JP4831224B2 - Relay device and program, relay system, and communication system - Google Patents

Description

  The present invention relates to a relay device and program, a relay system, and a communication system, and can be applied to a communication system that performs IP telephone communication, for example.

  Conventionally, in real-time communication such as IP telephone, media packets such as voice and video are transmitted and received using RTP (Realtime Transport Protocol; IETF RC3550). Further, when encrypting a media packet, SRTP (Secure RTP; IETF RFC3711) is used.

  When connecting networks having different policies by a relay device, a configuration is considered in which encryption is performed on one network and encryption is not performed on the other network.

  In this case, negotiations for establishing an encryption session between terminals are performed, but the terminal capabilities become inconsistent, so communication is not possible, or the network side where encryption is performed cannot be encrypted in plain text. Communicate.

  It is desirable to establish a cryptographic session within the network of the policy to be encrypted and establish a non-cryptographic session for communication in the network of the policy that is not encrypted. In order to realize this, it is necessary to terminate the encryption session and the non-encryption session in the relay device and connect the corresponding session by the relay device. Furthermore, when the relay apparatus has a redundant configuration, it is necessary to continue the session even if the system is switched.

  As a conventional technique for terminating a session and relaying it to the other, there is a technique described in Patent Document 1. The relay device described in Patent Document 1 realizes mutual communication between networks having different policies.

  However, in the technology described in Patent Document 1, relaying can be performed in an appropriate manner even when networks having different policies are connected, but redundancy of the relay device is not considered. For this reason, when the system is switched, the terminal needs to reconnect the session again. In addition, when the relay device has a redundant configuration, even if a system switchover occurs, in order to appropriately perform encryption and decryption, information for encryption and decryption is synchronized between the devices that configure redundancy. There is a need.

  Therefore, there is a technique described in Patent Document 2 as a technique related to a network device having a redundant configuration. The network media device described in Patent Document 2 is a network device having a redundant configuration.

JP 2006-32997 A JP 2007-306562 A

  However, although the technology described in Patent Document 2 considers a redundantly configured device, it does not consider application to a repair device. Further, after the system is switched, the value to be actually used is determined by calculation, but the accuracy is low. For example, since the sequence number after the system is switched greatly increases, there is a problem that a normal receiving terminal recognizes that a large amount of packet loss has occurred.

  Therefore, a relay device that relays packets flowing between communication devices with different communication conditions can maintain the continuity of a session between communication devices in a redundant communication system even if the relay device system is switched. Devices and programs, relay systems, and communication systems are desired.

The first aspect of the present invention is capable of communicating with other communication devices using at least SRTP and SRTCP, and with the first communication device capable of communicating with other communication devices using at least RTP and RTCP. A plurality of relay devices for relaying packets flowing between the second communication devices, the relay device including an active relay device operating as a normal operation system and a standby system operating as a normal standby system; In a relay system including a relay device, (1) the active relay device (1-1) analyzes a packet of a communication session between the first communication device and the second communication device. Te, including current SRTCP index value of the communication session, the first continuity information obtaining means for obtaining the continuity of information relating to continuity of packets of the communication session, (1-2) above The received packet received from the first communication device or the second communication device, by utilizing the continuity information in the first continuity information acquisition unit acquires, can receive the received packet destination communication devices When an RTCP packet destined for the second communication device is received from the first communication device, it is converted into an SRTCP packet using the SRTCP index value included in the continuity information. a first packet conversion means, (1-3) a first packet transmission means for the first packet conversion means for transmitting the converted packet to the destination of the packet, (1-4) the first a timing information holding means for holding the timing information relating to the arrival timing of the RTCP packet from the communication device, (1 5) said first continuity information acquisition unit acquires Continued resistance information and notification information including timing information which the timing information holding means is held, and a continuity information synchronization means for applying to the relay device of the standby system, (2) the standby system of the relay device, (2-1) Notification information holding means for receiving and holding notification information from the active relay device; (2-2) After the relay device is switched from the standby system to the active system, When an RTCP packet is received from the first communication device, an estimation means for estimating an SRTCP index value in the current communication session using the notification information received from the active relay device most recently, (2- 3) Analyzing the packet of the session and including the current SRTCP index value of the communication session with the SRTCP index value estimated by the estimation means as an initial value. A second continuity information obtaining means for obtaining the continuity of information of the serial communication session, (2 4) the relay device, if the turn from the operation system from the standby system, the first communication device or the the received packet received from the second communication device, by using the continuous property information which the second continuity information acquisition means is retained, the received packet destination communication device into a possible format received A second packet to be converted into an SRTCP packet using an SRTCP index value included in the continuity information when an RTCP packet addressed to the second communication device is received from the first communication device conversion means, and having a (2-5) a second packet transmission means for the second packet conversion means for transmitting the converted packet to the destination of the packet.

