail transmission/receiver module 1 that the form of concrete deposit data position with pathname provided, after this, the fax control module 41 just send one the fax acknowledge message show the facsimile signal that begins to handle and send required transmission to mail transmission/receiver module 1.

In second step, as shown in Figure 3, fax control module 41 judges whether to carry out facsimile transmission, if its submodule call state machine 412 has been operated at full capacity, then send failure, fax control module 41 will circular mail transmission/receiver module 1, allows it do further processing.But in the time of most is successful, and then its interface function that can call submodule call state machine 412 produces one tunnel new state, and with the IP address of opposite end with the facsimile data path of client information and required transmission etc. is all carried out record.

In the 3rd step, as shown in Figure 4, facsimile posting is handled by fax control module 41 modules fully.At first, it sends sip message to the opposite end by Call Control Block 43, and both sides will carry out the connection of link, and finish the negotiation of some necessary parameter.After this, fax control module 41 thinks that link sets up, and can switch on the process of transmission medium.At this moment, fax control module 41 sends and passes through T.38 finished fax signaling of agreement and facsimile signal just by medium process module 42, communicates with the opposite end, and cut off link behind end of transmission.In this process, in case make a mistake (can't connect as the opposite end etc.), the control module of then faxing 41 will finish this transmission, and to the reason of mail transmission/receiver module 1 reporting errors.If All going well, fax managing module 411 also could send to mail/receiver module 1 report would this time send successfully.

In above-mentioned argumentation, its transmission course is to be based upon intermodule on can the basis of good collaboration with.Module may be implemented as process separately in realization, also might be implemented as functional form, so it is extremely important to define the form of intermodule message transmission.Below just the communication format of intermodule is carried out standard, for the communication between process, as shown in Figure 5 message format of definition then.Wherein, sending module numbering is ID number of each module of providing in advance with accepting the module numbering, and message id number shows it is which kind of message, and its particular content is providing in the message content field subsequently.And for the message transmission of type function, definition message format as shown in Figure 6 then: in this form, the corresponding state with each road of status number, message id has been stipulated the kind of message, its content appears in the message content field.

So just be divided into more clear and several submodules function opposite independent according to function Fax Server 4, the realization of each module can be relatively independent, and can debug one by one in later stage debugging work, can improve the efficient of whole development process.

Fax managing module 411 is control centres of whole Fax Server 4, and the collaborative work of other submodules is had important effect, mainly is responsible for the acceptance and the transmission of message.Its groundwork flow process shown in Figure 7 is as follows:

The 1st step: the fax managing module is blocked on the message queue,

The 2nd step: the fax managing module is cancelled breath from message queue,

The 3rd step: the fax managing module judges whether message is effective, as if being judged as is, the fax managing module passes to the call state machine module by the function of the driving condition machine that calls the call state machine module and provide with message; If be judged as not, then abandon message and got back to for the 1st step;

The 4th step: the fax managing module obtains function return value, and sends a message to corresponding module according to function return value, returns for the 1st step.

Medium process module 42 itself is implemented as an independent process.This process is that the select system call by the (SuSE) Linux OS standard is blocked on one group of interprocess communication connects, in case there is an information to arrive, this process will be recovered to carry out, because the main control module of medium process module 42 is media state control modules, Gu Qihui takes the lead in obtaining carrying out.After the operation of media state control module, it at first obtains a complete message from interface, the form of message is the consolidation form that meets interprocess communication equally, find the structure of corresponding session then according to the target session ID in the message content, analyze then under this session state of living in, whether the message that is received is effective, because can only accept certain several message under a kind of state, other message are not responded, if effectively then produce corresponding state and migrate, the function that calling submodule provides carries out respective handling, is connected the message that state is migrated generation by the interprocess communication with fax control module 41 at last and goes back with the transmission of interprocess communication standard message format.Its complete handling process is as shown in Figure 8:

The 1st) step: Select calls obstruction, and message is arranged, and process obtains to carry out; Select is a function, management multichannel message, i.e. a massage set.If the message event in this massage set does not all take place, then will call the process of Select function always and block always at ordinary times; Some or several message event in this massage set take place, and at this moment, Select wakes process up from blocked state, and tells that process specifically is which message event has taken place, and process is down continued to be carried out, and handles these message event;

The 2nd) step: medium process module obtains a piece of news, and the validity of message is judged, if be judged as is, then sends Target id according to message and finds corresponding session; If be judged as not, then return the 1st) step; Judge simultaneously whether the message obtained is establishment information, being judged as is to create or discharge a dialogue, is judged as otherwise returns the 1st) step;

The 3rd) step: medium process module is judged the validity of message under read states, is judged as to be, then calls the interface function of corresponding module, if be judged as not, then returns the 1st) step;

The 4th) step: medium process module judges whether to need to send message, if be judged as is, then sends a message to fax control module 41, returns the 1st) step; If be judged as otherwise directly return the 1st) step.

