JP2002354045A - Gateway device - Google Patents

Abstract

(57) Abstract: Provided is a gateway device capable of speeding up Web access and reducing a network bandwidth with a Web server. SOLUTION: In a network configuration in which a first network to which a user terminal is connected is connected to one of a plurality of third networks accommodating an information providing terminal via a second network, A gateway device that connects a cache terminal, a determination unit that determines a request content of a packet transmitted from a user terminal to an information providing terminal, and data required by the packet. In this case, the data stored in the cache terminal is transmitted to the user terminal; otherwise, the connection from the gateway device to the information providing terminal is set in the second network, and the information included in the packet from the user terminal is set. Transfer means for transferring the data from the information providing terminal, and a cache terminal for transferring the data obtained from the information providing terminal. Means for sending to the end.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network connection device for connecting networks.

[0002]

2. Description of the Related Art Nowadays, on the Internet, Web access traffic accounts for more than 70% of traffic. This web access speedup and W
Aiming at reduction of network bandwidth with eb server, W
The eb caching technology has been actively studied. Web
The caching technique is to install a Web caching server in an access network and cache data of the Web server, thereby reducing the bandwidth of the core network and increasing the speed of Web access from terminals.

There are two types of Web caching technologies in which Web access from a terminal is performed via a Web cache server. The first is to use a Web cache server as a proxy server to relay and manage access from an internal network such as a LAN to the external Internet.
Server to prevent unauthorized access to the internal network)
A proxy method in which the IP address of a Web cache server is specified in the proxy settings of the terminal's Web browser. The second method is to select Web access traffic at a router (such as an access gateway) connecting the access network and the terminal. This is a transparent system in which data is forcibly transferred to a Web cache server.

[0004] In the field of access networks, Internet service providers (hereinafter referred to as ISPs) have been independently distributing access points in each region in the access network field. However, recently, an ISP network selection type IP network system in which a communication carrier provides a common access point to each ISP called a regional IP network, and each ISP has a connection point with the regional IP network. Is emerging. In this configuration, the access point between the local IP network and the user is LAC (L2TP Ac).
Access Concentrator)
The access point between the local IP network and each ISP is LN
An access gateway called S (L2TP Network Server) is installed. In such ISP network selection type IP network system, LAC and L
An L2TP (Layer 2 Tunneling Protocol) connection is set between the NSs, and a PPP connection from the user is set in the L2TP to the LNS via the LAC.

[0005]

The above ISP selection type IP
In a network system, it is conceivable to install a Web cache server in the LAC unit in order to reduce the network load between the LAC and the LNS. However, L2
In the case of a TP type access network, the user I
Since P packets are transferred within the PPP connection,
A general LAC only performs delivery of a PPP connection. Therefore, there is a problem that an IP packet cannot be taken out from the PPP connection, and a Web cache server cannot be installed at the position of the LAC.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to increase the speed of Web access and the W
An object of the present invention is to provide a gateway device capable of reducing a network bandwidth with an eb server.

[0007]

In order to solve the above-mentioned problems, the present invention provides a method in which a first network to which a user terminal is connected is provided with information for providing information via a second network. In a network configuration connected to any one of a plurality of third networks accommodating a providing terminal, a gateway device connecting between the first and second networks, wherein the gateway device stores data acquired from the information providing terminal. Means for connecting a cache terminal for storing the packet, and determining the request content of the packet transmitted from the user terminal to the information providing terminal. If the result of the determination is that the data requested by the packet is in the cache terminal, The data stored in the cache terminal is transmitted to the user terminal. If the data is not stored in the cache terminal, the data is stored in the second network. A transfer means for setting a connection from the gateway device to the information providing terminal, transferring information included in a packet from the user terminal through the connection, and acquiring data from the information providing terminal based on the request content from the user terminal. And a data acquisition means for sending the acquired data to the cache terminal.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a diagram showing a configuration of a network system according to a first embodiment. In the first embodiment, in an ISP selection type IP network system, a Web is set by a proxy setting method.
A description will be given of a case in which the traffic b is transferred to a Web cache server and a network system is configured using a gateway device as an LAC.

User terminals (101-1 to 101-m)
Is an access line (1) for a telephone network, ADSL, CATV, etc.
02-1 to 102-m), the connection is made to the LAC (104) by the access gateway system to which the present invention is applied. The local IP network (105) is connected to the LNS (107
-1 to 107-n), the ISP network (10
8-1 to 108-n), and the ISP network (108-1 to 108-n) is connected to the router (109-1 to 109-1).
109-n), and is connected to the Internet (110). The LAC (104) has a LAN
The Web cache server (112) is connected via (113). Each IS is stored in the cache server (112).
A plurality of IP addresses corresponding to P are assigned.

