JP2005057558A - Connection server distribution method and packet exchange device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection server distribution method and a packet exchange device with which an operation is made efficient and can be shortened since a subscriber terminal can manage only one tunnel and it is not necessary to request a change of IP address information of an information supply server from a manager of a second information management server and with which a processing load can be reduced since determination of a region to which the subscriber terminal belongs is not required in the second information management server. <P>SOLUTION: The packet exchange device 102 collates and decides reference destination server information received from a subscriber terminal 101 with server information of information supply server 105. When it is decided that a prescribed condition is not satisfied, it is transmitted and transferred. When it is decided to satisfy the prescribed condition, a header and a protocol of a packet are converted, and are transmitted to a first information management server 110. They are converted into those of a response packet based on information on the subscriber terminal of the response packet and network tunnel information, and they are transmitted to the subscriber terminal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a connection server distribution method and a packet switching apparatus for providing a streaming service to a subscriber terminal through a content server of a content distribution network.

  In recent years, broadband content services using streaming data such as moving images and voices are being started over the Internet. The configuration of a conventional content service system that realizes the above service will be described with reference to FIG. FIG. 14 is a diagram for explaining the configuration of a conventional content service system. As shown in FIG. 14, a subscriber terminal 1401 is connected to a first network terminating device 1408 that is an interconnection point with the ISP network 1403 via an L2SW 1402 and communicates with the Internet 1404 through the ISP network 1403. . The content distribution network 1406 in which the content server 1405 is installed is connected to the L2SW 1402 via the second network termination device 1409.

  The L2SW 1402, the content distribution network 1406, and the second network termination device 1409 are installed for each subscriber area unit that is arbitrarily defined. A DNS server 1407 installed in the ISP network 1403 stores subscriber terminal information, which is information on the area to which the subscriber terminal 1401 belongs, and the IP address of the content server 1405 for each subscriber area unit. Accordingly, the DNS server 1407 determines the region to which the subscriber terminal 1401 belongs based on the subscriber terminal information in response to the access request to the content server 1405 received from the subscriber terminal 1401, and the region to which the subscriber terminal 1401 belongs. The IP address of the content server 1405 corresponding to is notified to the subscriber terminal 1401.

  Here, the access operation from the subscriber terminal 1401 to the content server 1405 in the conventional content service system will be described with reference to FIG. The subscriber terminal 1401 transmits a DNS inquiry packet in which the subscriber terminal IP address and the server name of the content server 1405 are set to the DNS server 1407 (S1501). The DNS server 1407 receives the DNS inquiry packet, acquires the subscriber terminal IP address and the server name of the content server 1405 set in the DNS inquiry packet, and stores the subscriber terminal information and the IP of the content server 1405. The area to which the subscriber terminal 1401 belongs is determined based on the address information, and the IP address of the content server 1405 corresponding to the content server name corresponding to the determined area is derived. The DNS server 1407 transmits a DNS response packet in which the IP address of the content server 1405 is set to the subscriber terminal 1401 (S1502).

The subscriber terminal 1401 acquires the IP address of the content server 1405 from the DNS response packet, generates a service request packet having the IP address of the content server 1405 as a transmission destination, and transmits it (S1503). The content server 1405 receives the service request packet from the subscriber terminal 1401, and starts packet distribution of the corresponding content data to the subscriber terminal 1401 (S1504). In this way, the subscriber terminal 1401 acquires the IP address of the content server 1405 and acquires content data. The content service system as described above is disclosed in Non-Patent Document 1 below.
http://tiis.hitachi.co.jp/catalog/pdf/ip/ag8100.pdf

  However, in the conventional content service system disclosed in Non-Patent Document 1, between the subscriber terminal 1401 and the first network termination device 1408 and between the subscriber terminal 1401 and the second network termination device 1409. Since a tunnel, which is a separate virtual dedicated line, is established, the subscriber terminal 1401 must manage a plurality of tunnels, and a dedicated device must be installed in the subscriber terminal 1401. there were. Further, since the DNS server 1407 centrally manages the IP addresses of the content servers 1405 in each region, the IP address of the content server 1405 is changed in each region, and an IP address is added when a new content server 1405 is installed. When an IP address is deleted due to the abolition of the content server 1405, it is necessary to perform operations such as changing, adding, and deleting the IP address information of the content server 1405 to the DNS server 1407. When performing the above operations, if the administrators of the content distribution network 1406 and the DNS server 1407 are different, the IP address information of the content server 1405 is changed or added to the administrator of the DNS server 1407 each time. There is a problem that it is necessary to make a request for deletion, etc., and it takes time and effort to make changes. In addition, since the DNS server 1407 has to determine the area to which the subscriber terminal 1401 belongs, there is also a problem that the processing load increases.

  The present invention has been made to solve the above-mentioned problem, and the subscriber terminal only needs to manage one tunnel, and changes and additions of the IP address information of the content server to the administrator of the DNS server. Since it is not necessary to make a request for deletion or the like, it is possible to improve the efficiency and shortening of operations such as change, and it is not necessary to determine the area to which the subscriber terminal belongs in the DNS server, thereby reducing the processing load. It is an object of the present invention to provide a connection server distribution method and a packet switching apparatus that can be used.

