JP6031005B2 - Communication device - Google Patents

Description

  The present invention relates to a technique for avoiding leakage of route information of a communication network and a technique for continuing a communication service even when a node of the communication network cannot be used.

  In a system called IMS (IP Multimedia Subsystem), even if a user roams (the network of another company used at the roaming destination is called a visited network), it is received on the home network (network with which the terminal is contracted) Provide service. To realize this, when the user roams, a register request signal is transmitted and responded between the terminal and the SIP server (C-CSCF) of the home network, and the location registration of the terminal is performed by the C-CSCF of the home network. Do. Furthermore, the routing path through which the signal passes at the time of outgoing / incoming call is determined by writing the path information in the path header of the register request signal. The communication service using the roaming terminal is performed using the routing route determined at the time of location registration. However, since the route information is shared between the visited network and the home network, the visited network (or the home network) is the home network (or the home network). There is a problem that the route information (topology and routing table) is known to the visited network. Further, if a failure occurs in a device constituting a network such as a node or a link on the routing path after the routing path is determined, the service cannot be provided because the path change function is not provided.

  Therefore, a means for easily avoiding leakage of route information and interruption of network communication service during roaming is required. A detailed description of the system operation at the time of roaming can be found especially in a specification published by a standardization organization such as 3GPP (3rd Generation Partnership Project).

(Conventional device and system contents)
(1) Route determination procedure based on register request signal / response signal during roaming FIG. 10 shows a conventional method for registering a register request signal (REGISTER) as a C-CSCF of a home network because a roaming terminal (SIP-UA_A) performs location registration. The flow of a process until it sends to (SIP server which performs session control) is shown.

  S1: When the user roams, SIP-UA_A performs location registration when the power is turned on or the area changes.

  First, SIP-UA_A transmits a register request signal to P-CSCF # 1 of the visited network.

  S2: P-CSCF # 1 assigns its own address (for example, <sip: pcscf # 1.visited.net>) to the path header of the register request signal (“Path” in the figure, the same applies hereinafter), and the register request signal Are transferred to the I-CSCF # 1 (SIP server that performs relay processing) of the visited network according to the routing rule of the visited network.

  S3: Similarly, I-CSCF # 1 assigns its own address (for example, <sip: icscf # 1.visited.net>) to the path header, and similarly transfers it to I-CSCF # 2.

  S4: Similarly, I-CSCF # 2 assigns its own address (for example, <sip: icscf # 2.visited.net>) to the path header, and similarly transmits to I-CSCF # 4.

  S5: Similarly, the I-CSCF # 4 assigns its own address (for example, <sip: icscf # 4.home.net>) to the path header, and similarly transfers it to the C-CSCF.

  S6: The C-CSCF takes out the route information described in the path header of the register request signal and stores it as route information.

  S7: The C-CSCF responds with a register request signal path header (path from P-CSCF # 1 to I-CSCF # 4) and a service route header (path from C-CSCF to I-CSCF # 2). (200 OK signal) is sent to I-CSCF # 4. The service route header is “Service-Route” in the figure, and so on.

  Note that the C-CSCF stores a route from the C-CSCF to the P-CSCF # 1 as route information (in the figure, “Route”, and the same applies hereinafter).

  S8: The response signal traces the route through which the register request signal passes based on the path header, and arrives at the roaming terminal.

  S9: The roaming terminal extracts route information from P-CSCF # 1 to C-CSCF from the path header and service route header of the response signal, and stores them as route information.

(2) Routing after route determination by register request signal / response signal After the route determination by register request signal / response signal, the incoming / outgoing SIP signal from the roaming terminal follows the route determined in “(1) Route determination procedure”. Flowing. Specifically, the outgoing / incoming SIP signal passes through the SIP server (P-CSCF, I-CSCF, C-CSCF) through which the register request signal passes.

  FIG. 11 shows an example of conventional routing of an INVITE signal at the time of transmission from SIP-UA_A to a terminal (SIP-UA_B) in a home network.

  S1: SIP-UA_A transmits an INVITE signal to SIP-UA_B at the time of outgoing call, and determines that the destination of the INVITE signal is P-CSCF # 1 based on the route information stored in S9 of FIG. Route information is added to the INVITE signal and transmitted to P-CSCF # 1.

  S2: P-CSCF # 1 receives the INVITE signal from SIP-UA_A. Then, P-CSCF # 1 determines that the transfer destination is I-CSCF # 1 from the route information, deletes its own address from the route information, and transfers the INVITE signal to I-CSCF # 1.

  S3: The I-CSCF # 1 receives the INVITE signal from the P-CSCF # 1. Then, the I-CSCF # 1 determines from the route information that the transfer destination is the I-CSCF # 2, deletes its own address from the route information, and transfers the INVITE signal to the I-CSCF # 2.

  S4: The I-CSCF # 2 receives the INVITE signal from the I-CSCF # 1. Then, the I-CSCF # 2 determines from the route information that the transfer destination is the I-CSCF # 4, deletes its own address from the route information, and transfers the INVITE signal to the I-CSCF # 4.

