JP2018170542A - Enum/dns query control system and enum/dns query control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To preferentially process an ENUM/DNS query from a specific terminal without providing a dedicated ENUM/DNS server.SOLUTION: A call control server 2 changes a top level domain included in an ENUM/DNS query for inquiring connection destination information corresponding to the destination terminal included in a connection request from a terminal 1 according to the priority of the terminal 1, and an ENUM/DNS server 31 for caching sends the ENUM/DNS query from the call control server 2 to an IP address of an ENUM/DNS server 32 for authority which differs depending on the top level domain included in the ENUM/DNS query, and a router 4 converts a source IP address of the ENUM/DNS query from the ENUM/DNS server 32 for caching into a different IP address according to the destination IP address of the ENUM/DNS query.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for preferentially controlling a specific ENUM (E.164 Number Mapping) / DNS (Domain Name System) query.

  Conventionally, in an IP network, an ENUM / DNS query control system has been proposed as a mechanism in which a device (such as a call control server) in a communication carrier network associates a telephone number with a URI (Uniform Resource Identifier). In this ENUM / DNS query control system, a call control server installed in a telecommunications carrier's network connects connection destination information (IP address, domain name, etc.) for the telephone number of a terminal (IP phone, etc.) to be connected. To the ENUM / DNS server and performs routing based on the connection destination information.

  This ENUM / DNS server accepts access from a plurality of call control servers and the like installed in the communication carrier network, and also has a large number of terminals (IP phones, etc.) accommodated in one call control server. Access from a huge number of terminals will be accepted. In the ENUM / DNS query control system, the call control server generates an ENUM / DNS query conforming to the ENUM protocol and inquires connection destination information (IP address, domain name, etc.).

  The inquiry by this ENUM / DNS query causes a congestion state particularly when a large number of calls to the affected area occur due to a disaster or the like. Then, in the ENUM / DNS server, the response time for the inquiry from the call control server becomes long, or in the worst case, the response cannot be made, resulting in an increase in connection delay between terminals and a connection failure.

  In each telecommunications carrier, even in the event of an emergency such as a disaster, ENUM / DNS queries from high-priority user terminals such as police, fire departments, hospitals, etc. Need to be processed preferentially. For this reason, conventionally, the load is distributed by increasing the number of corresponding servers (scale-out) and distributing the inquiry to a plurality of servers (see Non-Patent Document 1).

  For example, when an ENUM / DNS server preferentially handles an ENUM / DNS query of a priority terminal of a priority user to be handled preferentially, a plurality of ENUM / DNS servers are provided. There is a technique for distributing an inquiry from the priority terminal to a dedicated ENUM / DNS server different from the general terminal of the general user.

  FIG. 8 is a diagram for explaining a system that preferentially processes a query from a priority terminal using a plurality of ENUM / DNS servers.

  As shown in FIG. 8, a general ENUM / DNS server 3 (3A) and a priority ENUM / DNS server 3 (3B) are installed. Then, the call control server 2 determines whether the received connection request is a connection request from the general terminal 1 (1A) or a connection request from the priority terminal 1 (1B). In response to a connection request from the general terminal 1 (1A), the call control server 2 transmits an ENUM / DNS query to the general ENUM / DNS server 3 (3A). On the other hand, the call control server 2 transmits an ENUM / DNS query to the priority ENUM / DNS server 3 (3B) for the connection request from the priority terminal 1 (1B).

  By doing so, even if a delay occurs in the general ENUM / DNS server 3 (3A) due to a large amount of call processing from the general terminal 1 (1A), the priority terminal Since the connection request from 1 (1B) is processed by the priority ENUM / DNS server 3 (3B), connection can be made without delay.

Shin Maruyama, 5 others, "Priority control of email reception using DNS that dynamically changes responses", Information Processing Society of Japan, Information Processing Society of Japan, Vol. 47, No. 4, April 2006, p. 1021-p.1030

  However, since the call control server 2 performs processing to distribute the connection request from the priority terminal 1 (1B) to the priority ENUM / DNS server 3 (3B), the general ENUM / DNS server 3 (3A) There was another problem that a priority ENUM / DNS server 3 (3B) had to be separately constructed.

  In order to solve this problem, it is conceivable to construct a general ENUM / DNS server and a priority ENUM / DNS server with one ENUM / DNS server.

  However, as shown in FIG. 9, the integrated ENUM / DNS server that is currently constructed includes a cache ENUM / DNS server 31 that temporarily stores the ENUM / DNS query received from the call control server 2, and It is constructed separately from an authoritative ENUM / DNS server 32 that performs conversion processing to connection destination information based on the ENUM / DNS query transmitted from the cache ENUM / DNS server 31.