The second aspect of the present invention is capable of communicating with the first communication device capable of communicating with other communication devices using at least RTP and RTCP, and with other communication devices using at least SRTP and SRTCP. In an operation relay device that operates as a normal operation system, which constitutes a relay system that relays packets flowing between the second communication devices, (1) the first communication device and the second communication device First continuity information acquisition means for analyzing continuity information relating to continuity of packets of the communication session, including a current SRTCP index value of the communication session, , (2) the received packet received from the first communication device or the second communication device, utilizing the continuity information in the first continuity information acquisition unit acquires Been made to convert the received packet to the destination communication device capable of receiving formats, when receiving the RTCP packet addressed to the second communication device from the first communication apparatus, included in the continuity information First packet converting means for converting the packet into an SRTCP packet using the SRTCP index value, and (3) first packet transmitting means for transmitting the packet converted by the first packet converting means to the destination of the packet; (4) timing information holding means for holding timing information related to the arrival timing of the RTCP packet from the first communication device; ( 5 ) continuity information acquired by the first continuity information acquiring means ; and operation notification information including timing information which the timing information holding means is held, in the relay system, as a normal standby system And having a continuity information synchronization means for applying to the relay device that the standby system.

The third aspect of the present invention is capable of communicating with the first communication device capable of communicating with other communication devices using at least RTP and RTCP, and with other communication devices using at least SRTP and SRTCP. In a standby relay device that operates as a normal standby system and that constitutes a relay system that relays packets flowing between the first communication device and a second communication device having different communication conditions, (1) the relay In the system, the packet of the communication session including the current SRTCP index value of the communication session between the first communication device and the second communication device from the active relay device operating as a normal operation system of the continuity information relating to continuity, the notification information including timing information related to the arrival timing of the RTCP packet from the first communication device A notification information storage means for storing and Shin, (2) the relay device, after been switched to the active system from the standby system, if the first receiving the RTCP packet from the first communication device, the operation to date Using the notification information received from the relay device of the system, estimating means for estimating the SRTCP index value in the communication session; and (3) analyzing the packet of the session and calculating the SRTCP index value estimated by the estimating means. The second continuity information acquisition means for acquiring the continuity information of the communication session including the current SRTCP index value of the communication session as the initial value, and the relay device has been switched from the standby system to the active system If the received packet received from the first communication device or the second communication device, said second continuity information acquisition means is held By utilizing the connection of information, be one that converts the received packet to the destination communication device capable of receiving formats, when receiving the RTCP packet addressed to the second communication device from the first communication device a, and transmits the second packet conversion means for converting SRTCP packets using the SRTCP index value included in the continuity information, (4) a packet which the second packet conversion means is converted to the destination of the packet And second packet transmission means.

A relay program according to a fourth aspect of the present invention includes: (1) a first communication device capable of communicating with another communication device using at least RTP and RTCP ; and at least another communication device using SRTP and SRTCP. (2) the above-mentioned computer mounted on an active relay device that operates as a normal operation system and that constitutes a relay system that relays a packet flowing between a second communication device capable of communication; Analyzing a packet of a communication session between one communication device and the second communication device to obtain continuity information related to the continuity of the packet of the communication session, including a current SRTCP index value of the communication session a first continuity information acquisition means for acquiring, (3) a received packet received from the first communication device or the second communication device, the first continuity By utilizing the continuity information distribution acquisition means has acquired, be one that converts the received packet to the destination communication device capable of receiving formats, from the first communication device addressed the second communication device First packet conversion means for converting into an SRTCP packet using the SRTCP index value included in the continuity information when an RTCP packet is received ; and (4) the packet converted by the first packet conversion means First packet transmitting means for transmitting to a packet destination; (5) timing information holding means for holding timing information related to the arrival timing of the RTCP packet from the first communication device; and ( 6 ) the first continuity information continuity information acquisition means has acquired, and a notification information including timing information which the timing information holding means is held, the relay In the stem, characterized in that to function as continuity information synchronization means for applying to the standby system relay device operating as normal standby.