  S5: The I-CSCF # 4 receives the INVITE signal from the I-CSCF # 2. Then, the I-CSCF # 4 determines from the route information that the transfer destination is the C-CSCF, deletes its own address from the route information, and transfers the INVITE signal to the C-CSCF.

  S6: The C-CSCF receives the INVITE signal from the I-CSCF # 4, and receives the INVITE signal to the terminal (SIP-UA_B) based on the called telephone number described in the INVITE signal.

  FIG. 12 shows an example of routing of the INVITE signal at the time of transmission from SIP-UA_B to SIP-UA_A in the prior art.

  S1: SIP-UA_B transmits an INVITE signal to the C-CSCF.

  S2: The C-CSCF receives the INVITE signal, adds the route information stored in S6 of FIG. 10 to the INVITE signal, and transmits the INVITE signal to the I-CSCF # 4 based on the route information.

  S3: The I-CSCF # 4 receives the INVITE signal from the C-CSCF, deletes its own address from the route information, and transfers the INVITE signal to the I-CSCF # 2.

  S4: The I-CSCF # 2 receives the INVITE signal from the I-CSCF # 4, deletes its own address from the route information, and transfers the INVITE signal to the I-CSCF # 1.

  S5: The I-CSCF # 1 receives the INVITE signal from the I-CSCF # 2, deletes its own address from the route information, and transfers the INVITE signal to the P-CSCF # 1.

  S6: The call arrives at SIP-UA_A based on the SIP-UA_A telephone number described in the INVITE signal.

(3) Problems of the conventional system The conventional system has the following problems because the routing path determined at the time of the register request is not changed and the path information is shared between the visited network and the home network.

(A) Problem 1
After the routing path is determined, if a network component on the routing path fails, outgoing / incoming calls cannot be made.

  FIG. 13 shows an example of a transmission impossible state when I-CSCF # 1 breaks down during route routing in the prior art. FIG. 14 shows an example of an incoming call impossible state when I-CSCF # 1 fails during conventional route routing.

  The state in which calling and receiving cannot be performed continues until a register request signal is sent to the C-CSCF of the home network in order to perform location registration again, and routing that bypasses the faulty device is determined. The case where the location registration is performed again may be a case where the terminal moves across the service area, or the power is turned off and then restarted.

(B) Problem 2
Since the routing path is fixedly determined, when the network constituent devices on the routing path are congested, the load cannot be reduced by detouring or the like.

  In the example illustrated in FIG. 15, when I-CSCF # 1 is congested in a situation where two units (I-CSCF # 1 and I-CSCF # 3) having the same function are installed, I-CSCF # A terminal using 1 as a route cannot be changed to I-CSCF # 3 having a sufficient processing capacity. As a result, not only is it difficult to make a call, but congestion continues because the load on the I-CSCF # 1 is not reduced.

(C) Problem 3
Since the routing path is fixedly fixed, when a construction / setting change that requires the interruption of the function of the apparatus is performed on the network configuration apparatus on the routing path, the service is interrupted. FIG. 16 shows an example in which the I-CSCF # 1 is under construction during the route routing in the related art, and the function is stopped, so that the transmission is disabled. FIG. 17 shows an example in which the incoming call cannot be made for the same reason.

  Although the communication from the roaming terminal (SIP-UA_A) can be ensured by detouring to I-CSCF # 3, the detour cannot be ensured by the conventional method, so the communication cannot be secured.

(D) Problem 4
In the conventional system, the route through which the register request signal flows by using the register request signal and the response signal (200 OK) (the address of the SIP server in the visited network and home network) is changed to the visited network (other carrier network). And the home network (owner's network), and the route of the SIP signal for outgoing and incoming calls from the roaming terminal is determined. In this way, since routing information is shared between the visited network (other carrier network) and the home network (own carrier network), the routing route and network configuration of the own carrier network (connection of the SIP server) to the other carrier network It is not desirable from the viewpoint of equipment information protection.

  As a conventional technique for solving the problems 1, 2, and 3, a method using a function of assigning the same virtual IP address to a plurality of SIP proxy network IFs is conceivable. This will be described with reference to FIG. It is composed of duplicated I-CSCF (I-CSCF # 1 and I-CSCF # 3) and VRRP (Virtual Router Redundancy Protocol) compatible routers # 1 and # 2. Routers # 1 and # 2 are connected to I-CSCF # 1 and # 3, respectively. I-CSCF # 1 and I-CSCF # 3 are assigned the same address, and a virtual IP address is assigned to the router. I-CSCF # 1 and router # 1 are masters, I-CSCF # 3 and router # 2 are backups, and normally operate with I-CSCF # 1. When the I-CSCF # 1 breaks down, the VRRP function is used to switch from the router # 1 to the router # 2 and make a detour to the I-CSCF # 3. However, this method causes only an IP level failure detection, requires a VRRP-compatible router, and requires software for performing a switching process when an I-CSCF failure occurs, which causes an increase in cost.