[0010] Each ISP subscriber's user terminal (101-
1 to 101-m) connect to the Internet, a separate PPP connection (1) exists between the user terminal and the LAC.
02-1 to 102-m) are set, and the LAC can identify the user by the PPP connection (102-1 to 102-m). The LAC (104) is connected to the user terminal (101).
-1 to 101-m), the PPP connection (102
-1 to 102-m), upon receiving a primary authentication using a user name and a password, the LNS (107-1 to 107-n) of the ISP selected by the user
L2TP connection (106-1 to 106-)
Set n). User terminal (101-1 to 101-
m) from the PPP connection (102-1 to 102-)
m) is an L2TP connection (106-1 to 106-)
n) through LNS (107-1 to 107-n).

The L2TP connection (106-1)
To 106-n), the Web cache server (11
2) PPP connection (114-1 to 114) for connecting to the Web server (111) via each ISP
-N) is also set. Next, the user terminal (101-1)
Web browser application running on I
The Web server (111) installed on the Internet via the SP network (108-1)
A connection sequence from acquisition of content data to display is described.

FIG. 2 shows a connection sequence when the present invention is not applied and the cache server (112) is not installed. When the user instructs the Web browser application to display the content data on the Web server (111), the user terminal (10
1-1) sends an HTTP request message to the Web server (111). This HTTP request message is
The packet is sent to the PPP connection (102-1) as an IP packet having the IP address of the Web server (111) as the destination IP address (201). LAC (10
4) is the PP received from the user terminal (101-1).
The P frame is transferred to the L2TP connection (106-1) with the LNS (107-1). At this time, the L2TP header, UDP header, I
A P header is added (202). Newly added I
The destination IP address of the P header is LNS (107-1)
IP address. The IP packet (202) that has been routed in the regional IP network and arrived at the LNS (107-1) is sent to the LNS (107-1) by the L2TP.
After termination (removal of the IP header, UDP header, and L2TP header) and termination of the PPP (removal of the PPP header), the packet is transferred to the Web server (111) (203).

In the Web server (111), the received H
The content data indicated by the URL described in the TTP request message is transmitted to the user terminal (101-1) as an HTTP response message (204). LN
In S (107-1), a PPP header is added,
Further, an L2TP header, a UDP header, and an IP header are added, and the packet is transmitted to the L2TP connection (106) (205). In the LAC (104), L2TP termination is performed and transferred to the user terminal (101-1) (20).
6). The content data obtained in this way is
Displayed by a Web browser application.

In the above sequence, the HTTP request message for the user terminal (101-1) to acquire the content data on the Web server (111) is always transferred to the Web server (111).
Then, response processing is performed. The user terminal (101-
HTT sent and received between 1) and Web server (111)
P request message and response message are LAC
(104), but as a PPP frame P
It only passes through the PP connection, and is not routed by the IP header in the PPP frame.

Next, a case where the gateway device according to the first embodiment is applied and a Web cache server (112) is installed in the LAC (104) will be described. FIG. 3 is a diagram illustrating a connection sequence according to the first embodiment.

In the network system to which the first embodiment of the present invention is applied, the user terminal (101
-1 to 101-m), the IP address of the Web cache server (112) corresponding to the ISP selected by each user is provided to the Web browser application.
It is assumed that it is set as a proxy.

FIG. 3A shows a connection sequence in the case where Web content data requested by the user is stored in the cache server (112) and a hit occurs. When the user instructs the Web browser application to display the content data on the Web server (111), the user terminal (101-1) sets the Web server (11
Send an HTTP request message for 1). This HTTP request message has an IP address of the Web cache server (112) corresponding to the ISP selected by the user as a destination IP address by proxy setting.
PPP connection as P packet (102-1)
(301). The LAC (104) extracts the destination IP address from the IP packet in the PPP frame received from the user terminal (101-1), and compares the extracted IP address with the IP address of the Web cache server (112).
If they match, an IP packet is extracted from the PPP frame and transferred to the Web cache server (112) (302).

The Web cache server (112) checks the URL (Unif) described in the received HTTP request message.
orm Resource Locator: used on the Internet,
A search is performed to determine whether data of the standard for designating a connection destination) exists in cache data. If the data is found as a result of the search, the cache data is sent to the user terminal (101-1) as an HTTP response message (3.
03). The LAC (104) determines that the destination IP address of the received IP packet is the I of the user terminal (101-1).
It identifies that it is a P address, adds a PPP header, and inserts it into the PPP connection (102-1) with the user terminal (101-1) (304). The user terminal (101-1) displays the content data obtained in this way by using a Web browser application.

