JP5025449B2 - Relay communication system - Google Patents

Description

  The present invention relates to a relay communication system including a private network that does not assume call control / call management, a global network that includes call control / call management, and a relay communication device that connects the private network and the global network. is there.

  When comparing communication between the private network to which the terminal belongs and the global network, the private network can perform high-speed communication at low cost, but the global network is low-speed and expensive compared to communication in the private network. For this reason, in the global network, various systems are used to increase the speed. However, in the private network, high-speed communication can be easily performed, so the system may not change greatly in the future. Therefore, in communication between gateway devices in the global network, a method of changing the communication method to a communication method different from that of the private network is an effective means.

  As one of the means, in recent years, a technology that establishes a call (hereinafter referred to as a session) in a global network by using a call control protocol originally developed for an IP telephone and realizes call control and call management is promising. ing. In this technology, a relay communication device for passing communication data from a terminal not supporting the call control protocol of the private network through a session established in the global network is installed at the contact point between the global network and the private network.

  At this time, since the relay communication device handles communication as many as the number of terminals accommodated in the private network, a very large load is applied to the relay communication device. Corresponding to this, for example, according to Patent Document 1, a VoIP (Voice over Internet Protocol) packet relay communication apparatus integrates VoIP packets from different transmission terminals to the same destination, and routes the integrated packets. This reduces the load on the relay communication device.

JP 2005-311910 A

  However, the relay communication device establishes a session for each connection request of individual communication connections of the subordinate communication terminals. For this reason, when a large number of connection requests are made in a short time, a session is established for each connection request. This also causes a large load on the relay communication apparatus. The technique of Patent Document 1 does not solve this problem.

  The present invention has been made in view of the above, and an object of the present invention is to provide a relay communication system that reduces the load caused by the session establishment operation in the relay communication apparatus.

In order to solve the above-described problems and achieve the object, the present invention provides a call between a plurality of first communication networks not assuming a call control function in which a terminal is accommodated and the plurality of first communication networks. a second communication network having a control / call management capabilities, in the relay communication system and a relay communication device for connecting the said the first communication network a second communication network, the relay communication system, the self apparatus When the first packet is received with the terminal in the first communication network subordinate to the sender as the transmission source and the terminal in the first communication network under the other relay communication apparatus (hereinafter referred to as another apparatus) as the transmission destination The second communication network between the own device and the other device based on the destination address and port number and the source address and port number included in the packet. A signaling processing function unit establishing a call in over click, after the call between the own apparatus and the other device is established, the terminal of the first communication network under the relay transmitter is self apparatus The packet can pass through a call between the established device and the other device when the packet that is the transmission source and the destination is the terminal in the first communication network under the control of the other device. So that the packet is encapsulated using a predetermined header specific to the call, and the own device from the terminal in the first communication network under the other device to the first communication network under its own device An encapsulation processing function unit that removes the predetermined header from the packet and decapsulates the packet when the encapsulated packet transmitted through the call with the internal terminal as the transmission destination is captured; Dress The packet encapsulation processing function unit is encapsulated, and the call determination processing function unit to be transferred to the other device through the call, the decapsulated packet, belonging to a first communication network under the own device And a communication control function unit that transfers the packet to a destination terminal of the packet.

  According to the present invention, the relay communication device establishes a session with another relay communication device in advance and encapsulates the packet so that it can pass through the above-described session. However, since it becomes possible to pass the same session without establishing each session for each communication connection, it is possible to obtain a relay communication system that reduces the load caused by the session establishment operation in the relay communication device. There is an effect.

  Embodiments of a relay communication system according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
In the first embodiment, a description will be given assuming that a widely used SIP (Session Initiation Protocol) is used as the call control protocol. FIG. 1 is a diagram illustrating an example of a network configuration according to a first embodiment of a relay communication system according to the present invention.

  In the relay communication system 1 shown in FIG. 1, private networks 11 and 12 that do not involve call control are connected to a global network 10 via relay communication apparatuses 111 and 112, respectively. The global network 10 is a network with call control / call management. The private network 11 and the private network 12 accommodate a terminal 101 and a terminal 102, respectively. The terminal 101 and the terminal 102 are computer terminals and communicate with each other using UDP (User Datagram Protocol).