  The above is the prior art that solves the problems 1, 2, and 3. However, there is no prior art that solves the problem 4.

3GPP TS 24.229

  Therefore, there is a need for a technique that avoids leakage of route information of the communication network without using the technique of FIG. In addition, there is a need for a technique for continuing communication services even when a node of a communication network cannot be used due to failure, congestion, or construction.

  The present invention has been made in view of the above problems, and a first object is to provide a technique for avoiding leakage of route information of a communication network. A second object is to provide a technique for continuing a communication service even when a node of a communication network cannot be used.

In order to solve the above-described problem, the first aspect of the present invention provides a communication device that is a node constituting a communication network, for each destination of a communication signal, the next destination when the signal is sent to the destination. The adjacent node adjacent to the communication device that can be grouped, a path information table that stores whether the adjacent node is normal or abnormal for each group , and an adjacent node that monitors whether the adjacent node is normal or abnormal for each group If an abnormality is detected in the monitoring unit, the adjacent node, a table update unit that changes the state of the adjacent node from a normal state to an abnormal state in the route information table, and a communication signal for any of the adjacent nodes At the time of transmission, it is determined whether the adjacent node is normal or abnormal with reference to the route information table. If the adjacent node is abnormal, the route information table Another neighbor nodes of the same group which is a Oite normal, characterized in that it comprises a bypass processing unit to be selected as the detour destination of the communication signals.

The second invention is a communication device that relays communication signals between the communication network and the external network, the routing information indicating a route of a communication signal in the communication network, in order to avoid the leakage of the route information A correspondence table that stores dummy values in association with each other, and indicates a path of the communication signal in the communication network included in the communication signal when the communication signal received from within the communication network is transmitted to the external network. The route information is replaced with a dummy value indicating the route information, and the transmission processing unit that associates the route information with the dummy value and stores the correspondence information in the correspondence table; and the communication signal received from the external network is the communication When transmitting in the network, the routing information corresponding to the dummy value included in the communication signal is read from the correspondence table and the dummy value of the communication signal is replaced with the routing information. Characterized in that it comprises a part.

According to a third aspect of the present invention, there is provided a communication apparatus that is a node constituting a communication network and relays a communication signal between the communication network and an external network, for each destination of the communication signal in the communication network. The adjacent node adjacent to the communication device that can be the next destination when sending a signal to the ground is grouped, a path information table storing whether the adjacent node is normal or abnormal for each group , and the group for each group An adjacent node monitoring unit that monitors whether an adjacent node is normal or abnormal, and a table update unit that changes the state of the adjacent node from a normal state to an abnormal state in the path information table if an abnormality of the adjacent node is detected When the communication signal is transmitted to any of the adjacent nodes, it is determined whether the adjacent node is normal or abnormal with reference to the route information table. Route information indicating that if an abnormality, and the alternate route processing unit to select another neighbor nodes of the same group which is a normal in the route information table as the detour destination of the communication signal, the path of the communication signal in the communication network When, upon transmitting the correspondence table stores an association with a dummy value to avoid leakage of the route information, the communication signal received from within said communication network to the external network, contained in the communication signal A transmission processing unit that replaces the path information indicating the path of the communication signal in the communication network with a dummy value indicating the path information, and stores the path information and the dummy value in association with each other in the correspondence table; When transmitting a communication signal received from the external network into the communication network, path information corresponding to a dummy value included in the communication signal is obtained from the correspondence table. Reading, dummy values of the communication signal; and a reception processing unit for replacing to the path information.

  According to the first aspect of the present invention, the communication service can be continued even when the node of the communication network cannot be used. According to the second aspect of the present invention, it is possible to avoid leakage of route information of the communication network. According to the third aspect of the present invention, the communication service can be continued even when the node of the communication network cannot be used, and the leakage of the route information of the communication network can be avoided.