A relay program according to a fifth aspect of the present invention includes: (1) a first communication device capable of communicating with another communication device using at least RTP and RTCP ; and at least another communication device using SRTP and SRTCP. A computer installed in a standby relay device that operates as a standby standby system and that constitutes a relay system that relays packets flowing between a second communication device capable of communication and (2) the relay In the system, the packet of the communication session including the current SRTCP index value of the communication session between the first communication device and the second communication device from the active relay device operating as a normal operation system notification information including the the continuity information relating to continuity, and timing information relating to the arrival timing of the RTCP packet from the first communication device A notification information holding means for holding receive, (3) the relay device, after been switched to the active system from the standby system, if the first receiving the RTCP packet from the first communication device, the up to date (4) an estimation means for estimating an SRTCP index value in the communication session using notification information received from an active relay device; and (4) an SRTCP index value estimated by the estimation means by analyzing the packet of the session. Second continuity information acquisition means for acquiring continuity information of the communication session including the current SRTCP index value of the communication session with the initial value as the initial value, and ( 5 ) the relay device is changed from the standby system to the active system. off when replaced, the received packet received from the first communication device or the second communication device, said second continuity information acquiring hands There utilizing the held continuous INFORMATION been made to convert the received packet to the destination communication device capable of receiving formats, RTCP from the first communication device addressed the second communication device A second packet conversion means for converting the packet into an SRTCP packet using the SRTCP index value included in the continuity information when receiving the packet; and ( 6 ) the packet converted by the second packet conversion means It is made to function as a 2nd packet transmission means to transmit to the destination.

The sixth aspect of the present invention is capable of communicating with the first communication device capable of communicating with other communication devices using at least RTP and RTCP, and with other communication devices using at least SRTP and SRTCP. In a communication system including a second communication device and a relay system that relays a packet flowing between the first communication device and the second communication device, the relay system according to the first aspect of the present invention is used as the relay system. Is applied.

  According to the present invention, a relay device that relays packets flowing between communication devices having different communication conditions maintains the continuity of a session between communication devices in a redundant communication system even when the relay device system is switched. be able to.

It is the block diagram shown about the functional structure of the relay apparatus which concerns on embodiment. 1 is a block diagram illustrating an overall configuration of a communication system according to an embodiment. It is explanatory drawing shown about the example of the content of the session information table which concerns on embodiment. It is explanatory drawing shown about the example of the content of the SRTP transmission / reception information table which concerns on embodiment. It is explanatory drawing shown about the example of the content of the SRTCP transmission information table which concerns on embodiment. 5 is a flowchart showing the operation of the active relay device according to the embodiment. It is explanatory drawing shown about the operation | movement of the encryption process part in the active relay apparatus which concerns on embodiment. It is explanatory drawing shown about the operation | movement of the regular starting process in the relay system which concerns on embodiment. FIG. 5 is an explanatory diagram showing an operation of switching from an active relay device to a standby relay device according to an embodiment.

(A) Main Embodiment Hereinafter, an embodiment of a relay device and program, a relay system, and a communication system according to the present invention will be described in detail with reference to the drawings.

(A-1) Configuration of Embodiment FIG. 2 is a block diagram showing the overall configuration of the communication system 1 of this embodiment.

  In the communication system 1, a relay system 10 and communication terminals 21 and 22 are arranged. In the communication system 1, the number of communication terminals to be arranged is not limited.

  In the communication system 1, networks N1 and N2 that employ two IP communications are arranged, and a relay system 10 is arranged at the boundary between the two networks. Traffic between the two networks is transmitted by the relay system 10. Relay processing is performed.

  The communication terminal 21 is arranged on the network N1, and the communication terminal 22 is arranged on the network N2. The communication terminal 21 and the communication terminal 22 communicate via the relay system 10.

  Further, it is assumed that the network N2 has a policy for applying encryption to packets to be transmitted and received, and the network N1 has a policy for not requiring encryption for packets to be transmitted and received. That is, the packet transmitted / received by the communication terminal 21 is not encrypted, but the packet transmitted / received by the communication terminal 22 is encrypted. Thus, since the communication conditions regarding encryption differ between the communication terminal 21 and the communication terminal 22, in the communication system 1, the relay system 10 converts packets flowing between the communication terminal 21 and the communication terminal 22 to communicate with each other. .

In the communication system 1, communication between the communication terminal 21 and the communication terminal 22 is call controlled using SIP (Session Initiation Protocol) (call control may be performed using a call control device (not shown)). Shall be. Also, media traffic (voice and video, etc., the contents of which are not limited to), the communication terminal 21 side is performed using the RTP and RTCP (RTP Control Protocol), the communication terminal 22 side, SR TP and Communication using SRTCP (Secure RTCP) is performed. Therefore, packet conversion is performed by the relay system 10, and mutual communication between the communication terminal 21 and the communication terminal 22 is realized.

  Next, a detailed configuration of the relay system 10 will be described.

  As shown in FIG. 2, the relay system 10 has a redundant configuration with two relay devices 100 (100-1 and 100-2), and the relay device 100-1 operates as a normal operation system. The relay device 100-2 has a so-called active / standby configuration that operates as a normal standby system. When a failure or the like occurs in the relay device 100-1, the relay device 100-2 is switched to the active system and operates. In FIG. 2, the relay system 10 is configured with two active and standby relay devices 100 each, but includes a plurality of standby relay devices and a total of three or more. It is good also as a structure.