FIG. 3B shows a connection sequence when the Web content data requested by the user is not stored in the cache server (112). As in the case of FIG. 3A, the HTTP request message sent from the user terminal is transferred to the Web cache server (112) by the LAC (104) (301, 302).
The Web cache server (112) receives the received HTT
A search is performed to determine whether the data of the URL described in the P request message exists in the cache data. As a result of the search, if no hit is found, the Web cache server (11
2) is the I of the Web server having the host name of this URL.
After inquiring the P address to a DNS (Domain Name System: a method for managing the correspondence between a domain name and an IP address on a network or a database) server, an HTTP request is sent as an IP packet having the Web server (111) as a destination IP address. Send the message (305). L
The AC (104) determines the ISP to which the user belongs from the source address of the IP packet received from the Web cache server, and the LNS (107-1) of the ISP
A new PPP connection is set up in the L2TP connection with. To the IP packet, a PPP header is added, and further, an L2TP header, a UDP header, and an IP header are added, and the L2TP connection (106-
1) (306). L in LNS (107-1)
After 2TP termination and PPP termination, it is transferred to the Web server (111) (307).

In the Web server (111), the received H
The content data indicated by the URL described in the TTP request message is used as the HTTP response message as the Web
It is sent to the cache server (112) (30
8). In the LNS (107-1), a PPP header is added, and an L2TP header, a UDP header,
With a P header added, the L2TP connection (10
It is sent to 6) (309). In the LAC (104), L2TP termination and PPP termination are performed and transferred to the Web server (111) according to the destination IP address (31).
0). The Web server (111) stores the received Web content data as cache data, and further stores the user terminal (101-101) as the original data request source.
In response to 1), Web content data is transmitted as an HTTP response message (303). LAC (104)
Identifies that the destination IP address of the received IP packet is the IP address of the user terminal (101-1), adds a PPP header, and
1) and is inserted into the PPP connection (102-1) (304). The user terminal (101-1) displays the content data obtained in this way by using a Web browser application.

Next, the configuration of the gateway device according to the first embodiment will be described. FIG. 4 is a diagram illustrating a configuration of the gateway device according to the first embodiment. The gateway device (104) is an access line network, Web
Interface circuits (401, 403, 40) for connecting to the cache server and the regional IP network, respectively.
5), interface circuits (401, 403, 405)
And a protocol processing circuit (402, 404, 406) for performing protocol processing on data transmitted and received by the internal switch circuit (407), and a device control circuit (408).

Interface circuits (401, 403, 4)
05) transmits and receives data according to the physical line type (Ethernet (registered trademark), ATM, etc.) of the connected network. Protocol processing circuits (402, 404,
406) are interface circuits (401, 403, 4)
05) performs protocol processing on the data transmitted and received. The internal switch circuit (407) transfers data transferred from the protocol processing circuit (402, 404, 406) according to the destination information of the received information. The device control circuit (408) controls the inside of the device according to the setting information from the setting terminal (409), collects alarms and statistical information, and notifies the setting terminal (409) of information.

FIG. 5 shows a protocol processing circuit (402, 40).
4, 406). Protocol processing circuit (4
02, 404, and 406) include a CPU (501), a memory (502), and a line interface reception buffer (50).
3) It is composed of a line interface transmission buffer (504), an internal switch transmission buffer (505), an internal switch reception buffer (506), and a communication interface circuit between CPUs (507). Have the same hardware configuration.

In the memory (502), a protocol processing program (508), a user terminal information management table (509), and an ISP information management table (510) are arranged. The protocol processing program (508) is a program corresponding to each processing in the access line network compatible protocol processing circuit (402), the cache server compatible protocol processing circuit (404), and the IP network compatible protocol processing circuit (406). When the CPU (501) executes the protocol processing program (508), the protocol processing is performed on the transmission / reception data.
The CPU (501) communicates with an external protocol processing circuit and device control circuit (408) via the inter-CPU communication interface circuit (507) to exchange management information, alarms, and statistical information necessary for protocol processing. To send and receive.