In sum, the stage of fax is according to the regulation of agreement T.30, mainly is divided in process before call setup, the message, the message behind process, the message process and calls out five stages that discharge, called after A, B, C, five stages of D, E respectively.Wherein call establishment stage is that the two ends of transmitting will be made a call by the calling party, and the callee should be responded, it is similar that this process and phone are set up the process of conversing, it should be finished by Call Control Block 43, and before the message in the process, message behind process, the message this three phases of process be the distinctive stage of fax, comprise consultation parameter, training channel and transmitting facsimile data etc., T.38 agreement has detailed regulation to a little processes, so it should belong to medium process module 42 and finish.The last stage is called out the release stage, is to disconnect the process that connects, and therefore the clearing phase of similar and plain old telephone should belong to Call Control Block 43 and finish.It is as follows to send the main flow process of fax, and all are well on to suppose time process, and mistake does not take place:

1) by fax control module 41 send create sessions message to medium process module 42, notify it will create one tunnel new session status.Medium process module 42 is returned the message of creating this session success, and the state in the medium process module 42 can be transitted towards creation state simultaneously, and the state in the fax control module 41 will idle condition be transformed to fax and changes state at the beginning.This stage belongs to initial phase, does not still belong in five stages of faxing any one.

2) send the exhalation message to Call Control Block 43 by fax control module 41, and the information of the opposite end that will call out on subsidiary, finish the whole process of calling by Call Control Block 43, the state in the control module of faxing simultaneously 41 becomes just at call state.After this process was accepted, Call Control Block 43 will be to the success of fax control module 41 reporting call, and link is set up.This process belongs to the A stage of fax.

3) send message to medium process module 42 by fax control module 41, notify it to begin to carry out speech play, and at the same time the link information of having set up is passed to medium process module 42, initiate self a timer of 3 seconds simultaneously, be used for regularly.Medium process module 42 will be play one section dialing music, simulate the tradition fax and switch to the needed fax switching of FAX mode sound from telephone state, at this moment, medium process module 42 is in plays voice status, and fax control module 41 still is in just at call state.This process still belongs to the A stage.

4) after playing dialing tone, the opposite end can at first switch to the fax pattern, and Call Control Block 43 can obtain the opposite end and switch the information that finishes, and this message is reported to fax control module 41.At this moment, fax control module 41 can be sent out message and give medium process module 42, makes it switch to FAX mode, and the message of medium process module 42 meeting report state handover success.At this moment medium process module 42 is in the id information state that obtains, and fax control module 41 is in the fax capability negotiation stage.Begin to enter the B stage of fax.

5) by the communicating by letter of fax control module 41 and opposite end, finish the task of B, C, D three phases, this process all is responsible for by fax control module 41, and after process finishes, the message that finishes to the 41 report transmissions of fax control module.Fax control module 41 is in the facsimile transmission state always in this process, and medium process module 42 with experience information judgement, wait for the opposite end send, train, just in the stages such as transmission page, DTD and conversation ends.After this process finished, the D stage also just was through with at this point.

6) fax control module 41 sends message to Call Control Block 43, allows it discharge link, sends message again to medium process module 42 simultaneously, allows its release just now in order to send all resources that No. one fax is applied for, this process is a stage E.At this point, one step completed facsimile posting just is through with.

The main flow process of receiving faxes following (all are well on same hypothesis time process, and mistake does not take place):

1) at first by sending message, notice fax control module 41 has the calling of an opposite end to enter to Call Control Block 43, and fax control module 41 can think that call link begins to set up, and switches its state.From then on process begins, and enters stage A.

2) fax control module 41 sends message to medium process module 42, notify it to create one tunnel session, if this operation runs succeeded, then medium process module 42 can be returned acknowledge message, and make fax control module 41 generation states migrate, and notification call control module 43 transmission confirmation signals, show the foundation of link.At this moment, be in the A stage.