The flow of processing until the roaming terminal (SIP-UA_A) sends a register request signal to the C-CSCF of the home network in order to perform location registration is shown. This shows a part of the configuration of I-CSCF # 2, and particularly shows a configuration for avoiding leakage of route information. The flow of processing until the C-CSCF sends a response signal to the register request signal to the I-CSCF # 2 is shown. The flow of a process until I-CSCF # 2 sends the received response signal to a roaming terminal is shown. The example of the routing of the INVITE signal at the time of transmission from the roaming terminal (SIP-UA_A) to the terminal (SIP-UA_B) in the home network is shown. The example of the routing of the INVITE signal at the time of the incoming call from SIP-UA_B to SIP-UA_A is shown. The flow of processing in the case where an outgoing call from SIP-UA_A to SIP-UA_B is communicated when I-CSCF # 1 fails will be shown. This shows a part of the configuration of P-CSCF # 1, and particularly shows a configuration for solving problems such as failures, congestion, and service interruption due to construction. The flow of a process in the case of communicating the incoming call from SIP-UA_B to SIP-UA_A is shown. Conventionally, since the roaming terminal (SIP-UA_A) performs location registration, the flow of processing until the register request signal (REGISTER) is sent to the C-CSCF (SIP server that performs session control) of the home network is shown. The example of the routing of the INVITE signal at the time of the transmission to the terminal (SIP-UA_B) in a home network from SIP-UA_A in the past is shown. The example of the routing of the INVITE signal at the time of the transmission from SIP-UA_B to SIP-UA_A in the past is shown. In the related art, an example of a transmission impossible state when I-CSCF # 1 fails during route routing is shown. Conventionally, an example of an incoming call impossible state when I-CSCF # 1 fails during route routing will be described. In the related art, an example of a transmission impossible state when I-CSCF # 1 is congested during route routing is shown. Conventionally, when route routing is performed conventionally, an example is shown in which I-CSCF # 1 is under construction and has stopped functioning, and thus cannot be transmitted. Conventionally, an example in which the I-CSCF # 1 is under construction and stopped functioning when performing route routing in the prior art, resulting in an incoming call impossible state. A detour process using a virtual IP address is shown.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the IMS system, the communication service using the roaming terminal is performed using the routing path determined at the time of location registration. However, after the routing path is determined, a failure or congestion of a network component device such as a node or link on the routing path is determined. If service is interrupted due to occurrence or construction, the service cannot be provided. Furthermore, since route information is shared between the visited network (other business operator's network) and the home network (owner's business operator network), the routing information and network configuration of the own operator's network can be grasped by the other operator's network, and the equipment information is protected. From the viewpoint of.

  As a means of solving failures, congestion, and problems caused by construction (eg, reliability degradation, service interruption, congestion expansion), the conventional technology has taken a redundant configuration, assigned the same address, It is necessary to develop software for switching equipment (bypassing).

  In the present embodiment, problems (for example, reliability) caused by failure, congestion, and construction under the condition that the conditions required by the conventional solutions are not required and the roaming procedure of the IMS system is not changed. Provide easy means to resolve degradation, service interruption, congestion expansion), and the routing information of the own operator network can be easily transferred to other operator networks without any changes to the conventional routing procedure. A technique for avoiding leakage will be described.

(1) Technology to avoid leakage of route information of own operator network to other operator networks Using FIG. 1, FIG. 2, FIG. 3, and FIG. A technique for avoiding leakage to the public network will be described. In the figure, P-CSCF # 1, I-CSCF # 1, I-CSCF # 2, I-CSCF # 3, I-CSCF # 4, and C-CSCF are SIP servers.

  FIG. 1 shows the flow of processing until a roaming terminal (SIP-UA_A) sends a register request signal (REGISTER) to a C-CSCF (SIP server for session control) of the home network in order to perform location registration.

  S1: The roaming terminal (SIP-UA_A) transmits a register request signal to P-CSCF # 1 of the visited network.

  S2: P-CSCF # 1 receives the register request signal from the terminal, assigns its own address (for example, <sip: pcscf # 1.visited.net>) to the path header, Transfer to I-CSCF # 1 of the visited network according to the routing rules of the visited network.

  S3: The I-CSCF # 1 receives the register request signal from the P-CSCF # 1, assigns its own address (for example, <sip: icsccf # 1.visited.net>) to the path header, and sends the register request signal. Then, the packet is transferred to the I-CSCF # 2 of the visited network according to the routing rule of the visited network.

  FIG. 2 shows a part of the configuration of I-CSCF # 2, and particularly shows a configuration for avoiding leakage of route information.

  The I-CSCF # 2 is a communication device that relays communication signals between a communication network (here, a visited network) and an external network (here, a home network). The I-CSCF # 2 externally transmits the communication signal received from the communication network and the correspondence table 11 that stores the path information indicating the path of the communication signal in the visited network and the dummy value indicating the path information in association with each other. When transmitting to the network, the path information indicating the path of the communication signal in the communication network included in the communication signal is replaced with a dummy value indicating the path information, and the path information and the dummy value are associated with each other. When transmitting the communication signal received from the transmission processing unit 12 stored in the correspondence table 11 and the external network into the communication network, the path information corresponding to the dummy value included in the communication signal is read from the correspondence table 11. The reception processing unit 13 replaces the dummy value of the communication signal with the path information.

Although not shown, I-CSCF # 4 also has the same configuration. Returning to FIG.

  S4: The I-CSCF # 2 receives the register request signal from the I-CSCF # 1. When the transmission processing unit 12 transmits a register request signal to the home network (other network), the route information (route to I-CSCF # 2) of the visited network (own network) described in the path header of the register request signal In order to avoid leakage of information (P-CSCF # 1, I-CSCF # 1)), it is replaced with a dummy value (for example, SIP: B.visited.net), and further, its own address (<sip: icscf # 2) .Visited.net>) and a register request signal is transmitted to I-CSCF # 4.