  In order to achieve the above object, according to the present invention, the packet switching apparatus collates the inquiry server information included in the packet received from the subscriber terminal with the server information of the information providing server stored in the packet switching apparatus in advance. And when the packet switching apparatus determines that the predetermined condition is not satisfied as a result of the collation determination, the step of transparent transfer to the interface connected to the predetermined network, and the result of the packet switching apparatus determining the collation When it is determined that the predetermined condition is satisfied, the packet header is converted based on the server information of the first information management server stored in advance in the packet switching apparatus, and the communication protocol of the network tunnel is changed to the communication of the service network. The protocol conversion step to the protocol and the packet switching device A packet transmitted to the communication protocol of the service network is transmitted to a first information management server installed in the service network, and a packet switching device is included in the packet transmitted to the first information management server In response to the inquiry server information, the subscriber terminal information in the response packet including the response information received from the first information management server and the subscriber terminal as the transmission destination, the network termination device, and the subscription The subscriber terminal transmits the response packet that is transmitted / received to / from the subscriber terminal via the packet switching apparatus, acquired by the packet switching apparatus at the time of the transmission / reception, and stored in a predetermined storage area of the packet switching apparatus Network tunnel information corresponding to subscriber terminal information based on the network tunnel information used for transmission to Searching for information, converting the header of the response packet based on the searched network tunnel information, converting the communication protocol of the service network to the communication protocol of the network tunnel, and the packet switching apparatus comprising: Transmitting the response packet converted into the protocol to the subscriber terminal.

  That is, according to the present invention, a subscriber terminal, an interface connected to the subscriber terminal, an interface connected to a predetermined network, and a service network operated with a policy different from the predetermined network are connected. A packet switching device having an interface to be operated, a first information management server installed in the service network, an information providing server installed in the service network, the packet switching device, and the service network. A router installed in between, a network termination device installed between the subscriber terminal and the predetermined network, and a second information management server installed in the predetermined network, A tunneling protocol is used between the subscriber terminal and the predetermined network. A connection server distribution method in a network system connected using a network tunnel, in which the packet switching device is stored in advance in the packet switching device and reference destination server information included in a packet received from the subscriber terminal A step of collating and determining server information of the information providing server; and if the packet switching device determines that the predetermined condition is not satisfied as a result of the collation determination, the packet switching device is transparent to the interface connected to the predetermined network. And when the packet switching device determines that a predetermined condition is satisfied as a result of the collation determination, based on server information of the first information management server stored in advance in the packet switching device. The header of the packet is converted and the network token is converted. Protocol conversion of the communication protocol of the network to the communication protocol of the service network, and the packet switching device placing the packet converted into the communication protocol of the service network in the service network Transmitting to the management server; response information received from the first information management server by the packet switching device with respect to the inquiry server information included in the packet transmitted to the first information management server; The information on the subscriber terminal in the response packet including the information on the subscriber terminal as the transmission destination and the network terminal device and the subscriber terminal are transmitted / received via the packet switching device, and the transmission / reception is performed. The packet switching device acquires and stores the predetermined storage area of the packet switching device. The network tunnel information corresponding to the information of the subscriber terminal is searched based on the network tunnel information used when transmitting the response packet to the subscriber terminal stored in the area, and the searched network Converting the header of the response packet based on tunnel information, converting the communication protocol of the service network to the communication protocol of the network tunnel, and converting the packet switching apparatus to the communication protocol of the network tunnel And transmitting a response packet to the subscriber terminal.

  With this configuration, the subscriber terminal only needs to manage one tunnel, and it is necessary to request the administrator of the second information management server to change, add, or delete the IP address information of the information providing server. Therefore, it is possible to improve the efficiency and shortening of operations such as change, and it is not necessary to determine the area to which the subscriber terminal belongs in the second information management server, so that the processing load can be reduced.

  In the connection server distribution method of the present invention, it is a preferable aspect of the present invention that the service network is a content distribution network. With this configuration, content information can be provided.

  In the connection server distribution method of the present invention, it is a preferable aspect of the present invention that the communication protocol of the network tunnel is PPPoE (Point to Point Protocol over Ethernet (registered trademark)). With this configuration, it is possible to increase the efficiency and shortening of operations such as changes in the service network administrator, and to reduce the processing load on the second information management server.

  Further, in the connection server distribution method according to the present invention, when the packet switching apparatus receives a PPPoE packet for assigning an IP address to the subscriber terminal, the network tunnel information is acquired and stored. Is a preferred embodiment. With this configuration, it is possible to delete processing overhead related to network tunnel information registration processing in the packet switching apparatus.

  Further, in the connection server distribution method according to the present invention, the packet when the packet exchange apparatus determines that a predetermined condition is satisfied as a result of the collation determination of the inquiry destination server information and the server information of the information providing server. In the header conversion, the transmission destination MAC address of the Ether header is changed from the MAC address of the network termination device to the router installed at the end point of the service network or the first information management server installed in the service network. The MAC address of the subscriber terminal is converted from the MAC address of the subscriber terminal to the MAC address of the packet switching device, and the destination IP address of the IP header is set in the predetermined network. 2 from the IP address of the information management server 2 It is a preferred aspect of the present invention to convert the first information management server IP address to be placed in over click. With this configuration, it is possible to grasp the transmission destination and transmission source of the packet after passing through the packet switching apparatus.

  In the connection server distribution method of the present invention, the search for the network tunnel information corresponding to the subscriber terminal information included in the response packet is a search based on a destination IP address included in the subscriber terminal information. This is a preferred embodiment of the present invention. With this configuration, the network tunnel information of the subscriber terminal can be acquired efficiently.

  In the connection server distribution method of the present invention, as a result of the packet switching device searching the network tunnel information corresponding to the subscriber terminal information included in the response packet, the corresponding network tunnel information cannot be obtained. In some cases, discarding the response packet is a preferred aspect of the present invention. With this configuration, unnecessary packets are not transmitted to the subscriber terminal, and wasteful consumption of the communication bandwidth of the subscriber terminal can be eliminated.

  Further, in the connection server distribution method of the present invention, the packet switching device searches the network tunnel information corresponding to the information of the subscriber terminal, and uses the response packet header based on the searched network tunnel information. In the case of conversion, the destination MAC address of the Ether header is determined from the MAC address of the router installed at the end point of the service network or the first information management server installed in the service network. The MAC address is converted, the source MAC address is converted from the MAC address of the packet switching device to the MAC address of the subscriber terminal, and the source IP address of the IP header is installed in the service network. IP address of information management server Et al, converting the IP address of the second information management server that is installed in the predetermined network is a preferred embodiment of the present invention. With this configuration, the subscriber terminal recognizes that the first information management server to be connected is the second information management server installed in a predetermined network, so that the response information for the output packets matches. Can be processed efficiently.