  Next, the internal configuration of the relay device 100 (100-1, 100-2) will be described. In this embodiment, the relay apparatuses 100-1 and 100-2 will be described as having the same configuration.

  FIG. 1 is a block diagram showing a functional configuration inside the relay apparatus 100 (100-1, 100-2).

  Here, the relay apparatus 100 (100-1, 100-2) is, for example, an information process having a CPU, a ROM, a RAM, and the like for executing communication processing, data processing, and the like in addition to hardware communication means. A device may be installed and a program (including the relay program of the embodiment) executed by the information processing device may be installed and constructed. FIG. 1 shows a functional configuration of the relay device 100 (100-1, 100-2) including the above-described program.

  The relay device 100 includes a network interface unit 101, a packet determination unit 102, an encryption processing unit 103, a redundancy processing unit 104, a session information table 105, an SRTP transmission / reception information table 106, and an SRTCP transmission information table 107.

  The network interface unit 101 functions as an interface for connecting to the network in the relay device 100, and transmits and receives packets. Note that the method of connecting the network interface unit 101 to the network is not limited.

  The packet determination unit 102 has a function of extracting header information from the received packet and searching for corresponding session information from the session information table 105. The packet determination unit 102 determines whether the notification information is from another system.

  The encryption processing unit 103 performs encryption or decryption on the received packet according to information in each table described later. Details of the processing of the cryptographic processing unit 103 will be described later.

  The redundancy processing unit 104 periodically notifies the standby relay device of information in the SRTP transmission / reception information table 106 and the SRTCP transmission information table 107 if the relay device is an active system. If the relay device is a standby system, the information notified from the active relay device is set in its own table. Details of the processing of the redundancy processing unit 104 will be described later. The information in the session information table 105 may be notified from the active system to the standby system.

  Next, the contents of each table (session information table 105, SRTP transmission / reception information table 106, SRTCP transmission information table 107) included in the relay apparatus 100 will be described.

  The session information table 105 is a table used for specifying what processing is to be executed for the received packet.

  FIG. 3 is an explanatory diagram showing the contents of the session information table 105.

  As shown in FIG. 3, the session information table 105 includes information on items of a session number, a transmission source IP address, a transmission source port number, a destination IP address, a destination port number, a type, and security information.

  In FIG. 3, the IP address of the communication terminal 21 is 10.0.0.1, and the IP address of the communication terminal 22 is 192.168.0.1.

  The session number is an identifier for identifying each session in the relay apparatus 100, and a different session number is assigned to each session, and a common session number is applied to each table.

  In FIG. 3, it is assumed that the communication between communication terminals is handled as a separate session for each direction, and is further handled as a different session in RTP and RTCP (or SRTP and SRTCP). Therefore, in FIG. 3, the communication between the communication terminal 21 and the communication terminal 22 is shown by four sessions of session numbers 1 to 4.

  The packet determination unit 102 extracts information on the source IP address, source port number, destination IP address, and destination port number of the received packet, and searches the session information table 105 for information (row) that matches the extracted information. The type and security information in the information (row) are extracted.

  The type is information indicating what kind of processing is performed on the received packet. In this embodiment, as an example, “RTP” (processing at the time of RTP packet reception, which is encrypted and transmitted) ), “RTCP” (process when RTCP packet is received, encrypted and transmitted), “SRTP” (process when SRTP packet is received, decrypted and transmitted), “ The description will be made on the assumption that it is indicated by any one of “SRTCP” (processing when SRTCP packet is received and decrypted and transmitted). Note that the content according to the communication control method and the encryption method used in the communication system 1 may be applied to the type information.

  The security information is a plurality of pieces of information for encryption and decryption. For example, information such as “encryption algorithm”, “encryption key”, “authentication algorithm”, and “authentication key” defined in IETF RFC3711 Is applicable. In this embodiment, all items of “encryption algorithm”, “encryption key”, “authentication algorithm”, and “authentication key” are registered in the item “security information” of the session information table 105. As will be described, the format is not limited as long as the received packet is information for performing encryption or decryption. In the communication system 1, when another encryption method is adopted, information corresponding to the encryption method is registered in the security information.

  In FIG. 3, the items of security information are displayed as “information 1”, “information 2”, etc. for the sake of simplicity, but in reality, the above information is included. ing.

  The SRTP transmission / reception information table 106 is information used when the encryption processing unit 103 encrypts the received RTP packet and transmits it as an SRTP packet, or decrypts the received SRTP packet and transmits it as an RTP packet.

  FIG. 4 is an explanatory diagram showing an example of the contents of the SRTP transmission / reception information table 106.