  Next, the functional configuration of the relay communication apparatuses 111 and 112 will be described. FIG. 2 is a diagram illustrating the functional configuration of the relay communication device 111 and the relay communication device 112. Since the functional configurations of both relay communication apparatuses are the same, only the relay communication apparatus 111 will be described for the functional configuration.

  2, the relay communication device 111 includes a signaling processing function unit 211, a SIP session determination processing function unit 212, an encapsulation processing function unit 213, and a communication control function unit 214. The relay communication device 111 is a computer that includes a control unit, a storage unit, and a communication unit, and the functional units are generated by the cooperation of the control unit, the storage unit, and the communication unit.

  The signaling processing function unit 211 has a function of instructing the communication control function unit 214 to establish a SIP session with another relay communication device (here, the relay communication device 112) in advance. The SIP session is individually established by the address of the source terminal, the port number of the source terminal, the address of the destination terminal, and the port number of the destination terminal. The session established in advance by the signaling processing function unit 211 is a pseudo UDP packet created based on a predetermined address and port number so as to be a unique communication between the relay communication device 111 and the relay communication device 112. Established based on. In the established session, the bandwidth and priority requested by the signaling processing function unit 211 are secured.

  When the encapsulation processing function unit 213 receives a UDP packet addressed to another terminal (the terminal 102 in this case) from the terminal 101 via the communication control function unit 214, the encapsulation processing function unit 213 receives the UDP packet by the function of the signaling processing function unit 211. In order to pass the established session with the relay communication apparatus 112 under the control of the UDP packet destination terminal 102, the UDP packet is created based on the predetermined address and port number. It is encapsulated by adding a pseudo UDP header and transferred to the SIP session determination processing function unit 212. When the encapsulated packet received through the session is received via the communication control function unit 214, the encapsulation is released by removing the pseudo UDP header, and the encapsulated packet is transferred to the communication control function unit 214.

  FIG. 3 schematically shows a UDP packet before encapsulation and a UDP packet after encapsulation.

  In FIG. 3, the UDP packet before encapsulation has an IP header 301, a UDP header 302, and a data part 303. On the other hand, the packet encapsulated with the pseudo UDP header includes the IP header 301, the UDP header 302, and the data portion 303 of the UDP packet, and the IP header 311, the UDP header 312 and the encapsulation information 313 constituting the pseudo UDP header. It is added. The encapsulation information 313 describes information that the IP header 301, the UDP header 302, and the data portion 303 are in the data portion of the packet encapsulated with the pseudo UDP header. As a result, the IP header 301, the UDP header 302, and the data portion 303 are treated as the data portion of the encapsulated packet. That is, the IP header 301 ′, UDP header 302 ′, and data portion 303 ′ shown in the encapsulated packet are completely equivalent to the IP header 301, UDP header 302, and data portion 303, respectively.

  Returning to FIG. 2, when the SIP session determination processing function unit 212 receives the packet encapsulated with the pseudo UDP header by the encapsulation processing function unit 213, the SIP session determination processing function unit 212 analyzes the pseudo UDP header of the packet and It is determined that the packet is passed through the session with the own device 111, and the communication control function unit 214 is instructed to transmit the packet to the relay communication device 112 through the session.

  When the communication control function unit 214 receives a UDP packet addressed to the terminal 102 from the terminal 101 under its control, the communication control function unit 214 transmits the packet to the encapsulation processing function unit 213. In addition, when the encapsulated packet is received from the relay communication device 112, the packet is transmitted to the encapsulation processing function unit 213. When receiving the decapsulated UDP packet from the encapsulation processing function unit 213, the destination is confirmed and the packet is transmitted to the terminal 101 under its own apparatus 111. Further, the communication control function unit 214 transmits and receives a message for establishing a session according to a command from the signaling processing function unit 211. Further, the communication control function unit 214 transmits the encapsulated packet to the relay communication device 112 through the previously established session in response to a command from the SIP session determination processing function unit 212.

  The relay communication device 112 has the same configuration as that of the relay communication device 111. However, in order to explain the flow of packet transfer, each function unit includes a signaling processing function unit 211 and a SIP session determination processing function unit 212. Like the encapsulation processing function unit 213 and the communication control function unit 214, different reference numerals are assigned to the functional units of the relay communication device 111. In addition, unless otherwise specified, when describing as a relay communication device, the relay communication device 111 and / or the relay communication device 112, and when expressing as between relay communication devices, the relay communication device 111 and the relay communication device 112 It will point to between.