Interface circuits (401, 403, 4)
05) is received by the protocol processing circuit (4).
02, 404, 406) and stored in the line interface reception buffer (503). The data in the line interface receive buffer (503) is
After being subjected to protocol processing by (501), it is transferred to the internal switch (407) via the internal switch transmission buffer (505). The data transferred from the internal switch (407) is stored in the internal switch reception buffer (50).
6). Internal switch receive buffer (50
The data in 6) is subjected to protocol processing by the CPU (501), and then processed by the line interface transmission buffer (50).
4), the interface circuit (401, 40)
3, 405).

Interface circuits (401, 403, 4)
05) -protocol processing circuit (402, 404, 40)
FIG. 6 shows the data format transferred between 6).
The data (601) to be transferred includes a header (60) including the identification ID information of the PPP connection to which the data is transferred.
2) is added and transferred. However, when the data is not associated with the PPP connection to which the data is transferred, a magic number indicating that fact is added as a header.

Interface circuits (401, 403, 4)
FIG. 7 shows a data format transferred between the internal switch (05) and the internal switch (407). Data to be transferred (70
1) is added with a header (702) including identification ID information of a PPP connection to which data is transferred and a header (703) including internal switch transfer destination information and transferred.

FIG. 8 shows an example of the user terminal information (509) stored in the memory. In the first embodiment, user terminal information is stored in the management table (509).
The management information of the user terminal connected to the ISP is stored. The management information includes an IP address of the user terminal, an identification ID of a PPP connection between the user terminal and the LNS, an ISP to which the user belongs, and a protocol field compression (PFC: Protocol Fiel) which is an LCP (Link Control Protocol) setting option of the PPP connection.
d Compression) Setting value, Address / Control Field Compression (ACFC)
Set value, tunnel ID when PPP connection is set in L2TP connection, and session I
D and the like.

FIG. 9 shows an example of the ISP information management information (510) stored in the memory. In the first embodiment, the ISP information management information is stored in a table (51).
0), and the table stores management information of each ISP. The management information includes the address value assigned to each ISP as the IP address of the Web cache server (112), the LNS (107-1 to 107-
n) IP address value, the Web cache server (11
2) ID and LC of LAC-LNS PPP connection used by proxy for connection with Web server
P option setting value, tunnel ID when the PPP connection is set in the L2TP connection, and
Next, the flow inside the LAC of the data transferred to the LAC (104) including the session ID and the like will be described. FIG. 10 shows the flow of data transferred to the LAC (104) inside the LAC. The processing of the PPP frame transferred from the access line network side is distributed by the access line network compatible protocol processing circuit (402) according to the upper layer protocol. Upper layer protocol is PPP LC
In the case of P or NCP (Network Control Protocol), LCP and NCP processing are performed, respectively. If the upper layer protocol is IP, the destination IP
Processing is further sorted by address. If it is addressed to a Web cache server, it is subjected to PPP termination processing and sent to the cache server. When the PPP upper layer protocol is not any of LCP, NCP and IP,
b The IP packet not addressed to the cache server is transferred to the IP network compatible protocol processing circuit (406) and inserted into an appropriate L2TP connection.

IP packets transferred from the Web cache server are sorted according to the destination IP address.
The data including the HTTP response message is transferred to the access network side. If it is not the IP address of any user terminal, it is transferred to the IP network compatible protocol processing circuit (406) as data including an HTTP request message and inserted into an appropriate L2TP connection.

The processing of the L2TP frame transferred from the IP network side is distributed according to the transferred PPP connection. When the packet is transferred within the PPP connection set between the user terminal and the LNS, the packet is transmitted to the access line network side. When the packet is transferred within the PPP connection set between LAC and LNS, W
The data is transferred to the eb cache server side.

Next, the contents of the protocol processing in the access line network compatible protocol processing circuit (402) will be described. FIG. 11 is a diagram showing a process for a PPP frame stored in the line interface reception buffer (503) in the access line network compatible protocol processing circuit (402).

The CPU (501) sends the PPP frame and the P frame from the line interface reception buffer (503).
Identification I of the PPP connection to which the PP frame is transferred I
D is taken out (S1101). At this time, since the header format of the PPP frame depends on the setting value of the LCP setting option of the PPP, the header format is referred to the user terminal management table (509).

The protocol of the frame is identified by the protocol field of the PPP frame (S1102, S1102).
1103), LCP or NCP, P
The LCP packet processing and the NCP packet processing are performed on the PP frame (S1107, S1108).

If the protocol of the PPP frame is IP (S1104), the user terminal management table (50)
9) and the ISP information management table (510),
The IP address of the Web cache server assigned to the ISP to which the user who transmits the PPP frame belongs is derived, and is compared with the destination IP address field of the IP packet in the PPP frame (S1105). If they match, the PPP connection identification ID information (702) to which the PPP frame is transferred and the internal switch transfer destination information (703) indicating that the transfer destination is the Web cache server compatible protocol processing circuit (404) are added. Then, it is stored in the internal switch transmission buffer (505) (S110).
9), end the processing.