  A session number similar to the session number in the session information table 105 described above is applied. In FIG. 4, information on session numbers 1 and 3 is shown. As shown in FIG. 3, session number 1 is a session related to an RTP packet transmitted from communication terminal 21 to communication terminal 22, and session number 3 is an SRTP packet transmitted from communication terminal 22 to communication terminal 21. This is the session.

  s_l represents the maximum value of the sequence number of the received RTP packet.

  In addition, ROC (Roll 0ver Counter) indicates the number of times that the 16-bit sequence number has overflowed.

  The SRTCP transmission information table 107 is information used in the encryption processing unit 103 to encrypt the received RTCP packet and transmit it as an SRTCP packet.

  FIG. 5 is an explanatory diagram showing an example of the contents of the SRTCP transmission information table 107.

  A session number similar to the session number in the session information table 105 described above is applied. In FIG. 5, information on session number 2 is shown. As illustrated in FIG. 3, the session number 2 is a session related to an RTCP packet transmitted from the communication terminal 21 to the communication terminal 22.

  The SRTCP index is information included in the SRTCP packet and is the value of the SRTCP index transmitted last.

  The packet processing count is the total number of SRTCP packets processed from the start of the session.

  The average RTCP reception interval, the previous reception time, the notification delay time, and the notification reception interval are information used for calculating the SRTCP index when the standby relay device is switched to the active system.

  Each entry in the session information table 105 is set by signaling such as SDP before a media packet is transmitted / received. Specifically, for example, the corresponding information is obtained from the c line, the m line, and the a line of the SDP message transmitted by the communication terminal. In addition, each entry in the SRTP transmission / reception information table 106 and the SRTCP transmission information table 107 is given 0 as an initial value.

(A-2) Operation | movement of embodiment Next, operation | movement of the communication system 1 of this embodiment which has the above structures is demonstrated.

(A-2-1) Operation of Active Relay Device First, the received packet processing operation in the active relay device 100-1 will be described.

  FIG. 6 is a flowchart illustrating an operation of received packet processing in the relay device 100.

  In the relay device 100-1, when the packet determination unit 102 receives a packet from the network interface unit 101 (S101), the header information of the received packet is extracted, and the received packet, the transmission source IP address, the transmission source port number, Information of a type with the same destination IP address and destination port number is retrieved from the session information table 105 (S102).

  Then, the encryption processing unit 103 converts the received packet (encryption or decryption) according to the retrieved type, and updates the tables (SRTP transmission / reception information table 106, SRTCP transmission information table 107) as necessary. (S103), and the converted packet is transmitted to the destination communication terminal (S104).

  Next, details of the received packet conversion process and table update in step S103 will be described for each type detected in step S102.

  FIG. 7 is a flowchart illustrating the processing in step S103 described above.

  FIGS. 7A to 7D describe the processing of the encryption processing unit 103 in the above-described step S103 when the type detected in the above-described step S102 is RTP, RTCP, SRTP, SRTCP, respectively. ing.

  Next, when the type detected in step S102 is RTP (when the received packet is an unencrypted RTP packet), the processing of the encryption processing unit 103 in step S103 is shown in FIG. Will be described.

  First, the encryption processing unit 103 acquires encryption parameters from the security information in the session information table 105 (S201).

  Next, the encryption processing unit 103 calculates ROC and s_l for encryption (S202). This may be calculated by the method described in Appendix A of RFC3711.

  Next, the received packet is encrypted using the parameters calculated in step S202 (S203).

  Then, the value of the SRTP transmission / reception information table 106 is updated by the encryption processing unit 103 to the values of ROC and s_l calculated in step S202 described above (S204), and the process ends.

  Next, FIG. 7B shows the processing of the encryption processing unit 103 in step S103 described above when the type detected in step S102 is RTCP (when the received packet is an unencrypted RTCP packet). Will be described.

  First, the encryption processing unit 103 detects the session number related to the received packet from the session information table 105, and the information on the session number is detected from the SRTP transmission / reception information table 106 and the SRTCP transmission information table 107. Then, the RTCP reception interval related to the session is calculated by the following equation (1) (S301).

Average RTCP reception interval =
(Average RTCP reception interval × number of packet processes + ΔT) / (number of packet processes + 1) (1)
In Equation (1), ΔT is the difference between the time when the current RTCP packet is received and the time when the previous RTCP packet is received.

  Then, the cryptographic processing unit 103 records the average RTCP reception interval SRTCP transmission information table 107 calculated by the equation (1), and further records the current RTCP packet reception time in the SRTCP transmission information table 107 as the previous reception time. (S302).

  Next, the encryption processing unit 103 detects security information related to the received packet from the session information table 105, and obtains parameters for encryption (S303).

  Next, the encryption processing unit 103 adds 1 to the SRTCP index of the corresponding entry in the SRTCP transmission information table 107 and the number of packet processes (S304), and encryption is performed using the information (S305).