  Next, the operation of the first embodiment of the relay communication system of the present invention will be described. FIG. 4 is a sequence diagram for explaining the operation of the relay communication system according to the first embodiment.

  In FIG. 4, first, a session using a pseudo UDP packet is established between the relay communication device 111 and the relay communication device 112 by the signaling processing function units 211 and 221 (step S1). Specifically, in the session establishment operation, the signaling processing function unit 211 transmits an “INVITE” message to make a call, and in the relay communication device 112 that has received the INVITE message, the signaling processing function unit 221 sets “200 Respond by sending an "OK" message. In the relay communication device 111 that has received the response, the signaling processing function unit 211 transmits an “ACK” message. The relay communication device 112 receives the “ACK” message, and a session is established between both relay communication devices. Bandwidth and priority are set in the body part of the “INVITE” message according to the SDP (Session Description Protocol) standard, and the bandwidth and priority of the established session are secured.

  Next, when the relay communication apparatus 111 receives a UDP packet addressed from the terminal 101 to the terminal 102, the communication control function unit 214 transmits the packet to the encapsulation processing function unit 213, and adds a pseudo UDP header to the packet. The encapsulated packet is transferred to the relay communication device 112 by the SIP session determination processing function unit 212 (step S2).

  When the relay communication device 112 receives the encapsulated packet, the packet is transferred to the encapsulation processing function unit 223 via the communication control function unit 224 to be decapsulated, and the decapsulated packet Is transmitted to the terminal 102 via the communication control function unit 224 (step S3).

  In this way, in UDP packet communication between terminals belonging to different private networks, a UDP packet transmitted to other terminals is used between the relay communication devices at the point of contact between each private network and the global network using a pseudo UDP header. By encapsulating, it becomes possible to pass through a session in which bandwidth and priority are established in advance in the global network between the relay communication apparatuses.

  Next, in the relay communication system according to the first embodiment of the present invention that operates as described above, when the terminal 101 is addressed to the terminal 102 and performs a plurality of different communications with UDP1, UDP2, UDP3,. explain. Different communications include communications such as when the source and / or destination port numbers are different.

  FIG. 5 is a diagram for explaining the operation of the relay communication system according to the first embodiment in this case. In FIG. 5, each time a relay communication apparatus 111 transfers a plurality of different UDP packets UDP1 to UDPn, a pseudo UDP header is added and transferred in order to pass the previously established session. Each time the device 112 receives the encapsulated packet, the device 112 decapsulates the received encapsulated packet and forwards it to the terminal 102.

  In this way, in UDP communication between terminals belonging to different private networks, the relay communication device encapsulates the UDP packet so that a plurality of different UDP packets can pass through the same session.

  Next, as shown in FIG. 6, in addition to the network configuration of FIG. 1, Embodiment 1 in the case where the private network 11 further has a terminal 103 and the private network 12 further has a terminal 104, respectively. The operation of the relay communication system will be described.

  For example, when the terminal 101 transmits a UDP packet to the terminal 104 and the terminal 103 to the terminal 104, the relay communication apparatus 111 that has received the packet for each UDP packet can pass through the same pre-established session. And encapsulate the packet. Further, the relay communication device 112 that has received the packet releases the encapsulation, and transfers the decapsulated packet to the terminal 104.

  As described above, even if the transmission source and / or transmission destination terminals are different UDP packets, the same session can be passed by being encapsulated by the pseudo-UDP header if the relay communication devices that pass through are the same.

  In the above description, the terminals 101 to 104 have been described as performing UDP communication. However, any type of communication method may be used as long as the type of communication can be determined in the relay communication device. . The terminals 101 to 104 are not limited to computers as long as they can perform a type of communication that can be identified by the relay communication device, and may be, for example, a network camera, a digital television, a network recorder, an AV device, or the like. .

  In addition, the session is established based on the pseudo UDP created based on the predetermined address and port number, but the transmission source described in the packet received first from the terminal under control by the relay communication device Further, the packet may be established based on the destination address and port number, and subsequent packets may be passed through the established session.