3) send message to medium process module 42 by Call Control Block 43, notify it to begin to carry out Fax over IP, and at the same time the link information of having set up is passed to medium process module 42, allow it play one section dialing music, simulate the tradition fax and switch to the needed fax switching of FAX mode sound from telephone state, at this moment, medium process module 42 is in plays voice status, this process is regularly, so do not need medium process module 42 to notify fax control module 41 after finishing.This process still belongs to the A stage.

4) fax control module 41 notice medium process module 42 are switched, and at this moment, both sides begin to carry out parameter consultation and training etc., and are carried out the real-time report of state by medium process module 42.This stage has belonged to the B stage of fax.

5) both sides carry out based on the T.38 communication of agreement, and transmit the state that carries out by medium process module 42 reports.This stage mainly belongs to B, C, D three phases.

6) Call Control Block 43 is reported the message that the other side are hung up to fax control module 41, and 41 of control modules of fax are carried out corresponding state and switched, and discharge link, send message informing medium process module 42 simultaneously and carry out the release of resource.This process belongs to the E stage of fax.

In above-mentioned process, can see that obviously fax control module 41 is the cores that are in the process control of whole fax, it is by the maintenance of oneself state and migrating of state, constantly send various message to medium process module 42 and Call Control Block 43, make these two modules finish function corresponding, thus the whole process of coordinating of finishing fax.

The major function of Call Control Block 43 is to provide simple, a unified programming interface for the SIP on upper strata uses.Functions such as calling, reservation, transfer, transmission/reception DTMF are provided, and this module externally provides a unified call control protocol interface, and this interface comprises three class orders: user command, call command, control command.Request/answer-mode is used in order.

Call Control Block 43 is integrated Session Initiation Protocol stack and rtp stack, and finish management to two protocol stacks by the control of state machine, keep a residing state of session.Session Initiation Protocol is mainly used in the initiation of session, the affirmation of session, and it can simulate dialing on the PSTN network and the process of initiation connection, and rtp stack is the carrying of main voice then.Therefore, this module is divided into two modules by function, mainly calls out by the Session Initiation Protocol stack and process such as negotiation for one, and another mainly carries out the carrying of voice by the RTP built-in function.

The function that Call Control Block and speech control module are responsible for calling Session Initiation Protocol stack and rtp stack respectively communicates.Call Control Block particularly also needs the maintain sessions call state and comes to communicate with the SIP application program by transmission of messages.The message of this communication promptly will meet call control protocol, and agreement comprises three class orders: user command, call command, control command.Specifically mainly be described below:

User command: this group command mainly comprises lands and withdraws from two orders, and for using Call Control Block 43, it can only send.After landing success, withdraw from before the user be in line states.Only be in line states, could use call command and control command.Each connection can only have a user online at one time.SIP uses can set up a plurality of the connection with Call Control Block.Land and be used for user registration and land, to the enough resources of system request, also want timed sending to activate after the registration and register in the time of registration.Withdraw from and be used for the user and withdraw from, cancel the resource of its application simultaneously.

Call command: this group command is mainly used in and makes a call, and connects, and operation such as hangs up, and can send and receive.Making a call must be first order of calling out, and it need specify the unique call-id of the overall situation, in order to identify this calling.The order that makes a call can be used by SIP and be initiated, and this moment, SIP used as the calling party; Perhaps initiated by Call Control Block, this moment, the SIP application was the callee.The order that connects can only could be initiated under the state of call setup or shake bell, calls out after replying to be in connection status.Ath command can be in free position, and except idle condition, following initiation stops a calling.

Control command: this group command mainly plays control action in session, control command comprises HOLD, REFER, four orders of AUDIO, DTMF, for the module of using CCM, HOLD, AUDIO can only send, REFER, DTMF can send and receive, notice that control command does not change call state.The HOLD order promptly keeps/fetches order.If specified sid, be exactly the sid that only keeps appointment, otherwise keep all sid.The REFER order is the calling transfer order.The AUDIO order is voice control command with the DTMF order, can change the voice send mode of CCM module.

Mentioned order that is to say that SIP application person can issue the message of Call Control Block, and this message has set form.

9 kinds of states that Call Control Block 43 has are respectively idle (IDLE) state, (INVITING) state that makes a call, call setup (INVITED) state, acceptance (ACCEPTED) state, shake bell (RINGING) state, calling transfer (OFFERING) state, connection (CONNECTED) state, stop (TERMINATING) state, stop (TERMINATED) state.

