JP2008011072A - Transmitting and receiving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmitting and receiving method of selecting a combination of a flow and a path with which two terminals which are communicating with each other can communicate with correct data even if two or more events occur to one or both of the terminals simultaneously. <P>SOLUTION: When an event occurs, a child process or child thread is generated and a parent process is made to be always adaptive. Further, a lock function is provided for data that a communication management section holds, and sequential access is gained. Further, a message reported through a network is provided with a management number to judge which information is latest. Further, when communication media are transmitted, down path information is sent back. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transmission / reception method having a communication path selection function in a third layer mobility management protocol such as MobileIP and allocating a band to an application.

  In recent years, research and development of mobility support in the IP layer such as MobileIPv6 (Mobility Support in IPv6, RFC3775) has been actively conducted. MobileIP is a third-layer protocol in the (OSI; Open Systems Interconnection) 7-layer model that hides the movement of clients (network / communication media switching, communication interruption, etc.) from higher-level applications and continues communication. Technology. This MobileIP is composed of nodes called a mobile node (MN), a home agent (HA), and a correspondent node (CN).

  A mobile node (MN) always has an invariable address called a home address, and a node that manages the address is a home agent (HA). When the MN connects to a network other than the home link that is the HA link, the MN obtains an address called a care-of address (CoA) by some means (RA, DHCPv6, etc.). The CoA obtained here is notified to the HA by a message “Binding Update”.

  As a result, when a node (= CN) that wants to communicate with the MN transmits a packet addressed to the home address, the home address reaches the HA once because the home address is the address of the link managed by the HA. At that time, the HA transfers the home address to the associated CoA. As a result, the MN can always communicate with the home address. In the MN, an application operating on the MN always uses the IP address called the home address for communication.

  CoA is used as the source address or destination address of an actual IPv6 (Internet Protocol Version 6) packet. Further, in order to conceal the movement from the upper application, techniques such as IPv6 over IPv6 encapsulation and mobility header are used. As a result, the home address is notified to the application, and the IPv6 address (CoA) actually used is concealed. As a result, the application has the following characteristics.

  (1) When there is connectivity with a network, communication is always possible using a home address. (2) During communication, handover to a plurality of different networks can be performed. That is, the MobileIP compatible terminal can have a plurality of communication media (for example, NIC: Network Interface Card), and can perform handover across the plurality of communication media.

  In addition, when MobileIP has a plurality of CoAs, it is often said that it can realize multihome using a plurality of communication media simultaneously. However, in the actual MobileIP specification, multihome cannot be realized. Therefore, as one means for realizing this, since all CoAs should be notified to the communication partner and the HA, the MobileIP specification “draft-ietf-monami6- "multiplecoa" has been proposed. Further, Patent Document 1 is known as a technique for simultaneously using a plurality of communication media.

In addition, in the L3 mobility protocol with multi-home function represented by “draft-ietf-monami6-multiplecoa”, policy routing setting and application operation are performed in END terminal communication in order to increase the use value of the function. Cooperation is required.
In order to solve these problems, a technology has been proposed in which policy routing is set for each application according to the preference of the application, and each application can communicate in a band suitable for the policy routing setting. Yes.
Special table 2004-528765 gazette

  However, in the above sequence, in response to a sequence, an event such that one of the communication media becomes unusable in both END terminals or an event such as the availability of some communication media occurs at the same time. It remains unresolved.

  For example, as shown in FIG. 20A, in the initial communication start sequence, the communication management unit of the terminal 10 receives flow information (including whether or not to become an initiator) from an application, and is to become an initiator. Transmits the NIC information of the communication media to the communication partner terminal 11. As a result, path information is obtained from the other party. This path information includes both uplink and downlink.

  If this is applied when both events occur simultaneously in both communication terminals in communication, the following situation occurs. For example, as shown in FIG. 20B, on the communication terminal side where an event has occurred, communication media information is transmitted to the communication partner as much as possible as an initiator. At this time, since it becomes an initiator, it is expected that path information will be returned from the communication partner terminal. If this occurs simultaneously in both communication terminals, both become initiators, and there is a problem that even if communication media is received, the path information cannot be returned, that is, a so-called sequence falls into a deadlock state.

  In the present invention, in order to solve the above-described problem, when an event occurs, a child process or a child thread is generated to respond to the event, and the parent process can always respond to the event. In addition, a lock function is provided for data held by the communication management unit so that access is performed sequentially. Further, a management number is provided in a message notified via the network so that it can be determined which information is the latest. Also, whenever communication media information is transmitted, downlink or uplink path information is transmitted.

  The transmission / reception method according to the present invention receives flow information, reception of change of own communication media, and reception of completion of path status when transmitting / receiving one or more flows between two communication terminals using one or more paths. When receiving one or more events of receiving path information, receiving changes in communication media on the other side, receiving path priority, and receiving selected path information, create a child thread for each event And selecting a combination of flow and path.

The child thread for each event locks the database, performs a predetermined process such as writing or reading information related to each event, unlocks the database, and then the child thread sends information to the partner communication terminal. Quit by sending etc.
In addition, when performing the above transmission / reception, the communication terminal has at least the communication partner address as communication partner information of the communication partner, as well as its own communication media management number, the other party communication media management number, its own path management number, Any one of the other party path management number, the own party priority management number, and the other party priority management number is used.

  According to the present invention, it is possible to continue communication without causing a deadlock even if an event occurs simultaneously in two communication terminals in communication. Further, even when a plurality of events occur within a minute time, it is possible to finally have correct information, and correct communication can be continued. Furthermore, even in the case of a one-way application such as video streaming, it is only necessary to hold a one-way path without performing special processing, and it is not necessary to hold / transmit / receive useless data.

  The outline of the present invention will be described with reference to the drawings. FIG. 1A is a schematic diagram of a system configuration using an example of video streaming. One terminal 10 has an IP 10 as a home address, NIC 100 and NIC 101 as communication media, and both of them have the Internet. Suppose you are connected to. The other terminal 11 (communication partner terminal of the terminal 10) has IP11 as a home address, NIC110 and NIC111 as communication media, and it is assumed that the NIC 110 is connected to the Internet.

  The configuration of the terminal 10 and the terminal 11 roughly includes a moving image transmission / reception application (13a, 13b), a communication management unit (14a, 14b), and a MultipleCoA unit (15a, 15b). Here, the communication management unit (14a, 14b) includes a communication media monitoring module 16, a path management module 17, and a path status acquisition module 18, as shown in FIG. The communication media monitoring module 16 mainly has a function of monitoring the NIC of the communication media, determining whether the NIC can be used, and receiving an event raised from the MultipleCoA. It has a function of notifying the management module 17.

