JP4882966B2 - Proxy server, communication program, and communication system - Google Patents

Description

  The present invention relates to a proxy server, a communication program, and a communication system, and can be applied to a CSCF (Call / Session Control Function) on an IMS (IP Multimedia Subsystem) system, for example.

  IMS is a central technology in the next generation network (NGN), and the CSCF is an extremely important node in IMS, and processes a SIP message as a SIP (Session Initiation Protocol) server. Depending on the function, the CSCF belongs to one of three types: P-CSCF (Proxy-CSCF), I-CSCF (Interrogating-CSCF), and S-CSCF (Serving-CSCF) (see Non-Patent Document 1).

  The P-CSCF is placed on the Visited network and is positioned as a SIP server that is the first contact point between the IMS terminal and the IMS network. From the SIP point of view, all requests transmitted and received by the IMS terminal pass through the P-CSCF (see Non-Patent Document 1).

The P-CSCF appropriately transfers the SIP signal received from the IMS terminal and the IMS network according to the route information set in the Route header or Contact header on the signal. However, the REGISTER request signal received from the IMS terminal is transferred by, for example, inquiring the address of the I-CSCF on the home network that is the transfer destination to a name resolution device such as a DNS server.
Gonzalo Camarillo, Miguel A. Garcia Martin, Takuya Sawada et al., Translated by Takuya Kashima, “IMS Standard Text NGN Core Technology”, published by Rick Telecom in July 2006 3rd Generation Partnership Project (3GPP), “IP Multimedia Call Control Protocol based on Session Initiation Protocol (SIP) and Session Description 29 (DP). Search], <URL: http://www.3gpp.org/ftp/Specs/archive/24_series/24.229/24229-810.zip> 3rd Generation Partnership Project (3GPP), “Signaling flows for the IP multi-media call control based on Session in ss. Month 29 search], <URL: http://www.3gpp.org/ftp/Specs/archive/24_series/24.228/24228-5f0.zip>

  In the P-CSCF, for example, in the configuration in which the DNS server is inquired about the transfer destination when the REGISTER request signal is received, there is a concern that the processing capacity of the DNS server may affect the performance of the P-CSCF. For example, since a large number of terminals reconnect simultaneously after recovery from a local power failure or network equipment failure, a large amount of REGISTER signals are generated in the P-CSCF, and a large amount of DNS is accompanied accordingly. An inquiry signal and a DNS response signal will be generated on the network.

  Therefore, in the proxy server (for example, P-CSCF), when the signal received from the terminal is transferred to the proxy server in the destination domain of the signal, an inquiry to the name resolution device (for example, DNS server) is unnecessary. Or a proxy server, a communication program, and a communication system that can reduce the number of inquiries.

Proxy server according to the first invention, the proxy server that forwards (1) a SIP signal received from the terminal, the SIP signal repeater disposed within the destination domain of the SIP signal, (2) in advance, Address information storage means for storing the address information of the SIP signal relay device for each domain in association with the domain name, and (3) when receiving the SIP signal from the terminal, from the destination information of the SIP signal, a domain name extracting means for extracting a domain name, (4) and the domain name extracting means has extracted domain name, based on the information the address information storage means stores, in the SIP signal received from the terminal and address acquisition means for acquiring the address of the SIP signal repeater which is placed on the destination in the domain, S received from (5) above the terminal The P signal, and having a signal transfer means for transferring the SIP signal repeater according to address the address acquisition means has acquired.

Communication program of the second invention, a computer mounted in the proxy server that forwards (1) a SIP signal received from the terminal, the SIP signal repeater in the destination domain of the SIP signal, in advance (2) , the address information of the SIP signal repeater for each domain, the address information storage means for storing in association with the domain name, receives the SIP signal from the (2) the terminal, from the destination information of the SIP signal, the destination A domain name extraction means for extracting the domain name of (3), and (3) a SIP signal received from the terminal based on the domain name extracted by the domain name extraction means and the information stored in the address information storage means and address acquisition means for acquiring the address of the SIP signal relay device of being located in the domain of the destination, it receives from (4) above the terminal The SIP signal, characterized in that to function as a signal transfer means for transferring the SIP signal repeater according to address the address acquisition means has acquired.