  S5: Further, the transmission processing unit 12 of the I-CSCF # 2 transmits a dummy value (SIP: B.visited.net) and route information to the I-CSCF # 2 (P-CSCF # 1 → I-CSCF # 1 → I-CSCF # 2) is associated and stored in the correspondence table 11.

  S6: The I-CSCF # 4 of the home network receives the register request signal from the I-CSCF # 2 of the visited network, and has its own address (for example, <sip: icscf # 4.home.net>) in its path header. And the register request signal is transferred to the C-CSCF of the home network according to the routing rule of the home network.

  S7: The C-CSCF extracts the route information described in the path header of the register request signal and stores it as route information.

  In this way, in the conventional method, the address of the server in the visited network through which the register request signal has been passed is described in the path header. However, in this method, a dummy value is written in the visited network. It is possible to avoid leakage of route information to the home network.

  Next, a procedure in which the C-CSCF of the home network that has received the register request signal transmitted from the roaming terminal (SIP-UA_A) sends a response signal to the roaming terminal will be described with reference to FIGS.

  FIG. 3 shows a processing flow until the C-CSCF sends a response signal to the register request signal to the I-CSCF # 2.

  S1: The C-CSCF includes a path header of the register request signal (the dummy value of the visited network and a route from I-CSCF # 2 to C-CSCF are described), and a service route header (C-CSCF to I- A response signal (200 OK signal) is added to the response signal (200 OK signal) and transmitted to the I-CSCF # 4.

  S2: I-CSCF # 4 receives a response signal from C-CSCF. The transmission processing unit 12 of the I-CSCF # 4 sets the path information from the I-CSCF # 4 to the C-CSCF as a dummy value (in the service route header of the response signal in order to avoid leakage of the path information in the home network. For example, it replaces with SIP: A.home.net) and transmits a response signal to I-CSCF # 2.

  S3: Also, the transmission processing unit 12 of the I-CSCF # 4 performs a dummy value (SIP: A.home.net) and path information (I-CSCF # 4 → C) from the I-CSCF # 4 to the C-CSCF. -CSCF) and store them in the correspondence table 11.

  In this way, in the conventional method, the address of the home network server through which the register request signal has passed is described in the path header. However, in this method, a dummy value (SIP: A.home.net) can prevent the home network route information from leaking to the visited network.

  FIG. 4 shows the flow of processing until I-CSCF # 2 sends the received response signal to the roaming terminal.

  S1: I-CSCF # 2 receives a response signal from I-CSCSF # 4 of the home network. The reception processing unit 13 of the I-CSCF # 2 reads out the route information corresponding to the visited network dummy value (SIP: B.visited.net) described in the path header of the response signal from the correspondence table 11. The dummy value of the path header is replaced with path information, and the replaced response signal is transmitted to I-CSCF # 1.

S2: The response signal reversely follows the route through which the register request signal passes based on the path header and arrives at the roaming terminal. S3: The roaming terminal receives the C-CSCF of the home network from the path header and service header of the received response signal. Route information is extracted and stored as route information.

  In the route information, the route information from the I-CSCF # 4 to the C-CSCF of the home network is replaced with a dummy value (SIP: A.home.net). Can be avoided.

  As described above, in the servers (I-CSCF # 2 and I-CSCF # 4 in the figure) that perform communication between the visited network and the home network, route information in the local network is displayed when communicating with other networks. By replacing it with a dummy value, it is possible to avoid leakage of route information in the own network to other networks. And, for the dummy value of the own network received from other networks, refer to the correspondence table between the route information and the dummy value, convert it to the route information in the own network, and realize the routing in the own network To do.

  FIG. 5 shows a routing example of the INVITE signal at the time of transmission from the roaming terminal (SIP-UA_A) to the terminal (SIP-UA_B) in the home network.

  S1: SIP-UA_A transmits an INVITE signal to SIP-UA_B at the time of outgoing call. Based on the route information generated in S3 of FIG. 4, it is determined that the destination of the INVITE signal is P-CSCF # 1, Route information is added to the INVITE signal and transmitted to P-CSCF # 1.

  S2: P-CSCF # 1 receives the INVITE signal from SIP-UA_A. Then, P-CSCF # 1 determines that the transfer destination is I-CSCF # 1 from the route information, deletes its own address from the route information, and transfers the INVITE signal to I-CSCF # 1.

  S3: The I-CSCF # 1 receives the INVITE signal from the P-CSCF # 1. Then, the I-CSCF # 1 determines from the route information that the transfer destination is the I-CSCF # 2, deletes its own address from the route information, and transfers the INVITE signal to the I-CSCF # 2.

  S4: The I-CSCF # 2 receives the INVITE signal from the I-CSCF # 1. Then, the I-CSCF # 2 determines from the route information that the transfer destination is the I-CSCF # 4, deletes its own address from the route information, and transfers the INVITE signal to the I-CSCF # 4.