  Further, according to the present invention, a subscriber terminal, an interface connected to the subscriber terminal, an interface connected to a predetermined network, and a service network operated with a policy different from the predetermined network are connected. A packet switching device having an interface to be operated, a first information management server installed in the service network, an information providing server installed in the service network, the packet switching device, and the service network. A router installed in between, a network termination device installed between the subscriber terminal and the predetermined network, and a second information management server installed in the predetermined network, A tunneling protocol is used between the subscriber terminal and the predetermined network. A packet switching apparatus of a network system connected using a network tunnel, the information providing server storing means for storing the server name and the IP address of the information providing server in association with each other, and the first information management server First information management server storage means for storing an IP address, and network tunnel information for storing network tunnel information of the network tunnel established between the subscriber terminal and the predetermined network for each subscriber terminal Storage means, registration means for acquiring the network tunnel information transmitted and received between the network terminating device and the subscriber terminal, and registering it in the network tunnel information storage means; and packets received from the subscriber terminal In the reference server information included and the information providing server storage means A determination unit for verifying the stored server name of the information providing server, and a result of the determination by the determination unit, if it is determined that the predetermined condition is not satisfied, the determination unit is connected to the predetermined network. Transparent transfer means for transparently transferring to the interface, and the first information stored in the first information management server storage means when it is determined that a predetermined condition is satisfied as a result of the determination by the determination means Based on the IP address of the management server, a first conversion unit that converts the header of the packet and converts the communication protocol of the network tunnel into a communication protocol of the service network; and the packet converted by the first conversion unit Is transmitted to the first information management server installed in the service network. And the response information received from the first information management server and the information on the subscriber terminal as the transmission destination with respect to the inquiry destination server information included in the packet transmitted to the first information management server. And searching for the network tunnel information corresponding to the subscriber terminal information based on the information on the subscriber terminal in the response packet including the network tunnel information stored in the network tunnel information storage means. Second response means for converting the header of the response packet based on the network tunnel information and converting the communication protocol of the service network into the communication protocol of the network tunnel; and the response packet converted by the second conversion means Second transmission means for transmitting the message to the subscriber terminal Packet exchange apparatus is provided.

  With this configuration, the subscriber terminal only needs to manage one tunnel, and it is necessary to request the administrator of the second information management server to change, add, or delete the IP address information of the information providing server. Therefore, it is possible to improve the efficiency and shortening of operations such as change, and it is not necessary to determine the area to which the subscriber terminal belongs in the second information management server, so that the processing load can be reduced.

  In the packet switching apparatus of the present invention, it is a preferable aspect of the present invention that the service network is a content distribution network. With this configuration, content information can be provided.

  In the packet switching apparatus of the present invention, it is a preferable aspect of the present invention that the communication protocol of the network tunnel is PPPoE (Point to Point Protocol over Ethernet (registered trademark)). With this configuration, it is possible to increase the efficiency and shortening of operations such as changes in the service network administrator, and to reduce the processing load on the second information management server.

  In the packet switching apparatus of the present invention, it is preferable that the registration unit obtains and registers the network tunnel information when receiving a PPPoE packet for assigning an IP address to the subscriber terminal. It is an aspect. With this configuration, it is possible to delete processing overhead related to network tunnel information registration processing in the packet switching apparatus.

  Also, in the packet switching apparatus of the present invention, the packet header conversion when the determination means determines that a predetermined condition is satisfied as a result of checking the reference server information and the server name of the information providing server. The first conversion means converts the destination MAC address of the Ether header from the MAC address of the network terminating device to the router installed at the end point of the service network or the first network installed in the service network. Convert to the MAC address of the information management server, convert the source MAC address from the MAC address of the subscriber terminal to the MAC address of the packet switching device, and set the destination IP address of the IP header in the predetermined network The service network from the IP address of the second information management server Converting the first information management server IP address to be placed in the click is a preferred embodiment of the present invention. With this configuration, it is possible to grasp the transmission destination and transmission source of the packet after passing through the packet switching apparatus.

  In the packet switching apparatus according to the present invention, in the search for the network tunnel information corresponding to the information on the subscriber terminal included in the response packet, the second conversion means transmits the transmission included in the information on the subscriber terminal. Searching based on the destination IP address is a preferred aspect of the present invention. With this configuration, the network tunnel information of the subscriber terminal can be acquired efficiently.

  In the packet switching apparatus of the present invention, as a result of searching the network tunnel information corresponding to the subscriber terminal information included in the response packet, the second conversion means obtains the corresponding network tunnel information. It is a preferable aspect of the present invention to discard the response packet when there is not. With this configuration, unnecessary packets are not transmitted to the subscriber terminal, and wasteful consumption of the communication bandwidth of the subscriber terminal can be eliminated.

  Further, in the packet switching apparatus of the present invention, when the network tunnel information corresponding to the subscriber terminal information is searched and the header of the response packet is converted based on the searched network tunnel information, 2 conversion means calculates the destination MAC address of the Ether header from the MAC address of the router installed at the end point of the service network or the first information management server installed in the service network. The MAC address of the packet switching device is converted from the MAC address of the packet switching device to the MAC address of the subscriber terminal, and the source IP address of the IP header is installed in the service network. From the IP address of the information management server Converting the IP address of the second information management server installed in a given network is a preferred embodiment of the present invention. With this configuration, the subscriber terminal recognizes that the first information management server to be connected is the second information management server installed in a predetermined network, so that the response information for the output packets matches. Can be processed efficiently.