If the protocol of the PPP frame is not IP, or even if it is IP, the destination IP address is We
If it does not match the IP address of the cache server, a process of transferring the PPP frame to the IP network compatible protocol processing circuit is performed (S1109), and the process ends.

With the above processing, the user terminal (101-
1 to 101-m), the PPP frame including the HTTP request message transmitted from the Web cache server (1
In the direction 12), other PPP frames are sent to the IP network (10
5) Transfer in the direction.

FIG. 12 is a diagram showing a process for a PPP frame stored in the internal switch reception buffer (506) in the access line network compatible protocol processing circuit (402).

The CPU (501) extracts from the internal switch reception buffer (506) the identification information of the PPP frame and the PPP connection to which the PPP frame is to be transferred, and the internal switch transfer destination information (S1201). PP
The P frame is added with the identification ID of the PPP connection and stored in the line interface transmission buffer (S120).
2), end the process.

According to the above processing, the PPP frame transferred from the Web cache server (112) or the IP network (105) side receives the PPP connection identification I.
The information is transferred to the access circuit network interface circuit (401) together with the D information. The access line network compatible interface circuit (401) converts the PPP frame transferred from the access line network compatible protocol processing circuit (402) into an appropriate P
It is inserted into the PP connection and transferred to the user terminal that is the destination.

The protocol processing in the Web cache server compatible protocol processing circuit (404) will be described below. FIG. 13 is a diagram showing a process for an IP packet stored in the line interface reception buffer (503) in the Web cache server compatible protocol processing circuit (404).

The CPU (501) sends an IP packet and PP from the line interface reception buffer (503).
The P connection identification ID information is extracted (S130).
1). However, the IP packet transferred from the Web cache server is not associated with the PPP connection, and the PPP connection identification ID information is a magic number indicating that fact. The destination IP address value of the IP packet is compared with the user terminal IP address registered in the user terminal information management table (509) (S
1302). If the IP address matches any one of the user terminals, a PPP connection identification ID is acquired by referring to the entry (S1303), and the IP packet is converted into a PPP frame according to the LCP setting option. (S1304). A PPP connection identification ID is added, and internal switch transfer destination information (703) indicating that the transfer destination is the access line network compatible protocol processing circuit (402) is added and stored in the internal switch transmission buffer (505). (S1305), the process ends.

If the destination IP address is I
If it does not match the P address, the ISP information management table (510) is searched for an entry whose cache server IP address value matches the source IP address of the IP packet, and the PPP connection identification ID is obtained (S1306). ). According to the LCP setting option of the entry, the IP packet is converted into a PPP frame (S1307), and a PPP connection identification ID is added thereto, and the packet is transferred to the IP network protocol processing circuit (S13).
08), end.

With the above processing, the IP packet including the HTTP response message to the user terminal among the IP packets transmitted from the Web cache server (112) is the access line network compatible protocol processing circuit (402).
, Including the HTTP request message to the Web server
The P packet is an IP network compatible protocol processing circuit (406)
Can be forwarded to

FIG. 14 shows the processing for the PPP frame stored in the internal switch reception buffer (506) in the Web cache server compatible protocol processing circuit (404).

The CPU (501) extracts from the internal switch reception buffer (506) the identification ID information of the PPP frame and the PPP connection to which the PPP frame is to be transferred and the internal switch transfer destination information (S1401).
Extract IP packet from P frame (S140
2). A PPP connection identification ID is added to the extracted IP packet and stored in the line interface transmission buffer (S1403). At this time, the PPP connection identification ID to be added is a magic number indicating that the transfer data is not associated with the PPP connection.

With the above processing, the user terminal (101-
1-101-m) or the PPP frame transferred from the IP network (105) side is PPP terminated and
The P packet is transferred to the Web cache server compatible interface circuit (403). The IP packet is We
bCache server compatible interface circuit (403)
From, the Web cache server (112) that is the transmission destination
Is forwarded to IP network compatible protocol processing circuit (40
The protocol processing in 6) will be described below.

FIG. 15 shows a process for an IP packet stored in the line interface reception buffer (503) in the IP network protocol processing circuit (406). The IP packet is LAC (104) -LNS (10
7-1 to 107-n) are transferred within the L2TP connection.