  S5: The I-CSCF # 4 receives the INVITE signal from the I-CSCF # 2. From the correspondence table 11, the reception processing unit 13 of the I-CSCF # 4 receives route information (<sip: ccscf home) corresponding to the dummy value (SIP: A. home. Net) of the home network described in the INVITE signal. .Net>), the dummy value is rewritten to the route information, and the INVITE signal is transferred to the C-CSCF based on the route information.

  S6: The C-CSCF receives the INVITE signal from the I-CSCF # 4, and receives the INVITE signal to the terminal (SIP-UA_B) based on the called telephone number described in the INVITE signal.

  FIG. 6 shows an example of routing of the INVITE signal at the time of arrival from SIP-UA_B to SIP-UA_A.

  S1: SIP-UA_B transmits an INVITE signal to the C-CSCF.

  S2: The C-CSCF receives the INVITE signal, adds the route information stored in S7 of FIG. 1 to the INVITE signal, and transmits the INVITE signal to the I-CSCF # 4 based on the route information.

  S3: The I-CSCF # 4 receives the INVITE signal from the C-CSCF, determines that the transfer destination is I-CSCF # 2 from the route information, deletes its own address from the route information, and sends the INVITE signal to the I-CSCF. Transfer to # 2.

  S4: The I-CSCF # 2 receives the INVITE signal from the I-CSCF # 4. From the correspondence table 11, the reception processing unit 13 of the I-CSCF # 2 receives route information (<sip: icscf # 1visited) corresponding to the dummy value (SIP: B.visited.net) described in the route information of the INVITE signal. .Net> <sip: pcscf # 1visited.net>), the dummy value of the route information is replaced with the route information, the address of itself is deleted from the route information, and the INVITE signal is changed to I-CSCF # based on the route information. Forward to 1.

  S5: The I-CSCF # 1 receives the INVITE signal from the I-CSCF # 2. Then, the I-CSCF # 1 determines that the transfer destination is P-CSCF # 1 from the route information, deletes its own address from the route information, and transfers the INVITE signal to the P-CSCF # 1.

  S6: P-CSCF # 1 receives the INVITE signal from I-CSCF # 1, and arrives at SIP-UA_A based on the telephone number of SIP-UA_A described in the INVITE signal.

  As described above, for example, the I-CSCF # 2 associates and stores the path information indicating the path of the communication signal in the visited network and the dummy value indicating the path information in the communication network. When transmitting the communication signal received from the external network to the external network, the path information indicating the path of the communication signal in the communication network included in the communication signal is replaced with a dummy value indicating the path information, and the path information and the When transmitting the communication signal received from the external network into the communication network in association with the dummy value and stored in the correspondence table 11, the dummy value included in the communication signal is transmitted from the correspondence table 11. And the reception processing unit 13 that replaces the dummy value of the communication signal with the route information, so that the route information in the visited network leaks to the home network. It can be avoided.

  In addition, since the I-CSCF # 4 has the same configuration, it is possible to prevent the route information in the home network from leaking to the visited network.

(2) Technology for solving the problem of service interruption due to failure, congestion and construction Next, referring to FIG. 7, FIG. 8, and FIG. 9, when I-CSCF # 1 existing on the determined route fails Even if there is, a procedure for continuing the service by route change (detour) will be described.

  FIG. 7 shows the flow of processing when an outgoing call from SIP-UA_A to SIP-UA_B is communicated when I-CSCF # 1 fails.

  FIG. 8 shows a part of the configuration of the P-CSCF # 1, and particularly shows a configuration for solving problems such as failure, congestion, and service interruption due to construction.

  P-CSCF # 1 is a communication device that is a node constituting a communication network (herein, a visited network). The P-CSCF # 1 monitors the path information table 21 that stores whether the adjacent node is normal or abnormal for each adjacent node adjacent to the P-CSCF # 1, and monitors whether the adjacent node is normal or abnormal for each adjacent node If an adjacent node monitoring unit 22 and an adjacent node abnormality are detected, a table update unit 23 that changes the state of the adjacent node from a normal state to an abnormal state in the path information table 21 and any of the adjacent nodes When transmitting a communication signal, it is determined whether the adjacent node is normal or abnormal with reference to the path information table 21. If the adjacent node is abnormal, another adjacent node that is normal in the path information table 21 is determined. And a detour processing unit 24 that is selected as a detour destination of the communication signal.

  Here, for each destination of the communication signal, the route information table 21 groups adjacent nodes that are the next transmission destination when transmitting a signal to the destination, and stores whether each group is normal or abnormal.

  An adjacent node that is normal in the route information table 21 is a detour destination server (detour hop) when another adjacent node of the group is abnormal.

  Although not shown, other SIP servers have the same configuration.

  Returning to FIG. 7, the description will be continued.