The path management module 17 has a function for receiving flow information from the applications (13a, 13b), a function for receiving communication media information notified from the communication media monitoring module 16, a function for transmitting communication media information to the communication partner, and a communication medium from the communication partner. It has a function for receiving information, a path (combination of communication media) creation function, a priority determination function, a policy routing setting function, a bandwidth allocation notification function, a database function, and the like.
The path state acquisition module 18 has a function of acquiring a path state such as bandwidth information and delay time by measuring an END-END path or acquiring it from information held by a path state server. .

Here, for example, it is assumed that the following event occurs in the communication terminal.
(1) Start the communication terminal.
(2) Start communication between two communication terminals.
(3) On the communication terminal 10 side, the communication media NIC 101 becomes unusable.
(4) Thereafter, the communication media NIC 111 on the communication terminal 11 side can be used.

  First, the process at the time of starting the communication terminal (1) will be described with reference to the sequence diagram of FIG. For example, when the communication management unit 14a of the terminal 10 is activated, the communication media monitoring module 16 determines the currently usable communication media NIC and transmits a list of available communication media to the path management module 17 as communication media information. To do. The path management module 17 generates a child thread triggered by the reception of communication media information. The child thread accesses the database function of the path management module 17 and first locks the database. As a result, the database cannot be read or written by other than this child thread until the database is unlocked.

  By the way, in the following description of the present invention, the above description “locking the database” frequently appears. This is because while the thread A is locking the database, the thread B is the database. Say to refuse to try to access. That is, the B thread waits until the A thread unlocks the database. As a result, access to the database is always performed sequentially.

  In the system configuration as shown in FIG. 1, information on NICs 100 and 101 of communication media is written in the terminal 10, and information on the NIC 110 of communication media is written in the terminal 11. The communication media information has at least CoA (care of address) of the NIC. The communication media information is shown in FIGS. 3 (A) and 3 (B). FIG. 3A shows communication media information on the terminal 10 side. The NIC 100 has a CoA100 IP address and is 11 Mbps NIC both upstream and downstream, and the NIC 101 has a CoA101 IP address and 54 Mbps NIC both upstream and downstream. It is shown that. FIG. 3B shows communication media information on the terminal 11 side, and shows that the NIC 110 has an IP address of CoA 110 and is 11 Mbps NIC for both uplink and downlink. When the communication media information is written in the database, the database is unlocked and the child thread disappears.

  Next, the process of starting communication between the two communication terminals (2) will be described with reference to the sequence diagrams of FIGS. 1 and 4-1 to 4-6. First, as illustrated in FIG. 4A, communication related to call control is performed between the moving image transmission application 13b and the moving image reception application 13a, and the flow information is determined. The moving image receiving application 13a on the terminal 10 side notifies the determined flow information to the path management module 17 of the communication management unit 14a. This flow information is data as shown in FIG. 5, the source address of the flow is IP11, the destination address is IP10, that is, the flow information is downstream (direction from the terminal 11 to the terminal 10).

  The destination port is 9080, the source port is not specified, the preference level for the bandwidth BW1 (50 kbps) is essential (Must), the preference level for the bandwidth BW2 (400 kbps) is * 1, and the bandwidth BW3 The preference information is * 5, the preference level for delay is * 1, and the preference level for price is * 3. The path management module 17 of the communication management unit 14a starts to operate when triggered by notification of downstream flow information from the application. The path management module 17 that has received the downstream flow information generates a child thread.

  The generated child thread first locks the database of the path management module 17 and writes the acquired flow information. Next, communication partner information regarding the corresponding communication partner is read. In the case of this example shown in FIG. 4A, this information does not exist, but this information may exist when there is communication by another application. Next, it is checked whether there is a downlink path related to the communication partner (terminal 11). This is because there is a case where a downlink path already exists when communication between the terminal 10 and the terminal 11 is performed by another application. However, in this example, there is no other application, and the downlink path does not exist in the database, so the communication media information on the own side (terminal 10 side) is read and the communication partner information is written.

  At this time, the own communication media management number of the communication partner information is written as “+1” to the communication media management number of the communication partner information read earlier. In this example, since there was no communication partner information at the time of reading, as shown in FIG. 6A, the own communication media information management number is set to “1”, so the counterpart communication media management number is “0”. In the other party address, information is written as IP11. Thereafter, the database is unlocked, and the communication media information as shown in FIG. 3A and the communication media information management number on its own side (terminal 10 side) are displayed in the path management module 17 of the communication management unit of the communication partner (terminal 11). To be notified.

  Next, a process on the terminal 11 side that has received the communication media information from the terminal 10 will be described with reference to FIG. The terminal 11 generates a child thread triggered by receiving communication media information from the terminal 10. The created child thread first locks the database. Next, the communication partner information (terminal 10) is read, and the partner communication media information management number in the database and the communication media information management number on the terminal 10 side attached to the communication media information received from the terminal 10 are obtained. In comparison, if the received management number is larger, the check is OK. In this example of FIG. 4B, since there is no communication partner information, it is considered that the partner communication media information management number = 0 and 1> 0, so the check is OK. When the check is OK, the notified communication media information of the terminal 10 is written in the database.

  Also, the communication media information of the own side (terminal 11) is read, and path information as shown in FIG. 7A is created from the communication media information of the other party and the own communication media information. The path information includes a transmission source terminal identifier SrcAddr, a transmission destination terminal identifier DstAddr, usable bandwidth (blank here) in the path, delay time, price, transmission communication medium SrcNIC, transmission destination communication medium Information such as DstNIC. In this example, the source terminal for both path 1 and path 2 is a terminal having IP11, that is, terminal 11, the destination terminal is terminal 10 having IP10, and the source NIC for both path 1 and path 2 is NIC110. Only the destination NIC is different, indicating that the NIC 100 is used in the path 1 and the NIC 101 is used in the path 2.

  This path information is written in the database, and “+1” is written in the database as the value obtained earlier for the local path management number of the communication partner information. In this example, “0 + 1” is “1”, and the other party communication media information management number is written as the received number (= 1) as shown in FIG. When these writes are finished, the database is unlocked. Then, the path information is transmitted to the path management module 17 of the communication management unit of the terminal 10 together with its own (terminal 11) path management number (= 1). This child thread disappears when the path information is transmitted.

  Next, processing on the terminal 10 side after receiving path information from the terminal 11 will be described with reference to FIG. The path management module 17 of the terminal 10 receives the path information from the terminal 11, generates a child thread, and locks the database. Next, the communication partner information is read, the partner path management number is compared with the received terminal 11 side path management number, and if the received management number is larger, the check is OK, and the received path information is Write to the database. Also, “+1” is added to the partner path management number of the communication partner information, and the database is written into the database to unlock the database. The path information obtained here is sent to the path status acquisition module to request acquisition of the path status, and this child thread disappears.