  Therefore, ENUM / DNS is added with different source IP addresses (IPa, IPb) according to the priority of the source terminal so that the call control server 2 can determine the priority of the terminal by the ENUM / DNS server. Even if the query is transmitted to the ENUM / DNS server 31 for cache, the source IP address is the ENUM / DNS for cache at the time of query from the ENUM / DNS server 31 for cache to the authoritative ENUM / DNS server 32. The IP address (IPc) of the server 31, that is, the same source IP address that cannot distinguish between the general terminal 1 (1 A) and the priority terminal 1 (1 B), the general terminal 1 in the authoritative ENUM / DNS server 32 (1A) and the priority terminal 1 (1B) cannot be discriminated, and the operation in which the priority of the terminal is distinguished cannot be performed.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to preferentially process an ENUM / DNS query from a specific terminal without providing a dedicated ENUM / DNS server.

  In order to solve the above problems, an ENUM / DNS query control system according to claim 1 includes a call control server that transmits an ENUM / DNS query to an ENUM / DNS server, and an ENUM for query storage that stores the ENUM / DNS query. In the ENUM / DNS query control system, the call control server comprises: a / DNS server, and a transfer device that transfers the ENUM / DNS query from the query storage ENUM / DNS server to the query processing ENUM / DNS server. Includes a query change unit for changing the highest domain name included in the ENUM / DNS query for inquiring connection destination information corresponding to the destination terminal included in the connection request from the terminal according to the priority of the terminal. The query storage ENUM / DNS server is the call control server The ENUM / DNS query is transmitted to the address of the ENUM / DNS server for query processing that differs according to the highest domain name included in the ENUM / DNS query. An address conversion unit is provided that converts the source address of the ENUM / DNS query from the storage ENUM / DNS server to a different address according to the destination address of the ENUM / DNS query.

  An ENUM / DNS query control method according to claim 2 is a call control server that transmits an ENUM / DNS query to an ENUM / DNS server, a query storage ENUM / DNS server that stores the ENUM / DNS query, and the query storage. And a transfer device that transfers the ENUM / DNS query from the ENUM / DNS server for query to the ENUM / DNS server for query processing, wherein the call control server is included in the connection request from the terminal The query storage ENUM / DNS server performs a step of changing the highest domain name included in the ENUM / DNS query for inquiring connection destination information corresponding to the called destination terminal, according to the priority of the terminal, , The ENUM / DNS query from the call control server / Transfer to the address of the ENUM / DNS server for query processing that differs depending on the highest domain name included in the DNS query, and the transfer device sends the ENUM / from the ENUM / DNS server for query storage The step of converting the source address of the DNS query into a different address according to the destination address of the ENUM / DNS query is performed.

  According to the present invention, it is possible to preferentially process an ENUM / DNS query from a specific terminal without providing a dedicated ENUM / DNS server.

It is a figure which shows the whole structure and process outline | summary of an ENUM / DNS query control system. It is a figure which shows the functional block structure of a call control server. It is a figure which shows the functional block structure of the ENUM / DNS server for caches. It is a figure which shows the functional block structure of a router. It is a figure which shows the functional block structure of the ENUM / DNS server for authority. It is a figure which shows the data example of connection destination information. It is a figure which shows operation | movement of an ENUM / DNS query control system. It is a figure which shows the whole structure and process outline | summary of the conventional ENUM / DNS query control system. It is a figure which shows the whole structure and process outline | summary of the conventional ENUM / DNS query control system.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.

≪Overview≫
First, an outline of the ENUM / DNS query control system will be described. FIG. 1 shows the overall configuration and processing outline of the ENUM / DNS query control system 100.

<System configuration and processing overview>
The ENUM / DNS query control system 100 includes a call control server 2 that accommodates a plurality of terminals 1, a cache ENUM / DNS server 31 connected to the call control server 2, and an ENUM / DNS server 31 for the cache. And an authoritative ENUM / DNS server 32 connected to the router 4.

  The difference from the conventional system shown in FIG. 9 is that the call control server 2 changes the top level domain included in the ENUM / DNS query according to the priority of the terminal 1. Also, the cache ENUM / DNS server 31 sets a different destination IP address (destination IP address of the authoritative ENUM / DNS server 32) according to the top level domain included in the ENUM / DNS query. Further, the router 4 performs NAT conversion of the source IP address of the ENUM / DNS query into a different source IP address according to the destination IP address of the ENUM / DNS query.