The realization of voice service module is relatively simple, its state have only play voice with close two states of voice, its state is to be subjected to controlling of Call Control Block.After link establishment, Call Control Block will send message (its form is identical with foregoing command format) and give voice service module, allow it carry out mode switch, enter the broadcast voice status, and after link disconnected, it also can be notified voice service module that state is switched to and close voice status.

As shown in Figure 9, the concrete effect of each process of the present invention and thread is as follows:

The Call Control Block process: the main work of being responsible for the opposite end such as link establishment, wherein realized the content of Session Initiation Protocol, be to make a call and accept the carrying person of functions such as incoming call.

The medium process module process: T.30 this process mainly realized, agreement T.4 and T.38 is responsible for the transmission of physical signaling and data in facsimile posting, can be described as the core of responsible actual transmissions.

TCP server thread: be responsible for and the communicating by letter of mail transmissions/receiver module, monitor and the information receiving and transmitting of mail transmission/receiver module, formatting messages is sent in the message queue.

Call processing module TCP client thread: be responsible for and the communicating by letter of call processing module, the information receiving and transmitting of monitoring and call processing module sends to format messages in the message queue.

Media TCP client thread: be responsible for communicating by letter with medium process module, the information receiving and transmitting of monitoring and medium process module sends to format messages in the message queue.

Fax Control main thread: be responsible for the message in the processing messages formation, realize function to fax managing module and call state machine definition.

Fig. 9 has shown the software architecture of a complete Fax Server module.In this framework this module is embodied as 3 independently processes.

At first, fax control module process is the core of this module, and it is to be made of jointly fax managing module and two modules of call state machine, is administering the state and the information of whole fax.Because the relation between fax managing module and two modules of call state machine are mutual is very close, and the real-time of communication requires height very, so having synthesized a process with it, we realize, though done when the realizing partial destruction like this independence of module and the terseness of Module Division, but it can obtain huge performance boost, so still very wise.This process has a message queue, be used for collecting the message that other processes send over, and analyze, trigger then that corresponding state changes in the processing of fax managing module and the call state machine, meanwhile, be connected by the interprocess communication that is connected with other processes its work that needs other modules to finish is sent with the fixed format information form.Such as, be to set up the message that finishes now in the message queue by the connection that Call Control Block sends over, the control module of then faxing is accepted this message, and produce corresponding state and switch, be connected transmission message by interprocess communication at last, allow medium process module carry out further work with medium process module foundation.If other processes send message for the fax managing module, then it will organize plug on this message queue, till having new message to handle.Fax control module process also comprises three sub-threads, the task of these three sub-threads is very simple, it is exactly that constantly monitoring is connected the message arrival whether form up to specification is arranged with the interprocess communication that other processes are set up, if have, then be delivered to message queue, handle by the main thread of fax managing module.The reason that needs these three threads is that it can be blocked in each interprocess communication connection, when really message being arranged, carry out the delivery of message again to message queue, and do not need main thread to be in blocked state always, constantly monitor three interprocess communications and connect, thereby increased efficient.

Secondly, Call Control Block will be embodied as an independent process, and it mainly is responsible for connecting with far-end.The communication mode of itself and other process mainly contains 2 kinds, and the first, if it has message will report fax control module process, then, the message that send is sent to the fax control module by message queue.The fax control module obtains can doing corresponding processing after the message.The second, the Call Control Block module can be by being connected the task that the control module that obtains to fax requires it to finish with the interprocess communication of fax control.

At last, medium process module is embodied as independently medium process module process.Realized T.30 in this process, T.38 with T.4 wait agreement, this process also Call Control Block process with top is similar, send message by message queue to fax control module process on the one hand, and constantly monitoring is connected with the interprocess communication that fax control module process is connected, and is assigned to its work thereby finish fax control module process.

Claims (4)

1. Fax over IP device, comprise mail transmission/receiver module (1), session initiation protocol facsimile equipment (2), back-to-back user agent (3), it is characterized in that: also comprise Fax over IP server (4), the control command port of mail transmission/receiver module (1) is connected with Fax over IP server (4), and Fax over IP server (4) can send feedback information to mail transmission/receiver module (1) after receiving; First output of Fax over IP server (4) is connected with the input of session initiation protocol facsimile equipment (2), has realized T.38 flowing to the mutual conversion of fax paper form; Second output of Fax over IP server (4) is connected with back-to-back user agent's (3) input, has realized the encapsulation to SIP stack;

Described Fax over IP server (4) comprises fax control module (41), medium process module (42), Call Control Block (43);