  The path status acquisition module 18 acquires the path status based on the received path information. The path status may be acquired from a server on the network, or actually measured by END-END. When the network status is acquired by the path status acquisition module, the path management module is notified that the acquisition has been completed (FIG. 4-4). This data (acquisition completion) has values such as usable bandwidth / delay time / price of path information.

  FIG. 4-4 shows a processing sequence subsequent to FIG. 4-3, and the path management module 17 of the terminal 10 inputs a value such as usable bandwidth / delay time / price in response to the acquisition end message. Is possible. FIG. 7B shows path information after this value is entered in the path. First, the path management module 17 creates a child thread and path information as shown in FIG. 7B from the received path status acquisition end message, locks the database, and overwrites the path information. Next, the path information is read, and further the flow information is read to determine the path priority.

  The path priority order is a combination of each flow and path. In this example, there is only one flow, so there are the same number of combinations as the number of paths. This path priority is as shown in FIG. 8A as an example. For example, in the case of the combination 1, the flow 10-1 uses the path 1, 400 kbps, the score is 95, and the combination 2 In this case, path 2 is used, 2 Mbps, and the score is 103. This indicates that the terminal 10 side prefers the combination 2 more. When this path priority is determined, read the local priority management number of the communication partner information, write “+1” there as the new local priority management number, write the communication partner information to the database, and unload the database. Lock it. Next, a grandchild thread is generated to transmit this path priority. The grandchild thread transmits the path priority and the new own priority management number to the communication partner (terminal 11).

  Next, processing on the terminal 11 side that has received the path priority will be described with reference to FIG. The path management module 17 of the terminal 11 that has received the path priority order generates a child thread. The child thread first locks the database. Next, the communication partner information is read, and the partner priority order management number in it is acquired. If “the other party priority management number in the database <the received other party priority management number”, the following processing is performed with the check OK. First, one combination of path priorities transmitted by the other party is selected. Write it to the database as selected path information. Also, the received partner priority management number is written as communication partner information. Thereafter, the database is unlocked, and the selected path information is transmitted to the terminal 10. At this time, the path priority is transmitted by the received partner priority management number, and the child thread disappears.

  Next, processing on the terminal 10 side that has received the selected path information will be described with reference to FIG. When the terminal 10 receives the selected path information from the terminal 11, it first locks the database with a grandchild thread that has not been terminated. Next, the communication partner information regarding the terminal 11 is read, and its own priority management number is acquired. In the case of “your own priority management number in the database” ≦ “received own priority management number”, the path selected as the check OK is written to the database and the database is unlocked. Based on the selected path information, the network state is notified to the application (video receiving application) 13a. This network state is information as shown in FIG. 8B, and includes information such as bandwidth, delay time, and price that the flow can use to the maximum.

  Also, before and after this, a routing policy is set. This is performed using an IF (InterFace) of a multi-home compatible protocol such as MultipleCoA. The information necessary at this time is information as shown in FIG. 8C. The source terminal identifier SrcHoA, the source port number, the destination terminal identifier DstHoA, the destination port number, and the four A flow can be uniquely identified by information, and these four pieces of information are flow identifiers. On the other hand, SrcNIC that is a transmission source communication medium and DstNIC that is a transmission destination communication medium are followed by information for routing a flow.

  As a result, the routing policy of the flow 10-1 is set to route from the transmission source NIC 110 to the transmission destination NIC 101. In addition, the application 13a notified of the network status described above selects content corresponding to the maximum available bandwidth of the network information, presents price information to the user based on the price, or delays. It is possible to adjust the buffer amount based on time. In this example, as a result, it is determined that 2 Mbps content can be acquired, and the moving image receiving application 13a of the terminal 10 notifies the moving image transmission application 13b and the information through the call control protocol to acquire 2 Mbps content. .

  Next, the case where the communication media NIC 101 becomes unusable on the communication terminal 10 side in (3) will be described. This event is an example in which the communication media NIC 101 is newly unavailable from the system configuration shown in FIG. 1 as in the system configuration shown in FIG. 9, and the processing for this event is performed in the sequence shown in FIGS. 10-1 to 10-6. This will be described with reference to the drawings.

First, as illustrated in FIG. 10A, the communication media monitoring module 16 of the terminal 10 detects that the communication media NIC 101 cannot be used. This judgment that it cannot be used is based on these complex factors, such as when the RSSI (Received Signal Strength Indicator) falls below a certain threshold, or when the congestion and S / N (Signal to Noise) ratio falls below a certain value. Various methods can be considered, such as making a judgment. However, these methods are not taken into consideration here because they are not points of the invention, and the communication media monitoring module 16 can determine whether or not the communication media NIC can be used, and if there is a change in the status of the communication media. It is important that the path management module 17 has a function of notifying communication media information.

  The communication media monitoring module 16 notifies the path management module 17 of the communication media information when the communication media NIC 101 becomes unusable. As shown in FIG. 11, the communication media information is information on the NIC 100 that is a currently usable communication media. The path management module 17 that has received the communication media information generates a child thread. Lock the database with the created child thread and overwrite the local communication media information. Next, the flow information of the communication partner information is read and the database is unlocked.

  Here, it is assumed that there is no upstream flow and there is a downstream flow. Since there is downstream flow information, a grandchild thread is generated to process it, and since there is no flow information for upstream, the grandchild thread is not generated. The descendant thread of the downstream flow information first locks the database, reads the communication partner information, then reads its own communication media information, writes "+1" to its own communication media management number, and writes the communication partner information Unlock the database. Then, the communication media information NIC 100 and its own communication media information management number (= 2) are transmitted to the communication partner path management module 17.

  Next, processing on the terminal 11 side that has received the communication media information NIC 100 will be described with reference to FIG. This processing sequence is the same as that in FIG. 4B described above, but the received communication media management number is “2” and the received communication media information is different. Since the communication media management number in the current database is “1”, the check is OK, the NIC 100 is overwritten in the database as the communication media of the terminal 10, and the communication media management number “2” of the other party is stored in the database as the communication partner information. Finally, the path information is transmitted to the terminal 10 as the terminal 11 side path management number (= 2).

  Next, processing on the terminal 10 side that has received the path information will be described with reference to FIG. This processing sequence is the same as that in FIG. 4C described above, but the current terminal 11 side path management number is “2” and the content of the received path information is different. Since the terminal 11 side path management number in the current database is “1”, the received path information is checked as OK, and the received path information is overwritten in the database. At this time, the values such as the available bandwidth / delay time / price are previously acquired. Also, the communication partner information related to the terminal 11 is written as the newly received partner path management number (= 2). Then, the path status acquisition module 18 is requested to acquire the path status.