  Next, FIG. 7C shows the processing of the cryptographic processing unit 103 in the above-described step S103 when the type detected in the above-described step S102 is SRTP (in the case of a received packet or an encrypted SRTP packet). It explains using.

  First, the encryption processing unit 103 acquires a parameter for decryption from the security information related to the received packet from the session information table 105 (S401).

  Next, the encryption processing unit 103 calculates ROC and s_l for encryption (S402). This may be calculated by the method described in Appendix A of RFC3711.

  Next, the received packet is decoded using the parameter calculated in step S402 (S403).

  Then, the value of the SRTP transmission / reception information table 106 is updated by the encryption processing unit 103 to the values of ROC and s_l calculated in step S402 described above (S404), and the process is terminated.

  Next, FIG. 7D shows the processing of the encryption processing unit 103 in the above-described step S103 when the type detected in the above-described step S102 is SRTCP (in the case of a received packet or an encrypted SRTCP packet). It explains using.

  First, the encryption processing unit 103 acquires a parameter for decryption from the security information related to the received packet from the session information table 105 (S501).

  Next, the received packet is decoded using the parameters acquired in step S501 (S502), and the process ends.

(A-2-2) Operation of Periodic Startup Process Next, information related to a session being processed periodically, that is, SRTP transmission / reception, from the active relay apparatus 100-1 to the standby relay apparatus 100-2. An operation (hereinafter referred to as “periodic activation process”) in which information of all entries in the information table 106 and the SRTCP transmission information table 107 is given will be described.

  FIG. 8 is a sequence diagram showing the operation of the regular activation process.

  First, in the relay device 100-1, a notification delay time that is one of the SRTCP transmission information tables 107 is calculated and registered. The notification delay time is calculated from the difference between the activation time of the current periodic activation process and the previous reception time of the SRTCP transmission information table 107 (hereinafter, using equation (2)) (S601).

Notification delay time = periodic start process start time−previous reception time (2)
Next, information of all entries in the SRTP transmission / reception information table 106 and the SRTCP transmission information table 107 is given from the active relay device 100-1 to the standby relay device 100-2 (S602).

  Next, when the standby relay apparatus 100-2 receives the notification information from the active relay apparatus 100-1 (S603), based on the received notification information, the SRTP transmission / reception information table 106 and the SRTCP transmission information table The information 107 is updated (S604). At this time, the time when the notification information is received is recorded as the notification reception time.

(A-2-3) Switching Operation Next, an operation when the relay device 100-2 is switched from the standby system to the active system will be described. The trigger for system switching is, for example, manual switching by a maintenance person or switching due to the occurrence of a failure in an active system device.

  FIG. 9 is a sequence diagram illustrating an operation when the active system is switched from the relay apparatus 100-1 to the relay apparatus 100-2.

  The standby relay apparatus 100-2 does not receive a packet from the communication terminal during normal times. Here, first, it is assumed that the relay apparatus 100-2 of the relay system 10 determines that the white has been switched to the active system in response to the reception of the packet from the communication terminal (S701).

  The specific contents of the conditions (trigger) for switching from the active relay apparatus 100-1 to the standby relay apparatus 100-2 and the switching method are not limited. The operation of the active relay device 100-1 may be monitored by a processing unit (or an external monitoring device), and the operation may be switched to the relay device 100-2 when a failure is detected. It should be noted that switching processing means such as an existing server device may be applied to the processing of switching from the active relay device 100-1 to the standby relay device 100-2.

  Next, when the relay device 100-2 is switched to the active relay device, the active processing is performed (S702).

  However, in order to encrypt the RTCP packet and transmit it as an SRTCP packet, it is necessary to recalculate the SRTCP index of each entry in the SRTCP transmission information table 107 (S703).

  In the processing of step S703, the redundancy processing unit 104 of the relay device 100-2 executes the following additional processing only for the first received RTCP packet processing for each session.

  First, in the redundancy processing unit 104, the switching delay time obtained by the difference between the time when the first RTCP packet is received and the time when the information notification is last received is calculated and set by the following equation (3).

Switching delay time = RTCP packet reception time−notification reception time (3)
Next, in the redundancy processing unit 104, the number of RTCP packet processes from the last reception of the information notification to the present is calculated and set by the following equation (4).

RTCP packet processing count =
(Switching delay time + notification delay time) / average RTCP reception interval (4)
Then, the redundancy processing unit 104 calculates and sets the SRTCP index to be used by the following equation (5).

SRTCP index = SRTCP index + RTCP packet processing count (5)
(A-3) Effects of Embodiment According to this embodiment, the following effects can be achieved.

  In the relay system, the active relay device periodically notifies the standby relay device of information, so that even if a system switchover occurs, the standby relay device has a high-precision sequence number and SRTCP index. Therefore, session continuity can be maintained.