A communication system according to a third aspect of the present invention is a communication having (1) a terminal and a proxy server that transfers a SIP signal received from the terminal to a SIP signal relay apparatus arranged in a destination domain of the signal. In the system, (2) the proxy server according to claim 1 is applied as the proxy server.

  In the proxy server, when the signal received from the terminal is transferred to the proxy server in the destination domain of the signal, it is possible to eliminate the inquiry to the name resolution device or reduce the number of inquiries.

(A) Main Embodiment Hereinafter, a first embodiment of a proxy server, a communication program, and a communication system according to the present invention will be described in detail with reference to the drawings. Note that the proxy server of the first embodiment is a P-CSCF.

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

  The communication system 1 is a communication system using IMS, and for example, processes a SIP message sent from the IMS terminal 30 connected to the Visited network 20.

  The home network 10 is a network that accommodates a domain whose domain name is “home1.net”, and includes I-CSCFs 11 and 12, S-CSCF 13, and HSS 14 as constituent elements.

  The Home network 15 is a network that accommodates a domain whose domain name is “home2.net”, and includes I-CSCFs 16, 17, S-CSCF 18, and HSS 19 as constituent elements.

  HSSs 14 and 19 are HSS (Home Subscriber Server) (see Non-Patent Document 1), and each domain has a database function for managing user information. The HSSs 14 and 15 are the same as the existing ones.

  The I-CSCFs 11, 12, 16, and 17 are arranged at the edges (edges) of the domain, and function as a proxy server such as relaying transmission / reception of signals between the P-CSCF 21 and servers in the domain. ing. The I-CSCFs 11, 12, 16, and 17 are the same as the existing ones.

  home1. In the net domain, two I-CSCFs 11 and 12 are arranged to have a redundant configuration. The I-CSCF 11 is mainly used as a primary I-CSCF at normal times, and the I-CSCF 12 is a secondary I-CSCF. Assuming that the I-CSCF 11 is mainly used when it does not operate due to a failure or the like. Also, home2. In the net domain, it is assumed that the I-CSCF 16 is used as a primary I-CSCF and the I-CSCF 17 is used as a secondary I-CSCF.

  The S-CSCFs 13 and 18 have a central function in the signal control plane in the domain and are the same as the existing ones.

  The Visited network 20 is connected to the Home network 10 and the Home network 15 and includes a P-CSCF 21 as a constituent element. In the communication system 1 of this embodiment, no DNS server is arranged in the visited network 20.

  The IMS terminal 30 is a terminal that transmits and receives a SIP message. Although two IMS terminals 30-1 and 30-2 are arranged in the visited network 20, the number of IMS terminals 30 is not limited. Here, it is assumed that transmission / reception of the SIP message by the IMS terminal 30 is performed via the P-CSCF 21.

  The P-CSCF 21 functions as a proxy server when the IMS terminal 30 transmits and receives a SIP message, and has a REGISTER transfer information table 40. The P-CSCF 21 is a device having an interface for communicating with other communication devices (such as a CPU, ROM, RAM, EEPROM, hard disk, etc.) and a program (not limited to one device). 1 is constructed by installing the communication program of the embodiment, etc., and can be functionally shown as in FIG.

  The REGISTER transfer information table 40 manages the I-CSCF address for each domain in association with the domain name when the P-CSCF 21 transfers the SIP message received from the IMS terminal 30 to the I-CSF. It is.

  For example, when a REGISTER request is given from the IMS terminal 30, the P-CSCF 21 extracts a destination domain name from information on a URI (Uniform Resource Identifier) of the destination of the request, and in the domain of the extracted domain name The IP address of the I-CSCF is retrieved from the REGISTER transfer information table 40 and acquired. Then, the P-CSCF 21 transfers the REGISTER request received from the IMS terminal 30 to the I-CSCF of the acquired IP address.

  FIG. 2 is an explanatory diagram showing an example of the configuration of the REGISTER transfer information table 40 held inside the P-CSCF 21.