  Next, processing on the terminal 10 side after the path status acquisition module 18 receives the acquisition request will be described with reference to FIG. This processing sequence is the same as that shown in FIG. In this example, since the path is only deleted, it is not necessary to newly acquire a path state, and the acquisition end is notified to the path management module 17. When the path management module 17 receives the acquisition completion, it generates a child thread, first locks the database, writes path information (there is no path information to be written in this sequence), and reads all path information from the database. The flow information is also read, the path priority is determined, the path priority management number of the communication partner information is overwritten with “+1”, and the database is unlocked. Next, a grandchild thread is generated and the path priority is transmitted to the terminal 11 together with the path priority management number (= 2).

  Next, processing on the terminal 11 side that has received the path priority will be described with reference to FIG. This processing sequence is the same as that shown in FIG. That is, the terminal 11 that has received the path priority order generates a child thread, first locks the database, and checks the other party (terminal 10) side priority order management number. In this example, since the other party priority management number in the database is “1” and the received other party priority management number is “2”, the check is OK, and the selected path information is generated. The selected path information is written into the database, the other party priority management number of the communication partner information is written as “2”, the database is unlocked, and the selected path information is transmitted. In this case, the priority management number (= 2) on the terminal 10 side is also transmitted simultaneously.

  Next, processing on the terminal 10 side that has received the selected path information will be described with reference to FIG. This processing sequence is the same as that shown in FIGS. That is, when the selected path information is received, the database is locked, the communication partner information is read, and the own priority management number is checked. In this example, since the own priority management number in the database is “2” and the received own priority management number is also “2”, the check is OK. Therefore, the selected path information is written in the database, the network status is transmitted to the moving image receiving application 13a, the routing policy is notified using MultipleCoA-IF, and the application communicates with the optimum bandwidth through call control. become.

  Next, a case where the communication media NIC 111 on the communication terminal 11 side in (4) can be used will be described. As shown in the system configuration of FIG. 12, this event is an example in which the communication media NIC 111 can be used from the system configuration of FIG. 9, and the processing for this is illustrated in the sequence diagrams of FIGS. 13-1 to 13-5. Will be described.

  First, as shown in FIG. 13A, the communication media monitoring module 16 of the terminal 11 detects that the NIC 111 of the communication media that could not be used can be used. As a result, information on NIC 110 and NIC 111 as shown in FIG. 14 is notified to the path management module 17 as communication media information. The path management module 17 that has received the communication media information generates a child thread. Next, the database is locked, the communication partner information is read, and the local communication media information is overwritten. In addition, the flow information is read, the communication media management number on its own side is “+1” to “2”, the communication partner information is overwritten, and the database is unlocked.

  Since there is no downstream flow and only upstream flow in the flow information, a grandchild thread for performing processing when there is upstream flow is generated. Next, this grandchild thread locks the database, reads the partner communication media information and the local communication media information, creates path information, overwrites this path information, and manages the local path in the communication partner information. The communication partner information is written in the database as “3” by adding “+1” to the number. Then, after unlocking the database, the path information as shown in FIG. 15 and the own path management number (= 3) are transmitted to the terminal 10.

  Next, processing on the terminal 10 side that has received the path information will be described with reference to FIG. This processing sequence is the same as that of FIGS. 4-3 and 10-3 described above. That is, when the terminal 10 receives the path information, the path management module 17 generates a child thread. The child thread locks the database, reads the communication partner information, and checks the partner path management number.

  Here, since the path management number on the terminal 11 side in the database is “2” and the received path management number is “3”, the check is OK. Since the check is OK, the path information is overwritten, and the partner path management number of the communication partner information is overwritten as “3”. After unlocking the database, the path status acquisition module 18 is requested to acquire the path status. Since the path status acquisition module 18 has already acquired the path status for the path 1 in FIG. 15 in the event of (2) described above (see FIG. 7), the path status acquisition module 18 acquires the path status related to the path 2. After completion of acquisition, the path management module 17 is notified of the end of acquisition.

  Next, processing on the terminal 10 side after receiving the end of acquisition of path information will be described with reference to FIG. This processing sequence is the same as that in FIGS. 4-4 and 10-4 described above. That is, when the end of acquisition of the normal state of the path is received, a child thread is generated, the database is locked, the path information is written, the path information is read, and the flow information is read. Then, the path priority order is determined, the communication partner information is read, the local path priority management number of the communication partner information is overwritten with “+1”, and the database is unlocked. Next, a grandchild thread is generated, and the path priority is transmitted to the terminal 11 together with the path priority management number (= 3).

  Next, processing on the terminal 11 side that has received the path priority will be described with reference to FIG. This processing sequence is the same as that in FIGS. 4-5 and 10-5 described above. That is, the terminal 11 that has received the path priority order generates a child thread. First, the database is locked, and the priority management number on the terminal 10 side of the partner information is checked. In this example, the other party priority management number in the database is “2”, and the newly received other party priority management number is “3”. Therefore, the check is OK, and the selected path information is generated. The selected path information is written into the database, the partner side priority management number of the communication partner information is written as “3”, the database is unlocked, and the selected path information is transmitted. In this case, the terminal 10 side priority management number (= 3) is also transmitted simultaneously.

  Next, processing on the terminal 10 side that has received the selected path information will be described with reference to FIG. This processing sequence is the same as that in FIGS. 4-6 and 10-6 described above. That is, when the selected path information is received, the database is locked, the communication partner information is read, and the own priority management number is checked. In this example, since the own priority management number in the database is “3” and the newly received own priority management number is also “3”, the check is OK. Therefore, the selected path information is written in the database, the network state is transmitted to the application, the routing policy is notified using MultipleCoA-IF, and the application communicates with the optimum bandwidth through call control.

Next, an embodiment for specific event occurrence in the transmission / reception method of the present invention will be described with reference to the flowcharts of FIGS. Note that. The main features of the present invention are summarized in the following three points.
1. 1. Event separation 2. Create a child thread for each event and lock / unlock the database Control number check

Specific events are as follows.
[1] Receive flow information from application (from application)
[2] Receiving changes in communication media on the local side (from the communication media monitoring module)
[3] Receiving end of path status acquisition (from path status acquisition module)
[4] Receive path information (from communication partner path management module)
[5] Receiving change of communication media on the other side (from communication partner path management module)
[6] Receive path priority (from communication partner path management module)
[7] Receive selected path information (from communication partner path management module)
Of these, regarding [7], a message is not necessarily transmitted from the path management module to the parent thread, and a child thread has already been generated in the previous sequence and may be processed by the child thread. is there.