  In addition, the relay communication device has been described as encapsulating with a pseudo UDP header in order to pass a packet through a pre-established session, but the pseudo header communication method is not limited as long as the same session can be passed through. For example, it may be a pseudo header by TCP (Transmission Control Protocol).

  Further, although the protocol that is followed by the session established between the relay communication apparatuses is not specified, it may be performed by a protocol suitable for the network between the relay communication apparatuses. For example, when the relay communication apparatuses 111 and 112 are an IPv6 network, a session is established by IPv6. At this time, if the packet addressed to the terminal belonging to the private network 12 received by the relay communication apparatus 111 from the subordinate terminal is based on IPv4, the relay communication apparatus 111 performs encapsulation in the IPv6 format. Thus, when the network protocol in the private network and the network protocol between the relay communication devices are different, the packet format may be appropriately converted and transferred in the relay communication device.

  Further, although SIP has been described as a call control protocol, a session can be established between relay communication apparatuses, and any call control can be used as long as it is a protocol that can add a bandwidth or priority service to the established session. Regardless of the type of protocol.

  As described above, according to the relay communication system according to the first embodiment, the relay communication apparatus establishes a session with another relay communication apparatus in advance, and encapsulates the packet so as to pass through the session. Therefore, even if packets are in different communication connections, the same session can be passed without establishing each session for each communication connection, reducing the load caused by the session establishment operation in the relay communication device. A relay communication system can be obtained.

Embodiment 2. FIG.
The relay communication system according to the second embodiment of the present invention is characterized in that the bandwidth reserved for a session is changed in accordance with the bandwidth consumption of communication that allows a previously established session to pass. Since the configuration of the relay communication device and the network configuration of the relay communication system according to the second embodiment are the same as those of the first embodiment, description thereof will be omitted, and here the operation of changing the bandwidth, which is a feature of the second embodiment. Only will be described.

  In the relay communication system according to the second embodiment, the communication control function unit 214 monitors communication passing through the session, and the signaling processing function unit 211 conforms to the SDP standard in the body unit at a predetermined timing based on the monitoring result described above. Based on this, an “UPDATE” message in which a desired bandwidth is set is transmitted. Thus, the bandwidth secured by the session is changed without disconnecting the session.

  Here, the predetermined timing described above is a timing determined based on the bandwidth secured by the session and the communication passing through the session, and is set in advance by the administrator. For example, it may be the timing when the number of communication connections passing through the session changes. Further, the communication control function unit 214 may periodically measure the bandwidth consumption in the session and change the session bandwidth between the relay communication devices to a desired bandwidth each time.

  The desired bandwidth setting described above may be set in any manner. For example, the bandwidth consumption of communication passing through the session may be within the range of 50% to 80% of the bandwidth secured by the session. In this case, for example, the relay communication device periodically measures the bandwidth consumption, and when the used bandwidth falls below 50% of the bandwidth secured by the session, the bandwidth is changed so as to decrease. When 80% of the session bandwidth is exceeded, the bandwidth may be changed. However, in the initial state or when the number of communications becomes zero, it is not preferable to end the session. Therefore, it is better not to change the bandwidth even if it is less than 50%.

  Here, in the description of the relay communication system according to the second embodiment, the relay communication apparatus changes the session bandwidth by transmitting the “UPDATE” message. However, the change method is the specification of the call control protocol. Different methods may be taken depending on the situation. In short, the bandwidth secured by the session may be changed without disconnecting the session.

  Thus, according to the relay communication system according to the second embodiment, the relay communication apparatus according to the number of communication connections related to packets passing through the session established in advance and / or the consumed bandwidth in the session, Since the bandwidth secured by the session is changed, the communication band of the global network can be used more effectively than the relay communication system according to the first embodiment.

Embodiment 3 FIG.
The relay communication system according to Embodiment 3 is characterized in that when a plurality of sessions are established, a packet is selected and distributed for each communication connection. The configuration of the relay communication apparatus of the relay communication system according to the third embodiment is the same as that of the first and second embodiments, and thus the description thereof will be omitted. Here, a network configuration that establishes a plurality of sessions that are features of the third embodiment Will be explained.

  FIG. 7 shows an example of a network configuration in which two sessions for connecting private networks are established. In FIG. 7, the relay communication device 111 and the relay communication device 112 establish a session 401 and a session 402 by using the signaling processing function units 211 and 221.