  As a result, the source IP address of the ENUM / DNS query to the authoritative ENUM / DNS server 32 differs depending on the priority of the terminal 1, so that the authoritative ENUM / DNS server 32 The priority of the ENUM / DNS query can be determined based on the IP address. As a result, priority processing can be performed for the ENUM / DNS query from the priority terminal 1 (1B), and predetermined restriction processing can be performed for the ENUM / DNS query from the general terminal 1 (1A). It can process without generating.

  In this embodiment, since a general ENUM / DNS query and an ENUM / DNS query to be preferentially processed are processed by a single device, the authoritative ENUM / DNS server 32 responds to a general ENUM / DNS query. Then, the regulation process shown below is executed.

  The authoritative ENUM / DNS server 32 has an RRL (Response Rate Limiting) function used as a response to a DNS reflector attack that sends a large amount of the same query in an attack using the DNS server. The RRL is a function for controlling a rate of returning a response for an inquiry to a specific domain or a specific source IP address in order to prevent a DNS reflector attack. Using this RRL function, the authoritative ENUM / DNS server 32 regulates general ENUM / DNS queries.

  Hereinafter, with reference to FIG. 1, an outline of processing of the ENUM / DNS query control system 100 according to the present embodiment will be described.

  For the ENUM / DNS query for the connection request from the general terminal 1 (1A), the call control server 2 changes the top level domain included in the query to “e164enum.net1”, and the priority terminal 1 ( For the ENUM / DNS query for the connection request from 1B), it is predetermined to change the top level domain included in the query to “e164enum.net2”.

  Further, if the top level domain included in the ENUM / DNS query is “e164enum.net1”, the cache ENUM / DNS server 31 has “IPb” as the destination IP address to the authoritative ENUM / DNS server 32. If the top level domain included in the ENUM / DNS query is “e164enum.net2”, it is predetermined to set “IPc” as the destination IP address to the authoritative ENUM / DNS server 32. . “IPb” and “IPc” are both IP addresses provided in the authoritative ENUM / DNS server 32.

  If the destination IP address of the ENUM / DNS query is “IPb”, the router 4 sets “IPd” as the source IP address of the query, and the destination IP address of the ENUM / DNS query is “IPc”. Then, it is determined in advance that “IPf” is set as the source IP address of the query.

  In addition, the authority ENUM / DNS server 32 includes, as RRL settings for general ENUM / DNS queries, each of a monitored domain, a monitored source IP address, an allowable number of queries (/ second), and a limit ratio. Information is set in advance. Here, as shown in FIG. 1, “IPd” is set as the monitoring target transmission source IP address, xx query (/ second) is set as the allowable number of queries (/ second), and “1 / 2 ”is set.

  In the situation where the above settings are made, when the call control server 2 receives a connection request from the general terminal 1 (1A) (step S1), the call request is sent to the general terminal 1 based on the pre-stored priority terminal information. It is determined whether the request is from (1A) or the priority terminal 1 (1B) (step S2).

  Next, when the received connection request is a request from the general terminal 1 (1A), the call control server 2 reverses the destination telephone number specified in the connection request in order, and prefixes “e164enum.net”. For example, an ENUM / DNS query including “9.9.9.9.0.6.2.2.4.1.8.e164enum.net” is added, and the top level domain included in the query is changed to “e164enum.net1” (step S3). Thereafter, the call control server 2 transmits the query to the cache ENUM / DNS server 31 (step S4).

  Next, the ENUM / DNS server 31 for cache temporarily stores the ENUM / DNS query from the call control server 2 in the memory, and confirms the top level domain included in the query after a predetermined timing has arrived. Then, “IPb” corresponding to “e164enum.net1” is set as the destination IP address of the authoritative ENUM / DNS server 32 (step S5). Thereafter, the cache ENUM / DNS server 31 transmits an ENUM / DNS query to “IPb” of the authoritative ENUM / DNS server 32 (step S6). The predetermined timing is, for example, a timing that can be processed by the authoritative ENUM / DNS server 32 or a periodic timing.

  Next, when the router 4 receives the ENUM / DNS query from the cache ENUM / DNS server 31, since “IPb” is set as the destination IP address of the query, the source IP address of the query is changed to “ NAT conversion is performed to the source IP address of “IPd” (step S7). Thereafter, the router 4 transfers the query to the authoritative ENUM / DNS server 32 (step S8).

  Next, the authoritative ENUM / DNS server 32 confirms the transmission source IP address of the received ENUM / DNS query, and determines whether or not the IP address matches the monitored transmission source IP address “IPd”. . Since the ENUM / DNS server 32 matches the monitored source IP address “IPd”, the ENUM / DNS server 32 determines that it is an ENUM / DNS query for a connection request from the general terminal 1 (1A), and performs a restriction based on RRL. Execute (Step S9). Specifically, for example, if the number of queries per second exceeds xx for a connection request directed to the monitoring target domain “4.1.8.e164enum.net”, the response to the query is limited to ½. Execute the process.