  S1: The adjacent node monitoring unit 22 of each SIP server monitors whether the SIP server connected via the communication line is normal or abnormal (failure / congestion / under construction). For example, the adjacent node monitoring unit 22 of P-CSCF- # 1 monitors the states of adjacent I-CSCF # 1 and I-CSCF # 3. The adjacent node monitoring unit 22 of the I-CSCF # 1 monitors the states of the P-CSCF # 1 and I-CSCF # 2. The adjacent node monitoring unit 22 of I-CSCF # 3 monitors the states of P-CSCF # 1 and I-CSCF # 2. For example, the adjacent node monitoring unit 22 of P-CSCF # 1 monitors the states of P-CSCF # 1 and I-CSCF # 2.

  As described above, each SIP server sets a detour destination server (detour hop) in the path information table 21 when an abnormal state of the adjacent SIP server is detected. For example, the neighboring servers of P-CSCF # 1 are I-CSCF # 1 and I-CSCF # 3, and an abnormal state of I-CSCF # 1 (I-CSCF # 3) is detected in the path information table 21 The detour destination server at this time is set to be I-CSCF # 3 (I-CSCF # 1).

  S2: If the adjacent node monitoring unit 22 detects an abnormality (for example, a failure) of the I-CSCF # 1, the table updating unit 23 of the P-CSCF # 1 changes the state of the I-CSCF # 1 in the path information table 21. Change from normal state to abnormal state.

  S3: The P-CSCF # 1 receives the INVITE signal from the roaming terminal (SIP-UA_A) to the terminal (SIP-UA_B) of the home network. The detour processing unit 24 of the P-CSCF # 1 refers to the path information table 21 to determine whether the I-CSCF # 1 is normal or abnormal when transmitting this INVITE signal to the I-CSCF # 1 based on the route information. to decide. If the adjacent node is abnormal, the detour processing unit 24 selects a part of the same destination from the route information table 21, and another adjacent node that is normal in the part (here, I-CSCF # 3) As the detour destination of the INVITE signal.

  S4: P-CSCF # 1 replaces the address of I-CSCF # 1 described in the route information of the received INVITE signal with the address of I-CSCF # 3 selected as the detour destination, and replaces the INVITE signal with I- Transmit to CSCF # 3.

  If there are a plurality of other adjacent nodes that are normal, the highest priority node set in advance may be set as the detour destination, or the detour destination may be selected at random.

  S5: The I-CSCF # 3 receives the INVITE signal from the P-CSCF # 1. Then, the I-CSCF # 3 determines that the transfer destination is I-CSCF # 2 from the route information, deletes its own address from the route information, and transfers the INVITE signal to the I-CSCF # 2.

  S6: The I-CSCF # 2 receives the INVITE signal from the I-CSCF # 3. Then, the I-CSCF # 2 determines that the transfer destination is I-CSCF # 4 from the route information, deletes its own address from the route information, and transfers the INVITE signal to the I-CSCF # 4.

  S7: The I-CSCF # 4 receives the INVITE signal from the I-CSCF # 2. The reception processing unit 13 of the I-CSCF # 4 reads out the route information corresponding to the dummy value (SIP: A.home.net) described in the route information of the INVITE signal from the correspondence table 11, and uses the dummy value as the route. Replace with the information, and transfer the replaced INVITE signal to the C-CSCF based on the route information.

  S8: The C-CSCF arrives at the terminal (SIP-UA_B) from the incoming telephone number described in the INVITE signal.

  In addition, it is two SIP servers of adjacent P-CSCF # 1 and I-CSCF # 2 that detect the abnormality of I-CSCF # 1, and the detour processing in P-CSCF # 1 was described here. . A similar process is performed in I-CSCF # 2, which will be described with reference to FIG.

  FIG. 9 shows the flow of processing when an incoming call from SIP-UA_B to SIP-UA_A is communicated.

  S1: The adjacent node monitoring unit 22 of each SIP server monitors whether the SIP server connected via the communication line is normal or abnormal (failure / congestion / under construction). In the figure, I-CSCF # 2 is described, but the same processing is performed in other SIP servers.

  The adjacent nodes of I-CSCF # 2 are I-CSCF # 1 and I-CSCF # 3, and the path information table 21 of I-CSCF # 2 contains I-CSCF # 1 (I-CSCF # 3). It is set that the detour server when the abnormal state is detected is I-CSCF # 3 (I-CSCF # 1).

  S2: If the adjacent node monitoring unit 22 detects an abnormality (for example, a failure) of the I-CSCF # 1, the table updating unit 23 of the I-CSCF # 2 sets the state of the I-CSCF # 1 in the path information table to normal. Change from a state to an abnormal state.

  S3 to S5: Processing is performed in the same manner as S1 to S3 in FIG.

  S6: The I-CSCF # 2 receives the INVITE signal from the I-CSCF # 4. The detour processing unit 24 determines whether the I-CSCF # 1 is normal or abnormal with reference to the path information table 21 when transmitting the INVITE signal to the I-CSCF # 1 based on the route information. If the adjacent node is abnormal, the detour processing unit 24 selects a part of the same destination in the route information table 21, and another adjacent node that is normal in the part (here, I-CSCF # 3) As the detour destination of the INVITE signal.