  In such a network configuration, when the relay communication apparatus 111 receives a UDP packet addressed to the terminal 104 from the subordinate terminals 101 and 103, the encapsulation processing function unit 213 determines that the session 401 or the session 401 or It is determined which session of the session 402 is to be passed, and encapsulated with a pseudo UDP header so that the session determined to be passed can be passed. Here, the UDP packet from the terminal 101 is encapsulated with a pseudo UDP header so that the UDP packet from the terminal 401 and the UDP packet from the terminal 103 can pass through the session 402, respectively. The encapsulated packets are transferred to the relay communication device 112 through the session 401 and the session 402, respectively, by analyzing the pseudo UDP header by the SIP session determination processing function unit 212.

  Here, the above-mentioned preset rule may be any rule. For example, a limit is set on the number of communication connections that one session passes, and if the number of connections is within the limit, the session 401 is allowed to pass, and the communication exceeding the limit is allowed to pass the session 402. It's okay. Further, communication exceeding the bandwidth set for the session 401 may be passed through the session 402.

  Further, one session may be set for each address of a subordinate terminal. That is, session 401 may pass a packet from terminal 101 and session 402 may pass a packet from terminal 103, respectively. Further, a session that passes for each destination address may be set.

  In addition, a session may be established for each packet communication priority, and a packet may be assigned to which session is passed according to the priority. The priority may be divided into four stages, for example, highest priority, high priority, priority, and best effort.

  In addition, a session to be used may be distributed for each type of application that has created a packet in the terminals 101 to 104 or for each application. Examples of application types include Web, streaming, and telephone. Further, the session to be used may be distributed for each port number of the packet destination.

  Here, in the case of allocating packets to sessions according to the rules described above, when there are not enough sessions to be established in advance, a new session may be added and established. Moreover, you may comprise so that a bandwidth may be changed like the relay communication system in Embodiment 2. FIG. Also, the bandwidth and priority set for each session may be different.

  As described above, according to the relay communication system according to the third embodiment, when the relay communication apparatus has previously established a plurality of calls with the counterpart relay communication apparatus, it is established with the counterpart relay communication apparatus. The number of communication connections and / or the consumed bandwidth and / or the type of communication connection between terminals that allow a packet to pass through the selected call are monitored, and a call that allows a packet to pass is selected for each communication connection based on the monitoring result. Since it comprised, compared with the relay communication system by Embodiment 1-2, each communication connection can be managed efficiently.

Embodiment 4 FIG.
The relay communication system according to the fourth embodiment of the present invention is a relay communication system having the same configuration as that of the first to third embodiments, and the packet between terminals is a TCP packet. It is characterized in that the addition prevents the fragmentation caused by the increase in the packet size compared to the original TCP packet.

  First, a general TCP packet communication start method will be briefly described.

  TCP packet communication is started by establishing a TCP connection between terminals before transmitting and receiving data. In order to establish a TCP connection, the transmission-side terminal transmits a TCP SYN packet, which is a TCP packet in which a SYN flag is set as a transfer permission request, to the partner-side terminal. When receiving the TCP SYN, the receiving terminal sets an ACK flag indicating transfer permission, and transmits a TCP SYN + ACK packet to request the transfer permission to the transmitting terminal. When receiving the TCP SYN + ACK packet, the transmitting terminal transmits a TCP ACK packet to the receiving terminal in order to permit transfer. When the receiving terminal receives the TCP ACK packet, a TCP connection is started between both terminals, and a TCP packet in which data to be transmitted / received is embedded flows between the terminals. Such a method of establishing a TCP connection by transmitting / receiving a TCP SYN packet, a TCP SYN + ACK packet, and a TCP ACK packet is commonly called a three-way handshake.

  Since the relay communication apparatus according to the first to third embodiments encapsulates the packet using the pseudo header without interfering with the packet data, such a three-way handshake is encapsulated and transferred as it is. However, the relay communication apparatus according to the fourth embodiment sets the SYN flag among the packets sent from the subordinate terminals in order to prevent fragmentation caused by the increase in the packet size due to the addition of the pseudo header. The TCP packet is detected, and the optional MSS (Max Segment Size) of the TCP SYN packet is rewritten to a value obtained by subtracting the size of the pseudo header. The operation of detecting and rewriting the TCP SYN packet is performed by the encapsulation processing function unit 213.