Fax control module (41) comprises fax managing module (411) and call state machine module (412), also obtains the FAX mode notification message when fax managing module (411) realizes to the fax operation requests of the management of fax operation, the transmission/receiver module that handles postal matter (1), by interface control facsimile call process, is undertaken alternately by intermodule communication and mail transmission/receiver module (1); And call state machine module (412) is responsible for safeguarding facsimile call process status machine, is finished fax registration/cancellation, fax incoming call exhalation by interprocess communication;

Medium process module (42): realize T.38 flowing to the mutual conversion of fax paper form; And by interprocess communication, finish the mutual of the control of medium processing procedure and media session information between the call state machine module (412); The Real-time Transport Protocol destructing; The RTP passage is set up/is removed, the rtp streaming transmitting-receiving;

Call Control Block (43): realize the encapsulation of SIP stack, can finish the structure and the parsing of session initiation protocol, carry out the release that builds on of link with the opposite end of communicating by letter; And the call state machine module is used interprocess communication between (412), finishes call control procedure.

2. the described Fax over IP device of claim 1 sends the method for faxing, and it is characterized in that:

The first step, mail transmission/receiver module (1) is to fax control module (41) transmission information, after receiving information, fax control module (41) sends a confirmation to mail transmission/receiver module (1), require mail transmission/receiver module (1) that the form of concrete deposit data position with pathname provided simultaneously, fax control module (41) just sends a fax acknowledge message and shows the facsimile signal that begins to handle and send required transmission to mail transmission/receiver module (1);

Second step, fax control module (41) judges whether to carry out facsimile transmission, if the judgment is No, be that call state machine module (412) is operated at full capacity, then send failure, fax control module (41) will circular mail transmissions/receiver module (1), allows mail transmission/receiver module (1) repeating transmission; If the judgment is Yes, then its interface function that can call call state machine module (412) produces one tunnel new fax session, and with the IP address of opposite end with the facsimile data path of client information and required transmission etc. is all carried out record;

The 3rd step, Call Control Block (43) sends conversation initiating protocol message to the fax session callee, whether both sides carry out link and connect, and finish T.38 protocol version, whether shift out or insert filling bit when transmitting T.38 data among peak transfer rate, the process C, carrying out the ability conversion between linear format and the MMR form, carry out format conversion between linear format and JBIG form, be locally to produce information reconciliation such as training signal and send the mutual of information such as training signal, identify label.After receiving the confirmation of receipt that the callee sends, fax control module (41) thinks that link sets up, and can switch on the process of transmission medium; At this moment, fax control module (41) just sends by medium process module (42) passes through T.38 finished fax signaling of agreement and facsimile signal, and the callee communicates with fax session, and cuts off link behind end of transmission; In this process, if make a mistake, fax control module (41) will finish this transmission, and to the reason of mail transmission/receiver module (1) reporting errors; If do not send mistake, fax managing module (411) can this time send successfully to mail transmission/receiver module (1) report.

3. Fax over IP device according to claim 2 sends the method for fax, and it is characterized in that: the concrete work of fax managing module (411) is as follows:

The 1st step: the fax managing module is blocked on the message queue,

The 2nd step: the fax managing module is cancelled breath from message queue,

The 3rd step: the fax managing module judges whether message is effective, as if being judged as is, the fax managing module passes to call state machine module (412) by the function of the driving condition machine that calls the call state machine module and provide with message; If be judged as not, then abandon message and got back to for the 1st step;

The 4th step: the fax managing module obtains function return value, and sends a message to corresponding module according to function return value, returns for the 1st step.

4. Fax over IP device according to claim 2 sends the method for fax, it is characterized in that:

The concrete method of work of medium process module (42) is as follows:

The 1st) step: Select is a function, management multichannel message, i.e. a massage set; Select calls obstruction, in case the message of having detected, process obtains to carry out;

The 2nd) step: medium process module (42) obtains a piece of news, and the validity of message is judged, if be judged as is, then sends Target id according to message and finds corresponding session; If be judged as not, then return the 1st) step; Judge simultaneously whether the message obtained is establishment information, being judged as is to create or discharge a dialogue, is judged as otherwise returns the 1st) step;

The 3rd) step: medium process module is judged the validity of message under read states, is judged as to be, then calls the interface function of corresponding module, if be judged as not, then returns the 1st) step;

The 4th) step: medium process module judges whether to need to send message, if be judged as is, then sends a message to fax control module (41), returns the 1st) step; If be judged as otherwise directly return the 1st) step.

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