  According to the present invention, a subscriber terminal, an interface connected to the subscriber terminal, an interface connected to a predetermined network, and an interface connected to a service network operated with a policy different from the predetermined network A packet switching device, a first information management server installed in the service network, an information providing server installed in the service network, a router installed between the packet switching device and the service network, A network termination device installed between a subscriber terminal and a predetermined network and a second information management server installed in the predetermined network, and tunneling between the subscriber terminal and the predetermined network Network system connected using a network tunnel by protocol In the connection server distribution method in the system, the packet switching device collates and determines the reference server information included in the packet received from the subscriber terminal and the server information of the information providing server stored in the packet switching device in advance. If the packet switching device determines that the predetermined condition is not satisfied as a result of the collation determination, the packet switching device performs transparent transfer to an interface connected to the predetermined network, and the packet switching device performs the collation determination. If it is determined that the above condition is satisfied, the packet header is converted based on the server information of the first information management server stored in advance in the packet switching apparatus, and the communication protocol of the network tunnel is changed to the communication protocol of the service network. Protocol conversion step and packet switching equipment Transmitting the packet converted into the communication protocol of the service network to the first information management server installed in the service network, and the packet switching apparatus transmits the packet transmitted to the first information management server. Information of the subscriber terminal in the response packet including the response information received from the first information management server and the information of the subscriber terminal that is the transmission destination, the network termination device, When transmitting a response packet transmitted to and received from a subscriber terminal via a packet switching apparatus, acquired by the packet switching apparatus at the time of transmission and reception and stored in a predetermined storage area of the packet switching apparatus, to the subscriber terminal Based on the network tunnel information used, the network tunnel information corresponding to the subscriber terminal information is searched and searched. The header of the response packet is converted based on the received network tunnel information, the protocol conversion of the communication protocol of the service network to the communication protocol of the network tunnel, and the response in which the packet switching apparatus converts the protocol to the communication protocol of the network tunnel Transmitting the packet to the subscriber terminal, the subscriber terminal only needs to manage one tunnel, change the IP address information of the information providing server to the administrator of the second information management server, Since there is no need to make a request for addition, deletion, etc., it is possible to improve the efficiency and shortening of operations such as changes, and since the second information management server does not require determination of the area to which the subscriber terminal belongs, Processing load can be reduced.

  Further, according to the present invention, the subscriber terminal, the interface connected to the subscriber terminal, the interface connected to the predetermined network, and the service network operated with a policy different from the predetermined network are connected. A packet switching device having an interface, a first information management server installed in the service network, an information providing server installed in the service network, and a router installed between the packet switching device and the service network And a network termination device installed between the subscriber terminal and the predetermined network, and a second information management server installed in the predetermined network, and between the subscriber terminal and the predetermined network Network connected via a tunnel using the tunneling protocol And a first information management server for storing the IP address of the first information management server, the information providing server storage means for associating and storing the server name and the IP address of the information providing server. Between the storage means, the network tunnel information storage means for storing the network tunnel information of the network tunnel established between the subscriber terminal and a predetermined network for each subscriber terminal, and between the network terminating device and the subscriber terminal Registration means for acquiring transmitted and received network tunnel information and registering it in the network tunnel information storage means; reference destination server information included in the packet received from the subscriber terminal; and information providing server stored in the information providing server storage means Judgment means for collating the server name and the result of the collation judgment by the judgment means When it is determined that the predetermined condition is not satisfied, the transparent transfer means for transparently transferring to the interface connected to the predetermined network and the result of the collation determination by the determination means indicate that the predetermined condition is satisfied. Converts the header of the packet based on the IP address of the first information management server stored in the first information management server storage means, and converts the communication protocol of the network tunnel into the communication protocol of the service network. Included in the packet transmitted to the first information management server, the first transmission means for transmitting the conversion means, the packet converted by the first conversion means to the first information management server installed in the service network Response information received from the first information management server and additional information to be sent to the inquiry destination server information The network tunnel information corresponding to the subscriber terminal information is searched based on the subscriber terminal information in the response packet including the information on the subscriber terminal and the network tunnel information stored in the network tunnel information storage means. A second converting means for converting the header of the response packet based on the network tunnel information and converting the communication protocol of the service network into the communication protocol of the network tunnel; and the response packet converted by the second converting means is a subscriber terminal. Second transmission means for transmitting to the subscriber terminal, the subscriber terminal only needs to manage one tunnel, and the administrator of the second information management server can change or add the IP address information of the information providing server, Since there is no need to request removal, etc., To allow shrinkage also requires no determination of areas belongs the subscriber terminal in a second information management server, it is possible to reduce the processing load.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram for explaining a configuration of a network system according to an embodiment of the present invention. The subscriber terminal 101 is connected to a network termination device 108 that is an interconnection point with the ISP network 103 via the packet switching device 102, and communicates with the Internet 104 through the ISP network 103. Here, the predetermined network described above corresponds to the ISP network 103, for example. The subscriber terminal 101 and the ISP network 103 are configured by PPPoE (Point to Point Protocol over Ethernet (registered trademark)). The content distribution network 106 in which the content server 105 is installed is connected to the packet switching apparatus 102 via the router 109. Here, the service network described above corresponds to, for example, the content distribution network 106, and the information providing server described above corresponds to, for example, the content server 105.

  The packet switching device 102, the content distribution network 106, and the router 109 are installed for each arbitrarily defined subscriber area unit. The second DNS server 107 installed in the ISP network 103 performs IP address control for the subscriber terminal 101 to connect to the Internet 104. Here, the second information management server described above corresponds to the second DNS server 107, for example. The first DNS server 110 installed in the content distribution network 106 stores and manages the IP address of the content server 105 installed in the content distribution network 106. Here, the first information management server described above corresponds to the first DNS server 110.