  FIG. 8 schematically illustrates a normal TCP SYN packet before encapsulation and a TCP SYN packet subjected to MSS rewrite processing after encapsulation using a pseudo UDP header.

  In FIG. 8, a TCP SYN packet including an IP header 501, a TCP header 502, and a data portion 503 in which an area of 1460 bytes is secured by the MSS is a pseudo header when transferred to the global network. 511, UDP header 512, and encapsulation information 513 are added, and TCP header 502 ′ corresponding to TCP header 502 of the original TCP SYN packet is a value obtained by subtracting the size x of the pseudo header from the MSS value. It is rewritten as a certain 1460-x byte. The size of the encapsulated data portion 503 'corresponding to the data portion 503 secured in the original TCP SYN packet is 1460-x bytes. The IP header 501 ′ is equal to the IP header 501.

  As for the TCP SYN + ACK packet transmitted by the receiving terminal, the relay communication device at the contact point between the private network accommodating the receiving terminal and the global network replaces the MSS value and sends it to the global network in the same manner as described above.

  In this way, a packet with the SYN flag that has been rewritten with the MSS value reduced by the size of the pseudo header in the three-way handshake is transferred. By establishing the TCP connection between the terminals in this way, it is possible to prevent a fragment due to the size increase of the pseudo header from occurring in the TCP packet transmitted / received between the terminals.

  Such an operation will be described more specifically with reference to a sequence diagram. FIG. 9 is a sequence diagram illustrating an operation for establishing a TCP connection between terminals in the relay communication system according to the fourth embodiment. In this sequence diagram, it is described that TCP communication is performed between the terminal 101 and the terminal 102 shown in FIG.

  In FIG. 9, first, a SIP session is established in advance between relay communication devices (step S1). Next, when the relay communication device 111 receives a TCP SYN packet for starting a TCP connection with the terminal 102 as a partner from the terminal 101, the encapsulation processing function unit 213 of the relay communication device 111 is a TCP SYN packet. Detected, the MSS value is rewritten to be smaller by the size of the pseudo header, encapsulated with the pseudo header, and transferred to the relay communication device 112 through the previously established session by the SIP session determination processing function unit 212 (step S12). The packet that reaches the relay communication device 112 is decapsulated and transferred to the terminal 102. The MSS value of the TCP SYN packet reaching the terminal 102 is a value subtracted by the size of the pseudo header.

  Upon receiving this packet, the terminal 102 transmits a TCP SYN + ACK packet to the terminal 101. The relay communication device 112 that has received the TCP SYN + ACK packet rewrites the MSS value of the packet to a smaller size corresponding to the size of the pseudo header, encapsulates it with the pseudo header, and transfers the packet to the relay communication device 111 (step S13). When the relay communication device 111 receives the packet, the relay communication device 111 releases the encapsulation and transfers the packet to the terminal 101. The MSS value of the TCP SYN + ACK packet that reaches the terminal 101 is a value that is subtracted by the size of the pseudo header.

  When the terminal 101 receives this packet, it transmits a TCP ACK packet to the terminal 102. Packetization of the TCP ACK packet and cancellation of packetization are the same as in the first to third embodiments, and thus description thereof is omitted.

  When the terminal 102 receives the TCP ACK packet, a three-way handshake is established between the terminal 101 and the terminal 102, and a TCP connection is established (step S14). Here, since the three-way handshake is established by using the rewritten SYN flag packet with the MSS value reduced by the amount corresponding to the pseudo header, the data area of the data portion of the TCP packet passing through this TCP connection is equal to the size of the pseudo header. It will be limited to a small value.

  As described above, according to the relay communication system according to the fourth embodiment, the MSS value is configured to establish a TCP connection between terminals using the SYN flag packet rewritten by a smaller packet size that is increased by the encapsulation process. Therefore, more efficient TCP communication can be performed as compared with the relay communication system according to the first to third embodiments.

  As described above, the relay communication system according to the present invention is arranged at a contact point between a private network that does not assume call control / call management, a global network with call control / call management, and a private network and the global network. The present invention is useful when applied to a communication system including a relay communication device.