  First, “[1] Receive Flow Information from Application” will be described with reference to FIG. This notifies the application to request the communication management unit for routing setting and bandwidth allocation. This flow information includes a case where these are requested and a case where communication is terminated and the request is withdrawn. This can be viewed as a flow addition request and a flow deletion request from the path management module of the communication management unit. When the flow information is received (S100), a child thread based on the change of the flow information is generated (S101). The following processing is performed by this child thread.

  First, the database is locked (S102), and the acquired flow information is added (or deleted) to the database (S103). This database lock must be before the flow information is written. Communication partner information and flow information are acquired using the IP address of the communication partner obtained from the flow information as a key (S104). If there is no downstream flow in this flow information (S105 NO), the database is unlocked (S106), and the process is terminated (S107). If there is a downstream flow (S105 YES), the following processing is performed.

  As described above, path information is acquired using the IP address of the communication partner as a key (S108). If there is downlink path information (S109 YES), the database is unlocked (S110), the path status acquisition is requested (S111), and the child thread is terminated (S112). If there is no downlink path information (NO at S109), the communication media information of the communication partner is read (S113), the communication media management number of the communication partner information is increased (for example, +1), and then the communication partner information is written (S114). The database is unlocked (S115). Thereafter, the acquired own communication media information is transmitted (S116), and the child thread is terminated (S117).

  That is, the database is locked while the database data is being read or written. Further, it is necessary to unlock before acquiring a path status request to other modules, transmitting communication media information, and ending the thread.

  Next, “[2] Receiving change of own communication media state” will be described with reference to FIG. As shown in FIG. 16-2 (A), when it is detected (received) that a change has occurred in the communication media state on its own side (S200), first, a child thread is created (S201). Next, the database is locked (S202), and communication media information is written (S203). Next, the flow information is read (S204), and the database is unlocked (S205).

  Here, there are usually a plurality of pieces of flow information, and the number of communication partners is not necessarily one. Therefore, the flow information is checked for each communication partner, and if there is a downstream flow in communication with that partner (YES in S207), a child thread for transmitting communication media information is generated (S208). That is, when there are two communication partners and both have downstream flows, two child threads are generated here. Similarly, an upstream flow is also checked, and if there is an upstream flow (YES in S209), a child thread for path information transmission is generated (S210). Similarly to the communication media information transmission child thread, a plurality of child threads may be generated.

  Next, the processing of the communication media information sending thread (S209) will be described with reference to FIG. The child thread for communication media transmission is generated in a state where at least the IP address of the communication partner is known (S221). First, the database is locked (S222), the communication media information is read, the communication partner information is read using the IP address as a key (223), and the own communication media management number is increased and written to the communication partner information (S224). The database is unlocked (S225). Then, the communication media information and the increased own communication media management number are transmitted as a set to the communication partner (S226), and the child thread is terminated (S227).

  Next, processing of a child thread for transmitting path information will be described with reference to FIG. The child thread for transmitting path information is generated in a state in which at least the IP address of the communication partner is known in the same manner as the child thread for transmitting communication media (S231). First, the database is locked (S232). This locking must be done before reading the database data. Next, the communication media information is read, the other party communication media information is read using the IP address of the communication partner as a key, and the communication partner information is read (S233).

  Then, path information is generated based on the acquired communication media information and the partner communication media information (S234). Next, the path information and communication partner information are increased and written (S235), and the database is unlocked (S236). Note that the database must be unlocked after processing of communication media information acquisition, partner communication media information acquisition, and communication partner information writing. Then, the path information is transmitted together with the increased own path management number (S237), and the child thread is terminated (S238).

  Next, “[3] reception of completion of path status acquisition” will be described with reference to FIG. When the path status acquisition module acquires the path status, it notifies the path management module of the end of acquisition (S300). In the path management module, a child thread for performing a path status acquisition end process is generated (S301), and the path status included in the received acquisition end message is written in the database. Before that, the database is locked (S302). ). After locking the database, the network status such as bandwidth / delay / price is written in the corresponding path information (S303).

  Next, all path information is acquired using the IP address of the communication partner as a key, and all flow information with the communication partner is also acquired (S304). Thereafter, the own path priority management number of the communication partner information is increased and written in the database (S305), and the path priority is created from the path information and the flow information (S306). Next, the database is unlocked (S307), the created path priority is transmitted to the communication partner (S308), and the child thread is terminated (S309). Incidentally, the path priority order generation may be performed at any timing after the path information / flow information is read and before transmission to the communication partner.

  Next, “[4] Receiving path information” will be described with reference to FIG. When the path information is received (S400), first, a child thread is generated (S401). Next, the database is locked (S402), and communication partner information is acquired using the partner's IP address in the path information as a key (S403). Compare the partner path management number in the database with the partner path management number attached to the received path information, and if “path management number in database” <“received path management number”, check OK (S404 YES). If it is NG (S404 NO), the database is unlocked (S405), and the child thread is terminated (S406).

  If the check is OK, the received path information is written in the database (S407), and the communication partner information is written by substituting the newly received path management number as the partner path management number of the communication partner information (S408). . Thereafter, the database is unlocked (S409), a path status acquisition request is requested to the path status acquisition module (S410), and the child thread is terminated (S411). Here, the child thread does not necessarily have to be terminated, and may be left for receiving the selected path information.

  Next, “[5] Receiving change in communication medium on other side” will be described with reference to FIG. When a change in communication media information is received from the other party (S500), first, a child thread is generated (S501). Next, the database is locked (S502), and the communication partner information of the corresponding communication partner is read (S503). Compare the communication media management number of the other party in the database with the communication media management number of the other party attached to the received communication media information so that “communication media management number in the database” <“received communication media management number” If there is, check OK (S504 YES). If it is NG, the database is unlocked (S505), and the child thread is terminated (S506).

  If the check is OK (S504 YES), the received communication media information is written (S507), the communication media information and the communication media information is read (S508), path information is generated (S509), and the path information is Write (S510). Next, the own path management number of the communication partner information is incremented and written (S511), the database is unlocked (S512), the path information is transmitted (S513), and the child thread is terminated (S514).

  Next, “[6] Receive path priority” will be described with reference to FIG. When the path priority is received (S600), a child thread is generated as the path priority reception (S601). Next, the database is locked (S602), and communication partner information of the corresponding communication partner is acquired (S603). The other party priority management number of the communication partner information in the database is compared with the other party priority management number attached to the received path priority, and “priority management number in database” <“received priority management number” ", The check is OK (S604 YES). If it is NG (S604 NO), the database is unlocked (S605), and the child thread is terminated (S606).

  If the check is OK (YES in S604), the selected path information is generated from the received path priority order in consideration of the preference relating to own uplink (S607). The selected path information is written in the database (S608), and the partner path priority management number of the communication partner information is written as the received path priority management number (S609). Thereafter, the database is unlocked (S610), the selected path information is transmitted together with the path priority management number (S611), and the child thread is terminated (S612).