  Next, the block configuration of the packet switching apparatus 102 will be described with reference to FIG. As shown in FIG. 2, the subscriber interface 201 transmits and receives information to and from the subscriber terminal 101. The ISP interface 202 transmits / receives information to / from the second DNS server 107 and the Internet 104 in the ISP network 103. The content distribution network interface 203 transmits and receives information to and from the content server 105 and the first DNS server 110 in the content distribution network 106. The packet transfer unit 204 transfers various packets delivered from the packet identification / protocol conversion unit 205 described later to each interface. The packet identification / protocol conversion unit 205 identifies the transmission destinations of various packets based on the information in each table (see FIGS. 3 to 5) stored in the storage device 206 described later. Based on the information, protocol conversion is performed, and the packet is transferred to the packet transfer unit 204. The registration unit 207 is used when transmitting a DNS response packet and content data packet, which will be described later, transmitted and received between the network terminating device 108 and the subscriber terminal 101 via the packet switching device 102 to the subscriber terminal 101. Network tunnel information obtained and registered in a predetermined area of the storage device 206. The subscriber interface 201, ISP interface 202, content distribution network interface 203, packet transfer unit 204, packet identification / protocol conversion unit 205, and registration unit 207 correspond to, for example, a CPU. The storage device 206 corresponds to, for example, an HDD, a ROM, or a RAM.

  Next, each table stored in the storage device 206 will be described with reference to FIGS. FIG. 3 is a DNS transfer management table including information used for determination when transmitting a DNS inquiry packet in which the content server name of the content server 105 is set to the content distribution network 106. Here, the DNS inquiry packet is a packet for acquiring the IP address of the content server 105 transmitted from the subscriber terminal 101. The DNS transfer management table includes a server name of the content server 105 installed in the content distribution network 106 and a transmission destination interface number for connecting to the content distribution network 106 in which the content server 105 is installed. . The destination interface number will be described. For example, when there are a plurality of content distribution networks 106, each content distribution network 106 is assigned a number for identification. This identification number corresponds to the destination interface number. That is, if there are five content distribution networks 106, the destination interface numbers 1 to 5 exist.

  FIG. 4 is a DNS server IP address management table including information for transmitting a DNS inquiry packet to the content distribution network 106. The DNS server IP address management table is composed of the IP address of the first DNS server 110 and the destination interface number for connecting to the content distribution network 106 in which the first DNS server 110 is installed. The transmission destination interface number in FIG. 4 is the same as the transmission destination interface number described in FIG.

  FIG. 5 is a subscriber PPPoE information management table. As shown in FIG. 5, the subscriber PPPoE information management table includes the IP address of the subscriber terminal 101, the MAC address of the subscriber terminal 101, the Session-ID of the PPPoE header, the destination interface number, and the MAC address of the network termination device 108. It is composed of The information included in this table is used when a DNS response packet (described later) transmitted from the first DNS server 110 installed in the content distribution network 106 to the subscriber terminal 101 is transmitted to the subscriber terminal 101. It is done. It is also used when content data packets are transmitted from the content server 105 to the subscriber terminal 101. At this time, it is encapsulated in a PPPoE packet corresponding to the subscriber terminal 101. The information in the subscriber PPPoE information management table is PPPoE information acquired by the packet switching apparatus 102 from packets transmitted and received between the subscriber terminal 101 and the network terminating device 108. Here, the packet switching apparatus 102 may acquire PPPoE information only when receiving a packet for assigning an IP address from the network terminating apparatus 108 to the subscriber terminal 101. Thereby, the load of the acquisition process is reduced. Note that the above-described response packet corresponds to a DNS response packet.

  Next, an operation of accessing the content server 105 from the subscriber terminal 101 in the embodiment of the present invention will be described with reference to FIG. The subscriber terminal 101 transmits a DNS inquiry packet in which the content server name of the content server 105 is set to the second DNS server 107 installed in the ISP network 103 (step S601). When the packet switching apparatus 102 determines that the content server name set in the DNS inquiry packet matches the content server name stored in the DNS transfer management table shown in FIG. 3, the conversion of the Ether header of the DNS inquiry packet and The PPPoE capsule is released (details will be described later with reference to FIG. 10), and transmitted to the first DNS server 110 in the content distribution network 106 based on the DNS server IP address management table shown in FIG. 4 (step S602). ).

  The first DNS server 110 in the content distribution network 106 sets the IP address corresponding to the content server name set in the DNS inquiry packet in the DNS response packet, and transmits it to the packet switching apparatus 102 (step S603). The packet switching apparatus 102 receives the DNS response packet, retrieves PPPoE information corresponding to the subscriber terminal 101 that is the transmission destination from the subscriber PPPoE information management table shown in FIG. 5, and based on the retrieved PPPoE information, Conversion of the Ether header of the DNS response packet and PPPoE encapsulation are performed (details will be described later with reference to FIG. 11), and the result is transmitted to the corresponding subscriber terminal 101 (step S604).

  The subscriber terminal 101 that has acquired the IP address of the content server 105 transmits a service request packet having the IP address of the content server 105 as a transmission destination to the content server 105 (step S605). Upon receiving the service request packet addressed to the content server 105, the packet switching apparatus 102 converts the Ether header and releases the PPPoE capsule, and transmits the packet to the content server 105 of the content distribution network 106 (step S606). However, the destination IP address of the IP header is not converted. The content server 105 receives the service request packet and distributes the content data packet to the requesting subscriber terminal 101 (step S607). Upon receiving the content data packet, the packet switching apparatus 102 converts the Ether header and PPPoE encapsulation based on the PPPoE information shown in FIG. 5, and transmits the result to the corresponding subscriber terminal 101 (step S608). However, the source IP address in the IP header is not converted.

  Here, the format of the DNS inquiry packet and service request packet transmitted from the subscriber terminal 101 and the format of the DNS response packet transmitted from the first DNS server 110 are shown in FIGS. FIG. 7 shows a packet format structure when UDP is used, and FIG. 8 shows a packet format structure when TCP is used.