  Thereafter, when receiving a connection request from the priority terminal 1 (1B) (step S10), the call control server 2 determines whether the connection request is a request from the general terminal 1 (1A) based on the preferentially stored priority terminal information. It is determined whether the request is from the priority terminal 1 (1B) (step S11).

  Next, when the received connection request is a request from the priority terminal 1 (1B), the call control server 2 uses, for example, an ENUM / DNS query including “9.9.9.9.0.6.2.2.4.1.8.e164enum.net”. And the top level domain included in the query is changed to “e164enum.net2” (step S12). Thereafter, the call control server 2 transmits the query to the cache ENUM / DNS server 31 (step S13).

  Next, the ENUM / DNS server 31 for cache temporarily stores the ENUM / DNS query from the call control server 2 in the memory, and confirms the top level domain included in the query after a predetermined timing has arrived. Then, “IPc” corresponding to “e164enum.net2” is set as the destination IP address of the authoritative ENUM / DNS server 32 (step S14). Thereafter, the cache ENUM / DNS server 31 transmits an ENUM / DNS query to “IPc” of the authoritative ENUM / DNS server 32 (step S15).

  Next, when the router 4 receives the ENUM / DNS query from the cache ENUM / DNS server 31, since “IPc” is set as the destination IP address of the query, the source IP address of the query is changed to “ NAT conversion is performed to the source IP address of “IPf” (step S16). Thereafter, the router 4 transfers the query to the authoritative ENUM / DNS server 32 (step S17).

  Next, the authoritative ENUM / DNS server 32 confirms the transmission source IP address of the received ENUM / DNS query, and determines whether or not the IP address matches the monitored transmission source IP address “IPd”. . Since the ENUM / DNS server 32 does not match the monitored source IP address “IPd”, the ENUM / DNS server 32 determines that it is an ENUM / DNS query for a connection request from the priority terminal 1 (1B) and does not perform restriction control. Priority control is executed (step S18). Specifically, the ENUM / DNS server 32 searches the connection destination information and then executes a process of transmitting an ENUM / DNS response to the call control server 2.

  By doing so, according to the ENUM / DNS query control system 100, the ENUM / DNS query for the connection request from the general terminal 1 (1A) is properly regulated, and then the priority terminal 1 (1B) The ENUM / DNS query for the connection request can be preferentially processed without restriction. Therefore, even when a large number of connection requests are received due to the occurrence of a disaster, the ENUM / DNS query regarding the connection request from the priority terminal 1 (1B) is given priority by the ENUM / DNS server 32 as one chassis. Can be processed.

≪Configuration of each device≫
Next, the configuration of each device constituting the ENUM / DNS query control system 100 will be described.

<Call control server>
A functional block configuration of the call control server 2 is shown in FIG. The call control server 2 accommodates a plurality of terminals 1 including a general terminal 1 (1A) and a priority terminal 1 (1B). When a connection request from each terminal 1 is received, the call control server 2 An ENUM / DNS query requesting connection destination information (such as a URI) corresponding to the destination information (such as the telephone number of the destination terminal 1) is transmitted to the ENUM / DNS server 31. Then, the call control server 2 performs a call connection with the terminal 1 that is a destination based on the connection destination information. The call control server 2 is a SIP server that executes call processing based on, for example, SIP (Session Initiation Protocol).

  In the present embodiment, the call control server 2 includes a priority terminal determination unit 21, a query generation unit 22, a query change unit 23, a query transmission unit 24, a call connection processing unit 25, and a data storage unit 26. .

  The data storage unit 26 is a functional unit that stores priority terminal information and domain information. The priority terminal information is information that can specify whether or not the terminal 1 that has transmitted the connection request is the priority terminal 1 (1B). For example, it may be a list of identification information (telephone number or the like) of the terminal 1 to be the priority terminal 1 (1B) acquired by the network management device or the like. Number (etc.) may be given priority information (contract information). The domain information is information in which a domain corresponding to the priority of the terminal 1 is registered. For example, information in which the domain of “e164enum.net1” is associated with the telephone number of the general terminal and the domain of “e164enum.net2” is associated with the telephone number of the priority terminal is registered.

  When receiving a connection request from the terminal 1, the priority terminal determination unit 21 refers to the priority terminal information stored in the data storage unit 26, and the connection request from the terminal 1 is a connection request from the general terminal 1 (1A). Or a functional unit that determines whether the connection request is from the priority terminal 1 (1B).