  The REGISTER transfer information table 40 may store a plurality of REGISTER transfer information 400-1 to 400-N as shown in FIG.

  FIG. 3 is an explanatory diagram showing a configuration example of internal data of the REGISTER transfer information 400.

  FIG. 4 is an explanatory diagram showing details of information included in the REGISTER transfer information 400 shown in FIG.

  The REGISTER transfer information 400 (400-1 to 400-N) includes a domain name 401 (401-1 to 401-N), a primary I-CSCF host name 402 (402-1 to 402-N), and a primary I- It has a CSCF address 403 (403-1 to 403-N), a secondary I-CSCF host name 404 (404-1 to 404-N), and a secondary I-CSCF address 405 (405-1 to 405-N). .

  The domain name 401 is a name of a domain accommodated in the Home network to which the P-CSCF 21 is connected. This value is a key for searching on the REGISTER transfer information 400 and does not overlap between the REGISTER transfer information 400.

  The primary I-CSCF host name 402 and the primary I-CSCF address 403 are the host name and IP address of the I-CSCF that first tries to connect when the P-CSCF 21 transfers a REGISTER request signal to the Home network.

  The secondary I-CSCF host name 404 and the secondary I-CSCF address 405 are the host name and IP address of the I-CSCF that tries to connect when the connection to the primary I-CSCF fails.

  Each information in the REGISTER transfer information table 40 may be set / changed / referenced from the operator's terminal as maintenance operation data of the P-CSCF 21.

(A-2) Operation of Embodiment Next, an example of operation when the P-CSCF 21 in the communication system 1 of this embodiment having the above configuration receives a REGISTER request signal from the IMS terminal 30-1 will be described. To do.

  FIG. 5 is an example of information in the REGISTER transfer information table 40.

  FIG. 6 is a flowchart illustrating an operation when the P-CSCF 21 receives a REGISTER request signal from the IMS terminal 30-1.

  Here, it is assumed that the information stored in the REGISTER transfer information table 40 includes two pieces of information, REGISTER transfer information 400-1 and REGISTER transfer information 400-2, as shown in FIG. The REGISTER transfer information 400-1 includes “home1.net” as the domain name 401-1, “icscf1P.home1.net” as the primary I-CSCF host name 402-1, and “A” as the primary I-CSCF address 403-1. .A.A.1 ”,“ icscf1S.home1.net ”is set as the secondary I-CSCF host name 404-1, and“ A.A.A.2 ”is set as the secondary I-CSCF address 405-1. The REGISTER transfer information 400-2 includes “home2.net” as the domain name 401-2, “icscf2P.home2.net” as the primary I-CSCF host name 402-2, and “B” as the primary I-CSCF address 403-2. .B.B.1 ”,“ icscf2S.home2.net ”as the secondary I-CSCF host name 404-2, and“ B.B.B.2 ”as the secondary I-CSCF address 405-2 are set. And

  First, the P-CSCF 21 receives a REGISTER request signal from the IMS terminal 30-1, and acquires a request URI (destination identification information) set in the request line of the received REGISTER request signal (step S100). Here, it is assumed that “registrar.home2.net” is set as the request URI.

  Next, the P-CSCF 21 searches for the REGISTER transfer information 400 that matches the domain name 401 in the REGISTER transfer information table 40 using the domain name (home2.net) of the acquired request URI as a key (step S110).

  As a result of searching the REGISTER transfer information 400 in the P-CSCF 21, here, the REGISTER transfer information 400-2 in which the domain name 401 “home2.net” matching the request URI “registrar.home2.net” is set is obtained. It is detected (step S120).

  If the REGISTER transfer information 400 that matches the request URI is not searched in step S120, an error such as “403 (prohibited) error response” is issued from the P-CSCF 21 to the IMS terminal 30-1. A signal is returned (step S125), and the process ends.

  Next, the P-CSCF 21 uses the primary I-CSCF host name 402-2 and the primary I-CSCF address 403-2 address of the REGISTER transfer information 400-2 searched in the above-described step S120, and the IP address is set. The REGISTER request signal is transferred to the primary I-CSCF “icscf2P.home2.net” which is “BBBB1”, that is, to the I-CSCF 16 (step S130).