  In addition, since the “notification reception time” in the SRTP transmission / reception information table is set on the standby relay device side, accurate time synchronization is not performed between the active relay device and the standby relay device. In addition, there is an effect that the calculation accuracy does not deteriorate.

(B) Other Embodiments The present invention is not limited to the above-described embodiments, and may include modified embodiments as exemplified below.

(B-1) In the above-described embodiment, the relay device 100-1 and the relay device 100-2 are described as having the same configuration in order to simplify the description. Good.

  In other words, the relay device 100-1 may operate as a normal operation-type relay device, and may have only a configuration for notifying the relay device 100-2 of notification information. The relay device 100-2 is normally a standby relay device, updates the contents of each table based on the notification information from the relay device 100-1, and operates only as an active system after switching. You may make it provide.

(B-2) In each of the embodiments described above, the device to be processed by the relay device has been described as a communication terminal such as an IP telephone terminal. Another communication device that accommodates the terminal may be used.

(B-3) In each of the above embodiments, the relay system has been described as relaying an unencrypted RTP / RTCP packet and an encrypted SRTP / SRTCP packet. The protocol to be used is not limited to this, and other packets related to real-time communication may be applied. Even in such a case, the same effects as in the above embodiment can be obtained by replacing each piece of information in the tables shown in FIGS. 3 to 5 with information corresponding to the protocol.

  DESCRIPTION OF SYMBOLS 1 ... Communication system, N1 ... Network, N2 ... Network, 21, 22 ... Communication terminal, 10 ... Relay system, 100, 100-1, 100-2 ... Relay apparatus, 101 ... Network interface part, 102 ... Packet determination part, DESCRIPTION OF SYMBOLS 103 ... Encryption processing part 104 ... Redundancy processing part 105 ... Session information table 106 ... SRTP transmission / reception information table 107 ... SRTCP transmission information table

Claims (6)