The CPU (501) sends an IP packet and PP from the line interface reception buffer (503).
The P connection identification ID information is taken out (S150
1). However, the IP packet transferred from the IP network is P
It is not associated with the PP connection, and the PPP connection ID information is a magic number (dummy information) indicating that fact.

The L2TP frame is extracted by removing the IP header and the UDP header from the IP packet (S150).
2). An entry that matches the value of the tunnel ID field and session ID field in the L2TP header is found from either the user terminal information management table (509) or the ISP information management table (510) (S1503).
If an entry is found in the user terminal information management table, a PPP frame is extracted from the L2TP frame (S
1505) Adds the identification ID information of the PPP connection indicated by the entry, and transfers it to the access line network protocol processing circuit (402) (S1506).
If an entry is found in the ISP management information table, a PPP frame is extracted from the L2TP frame (S2).
1507), the identification information of the PPP connection indicated by the entry is added, and the packet is transferred to the Web cache server compatible protocol processing circuit (404) (S15).
08).

With the above processing, the IP network compatible protocol processing circuit (406) sends the Web server
The PPP frame including the HTTP response message toward the cache server (112) is transferred toward the Web cache server (112), and the other PPP frames are transferred toward the user terminals (101-1 to 101-m).

FIG. 16 shows an internal switch reception buffer (50) in the protocol processing circuit (406) corresponding to the IP network.
FIG. 6 is a diagram showing processing for a PPP frame stored in 6). The CPU (501) extracts, from the internal switch reception buffer (506), the PPP frame, the identification ID information of the PPP connection to which the PPP frame is transferred, and the internal switch transfer destination information (S1601). An entry having the same PPP connection ID is found from the user terminal information management table (509) and the ISP information management table (510) (S1602). The PPP frame is converted into an L2TP frame using the tunnel ID value and the session ID value of the L2TP connection indicated by the entry, and a UDP header and an IP header are added (S160).
3). A PPP connection identification ID is added to the extracted IP packet in the created IP packet and stored in the line interface transmission buffer (S1604).

By the above processing, the user terminal (101-
1-101-m) or a PPP frame transferred from the Web cache server (112) is inserted into a PPP connection set in an appropriate L2TP connection, and transferred to a designated destination. The protocol processing circuits (402, 404, and 406) perform the above-described processing, so that the LAC (104)
b. The cache server (111) is connected, and the IP network (11
The network load of 0) can be reduced. (Second Embodiment) A second embodiment of the present invention will be described below. The second embodiment is an embodiment in the case of a transparent system, and forcibly transfers Web traffic to a Web cache server in an ISP selection type IP network system. An example of the configuration of the entire network system using the gateway device according to the second embodiment as an LAC is shown in FIG. 1 as in the first embodiment.

First, the Web browser application running on the user terminal (101-1) transmits the Web content data of the Web server (111) installed on the Internet via the ISP network (108-1). A connection sequence from acquisition to display will be described.

FIG. 17 is a diagram for explaining a connection sequence until Web content data is displayed on a user terminal in the second embodiment. Unlike the connection sequence in the first embodiment (FIG. 3), an HTTP request message from a user terminal is sent out as an IP packet addressed to a Web server (1701). LAC (10
4) sets the destination IP address of the IP packet including the HTTP request message to the I
Rewrite the P address value and transfer it to the Web cache server (1702). Web cache server (11
In 2), the requested data is searched from the cache data, and if a hit is found, the data is transmitted to the user terminal as an HTTP response message (1703). If there is no hit, data is obtained from the Web server in place of the user terminal (1705-1710), and the HTTP response message is transmitted to the user terminal (170).
3). LAC uses HTT from Web cache server.
The source IP address of the IP packet containing the P response message is set to the IP of the Web server from which the user has requested data.
Rewrite to address value and send to user terminal (1
704). In the above sequence, the user terminal (1
01-1) is equivalent to a case where data is acquired by directly connecting to a Web server.

An example of the configuration of an access gateway system to which the present invention according to the second embodiment is applied is shown in FIG. 4 as in the first embodiment. However, the protocol processing in the access line network compatible protocol processing circuit (402) is different from that in the first embodiment.

Next, the protocol processing in the access line network compatible protocol processing circuit (402) in the second embodiment will be described. FIG. 18 is a diagram showing a configuration example of the access line network-compatible protocol processing circuit (402). In the second embodiment, an HTTP request message is stored in a memory (502) and a management table (1) is stored.
801) Configure. User terminal (101-1 to 101-
m) PP containing HTTP request message sent from
As will be described later, the P frame is sent to the access line network compatible protocol processing circuit (402) where the destination IP address of the internal IP packet is the IP address of the Web cache server.
The address value is rewritten and transferred to the Web cache server. Also, the HTTP response message from the Web server acquired by the Web cache server on behalf of the user terminal is transferred from the cache server to the user terminal. At this time, the source IP address is replaced with the destination IP address value rewritten first. Need to change. For this purpose, the HTTP request message management table (18
01) is arranged.