  The query generation unit 22 is a functional unit that generates an ENUM / DNS query. This ENUM / DNS query is for requesting connection destination information (such as a URI) corresponding to destination information (such as the telephone number of the destination terminal 1) attached to the received connection request. Generated in the format. For example, the E.D of the destination telephone number (for example, 0422-60-9999) included in the connection request received from the terminal 1 is displayed. 164 numbers (+ 81-422-60-9999) in reverse order, separated by dots, and prefixed with “e164enum.net” “9.9.9.9.0.6.2.2.4.1.8.e164enum.net” An ENUM / DNS query is generated as destination information.

  The query change unit 23 refers to the domain information stored in the data storage unit 26 and sets the domain of the ENUM / DNS query generated by the query generation unit 22 according to the determination result by the priority terminal determination unit 21 It is. For example, in the case of a connection request from the general terminal 1 (1A), the top level domain (e164enum.net) included in “9.9.9.9.0.6.2.2.4.1.8.e164enum.net” is changed to “e164enum.net1”. In the case of a connection request from the priority terminal 1 (1B), the top level domain is changed to “e164enum.net2”.

  The query transmission unit 24 is a functional unit that transmits the ENUM / DNS query changed by the query change unit 23 to the cache ENUM / DNS server 31.

  When the call connection processing unit 25 receives the ENUM / DNS response to the ENUM / DNS query from the authoritative ENUM / DNS server 32, the call connection processing unit 25 extracts the connection destination information attached to the ENUM / DNS response, and the connection destination information is extracted. A function unit that determines whether or not it is a local IP network and, if the connection destination information is the local IP network as a result of the determination, transmits a connection request to the terminal 1 indicated by the destination information and performs call connection It is. On the other hand, as a result of the determination, if the extracted connection destination information indicates another IP network (for example, an IP network of another communication carrier) instead of the local IP network, a connection request is made to the other IP network. Send.

<ENUM / DNS server for cache>
Next, the cache ENUM / DNS server 31 will be described. A functional block configuration of the cache ENUM / DNS server 31 is shown in FIG. The cache ENUM / DNS server 31 is a cache server that stores ENUM / DNS queries for a predetermined time before the authoritative ENUM / DNS server 32.

  In the present embodiment, the cache ENUM / DNS server 31 includes a query storage unit 311, a query transmission unit 312, a DNS address setting unit 313, and a data storage unit 314.

  The data storage unit 314 is a functional unit that stores DNS address information. The DNS address information is information in which the destination address of the authoritative ENUM / DNS server 32 that is the inquiry destination of the ENUM / DNS query is registered for each domain included in the ENUM / DNS query. For example, information in which a destination IP address of “IPb” is associated with a domain of “e164enum.net1” and a destination IP address of “IPc” is associated with a domain of “e164enum.net2” is registered.

  The query storage unit 311 is a functional unit that temporarily stores the ENUM / DNS query transmitted from the call control server 2.

  The query transmission unit 312 is a functional unit that reads an ENUM / DNS query from the query storage unit 311 at a predetermined timing and transmits the ENUM / DNS query to the authoritative ENUM / DNS server 32 via the router 4.

  The DNS address setting unit 313 refers to the DNS address information in the data storage unit 314, and according to the domain included in the ENUM / DNS query, the destination IP address (authoritative) of the ENUM / DNS query transmitted by the query transmission unit 312 The IP address of the ENUM / DNS server 32) is set. For example, when the domain included in the ENUM / DNS query is “e164enum.net1”, “IPb” is set as the destination IP address of the ENUM / DNS query, and when the domain is “e164enum.net2”, “IPc” is the destination. Set to IP address.

<Router>
Next, the router 4 will be described. A functional block configuration of the router 4 is shown in FIG. The router 4 is a router that performs NAT conversion of the source IP address of the ENUM / DNS query between the cache ENUM / DNS server 31 and the authoritative ENUM / DNS server 31.

  In the present embodiment, the router 4 includes a query transfer unit 41, an address conversion unit 42, and a data storage unit 43.

  The data storage unit 43 is a functional unit that stores conversion address information. The translated address information is information for translating the source IP address of the query according to the destination IP address of the ENUM / DNS query. For example, information in which a source IP address of “IPd” is associated with a destination IP address of “IPb” and a source IP address of “IPf” is associated with a destination IP address of “IPc” is registered. .

  The query transfer unit 41 is a functional unit that transfers the ENUM / DNS query transmitted from the cache ENUM / DNS server 31 to the authoritative ENUM / DNS server 32.

  The address conversion unit 42 is a functional unit that refers to the conversion address information in the data storage unit 43 and converts the source IP address of the query according to the destination IP address set in the received ENUM / DNS query. .