  Next, “[7] Receive selected path information” will be described with reference to FIG. First, when the selected path information is received, a child thread is generated for receiving the selected path information (S701). As for the case of receiving the selected path information, if the child thread is not terminated at the time of the above “[4] Receive path information”, the next child thread is not generated. May be. Next, the database is locked (S702), and the corresponding communication partner information is read (S703). By comparing the own priority management number of the communication partner information in the database with the own priority management number attached to the received selected path information, “the own priority management number in the database” ≦ “ If it is “the received own priority management number”, the check is OK (YES in S704). Only in this case, equals are entered. In the case of check NG (NO in S704), the database is unlocked (S705), and the child thread is terminated (S706).

  When the check is OK (YES in S704), the selected path information is written in the database (S707), the own priority management number of the communication partner information is written (S708), and the database is unlocked (S709). Thereafter, a routing policy is set using the interface (IF) of MultipleCoA, the network state that is information such as the allocated bandwidth is notified to the application (S710), and the child thread is terminated (S711).

  Next, the operation and effect of the present invention will be described with reference to FIGS. In the following description, as shown in the schematic diagram of the system configuration in FIGS. 17-1 to 17-3, a videophone is used as an application for communication between two terminals, and two flows of video and audio are performed. An example is bidirectional transmission / reception. Here, it is assumed that a series of processing sequences at the start of communication is completed, and communication with the optimum content has already been performed.

Now, in the transmission / reception between the two terminals, as shown in FIG. 17A, the terminal 10 communicates with the communication media NIC 100 and NIC 101, the terminal 11 is communicating with the communication media NIC 110 and NIC 111, and the NIC 112 becomes unusable. Suppose there is.
Here, as an event of transmission / reception between two terminals,
{1} When the NIC 112 of the communication media of the terminal 11 becomes usable, the NIC 111 becomes unusable almost at the same time. (Change from Fig. 17-1 to Fig. 17-2)
{2} The NIC 101 on the terminal 10 side becomes unusable almost simultaneously with the NIC 111 on the communication medium on the terminal 11 side becoming usable. (Change from Fig. 17-2 to Fig. 17-3)
This will be explained below.

  The above {1} is an example in which two events of the event that the communication media NIC 112 of the terminal 11 becomes usable and the event that the communication media NIC 111 becomes unusable occur at the terminal 11 almost simultaneously. This will be described with reference to the sequence diagram of FIG. The communication media monitoring module detects these events and notifies the path management module of communication media information. This may detect both events in a single monitoring, or may be detected in two parts. When both can be detected by one monitoring, the sequence is the same as usual. Here, an example in which detection is performed in two steps will be described.

  FIG. 18A illustrates a case where the communication media NIC 112 can be used slightly earlier than the communication media NIC 111 cannot be used. When the communication media NIC 112 becomes available, the generated child thread (child thread A) locks the database first, and the child thread (when the communication media NIC 111 becomes unavailable) Child thread B) cannot access the database.

  For this reason, the data of the child thread B, which is a slightly later event, is reflected later in the database, and the data in the database is correct. Here, since both the child thread A and the child thread B exist in both the upstream flow and downstream flow, as described in FIG. 16B, a child thread for transmitting communication media information and a child thread for transmitting path information are generated. The That is, for convenience, four child threads are generated. In FIG. 18-2, only the child threads (A-1, B-1) for transmitting communication media information are shown for easy understanding.

  As illustrated in FIG. 18B, the child thread A generates a child thread A-1 for transmission of communication media information. However, the communication media information to be transmitted by the child thread A-1 may be wrong. This is because the information is correct if the database is accessed after the information of the child thread B is reflected, but is not correct if accessed before that. Further, the child thread B generates a child thread B-1 for transmission of communication media information. The communication media information to be transmitted by the child thread B-1 is always correct with respect to the communication media information to be transmitted by the previous child thread A-1. This is because the child thread B-1 is generated after the information of the child thread B that generates the child thread B-1 is reflected in the database. That is, when viewing the access timing to the database, child thread A> child thread A-1, child thread B> child thread B-1 is established.

  Here, it is assumed that the transmission of the communication media information by the child thread A-1 is earlier than that of the child thread B-1. When attention is paid to the management number, if the communication media management number attached to the communication media information transmitted by the child thread A-1 is N, the communication media information transmitted by the child thread B-1 is: Since access to the database is sequential, the value is always N + 1 or more.

  Next, as shown in FIG. 18-3, the order of the communication media information transmitted by the child thread A-1 and the child thread B-1 is changed due to network jitter or the like while arriving at the terminal 10. Suppose. In this case, the terminal 10 processes the communication media information from the child thread B-1 that has arrived first. Here, the communication media information from the child thread B-1 is processed as the terminal 11 side communication media information management number N + 1. Then, the partner communication media management number in the partner terminal information regarding the terminal 11 in the terminal 10 is N + 1. Thereafter, the communication media information from the child thread A-1 arrives and is processed. However, since the management number is N, it becomes a check NG and is not processed.

  As a result, the sequence of the child thread B-1 born from the child thread B is advanced. Incidentally, when the communication media information of the child thread A-1 arrives first, the processing of the child thread A-1 is processed as usual, but immediately after that, the communication media information of the child thread B-1 is Since the process arrives and is processed as usual, the process of starting from the child thread B-1 is finally performed.

  The above example is a case where “the transmission by the child thread A-1 is earlier than the child thread B-1,” but conversely, “the transmission by the child thread B-1 is more than the child thread A-1. It may be “fast”. In this case, both the communication media information transmitted by the child thread A-1 and the communication media information transmitted by the child thread B-1 are after the child thread B, as shown in FIG. Information will be transmitted. The description of the subsequent sequence is omitted.

  Next, transmission of path information will be described. This is the same as transmission of communication media information. The child thread A generates a child thread A-2 for transmitting path information, and the child thread B generates a child thread for transmitting path information. B-2 is generated. Here, it is assumed that the child thread B is always processed after the child thread A. The child thread A-2 is later than the child thread A, but the time relationship with the child thread B is unknown. The child thread B-2 is always processed after the child thread B. That is, looking at the access timing to the database, child thread A> child thread A-2 and child thread B> child thread B-2 are established.

  Here, it is assumed that the transmission of path information by the child thread A-2 is earlier than that of the child thread B-2. When attention is paid to the management number of the path information, if the own side (terminal 11 side) path management number attached to the path information transmitted by the child thread A-2 is M, the communication media information transmitted by the child thread B-2 is Since access to the database is sequential, the value is always M + 1 or more.