  If there are a plurality of other adjacent nodes that are normal, the highest priority node set in advance may be set as the detour destination, or the detour destination may be selected at random.

  S7: The I-CSCF # 2 replaces the address of the I-CSCF # 1 described in the route information of the received INVITE signal with the address of the I-CSCF # 3 selected as the detour destination, and converts the INVITE signal to the I- Transmit to CSCF # 3.

  S8: The INVITE signal is routed based on the route information and arrives at SIP-UA_A.

  As described above, each SIP server monitors the path information table 21 that stores whether each adjacent node is normal or abnormal for each adjacent node, and monitors whether each adjacent node is normal or abnormal. If an adjacent node monitoring unit 22 detects an abnormality of the adjacent node, the table update unit 23 that changes the state of the adjacent node from the normal state to the abnormal state in the path information table 21 and communication with any of the adjacent nodes When transmitting a signal, it is determined whether the adjacent node is normal or abnormal with reference to the path information table 21. If the adjacent node is abnormal, another adjacent node that is normal in the path information table 21 is determined. Since the detour processing unit 24 is selected as a detour destination of the communication signal, after the route is determined by the register request signal / response signal Oite, even when the node on the route can not be used in such a failure, there is no communication interruption, it can be continued communication service.

  In particular, in I-CSCF # 2 having the configuration shown in FIG. 2, it is also possible to avoid that route information in the visited network leaks to the home network.

  In this embodiment, a register request signal, a response signal, and an INVITE signal are taken as examples of communication signals. However, the present invention is not limited to this, and a communication signal used in the communication network may be used. That is, in the present invention, communication signals are not limited to these signals.

  Further, as a dummy value, SIP: B. visited. Although a character string such as net is used, the present invention is not limited to this, and other forms of dummy values (for example, encryption) may be used. The dummy value is not limited to the server address.

P-CSCF # 1, I-CSCF # 1, I-CSCF # 2, I-CSCF # 4, C-CSCF SIP server 11 Correlation table 12 Transmission processing unit 13 Reception processing unit 21 Path information table 22 Adjacent node monitoring unit 23 Table update unit 24 Detour processing unit

Claims (3)

In a communication device that is a node constituting a communication network,
For each destination of the communication signal, adjacent nodes adjacent to the communication device that can be the next destination when the signal is sent to the destination are grouped, and for each group , whether the adjacent node is normal or abnormal is stored. A route information table;
An adjacent node monitoring unit that monitors whether the adjacent node is normal or abnormal for each group ;
If an abnormality of the adjacent node is detected, a table update unit that changes the state of the adjacent node from a normal state to an abnormal state in the path information table;
When transmitting a communication signal to any of the adjacent nodes, it is determined whether the adjacent node is normal or abnormal with reference to the path information table. If the adjacent node is abnormal, the path information table is normal. And a detour processing unit that selects another adjacent node of the same group as a detour destination of the communication signal. In a communication device that relays communication signals between a communication network and an external network,
A route information indicating a route of a communication signal in the communication network, a correspondence table that associates and stores the dummy value to avoid leakage of the route information,
When transmitting a communication signal received from within the communication network to the external network, the path information indicating the path of the communication signal in the communication network included in the communication signal is replaced with a dummy value indicating the path information. A transmission processing unit that associates the route information with the dummy value and stores them in the correspondence table;
When transmitting the communication signal received from the external network into the communication network, the path information corresponding to the dummy value included in the communication signal is read from the correspondence table, and the dummy value of the communication signal is determined as the path information. A communication device comprising: a reception processing unit replaced with In a communication device that is a node constituting a communication network and relays a communication signal between the communication network and an external network,
For each destination of a communication signal in the communication network, adjacent nodes adjacent to the communication device that can be the next destination when sending a signal to the destination are grouped , and the adjacent node is normal or abnormal for each group A route information table for storing
An adjacent node monitoring unit that monitors whether the adjacent node is normal or abnormal for each group ;
If an abnormality of the adjacent node is detected, a table update unit that changes the state of the adjacent node from a normal state to an abnormal state in the path information table;
When transmitting a communication signal to any of the adjacent nodes, it is determined whether the adjacent node is normal or abnormal with reference to the path information table. If the adjacent node is abnormal, the path information table is normal. A detour processing unit that selects another adjacent node of the same group as the detour destination of the communication signal;
A correspondence table that stores path information indicating a path of a communication signal in the communication network and a dummy value indicating the path information in association with each other;
When transmitting a communication signal received from within the communication network to the external network, the route information indicating the route of the communication signal in the communication network included in the communication signal is used to avoid leakage of the route information . A transmission processing unit for replacing the dummy information with the route information and the dummy value in association with each other and storing them in the correspondence table;
When transmitting the communication signal received from the external network into the communication network, the path information corresponding to the dummy value included in the communication signal is read from the correspondence table, and the dummy value of the communication signal is determined as the path information. A communication device comprising: a reception processing unit replaced with

Images