<ENUM / DNS server for authority>
Next, the authoritative ENUM / DNS server 32 will be described. A configuration block configuration of the authoritative ENUM / DNS server 32 is shown in FIG. The authoritative ENUM / DNS server 32 is provided with connection destination information, and returns a connection destination information corresponding to the destination information when receiving an inquiry from the call control server 2 by an ENUM / DNS query.

  Upon receiving the ENUM / DNS query, the authoritative ENUM / DNS server 32 extracts the source IP address information, and based on the source IP address, the ENUM / DNS query is sent from the general terminal 1 (1A). It is determined whether it is a query for a connection request from the priority terminal 1 (1B).

  The authoritative ENUM / DNS server 32 monitors the number of queries for connection requests from the general terminal 1 (1A), and if it receives more queries than allowed within a predetermined time, it uses RRL. Perform regulatory control. On the other hand, when the ENUM / DNS server 32 determines that the query is a query for a connection request from the priority terminal 1 (1B), the ENUM / DNS server 32 transmits an ENUM / DNS response to the call control server 2 without performing restriction control. Execute priority control.

  The authoritative ENUM / DNS server 32 is managed in a hierarchical structure (Tier 0 to Tier 2) as in the case of DNS, and is an upper layer when performing name (connection destination) resolution for destination information. A query is recursively / repetitively performed from the ENUM / DNS server managing Tier 0 or Tier 1 to the ENUM / DNS server managing Tier 2. In ENUM, each telecommunications carrier manages an ENUM / DNS server belonging to Tier 2, and stores connection destination information corresponding to each terminal 1 in each number band (for example, an area code).

  In this embodiment, the authoritative ENUM / DNS server 32 includes a priority query determination unit 321, a restriction processing unit 322, a connection destination information search unit 323, a query response unit 324, and a data storage unit 525. .

  The data storage unit 325 is a functional unit that stores RRL setting information and connection destination information. The RRL setting information is information on a monitoring target domain, a monitoring target transmission source IP address, an allowable number of queries (/ second), and a limit ratio. The connection destination information is information for converting the destination information into connection destination information.

  Here, the monitoring target domain indicates a domain in an area where congestion may occur due to, for example, a disaster or the like, or where congestion actually occurs. For example, “4.1.8.e164enum.net” is set for a predetermined area in Tokyo. As the monitoring source IP address, the call control server 2 is set with the source IP address “IPd” for the general terminal attached to the ENUM / DNS query for the connection request from the general terminal 1 (1A). The number of queries allowed (/ second) is set to xx queries (/ second) (for example, 50 queries / second). For example, “1/2” is set as the limit ratio.

  Upon receiving the ENUM / DNS query from the call control server 2, the priority query determination unit 321 extracts the source IP address attached to the ENUM / DNS query, and the source IP address is the monitored source IP address. It is a function part which determines whether it corresponds to.

  The priority query determination unit 321 determines that the extracted source IP address is an ENUM / DNS query for a connection request from the general terminal 1 (1A) if the extracted source IP address matches the monitoring target source IP address. The query is output to the restriction processing unit 322.

  On the other hand, when the extracted source IP address does not match the monitoring target source IP address, the priority query determination unit 321 determines that it is an ENUM / DNS query for a connection request from the priority terminal 1 (1B), The query is output to the connection destination information search unit 323 for priority processing.

  The restriction processing unit 322 is a functional unit that refers to the ENUM / DNS query acquired from the priority query determination unit 321 and determines whether the destination information is addressed to the monitoring target domain. When the restriction processing unit 322 is not addressed to the monitoring target domain, the restriction processing unit 322 outputs the ENUM / DNS query to the connection destination information search unit 323.

  On the other hand, if the restriction processing unit 322 is addressed to the monitoring target domain, the ENUM / DNS query is assumed to be a monitoring target query, and the number of queries is counted to be increased by “+1”, and the allowable number of queries (/ second). If it exceeds the limit, it will be regulated (destroyed etc.) according to the limit ratio. When the query is not regulated, the regulation processing unit 322 outputs the query to the connection destination information search unit 323.

  The restriction processing unit 322 stores, for example, each information of the monitoring target transmission source IP address, the number of queries allowed (/ second), and the restriction ratio in the storage unit 33 in advance, from a predetermined network management device or the like. The RRL regulation is executed in response to reception of information on the monitoring target domain regarding the area where the disaster or the like has occurred.

  When the connection destination information search unit 323 acquires the ENUM / DNS query, the connection destination information search unit 323 extracts the destination information attached to the ENUM / DNS query, refers to the connection destination information in the data storage unit 325, and It is a functional unit that searches for corresponding connection destination information. The connection destination information search unit 323 extracts connection destination information obtained as a result of searching for connection destination information, and outputs a processing instruction to the query response unit 324.