FIG. 19 is a diagram showing a configuration example of a table in the case where an HTTP request message is stored in a memory to form a management table (1801).

For the HTTP request message transmitted from the user terminal, the PPP connection ID of the PPP frame containing the message, the TCP (Transmission Co
ntrol Protocol) or UDP (User Datagram Protocol)
It is composed of a set of the source port number of l) and the destination IP address of the message.

Next, the LAC of the data transferred to the LAC
An internal flow will be described. FIG. 20 is a diagram illustrating the flow of data transferred to the LAC inside the LAC. The PPP frame transferred from the access line network side receives the access line network compatible protocol processing circuit (40).
In 2), the processing is sorted by the upper protocol.
If the upper layer protocol is PPP LCP or NCP, LCP and NCP processing are performed, respectively. If the upper layer protocol is IP, TCP /
Processing is further divided according to the destination port number of the UDP header. If the destination port number is 80 (HTTP well-known port number), after the destination IP address is rewritten to the IP address value of the Web cache server, P
After being subjected to PP termination processing, it is sent to the cache server. If the PPP upper layer protocol is not any of LCP, NCP and IP, and if the destination port number is not 80
The P packet is transmitted to a protocol processing circuit (50
6) and inserted into the appropriate L2TP connection.

IP packets transferred from the Web cache server are sorted according to the destination IP address. In the case of the IP address value of any user terminal,
The data including the HTTP response message is transferred to the access line network side, the source IP address field is rewritten to the IP address of the Web server, and then inserted into an appropriate PPP connection. If it is not the IP address of any user terminal, it is transferred to the IP network compatible protocol processing circuit (506) as data including an HTTP request message, and inserted into an appropriate L2TP connection.

The processing of the L2TP frame transferred from the IP network side is sorted by the transferred PPP connection. When the packet is transferred within the PPP connection set between the user terminal and the LNS, the packet is transmitted to the access line network side. When the packet is transferred within the PPP connection set between LAC and LNS, W
The data is transferred to the eb cache server side.

FIG. 21 is a diagram showing a process for a PPP frame stored in the line interface reception buffer (503) in the access line network compatible protocol processing circuit (402).

The CPU (501) sends a PPP frame and a P frame from the line interface reception buffer (503).
Identification I of the PPP connection to which the PP frame is transferred I
D is taken out (S2101). The protocol of the frame is identified by the protocol field of the PPP frame (S2102, S2103), and the LCP or NCP
, LCP packet processing and NCP packet processing are performed on the PPP frame. (S2110,
S2111).

The protocol of the PPP frame is identified (S2104), the IP is identified, and the upper layer protocol of the IP is identified (S2105).
The destination port number of P / UDP is identified (S210
6) If the destination port number is 80, which is a well-known port of HTTP, it is determined that the PPP frame is Web traffic, and the following processing is performed. That is, the connection identification ID of the PPP frame, TCP /
HTT for UDP source port number and destination IP address
After setting in the P request message management table (1801) (S2107), the destination IP address in the IP header is rewritten to the IP address of the Web cache server (S2108). Note that with the rewriting of the destination IP address, the header checksum of the IP header and the PPP
The FCS (Frame Check Sequence) of the frame is recalculated. The internal switch transmission buffer is added with the PPP connection identification ID information (702) for transferring the PPP frame and the internal switch transfer destination information (703) indicating that the transfer destination is the Web cache server compatible protocol processing circuit (404). Stored in (505) (S210
9), end the processing.

When the protocol of the PPP frame is not IP, the upper layer protocol is TCP or UDP even if it is IP.
Otherwise, if the destination port number is not 80 even if it is TCP / UDP, it is determined that the PPP frame is not Web traffic, and the PPP connection identification ID information (702) to be transferred and the transfer destination are the IP network compatible protocol processing. The internal switch transfer destination information (703) indicating the circuit (406) is added and stored in the internal switch transmission buffer (505) (S2112), and the process ends.

By the above processing, the user terminal (101-
1 to 101-m), the PPP frame including the HTTP request message transmitted from the Web cache server (1
In the direction 12), other PPP frames are sent to the IP network (10
5) Transfer in the direction.