  Next, setting of the content server name in the DNS inquiry packet will be described with reference to FIG. In the content server name, characters are divided into dot units, and the number of characters is set in the order of characters. For example, when the server name is “server1.cdn.xxx.co.jp”, as shown in FIG. 9, 7server13cdn3xxx2co2jp is set in the DNS inquiry packet. This interpretation will be described below. Since “server1” is composed of 7 characters, “server1” is represented as “7server1” in which 7 is assigned before “server1”. Hereinafter, “cdn”, “xxx”, “co”, and “jp” are similarly interpreted.

  Next, an example of packet conversion in the packet switching apparatus 102 when the DNS inquiry packet received from the subscriber terminal 101 is transmitted to the first DNS server 110 in the content distribution network 106 will be described with reference to FIG. The packet switching apparatus 102 performs the following steps (1) to (5). (1) The transmission destination MAC address (DA) of the Ether header is converted from the MAC address of the network terminating device 108 to the MAC address of the router 109 of the content distribution network 106. (2) The source MAC address (SA) of the Ether header is converted from the MAC address of the subscriber terminal 101 to the MAC address of the packet switching device 102. (3) Delete the PPPoE header. (4) Delete the PPP header. (5) The destination IP address of the IP header is converted from the IP address of the second DNS server 107 in the ISP network 103 to the IP address of the first DNS server 110 in the content distribution network 106.

  On the other hand, an example of packet conversion in the packet switching apparatus 102 when a DNS response packet received from the first DNS server 110 in the content distribution network 106 is transmitted to the subscriber terminal 101 will be described with reference to FIG. The packet switching apparatus 102 performs the following steps (1) to (5). (1) The transmission destination MAC address (DA) of the Ether header is converted from the MAC address of the packet switching apparatus 102 to the MAC address of the subscriber terminal 101. (2) The source MAC address (SA) of the Ether header is converted from the MAC address of the router 109 of the content distribution network 106 to the MAC address of the network termination device 108. (3) Add a PPPoE header. (4) Add a PPP header. (5) The source IP address of the IP header is converted from the IP address of the first DNS server 110 in the content distribution network 106 to the IP address of the second DNS server 107 in the ISP network 103.

  The MAC address of the subscriber terminal 101, the MAC address of the network terminating device 108, and the Session-ID of PPPoE used in the above conversion are the search keys for the IP address of the subscriber terminal 101 that is the destination IP address of the IP header. Is retrieved from the subscriber PPPoE information management table shown in FIG.

  Next, an example of processing in the packet switching apparatus 102 for a DNS inquiry packet or a service request packet (hereinafter referred to as a transmission packet) received from the subscriber terminal 101 will be described with reference to FIG. The following steps are performed by the packet switching apparatus 102. When the packet switching apparatus 102 receives the transmission packet, it is determined whether the Ether Type of the Ether header is a value indicating a PPP Session Stage of 0x8864 (step S1201). If the determination results do not match, the ISP is determined. The data is transparently transferred to the interface 202 (step S1209), and the process ends (step S1210). If the determination results match, it is determined whether the TYPE of the PPPoE header is 0x01 and CODE is 0x00 (step S1202). If the determination results do not match, they are transparently transferred to the ISP interface 202 (step S1209). Processing ends (step S1210). If the determination results match, it is determined whether PROTOCOL in the PPP header is a value indicating an IP of 0x0021 (step S1203). If the determination results do not match, they are transparently transferred to the ISP interface 202 (step S1209). Processing ends (step S1210). If the determination results match, it is determined whether the destination IP address of the IP header is the IP address of the content server 105 (step S1204). If the determination results match, it is determined whether or not the destination port is a value indicating DNS of 0x35. If the determination results match, the protocol conversion shown in FIG. 10 is performed and transmitted from the corresponding interface. If the destination port is not a value indicating DNS of 0x35, the processing except for the conversion of the destination IP address in the IP header in the protocol conversion shown in FIG. 10 is performed and transmitted from the corresponding interface (step S1208). Then, the process ends (step S1210).

  If the determination results do not match, it is determined whether the Protocol in the IP header is a value indicating TCP of 0x06 or UDP of 0x11 (step S1205). If the determination results do not match, they are transparently transferred to the ISP interface 202 ( In step S1209), the process ends (step S1210). If the determination results match, it is determined whether the destination port is a value indicating DNS of 0x35 (step S1206). If the determination results do not match, it is transparently transferred to the ISP interface 202 (step S1209), and the process ends (step S1210). If the determination results match, it is determined whether or not there is a content server name in the DNS header that matches the content server name in the DNS transfer management table shown in FIG. 3 (step S1207). If the determination results do not match, it is transparently transferred to the ISP interface 202 (step S1209), and the process ends (step S1210). If the determination results match, it is determined whether or not the destination port is a value indicating DNS of 0x35. If the determination results match, the protocol conversion shown in FIG. 10 is performed and transmitted from the corresponding interface. The If the determination results do not match, the process of the protocol conversion shown in FIG. 10 excluding the conversion of the destination IP address in the IP header is performed, transmitted from the corresponding interface (step S1208), and the process ends (step S1210). ).

  Next, an example of processing in the packet switching apparatus 102 of a DNS response packet or content data packet (hereinafter referred to as a received packet) received from the first DNS server 110 or the content server 105 in the content distribution network 106 will be described with reference to FIG. Will be described. The following steps are performed by the packet switching apparatus 102. When the packet switching apparatus 102 receives a received packet from the content distribution network 106, it is determined whether the Ether Type of the Ether header is a value indicating an IP of 0x0800 (step S1301). The received packet is discarded (step S1305), and the process ends (step S1306). If the determination results match, the IP address of the subscriber terminal 101 is searched from the subscriber PPPoE information management table shown in FIG. 5 using the destination IP address of the IP header as a key, and the destination IP address of the IP header is subscribed. It is determined whether it is the IP address of the subscriber terminal 101 (step S1302). If it is determined that it is not the IP address of the subscriber terminal 101, the received packet is discarded (step S1305), and the process ends (step S1306). . If the IP address of the subscriber terminal 101 is determined, it is determined whether the Protocol in the IP header is a value indicating TCP of 0x06 or UDP of 0x11 (step S1303). The received packet is discarded (step S1305), and the process ends (step S1306). If the determination results match, it is determined whether or not the destination port is a value indicating DNS of 0x35. If the determination results match, the corresponding PPPoE information is obtained from the subscriber PPPoE information management table shown in FIG. Acquired, performs protocol conversion shown in FIG. 11, and is transmitted from the corresponding interface. If the determination results do not match, the corresponding PPPoE information is acquired from the subscriber PPPoE information management table shown in FIG. 5, and the protocol conversion shown in FIG. 11 excludes the conversion of the source IP address of the IP header. Is transmitted from the corresponding interface (step S1304).