  Here, FIG. 6 shows a data configuration example of the connection destination information. As shown in FIG. 6, connection destination information is stored in connection destination information in association with destination information. For example, the destination information includes E.D. based on the telephone number of the destination terminal 1. Information obtained by converting the 164 number into the domain format of the ENUM protocol is stored. In association with the destination information, the connection destination information includes, for example, the E.E. A URI including the 164 number and the domain (carrier_a.ne.jp) of the connection carrier is stored.

  Returning to FIG. 5, the query response unit 324 is a functional unit that generates an ENUM / DNS response with the connection destination information extracted by the connection destination information search unit 323 and transmits the ENUM / DNS response to the call control server 2.

≪Operation of ENUM / DNS query control system≫
Next, the operation of the query control method performed by the ENUM / DNS query control system 100 will be described. FIG. 7 is a diagram illustrating a processing flow of the query control method.

  First, after receiving a connection request from the terminal 1 (step S101), the call control server 2 determines whether the connection request is a connection request from the priority terminal 1 (1B) with reference to the priority terminal information. (Step S102).

  As a result of this determination, if it is determined that the request is not a connection request from the priority terminal 1 (1B), that is, a connection request from the general terminal 1 (1A), the call control server 2 refers to the domain information and / DNS query top-level domain is changed to “e164enum.net1” for general terminals, and the changed “9.9.9.9.0.6.2.2.4.1.8.e164enum.net1” is used for cache ENUM / DNS It transmits to the server 31 (step S103).

  On the other hand, if it is determined in step S102 that the request is a connection request from the priority terminal 1 (1B), the call control server 2 refers to the domain information and sets the top level domain of the ENUM / DNS query as the domain “ It is changed to “e164enum.net2”, and “9.9.9.9.0.6.2.2.4.1.8.e164enum.net2” after the change is transmitted to the ENUM / DNS server 31 for cache (step S104).

  Next, after receiving the ENUM / DNS query from the call control server 2 (step S105), the cache ENUM / DNS server 31 refers to the top level domain included in the ENUM / DNS query, and stores the DNS address information. Based on the IP address of the authoritative ENUM / DNS server 32 corresponding to the top level domain, an ENUM / DNS query is transmitted (step S106).

  Specifically, for example, when the top-level domain included in the received ENUM / DNS query is “e164enum.net1”, the destination IP address is set to “IPb” and transmitted, and when “e164enum.net2”, Set "IPc" as the destination IP address and transmit. “IPb” and “IPc” are both IP addresses provided in the authoritative ENUM / DNS server 32.

  Next, when the router 4 receives the ENUM / DNS query from the cache ENUM / DNS server 31 at the preceding stage of the authoritative ENUM / DNS server 32, the router 4 sends the source IP address corresponding to the destination IP address of the query. Obtained from the translated address information, the source IP address of the query is converted into the obtained IP address, and transferred to the authoritative ENUM / DNS server 32 (step S107).

  The operation in step S107 is performed using the NAT function provided in the router 4. The NAT function is generally a dynamic function of the router 4, but in this embodiment, the authority ENUM / DNS server 32 needs to determine the source of the ENUM / DNS query. An IP address to be used as an address needs to be registered in the router 4 as translated address information.

  Next, after receiving the ENUM / DNS query via the router 4 (step S108), the authoritative ENUM / DNS server 32 extracts the source IP address attached to the query, and the source IP address Is matched with the monitoring target transmission source IP address (step S109).

  Thereafter, if the extracted source IP address does not match the monitored source IP address, the authoritative ENUM / DNS server 32 determines that the ENUM / DNS query is a connection request from the priority terminal 1 (1B). Then, the process proceeds to step S11.

  On the other hand, if the extracted source IP address matches the monitored source IP address, the authoritative ENUM / DNS server 32 determines that the ENUM / DNS query is a connection request from the general terminal 1 (1A). Then, the process proceeds to step S1110.

  In step S110, the authoritative ENUM / DNS server 32 executes RRL restriction on the ENUM / DNS query for the connection request from the general terminal 1 (1A).

  Specifically, the authoritative ENUM / DNS server 32 includes the destination information attached to the received ENUM / DNS query in the monitored domain, and the number of queries allowed (/ second) (for example, xx / Sec), the processing restriction of “1/2” indicated by the restriction ratio is executed for the ENUM / DNS query for the connection request from the general terminal 1 (1A). That is, the authoritative ENUM / DNS server 32 discards the ENUM / DNS query for the connection request from the general terminal 1 (1A) at a rate of 1/2.