  Next, as shown in FIG. 18-5, it is assumed that the order of the path information transmitted by the child thread A-2 and the child thread B-2 has changed due to network jitter or the like while arriving at the terminal 10. In this case, reception of path information from the child thread B-2 is first processed by the terminal 10. Here, the path information from the child thread B-2 arrives as the terminal 11 side communication media information management number M + 1 and is processed. Then, the partner path management number in the partner terminal information regarding the terminal 11 in the terminal 10 is M + 1. Thereafter, the path information from the child thread A-2 arrives and is processed. However, since the management number is M, it becomes a check NG and is not processed.

  As a result, the sequence of the child thread B-2 born from the child thread B is advanced. Incidentally, when the path information of the child thread A-2 arrives first, the process of the child thread A-2 is processed as usual, but immediately after that, the path information of the child thread B-2 arrives. Since the process is also performed as usual, the process starting from the child thread B-2 is finally performed.

  The above example is a case where “the transmission by the child thread A-2 is earlier than the child thread B-2”, but conversely, “the transmission by the child thread B-2 is more than the child thread A-2. It may be “fast”. In this case, since the path information transmitted by the child thread A-2 and the path information transmitted by the child thread B-2 are after the child thread B, both of them transmit accurate information. The description of the subsequent sequence is omitted.

  Next, {2} is an example in which two events of an event that the communication media NIC 111 on the terminal 11 side can be used and an event that the communication media NIC 101 on the terminal 10 side cannot be used occur almost simultaneously. This will be described with reference to the sequence diagrams of FIGS.

  Here, paying attention to the processing on the terminal 11 side shown in FIG. Here, the timing for creating the path information is when the communication media information is received from the own communication media monitoring module and when the communication media information of the other party is received from the communication partner. Here, the child thread B writes the communication media information on its own side (terminal 11 side) into the database, and the child thread C writes the communication media information on the partner side (terminal 10 side) into the database. Further, the child thread B itself does not create path information. What is necessary here is that a path management number of its own side (terminal 11 side) is added to path information generated with correct data.

Therefore, all the access timings to the database are listed, and it is verified whether the path information is correct for each. Since access to the database of the child thread B-2 for path information transmission is always after the child thread B, the following three methods are conceivable.
<1> Child thread B → Child thread C → Child thread B-2
<2> Child thread B → Child thread B-2 → Child thread C
<3> Child thread C → Child thread B → Child thread B-2

  The sequence for <1> is shown in FIG. 19-2, the sequence for <2> is shown in FIG. 19-3, and the sequence for <3> is shown in FIG. 19-4. Here, since the correct path information is finally the NIC 100 only on the terminal 10 side and the NIC 110, NIC 111, and NIC 112 on the terminal 11 side, a path based on a combination of (NIC100) × (NIC110, NIC111, NIC112) is created. It will be good if it is.

  First, the case <1> will be described with reference to FIG. In this case, after the communication media information by the child thread B is reflected, the child thread C reads the communication media information and creates path information. Therefore, the path information created and transmitted by the child thread C and the path information created by the child thread B-2 are (NIC100) × (NIC110, NIC111, NIC112). The maximum management number on the terminal 11 side is created by the child thread B-1 (see FIG. 19-1), which reflects correct path information.

  Next, the case <2> will be described with reference to FIG. In this case, before the communication media information of the other party by the child thread C is reflected, the child thread B-1 (see FIG. 19-1) creates and transmits path information. For this reason, this path information has created incorrect path information of (NIC100, NIC101) × (NIC110, NIC111, NIC112). However, after that, when the child thread C creates the path information, since the communication media information of the other party (terminal 10 side) is reflected, the correct path by (NIC100) × (NIC110, NIC111, NIC112) Created and sent. Since this is after access by the child thread B-2, the terminal 11 side path management number attached to this path information is the terminal 11 side path attached to the path information transmitted by the child thread B-2. It becomes larger than the management number. As a result, correct path information is eventually reflected.

  Finally, the case <3> will be described with reference to FIG. In this case, before the communication media information (self side) by the child thread B is reflected, the child thread C creates and transmits path information. Therefore, the path information created by the child thread C is a path of (NIC100) × (NIC110, NIC112). However, since the child thread B-2 creates a path after the information of the child thread B is reflected later, the path information is based on the correct path information (NIC100) × (NIC110, NIC111, NIC112). Further, since the own path management number attached to the path information is always larger than that transmitted by the child thread C, the correct data is finally reflected.

Since the above sequence can be said to be exactly the same on the terminal 10 side, a detailed description thereof will be omitted. The points in the present invention are summarized as follows.
1. Clarify the sequence of events.
2. A management number is used separately for each side of data to be sent.
3. Lock and unlock the database when accessing it.
4). When there is a downstream flow, the communication media information is transmitted (or when there is an upstream flow, the communication media information is transmitted).
5. When there is an uplink flow, uplink path information is transmitted (or when there is a downlink flow, downlink path information is transmitted).
As described above, even when two or more events occur simultaneously in one or both of the two communicating terminals, it is possible to perform communication using correct data.