  In the connection server distribution method and packet switching apparatus according to the present invention, the subscriber terminal only needs to manage one tunnel, and the DNS server administrator can change, add, delete, etc. the IP address information of the content server. Therefore, it is possible to increase the efficiency and shortening of operations such as change, and it is not necessary to determine the area to which the subscriber terminal belongs in the DNS server, so that the processing load can be reduced. Therefore, the present invention is useful for a connection server distribution method and a packet switching apparatus for performing a streaming service to a subscriber terminal through a content server of a content distribution network.

Block diagram for explaining a configuration of a network system in an embodiment of the present invention Block configuration diagram of a packet switching apparatus according to an embodiment of the present invention The figure which shows the data structure of the DNS transfer management table in embodiment of this invention The figure which shows the data structure of the DNS server IP address management table in embodiment of this invention The figure which shows the data structure of the subscriber PPPoE information management table in embodiment of this invention The figure for demonstrating operation | movement of the access to a content server from the subscriber terminal in embodiment of this invention The figure which shows the structure of a packet format in case UDP is used for the packet format in embodiment of this invention. The figure which shows the structure of a packet format in case TCP is used for the packet format in embodiment of this invention. The figure for demonstrating the setting of the content server name of the DNS inquiry packet in embodiment of this invention The figure for demonstrating an example of the packet conversion in the packet switching apparatus in case the DNS inquiry packet received from the subscriber terminal in embodiment of this invention is transmitted to a content delivery network. The figure for demonstrating an example of the packet conversion in the packet switching apparatus in the case of transmitting the DNS response packet received from the content delivery network in embodiment of this invention to a subscriber terminal. The flowchart explaining an example of the processing operation in the packet switching apparatus of the DNS inquiry packet received from the subscriber terminal in the embodiment of the present invention. The flowchart explaining an example of the processing operation | movement in the packet switching apparatus of the DNS response packet or content data packet received from the content delivery network in embodiment of this invention The figure for demonstrating the structure of the conventional content service system The figure for demonstrating the access operation to the content server from the subscriber terminal in the conventional content service system

Explanation of symbols

101, 1401 Subscriber terminal 102 Packet converter 103, 1403 ISP network (predetermined network)
104, 1404 Internet 105, 1405 Content server (information providing server)
106, 1406 Content distribution network (service network)
107 Second DNS server (second information management server)
108 network termination device 109 router 110 first DNS server (first information management server)
201 Subscriber interface (second transmission means)
202 ISP interface 203 Content distribution network interface (first transmission means)
204 Packet transfer unit (transparent transfer means)
205 Packet identification / protocol conversion unit (determination means, first conversion means, second conversion means)
206 Storage device (information providing server storage means, first information management server storage means, network tunnel information storage means)
207 Registration section (registration means)
1402 L2SW
1407 DNS server 1408 First network terminator 1409 Second network terminator

Claims (16)