  Subsequently, in step S111, the authoritative ENUM / DNS server 32 extracts the destination information attached to the received ENUM / DNS query, refers to the destination information, and connects to the destination information. Search for destination information.

  Next, the authoritative ENUM / DNS server 32 generates an ENUM / DNS response with the searched connection destination information and transmits it to the call control server 2 (step S112).

  Finally, when receiving the ENUM / DNS response from the authoritative ENUM / DNS server 32, the call control server 2 extracts the connection destination information attached to the ENUM / DNS response and executes the process for call connection (Step S113).

  Specifically, if the extracted connection destination information is the local IP network, the call control server 2 transmits a call connection connection request to the terminal 1 indicated by the destination information. On the other hand, when the extracted connection destination information indicates another IP network (for example, the IP network of another communication carrier), the call control server 2 transmits a connection request to the other IP network. The process is terminated.

  As described above, according to the present embodiment, the call control server 2 determines the top level domain included in the ENUM / DNS query for inquiring the connection destination information corresponding to the destination terminal included in the connection request from the terminal 1. The ENUM / DNS server 31 for cache is changed according to the priority of the terminal 1, and the ENUM / DNS query from the call control server 2 is used for different authority depending on the top level domain included in the ENUM / DNS query. The router 4 sends the IP address of the ENUM / DNS query from the ENUM / DNS server 32 for the cache to the IP address of the ENUM / DNS server 32 according to the destination IP address of the ENUM / DNS query. Provide a dedicated ENUM / DNS server. Ku, can be processed ENUM / DNS queries from a particular terminal 1 preferentially.

  Finally, the ENUM / DNS query control system 100 described in the present embodiment can be realized by a computer such as a server device or a router device having a CPU, a memory, and the like. It is also possible to create a program for causing a computer to function as the ENUM / DNS query control system 100 and a storage medium for the program.

DESCRIPTION OF SYMBOLS 100 ... ENUM / DNS query control system 1 ... Terminal 1A ... General terminal 1B ... Priority terminal 2 ... Call control server 21 ... Priority terminal determination part 22 ... Query generation part 23 ... Query change part 24 ... Query transmission part 25 ... Call connection process Unit 26 ... Data storage unit 31 ... ENUM / DNS server for cache (ENUM / DNS server for query storage)
311 ... Query storage unit 312 ... Query transmission unit 313 ... DNS address setting unit 314 ... Data storage unit 32 ... ENUM / DNS server for authority (query processing ENUM / DNS server)
321 ... Preferential query determination unit 322 ... Restriction processing unit 323 ... Connection destination information search unit 324 ... Query response unit 325 ... Data storage unit 4 ... Router (transfer device)
41 ... Query transfer unit 42 ... Address conversion unit 43 ... Data storage unit

Claims (2)

A call control server that transmits an ENUM / DNS query to an ENUM / DNS server, a query storage ENUM / DNS server that stores the ENUM / DNS query, and the ENUM / DNS query from the query storage ENUM / DNS server In an ENUM / DNS query control system comprising a transfer device for transferring to an ENUM / DNS server for query processing,
The call control server
A query changing unit for changing the highest domain name included in the ENUM / DNS query for inquiring connection destination information corresponding to the destination terminal included in the connection request from the terminal according to the priority of the terminal;
The ENUM / DNS server for query storage is
A transmission unit that transmits an ENUM / DNS query from the call control server to an address of the query processing ENUM / DNS server that differs according to the highest domain name included in the ENUM / DNS query;
The transfer device is
An address conversion unit that converts the source address of the ENUM / DNS query from the ENUM / DNS server for query storage into a different address according to the destination address of the ENUM / DNS query;
An ENUM / DNS query control system characterized by the above. A call control server that transmits an ENUM / DNS query to an ENUM / DNS server, a query storage ENUM / DNS server that stores the ENUM / DNS query, and the ENUM / DNS query from the query storage ENUM / DNS server In the ENUM / DNS query control method performed by the transfer device for transferring to the ENUM / DNS server for query processing,
The call control server
Changing the highest domain name included in the ENUM / DNS query for inquiring connection destination information corresponding to the destination terminal included in the connection request from the terminal according to the priority of the terminal;
The ENUM / DNS server for query storage is
A step of transmitting an ENUM / DNS query from the call control server to an address of the ENUM / DNS server for query processing that differs according to the highest domain name included in the ENUM / DNS query,
The transfer device is
A step of converting the source address of the ENUM / DNS query from the ENUM / DNS server for query storage into a different address according to the destination address of the ENUM / DNS query,
An ENUM / DNS query control method characterized by the above.

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