  The P-CSCF 21 confirms the transfer result of the REGISTER request signal to the primary I-CSCF (I-CSCF16) (step S140), and when there is a response from the primary I-CSCF (I-CSCF16), The response is transferred to the IMS terminal 30-1 side (step S145), and the process is terminated.

  In the above-described step S140, when the transfer result is no response from the primary I-CSCF (I-CSCF16), the P-CSCF 21 uses the secondary I-CSCF of the REGISTER transfer information 400-2 searched in the above-described step S120. Using the host name 404-1 and the secondary I-CSCF address 405-1, the primary I-CSCF “icscf2S.home2.net” whose IP address is “BB.B.2”, that is, the I-CSCF 17 A REGISTER request signal is transferred to (step S150).

  The P-CSCF 21 confirms the transfer result of the REGISTER request signal to the secondary I-CSCF (I-CSCF 17) (step S160). If there is a response from the secondary I-CSCF, the response is the IMS terminal 30. -1 (step S165), and the process ends.

  In the above-described step S160, when the transfer result is no response from the secondary I-CSCF (I-CSCF 17), an error such as 504 (server timeout) is issued from the P-CSCF 21 to the IMS terminal 30-1. A signal is returned (step S170), and the process is terminated.

(A-3) Effects of Embodiment According to this embodiment, the following effects can be achieved.

  As shown in FIG. 6 described above, the P-CSCF 21 specifies the IP address of the I-CSCF on the Home network side based on the contents of the REGISTER transfer information table 40 when receiving the REGISTER request signal from the IMS terminal 30. A REGISTER request signal is being transferred. As a result, the IP address of the I-CSCF on the Home network side can be specified and the REGISTER request signal can be transferred without making a domain name inquiry to the DNS server.

  Also, when the REGISTER transfer information 400 that matches the request URI is not retrieved (see S125 in FIG. 6 above) or when there is no response from any I-CSCF (see S170 in FIG. 6 above). Returns an error signal to the IMS terminal 30. Thereby, for example, it is possible to prevent the response waiting state on the IMS terminal 30 side from being prolonged, and to quickly switch the connection from the IMS terminal 30 to another server or network.

  Further, in the REGISTER transfer information table 40 (REGISTER transfer information 400), the host name and address of the I-CSCF are held in two pieces of information, the primary side and the secondary side, so that the REGISTER request signal to the primary side I-CSCF Even if the transfer fails, the transfer of the REGISTER request signal to the secondary side I-CSCF can be attempted.

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

(B-1) In the first embodiment, only the primary and secondary I-CSCF host names and addresses are registered in the REGISTER transfer information, but the third and fourth I-CSCFs are registered. In the case of simultaneous failure of the primary I-CSCF and the secondary I-CSCF, the REGISTER request signal may be transferred to another I-CSCF.

(B-2) In the above description of the embodiment, the operation at the time of receiving the REGISTER request signal in the P-CSCF 21 has been described as an example. However, the SIP request signal reception in which route information in other SIP servers such as an INVITE message is not set. It may be applied to the operation of time.

(B-3) In the above embodiment, in the REGISTER transfer information 400 of the REGISTER transfer information table 40, the host name and IP address of the I-CSCF for each domain are stored, but only the IP address is stored. May be.

(B-4) In the above-described embodiment, the configuration in which the DNS server is not arranged in the Visited network 20 has been described, but the DNS server may be arranged. For example, when the P-CSCF 21 receives a REGISTER request from the IMS terminal 30 and the information shown in the REGISTER transfer information table 40 is searched by the operation shown in FIG. 6, the corresponding information is not detected. If the search result is “no information” in step S120 of FIG. 6, the DNS server may be inquired of the IP address of the I-CSCF. As a result, it is not necessary to make an inquiry to the DNS server for at least the IP address of the I-CSCF of the domain registered in the REGISTER transfer information table 40, so the number of inquiries to the DNS server can be reduced. . Further, when a DNS server is arranged in the Visited network 20, information read from the DNS server may be applied to the information stored in the REGISTER transfer information table 40.