2 is a diagram illustrating an example of a network configuration of a relay communication system according to Embodiment 1. FIG. 2 is a diagram illustrating a functional configuration of a relay communication apparatus according to Embodiment 1. FIG. FIG. 3 is a diagram schematically showing a UDP packet before encapsulation and a UDP packet after encapsulation in the relay communication system according to the first embodiment. 6 is a sequence diagram illustrating an operation of the relay communication system according to the first embodiment. FIG. FIG. 6 is a sequence diagram for explaining an operation when the relay communication apparatus according to the first embodiment performs a plurality of different communications. In the relay communication system of Embodiment 1, it is a figure explaining an example of the network structure where a some terminal exists in each private network. FIG. 10 is a diagram illustrating an example of a network configuration of a relay communication system according to a third embodiment. The normal TCP SYN packet before encapsulation in the relay communication system according to the fourth embodiment and the TCP SYN packet subjected to MSS rewrite processing after encapsulation using a pseudo UDP header will be schematically described. FIG. FIG. 10 is a sequence diagram for explaining the operation of the relay communication system according to the fourth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Relay communication system 10 Global network 11, 12 Private network 101, 102 Terminal 111, 112 Relay communication apparatus 211, 221 Signaling processing function part 212, 222 SIP session determination processing function part 213, 223 Encapsulation processing function part 214, 224 Communication Control function part 301, 301 'IP header 302, 302' UDP header 303, 303 'Data part 311 IP header 312 UDP header 313 Encapsulation information 401, 402 Session 501, 501' IP header 502, 502 'TCP header 503, 503 ′ Data part 511 IP header 512 UDP header 513 Encapsulation information

Claims (4)

A plurality of first communication networks not assuming a call control function in which terminals are accommodated; a second communication network between the plurality of first communication networks and having a call control / call management function; In a relay communication system comprising a relay communication device that connects a communication network and the second communication network,
The relay communication device is
Receives the first packet whose destination is the terminal in the first communication network under its own device and whose destination is the terminal in the first communication network under the control of another relay communication device (hereinafter referred to as another device) Signaling processing for establishing a call in the second communication network between the own device and the other device based on the destination address and port number and the source address and port number included in the packet. A functional part;
After the call between the own device and the other device is established, the relay communication device uses the terminal in the first communication network under its own device as the transmission source, and the first communication under the other device. When a packet whose destination is a terminal in the network is captured, a predetermined header peculiar to the call is set so that the packet can pass through the call between the established device and the other device. And encapsulates the packet, and the local device transmits the call from the terminal in the first communication network under the other device to the terminal in the first communication network under the local device as the transmission destination. An encapsulation processing function unit that, when capturing the encapsulated packet, removes the predetermined header from the packet and decapsulates the packet;
A call determination processing function unit that transfers the packet encapsulated by the encapsulation processing function unit of its own device to the other device through the call;
A communication control function unit that transfers the decapsulated packet to a destination terminal of the packet belonging to a first communication network under its own device;
A relay communication system comprising: The communication control function unit is configured to provide communication for packet communication between a terminal belonging to a first communication network under its own device and a terminal belonging to a first communication network under its other device. Monitor the number of connections and / or bandwidth consumed per call,
The signaling processing function unit changes a communication band secured by the call according to the number of connections and / or a consumed band,
The relay communication system according to claim 1. When the relay communication device has established a plurality of calls in advance with the other device,
The communication control function unit is configured to provide communication for packet communication between a terminal belonging to a first communication network under its own device and a terminal belonging to a first communication network under its other device. Number of connections and / or consumed bandwidth and / or address of terminal of transmission source of packet, transmission destination address of packet, transmission priority of packet, application using packet, or combination thereof Monitors the type of communication connection distinguished by each communication connection,
The encapsulation processing function unit performs communication connection for a call that allows a packet to pass among the plurality of calls based on the number and / or consumption band and / or type of the communication connection before packet encapsulation. Select every
The relay communication system according to claim 1 or 2. The relay communication device can set a SYN flag whose source is a terminal belonging to the first communication network under its own device and whose destination is a terminal belonging to the first communication network under its other device. When capturing a TCP packet
When encapsulating the TCP packet, the encapsulation processing function unit rewrites the value described in the MSS option of the TCP packet with a value obtained by subtracting the size that is increased by encapsulating the TCP packet. ,
The relay communication system according to any one of claims 1 to 3.

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