A first communication device capable of communicating with another communication device using at least RTP and RTCP, and a second communication device capable of communicating with another communication device using at least SRTP and SRTCP . A plurality of relay devices that relay packets flowing between them, the relay device including an active relay device that operates as a normal operation system and a standby relay device that operates as a normal operation standby system In the system,
The above operational relay device
Continuity related to the continuity of packets of the communication session, comprising analyzing a packet of a communication session between the first communication device and the second communication device and including a current SRTCP index value of the communication session First continuity information acquisition means for acquiring information;
The destination communication device receives the received packet received from the first communication device or the second communication device by using the continuity information acquired by the first continuity information acquisition means. When the RTCP packet addressed to the second communication device is received from the first communication device, the SRTCP packet is converted into the SRTCP packet using the SRTCP index value included in the continuity information. First packet converting means for converting;
First packet transmitting means for transmitting the packet converted by the first packet converting means to the destination of the packet;
Timing information holding means for holding timing information related to the arrival timing of the RTCP packet from the first communication device;
Continuity information synchronization means for providing the standby information relay apparatus with notification information including the continuity information acquired by the first continuity information acquisition means and the timing information held by the timing information holding means. ,
The standby relay device is
Notification information holding means for receiving and holding notification information from the active relay device;
When the RTCP packet is first received from the first communication device after the relay device is switched from the standby system to the active system, the latest information received from the active relay device is used. Estimating means for estimating an SRTCP index value in the current communication session;
Second continuity for analyzing the packet of the session and acquiring continuity information of the communication session including the current SRTCP index value of the communication session with the SRTCP index value estimated by the estimation means as an initial value Information acquisition means;
When the relay device is switched from the standby system to the active system, the second continuity information acquisition unit holds the received packet received from the first communication device or the second communication device . using the continuous property information, it is those that received packet destination communication device into a possible format received, receives the RTCP packet addressed to the second communication device from the first communication device A second packet conversion means for converting into an SRTCP packet using an SRTCP index value included in the continuity information ,
A relay system comprising: a second packet transmission unit configured to transmit the packet converted by the second packet conversion unit to a destination of the packet. A first communication device capable of communicating with another communication device using at least RTP and RTCP, and a second communication device capable of communicating with another communication device using at least SRTP and SRTCP . In an active relay device that operates as a normal operation system that constitutes a relay system that relays packets flowing between them,
Continuity related to the continuity of packets of the communication session, comprising analyzing a packet of a communication session between the first communication device and the second communication device and including a current SRTCP index value of the communication session First continuity information acquisition means for acquiring information;
The destination communication device receives the received packet received from the first communication device or the second communication device by using the continuity information acquired by the first continuity information acquisition means. When the RTCP packet addressed to the second communication device is received from the first communication device, the SRTCP packet is converted into the SRTCP packet using the SRTCP index value included in the continuity information. First packet converting means for converting;
First packet transmitting means for transmitting the packet converted by the first packet converting means to the destination of the packet;
Timing information holding means for holding timing information related to the arrival timing of the RTCP packet from the first communication device;
The relay of the standby system that operates as the standby system at the normal time in the relay system, the continuity information acquired by the first continuity information acquisition means and the notification information including the timing information held by the timing information holding means. And a continuity information synchronizing means for giving to the apparatus. A first communication device capable of communicating with another communication device using at least RTP and RTCP; and the first communication device capable of communicating with another communication device using at least SRTP and SRTCP. In a standby relay device that operates as a normal standby system, constituting a relay system that relays packets flowing between second communication devices having different communication conditions,
In the relay system, the communication session including a current SRTCP index value of a communication session between the first communication device and the second communication device from an active relay device operating as a normal operation system Notification information holding means for receiving and holding notification information including continuity information related to packet continuity and timing information related to the arrival timing of the RTCP packet from the first communication device ;
When the RTCP packet is first received from the first communication device after the relay device is switched from the standby system to the active system, the latest information received from the active relay device is used. Estimating means for estimating an SRTCP index value in the communication session;
Second continuity for analyzing the packet of the session and acquiring continuity information of the communication session including the current SRTCP index value of the communication session with the SRTCP index value estimated by the estimation means as an initial value When the information acquisition means and the relay device are switched from the standby system to the active system, the received packets received from the first communication device or the second communication device are acquired from the second continuity information. means utilizing the continuous property information held been made to convert the received packet to the destination communication device capable of receiving formats, from the first communication device addressed the second communication device Second packet conversion means for converting to an SRTCP packet using an SRTCP index value included in the continuity information when an RTCP packet is received ;
And a second packet transmitting means for transmitting the packet converted by the second packet converting means to a destination of the packet. A first communication device capable of communicating with another communication device using at least RTP and RTCP, and a second communication device capable of communicating with another communication device using at least SRTP and SRTCP . A computer installed in an active relay device that operates as a normal operation system that constitutes a relay system that relays packets flowing between them.
Continuity related to the continuity of packets of the communication session, comprising analyzing a packet of a communication session between the first communication device and the second communication device and including a current SRTCP index value of the communication session First continuity information acquisition means for acquiring information;
The destination communication device receives the received packet received from the first communication device or the second communication device by using the continuity information acquired by the first continuity information acquisition means. When the RTCP packet addressed to the second communication device is received from the first communication device, the SRTCP packet is converted into the SRTCP packet using the SRTCP index value included in the continuity information. First packet converting means for converting;
First packet transmitting means for transmitting the packet converted by the first packet converting means to the destination of the packet;
Timing information holding means for holding timing information related to the arrival timing of the RTCP packet from the first communication device;
The relay of the standby system that operates as the standby system at the normal time in the relay system, the continuity information acquired by the first continuity information acquisition means and the notification information including the timing information held by the timing information holding means. A relay program that functions as a means for synchronizing continuity information given to a device. A first communication device capable of communicating with another communication device using at least RTP and RTCP, and a second communication device capable of communicating with another communication device using at least SRTP and SRTCP . A computer mounted on a standby relay device that operates as a standby system in a normal state, constituting a relay system that relays packets flowing between them,
In the relay system, the communication session including a current SRTCP index value of a communication session between the first communication device and the second communication device from an active relay device operating as a normal operation system Notification information holding means for receiving and holding notification information including continuity information related to packet continuity and timing information related to the arrival timing of the RTCP packet from the first communication device ;
When the RTCP packet is first received from the first communication device after the relay device is switched from the standby system to the active system, the latest information received from the active relay device is used. Estimating means for estimating an SRTCP index value in the communication session;
Second continuity for analyzing the packet of the session and acquiring continuity information of the communication session including the current SRTCP index value of the communication session with the SRTCP index value estimated by the estimation means as an initial value When the information acquisition means and the relay device are switched from the standby system to the active system, the received packets received from the first communication device or the second communication device are acquired from the second continuity information. means utilizing the continuous property information held been made to convert the received packet to the destination communication device capable of receiving formats, from the first communication device addressed the second communication device Second packet conversion means for converting to an SRTCP packet using an SRTCP index value included in the continuity information when an RTCP packet is received ;
A relay program for causing a packet converted by the second packet converting means to function as a second packet transmitting means for transmitting the packet to a destination of the packet. A first communication device capable of communicating with other communication devices using at least RTP and RTCP, and a second communication device capable of communicating with other communication devices using at least SRTP and SRTCP ; In a communication system comprising a relay system that relays a packet flowing between the first communication device and the second communication device,
A communication system, wherein the relay system according to claim 1 is applied as the relay system.

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