(B-5) In the above embodiment, the example in which the present invention is applied to the P-CSCF has been described. However, the present invention may be applied to a proxy server other than the P-CSCF, such as a proxy server for WWW (World Wide Web). good.

It is a block diagram which shows the functional structure of the communication system which concerns on embodiment. It is explanatory drawing which shows the example of a structure of the REGISTER transfer information table which concerns on embodiment. It is explanatory drawing which shows the example of the internal data structure of REGISTER transfer information which concerns on embodiment. It is explanatory drawing shown about the detail of the information which REGISTER transfer information which concerns on embodiment has. It is explanatory drawing which shows the example of the information of the REGISTER transfer information table which concerns on embodiment. It is the flowchart explaining operation | movement when the proxy server (P-CSCF) which concerns on embodiment receives the REGISTER request signal from an IMS terminal.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Communication system, 10 ... Home network, 11, 12, 16, 17 ... I-CSCF, 13, 18 ... S-CSCF, 14, 19 ... HSS, 20 ... Visited network, 21 ... P-CSCF, 30, 30 -1, 30-2 ... IMS terminal, 40 ... REGISTER transfer information table, 400, 400-1, 400-2 ... REGISTER transfer information, 401, 401-1, 401-2 ... domain name, 402, 402-1, 402-2 ... Primary I-CSCF host name, 403, 403-1, 403-2 ... Primary I-CSCF address, 404, 404-1, 404-2 ... Secondary I-CSCF host name, 405, 405-1, 405-2 ... Secondary I-CSCF address.

Claims (7)

The SIP signal received from the terminal, the proxy server that forwards the SIP signal repeater disposed within the destination domain of the SIP signal,
Address information storage means for storing address information of the SIP signal relay device for each domain in advance in association with the domain name;
Upon receiving a SIP signal from the terminal, a domain name extracting means for extracting a destination domain name from destination information of the SIP signal;
Based on the domain name extracted by the domain name extraction unit and the information stored in the address information storage unit, the SIP signal relay device arranged in the destination domain of the SIP signal received from the terminal An address acquisition means for acquiring an address;
A proxy server, comprising: a signal transfer unit configured to transfer a SIP signal received from the terminal to a SIP signal relay device associated with an address acquired by the address acquisition unit. The address information storage means stores, for a domain in which a plurality of SIP signal relay devices are arranged, information on priority of each signal relay device together with address information of the SIP signal relay device,
The proxy server according to claim 1, wherein the signal transfer unit attempts to transfer a SIP signal received from the terminal in order from a SIP signal relay device having a higher priority. When the SIP signal transfer to all the SIP signal relay devices registered in the address information storage unit fails for the destination domain of the SIP signal received from the terminal, the signal transfer unit The proxy server according to claim 2, wherein an error signal is notified. When the address information of the SIP signal relay device arranged in the destination domain of the SIP signal received from the terminal is not stored in the address information storage unit, the address acquisition unit sends an error signal to the terminal. The proxy server according to any one of claims 1 to 3, wherein the proxy server is notified.   The proxy server according to claim 1, wherein the proxy server is a P-CSCF. The SIP signal received from the terminal, a computer mounted in the proxy server that forwards the SIP signal repeater in the destination domain of the SIP signal,
Address information storage means for storing address information of the SIP signal relay device for each domain in advance in association with the domain name;
Upon receiving a SIP signal from the terminal, a domain name extracting means for extracting a destination domain name from destination information of the SIP signal;
Based on the domain name extracted by the domain name extraction unit and the information stored in the address information storage unit, the SIP signal relay device arranged in the destination domain of the SIP signal received from the terminal An address acquisition means for acquiring an address;
A communication program for causing a SIP signal received from the terminal to function as a signal transfer unit that transfers to a SIP signal relay device associated with an address acquired by the address acquisition unit. In a communication system having a terminal and a proxy server that transfers a SIP signal received from the terminal to a SIP signal relay device arranged in a destination domain of the signal,
A communication system, wherein the proxy server according to claim 1 is applied as a proxy server.

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