A subscriber terminal,
A packet switching device having an interface connected to the subscriber terminal, an interface connected to a predetermined network, and an interface connected to a service network operated by a policy different from the predetermined network;
A first information management server installed in the service network;
An information providing server installed in the service network;
A router installed between the packet switching device and the service network;
A network termination device installed between the subscriber terminal and the predetermined network;
A second information management server installed in the predetermined network;
A connection server distribution method in a network system in which the subscriber terminal and the predetermined network are connected using a network tunnel according to a tunneling protocol,
The packet switching device collating and determining inquiry server information included in a packet received from the subscriber terminal and server information of the information providing server stored in advance in the packet switching device;
When the packet switching device determines that the predetermined condition is not satisfied as a result of the collation determination, transparently transfers to the interface connected to the predetermined network; and
When the packet switching device determines that the predetermined condition is satisfied as a result of the collation determination, the packet header is based on server information of the first information management server stored in advance in the packet switching device. Converting the communication protocol of the network tunnel to the communication protocol of the service network; and
The packet switching device transmitting a packet protocol-converted to a communication protocol of the service network to the first information management server installed in the service network;
Response information received from the first information management server and the subscriber terminal serving as a transmission destination for the inquiry server information contained in the packet transmitted to the first information management server by the packet switching device Information of the subscriber terminal in the response packet including the above information and is transmitted / received between the network terminating device and the subscriber terminal via the packet switching device, and at the time of the transmission / reception, the packet switching device The network corresponding to information of the subscriber terminal based on network tunnel information used when transmitting the response packet to the subscriber terminal, acquired and stored in a predetermined storage area of the packet switching device Tunnel information is searched, a header of the response packet is converted based on the searched network tunnel information, and the service network is converted. Comprising the steps of protocol conversion of communication protocol of the work to a communication protocol of the network tunnel,
The packet switching device transmitting a response packet converted into a communication protocol of the network tunnel to the subscriber terminal;
Connection server distribution method having.   The connection server distribution method according to claim 1, wherein the service network is a content distribution network.   The connection server distribution method according to claim 1 or 2, wherein a communication protocol of the network tunnel is PPPoE (Point to Point Protocol over Ethernet (registered trademark)).   The connection server distribution method according to claim 3, wherein the packet switching apparatus acquires and stores the network tunnel information when receiving a PPPoE packet for assigning an IP address to the subscriber terminal.   In the conversion of the header of the packet when the packet switching apparatus determines that a predetermined condition is satisfied as a result of the collation determination of the inquiry destination server information and the server information of the information providing server, the transmission destination of the Ether header The MAC address is converted from the MAC address of the network terminating device to the MAC address of the router installed at the end point of the service network or the first information management server installed in the service network, and the source MAC The address is converted from the MAC address of the subscriber terminal to the MAC address of the packet switching device, and the destination IP address of the IP header is converted from the IP address of the second information management server installed in the predetermined network. Of the first information management server installed in the service network Connection server distribution method according to one of claims 1 to 4 for converting the P address.   The search for the network tunnel information corresponding to the information on the subscriber terminal included in the response packet is a search based on a destination IP address included in the information on the subscriber terminal. Connection server distribution method described in 1.   The packet switching device discards the response packet when the corresponding network tunnel information is not obtained as a result of searching the network tunnel information corresponding to the information of the subscriber terminal included in the response packet. Item 7. The connection server distribution method according to any one of Items 1 to 6.   When the packet switching device searches the network tunnel information corresponding to the subscriber terminal information and converts the header of the response packet based on the searched network tunnel information, the destination MAC of the Ether header An address is converted from a MAC address of a router installed at an end point of the service network or the first information management server installed in the service network to a MAC address of the network termination device, and a source MAC address is converted The MAC address of the packet switching device is converted into the MAC address of the subscriber terminal, and the source IP address of the IP header is converted from the IP address of the first information management server installed in the service network Installed in the network Connection server distribution method according to any one of claims 1 7 for converting the second information management server IP address. A subscriber terminal,
A packet switching device having an interface connected to the subscriber terminal, an interface connected to a predetermined network, and an interface connected to a service network operated by a policy different from the predetermined network;
A first information management server installed in the service network;
An information providing server installed in the service network;
A router installed between the packet switching device and the service network;
A network termination device installed between the subscriber terminal and the predetermined network;
A second information management server installed in the predetermined network;
The packet switching device of a network system connected between the subscriber terminal and the predetermined network using a network tunnel according to a tunneling protocol,
Information providing server storage means for associating and storing a server name and an IP address of the information providing server;
First information management server storage means for storing an IP address of the first information management server;
Network tunnel information storage means for storing network tunnel information of the network tunnel established between the subscriber terminal and the predetermined network for each subscriber terminal;
Registration means for obtaining the network tunnel information transmitted and received between the network termination device and the subscriber terminal, and registering it in the network tunnel information storage means;
Determining means for collating and determining reference server information included in the packet received from the subscriber terminal and the server name of the information providing server stored in the information providing server storage means;
As a result of the collation judgment by the judgment means, when it is judged that the predetermined condition is not satisfied, the transparent transfer means for transparently transferring to the interface connected to the predetermined network;
As a result of the collation judgment by the judgment means, when it is judged that a predetermined condition is satisfied, based on the IP address of the first information management server stored in the first information management server storage means, First conversion means for converting a header of the packet and converting the communication protocol of the network tunnel to the communication protocol of the service network;
First transmission means for transmitting the packet converted by the first conversion means to the first information management server installed in the service network;
A response packet including response information received from the first information management server and information on the subscriber terminal serving as a transmission destination with respect to reference destination server information included in the packet transmitted to the first information management server The network tunnel information corresponding to the subscriber terminal information is retrieved based on the subscriber terminal information and the network tunnel information stored in the network tunnel information storage means, and the retrieved network tunnel information Second conversion means for converting the header of the response packet based on the protocol, and converting the communication protocol of the service network to the communication protocol of the network tunnel;
Second transmission means for transmitting the response packet converted by the second conversion means to the subscriber terminal;
A packet switching apparatus provided.   The packet switching apparatus according to claim 9, wherein the service network is a content distribution network.   The packet switching apparatus according to claim 9 or 10, wherein a communication protocol of the network tunnel is PPPoE (Point to Point Protocol over Ethernet (registered trademark)).   12. The packet switching apparatus according to claim 11, wherein the registration unit acquires and registers the network tunnel information when receiving a PPPoE packet for assigning an IP address to the subscriber terminal.   In the conversion of the header of the packet when it is determined that the predetermined condition is satisfied as a result of the determination unit collating the reference server information with the server name of the information providing server, the first conversion unit includes: Converting the destination MAC address of the header from the MAC address of the network termination device to the MAC address of the router installed at the end point of the service network or the first information management server installed in the service network; The source MAC address is converted from the MAC address of the subscriber terminal to the MAC address of the packet switching device, and the destination IP address of the IP header is changed to the IP of the second information management server installed in the predetermined network. The first information management server installed in the service network from the address Packet switching apparatus according to any one of claims 9 to convert the P address 12.   The search for the network tunnel information corresponding to the information on the subscriber terminal included in the response packet, wherein the second conversion means searches based on a destination IP address included in the information on the subscriber terminal. The packet switching device according to any one of 9 to 13.   The second conversion means discards the response packet when the corresponding network tunnel information is not obtained as a result of searching the network tunnel information corresponding to the subscriber terminal information included in the response packet. The packet switching device according to any one of claims 9 to 14. In the case where the network tunnel information corresponding to the subscriber terminal information is searched and the header of the response packet is converted based on the searched network tunnel information, the second conversion means transmits the Ether header destination The MAC address is converted from the MAC address of the router installed at the end point of the service network or the first information management server installed in the service network to the MAC address of the network termination device, and the source MAC An address is converted from a MAC address of the packet switching device to a MAC address of the subscriber terminal, and a source IP address of an IP header is converted from the IP address of the first information management server installed in the service network, The first installed in a predetermined network Packet switching apparatus according to any one of claims 9 to 15 for converting the information management server of the IP address.

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