1 is a schematic diagram of a system configuration for explaining an outline of the present invention. It is a sequence diagram explaining the process at the time of starting of a communication terminal. It is a figure which shows an example of the communication media information in FIG. It is a sequence diagram explaining the process in this invention. FIG. 4 is a sequence diagram subsequent to FIG. 4-1. FIG. 4 is a sequence diagram subsequent to FIG. FIG. 4 is a sequence diagram subsequent to FIG. 4-3. FIG. 4 is a sequence diagram subsequent to FIG. 4-4. FIG. 6 is a sequence diagram subsequent to FIG. 4-5. It is a figure which shows an example of the flow information in FIG. It is a figure which shows an example of the communication other party information in FIG. It is a figure which shows an example of the path information in FIG. It is a figure which shows an example of the network state in FIG. FIG. 2 is a schematic diagram when an event occurs in the system configuration of FIG. 1. It is a sequence diagram explaining the process after event occurrence. FIG. 10 is a sequence diagram subsequent to FIG. FIG. 10 is a sequence diagram subsequent to FIG. FIG. 10 is a sequence diagram subsequent to FIG. FIG. 4 is a sequence diagram subsequent to FIG. FIG. 6 is a sequence diagram subsequent to FIG. 10-5. It is a figure which shows an example of the communication media information notified after event occurrence. FIG. 10 is a schematic diagram when an event occurs in the system configuration of FIG. 9. It is a sequence diagram explaining the process after another event occurrence. It is a sequence diagram explaining the process after another event occurrence. It is a sequence diagram explaining the process after another event occurrence. It is a sequence diagram explaining the process after another event occurrence. It is a sequence diagram explaining the process after another event occurrence. It is a figure which shows an example of the communication media information at the time of another event occurrence. It is a figure which shows an example of the path information at the time of another event occurrence. FIG. 11 is a flow diagram when an event “receive flow information” occurs. FIG. 10 is a flow diagram when an event “receive communication media change” occurs. FIG. 10 is a flow diagram when an event of “reception of path status acquisition” occurs. FIG. 10 is a flow diagram when an event “receive path information” occurs. FIG. 10 is a flow chart due to the occurrence of an event “Reception of communication partner side communication media”. FIG. 10 is a flow diagram when an event “receive path priority” occurs. FIG. 10 is a flow diagram when an event “receive selected path information” occurs. It is a schematic diagram of the other system configuration explaining this invention. It is a schematic diagram when an event occurs in the system configuration of FIG. It is a schematic diagram when an event occurs in the system configuration of FIG. It is a sequence diagram explaining an example of the process in FIG. FIG. 19 is a sequence diagram illustrating a process different from FIG. FIG. 19 is a sequence diagram illustrating another process different from FIG. FIG. 19 is a sequence diagram illustrating another process different from FIG. FIG. 19 is a sequence diagram illustrating another process different from FIG. FIG. 17 is a sequence diagram illustrating a process when it is changed to FIG. FIG. 19 is a sequence diagram illustrating another process different from FIG. 19-1. FIG. 19 is a sequence diagram illustrating another process different from FIG. 19-1. FIG. 19 is a sequence diagram illustrating another process different from FIG. 19-1. It is a figure explaining the conventional subject.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,11 ... Communication terminal (terminal), 13a, 13b ... Application, 14a, 14b ... Communication management part, 15a, 15b ... MultipleCoA part, 16 ... Communication media monitoring module, 17 ... Path management module, 18 ... Path state acquisition module .

Claims (16)

A transmission / reception method for selecting a combination of a flow and a path when transmitting / receiving one or more flows with one or more paths between two communication terminals,
Receives flow information, receives changes in communication media on its own side, receives completion of path status acquisition, receives path information, receives changes in communication media on the other side, receives path priority, receives selected path information A transmission / reception method comprising: generating a child thread and selecting a combination of a flow and a path when detecting one or a plurality of events. When the flow information is received, a child thread for flow information is generated, and the child thread locks the database and writes the flow information, and then reads the flow information and the communication partner information of the communication partner from the database. ,
2. The transmission / reception method according to claim 1, wherein when there is no downstream flow, the child thread is terminated by unlocking a database. When the flow information is received, a child thread for flow information is generated, and the child thread locks the database and writes the flow information, and then reads the flow information and the communication partner information of the communication partner from the database. ,
2. The transmission / reception method according to claim 1, wherein when there is a downlink flow, path information is read, and when there is further downlink path information, the database is unlocked and a path status acquisition is requested. When the flow information is received, a child thread for flow information is generated, and the child thread locks the database and writes the flow information, and then reads the flow information and the communication partner information of the communication partner from the database. ,
Read the path information if there is a downstream flow, then read the local communication media information if there is no downstream path information, increase the local communication media management number and write the communication partner information, unlock the database, The transmission / reception method according to claim 1, wherein the transmission is performed together with the communication media information and the local communication media management number. Upon receiving the change of the communication media on its own side, a child thread for communication media information is generated, and the child thread locks the database and writes the communication media information, and then reads the flow information from the database. After that, unlock the database and check the flow for each communication partner,
The child thread for transmitting communication media information is generated when the communication partner has a downstream flow, and further, the child thread for transmitting path information is generated when the communication partner has an upstream flow. The transmission / reception method described.   After the child thread for transmitting the communication media information is generated, the child thread locks the database and reads the communication partner information and the communication media information, and then increases the communication media management number on its own side and writes the communication partner information. 6. The transmission / reception method according to claim 5, wherein after the database is unlocked, the communication media information is transmitted to a communication partner, and the child thread for transmitting the communication media information is terminated.   After generating the child thread for transmitting the path information, the child thread locks the database, reads communication partner information, communication media information, and partner communication medium information to generate path information, and then manages its own path. The communication partner information and the path information are written with increasing numbers, the database is unlocked, the path information is transmitted to the communication partner, and the path information transmission child thread is terminated. 5. The transmission / reception method according to 5.   When the path status acquisition end is received, a child thread for path status acquisition end is generated. The child thread locks the database and writes the path information, and then reads the communication partner's path information and flow information. The communication path information is written by increasing the own path priority management number, the database is unlocked, and then the path priority is generated and transmitted to the communication partner. Transmission / reception method.   When the path information is received, a child thread for path information is generated, the child thread locks the database and reads the communication partner information, and then “the partner path management number in the database” <“receive If it is "the other party path management number", the received path information is written as a check OK, and then the communication partner information is written with the received other party path management number to unlock the database, and then the path status is acquired. The transmission / reception method according to claim 1, further comprising:   10. If the “other party path management number in database” <“received party path management number” is not satisfied, the database is unlocked as a check NG and the child thread is terminated. The transmission / reception method described in 1.   Upon receiving the change of the other party communication media, a child thread for the other party communication media information is generated, and the child thread locks the database and reads the communication partner information. If “communication media management number” <“received other party communication media management number”, the other party communication media information received as check OK is written, and then the communication media information and the other party communication media information are read and passed. The transmission / reception according to claim 1, characterized in that information is generated and written, then the local path management number is increased, communication partner information is written to unlock the database, and then the path information is transmitted. Method.   If the “other party communication media management number in the database” <“received other party communication media management number” is not satisfied, the database is unlocked as a check NG and the child thread is terminated. The transmission / reception method according to claim 11.   When the path priority is received, a child thread for path priority is generated, and the child thread reads the communication partner information by locking the database, and then "the partner path priority management number in the database" ”<“ Received partner path priority management number ”, as a check OK, the selected path information considering the preference for uplink is generated and written, and then the received partner path priority management number is received. 2. The transmission / reception method according to claim 1, wherein the communication partner information is written to unlock the database, and then the selected path information is transmitted.   If “other party path priority management number in database” <“received partner path priority management number” is not satisfied, the database is unlocked as a check NG and the child thread is terminated. The transmission / reception method according to claim 13.   When the selected path information is received, a child thread for the selected path information is generated. The child thread locks the database and reads the communication partner information. If “priority management number” ≦ “received local path priority management number”, the path information selected as check OK is written, and then the received local path priority management number is written to unlock the database. Thereafter, the network state is notified through a MultipleCoA interface, and the transmission / reception method according to claim 1.   If “the local path priority management number in the database” ≦ “the received local path priority management number” is not satisfied, the database is unlocked as a check NG and the child thread is terminated. The transmission / reception method according to claim 15.

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