FIG. 22 is a diagram showing a process for a PPP frame stored in the internal switch reception buffer (506) in the access line network compatible protocol processing circuit (402). The CPU (501) extracts the PPP frame, the PPP connection identification ID information to which the PPP frame is transferred, and the internal switch transfer destination information from the internal switch reception buffer (506) (S2201). P
PP connection identification ID and TCP in PPP frame
A search is made for an entry whose destination port number in the / UDP header matches the PPP connection identification ID and the source port number in the HTTP request message management table (1801) (1902). The destination IP address value of the entry,
The source IP address field of the IP packet in the PPP frame is rewritten (S2203). With this rewriting, the header checksum of the IP header and the FCS of the PPP frame are recalculated. PP
The P frame is added with the identification ID of the PPP connection and stored in the line interface transmission buffer (S220).
4), end the process.

According to the above processing, the PPP frame transferred from the Web cache server (112) or the IP network (105) side receives the PPP connection identification I.
The information is transferred to the access circuit network interface circuit (401) together with the D information. The access line network compatible interface circuit (401) converts the PPP frame transferred from the access line network compatible protocol processing circuit (402) into an appropriate P
It is inserted into the PP connection and transferred to the user terminal that is the destination. Protocol processing circuits (402, 404,
406) performs the above-described processing to obtain LA
By connecting the Web cache server (111) to C (104), the network load on the IP network (110) can be reduced.

In the first embodiment and the second embodiment, an IP address for an ISP is assigned to one Web cache server, and users of all ISPs use the same Web cache server. It has a form. A Web cache server may be installed for each ISP, and the user of each ISP may use the Web cache server for the ISP.

[0071]

According to the present invention, in an ISP selection type IP network system, it is possible to provide a gateway device capable of speeding up Web access and reducing a network band with a Web server.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a network system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a connection sequence when a user terminal acquires data from a Web server in an ISP selection type IP network system.

FIG. 3 shows an embodiment of the present invention in which the user terminal is We
It is a figure showing the connection sequence which acquires data from server b.

FIG. 4 is a diagram illustrating a configuration example of a gateway device.

FIG. 5 is a diagram illustrating a configuration example of a protocol processing circuit.

FIG. 6 is a diagram showing a format of data transferred between an interface circuit and a protocol processing circuit.

FIG. 7 is a diagram showing a format of data transferred between a protocol processing circuit and an internal switch.

FIG. 8 is a diagram showing a configuration of a user terminal information table.

FIG. 9 is a diagram showing a configuration of an ISP information table.

FIG. 10 is a diagram illustrating a flow of data transferred to the LAC.

FIG. 11 is a diagram showing a process for data stored in a line interface reception buffer in an access line network compatible protocol processing circuit.

FIG. 12 is a diagram showing a process for data stored in an internal switch reception buffer in the access line network protocol processing circuit.

FIG. 13 is a diagram illustrating a process for data stored in a line interface reception buffer in a Web cache server compatible protocol processing circuit.

FIG. 14 is a diagram illustrating a process for data stored in an internal switch reception buffer in a Web cache server compatible protocol processing circuit.

FIG. 15 is a diagram showing a process for data stored in a line interface reception buffer in an IP network compatible protocol processing circuit.

FIG. 16 is a diagram showing a process for data stored in an internal switch reception buffer in an IP network compatible protocol processing circuit.

FIG. 17 is a diagram showing an embodiment of the present invention, in which the user terminal is W
FIG. 7 is a diagram showing a connection sequence for acquiring data from an eb server.

FIG. 18 is a diagram illustrating a configuration example of a protocol processing circuit.

FIG. 19 is a diagram illustrating a configuration example of an HTTP request message management table.

FIG. 20 is a diagram illustrating the flow of data transferred to the LAC.

FIG. 21 is a diagram illustrating processing on data stored in a line interface reception buffer in an access line network compatible protocol processing circuit.

FIG. 22 is a diagram showing processing for data stored in an internal switch reception buffer in the access line network protocol processing circuit.

[Explanation of symbols]

 101-1 to 101-m User terminal 102-1 to 102-m Access line 103-1 to 103-m PPP connection 104 LAC 105 Regional IP network 106-1 to 106-n L2TP connection 107-1 to 107-n LNS 108-1 to 108-n ISP network 109-1 to 109-n Router 110 Internet 111 Web server 112 Web cache server 113 LAN 401 Access network compatible interface circuit 402 Access network compatible protocol processing circuit 403 Cache server compatible interface circuit 404 Cache server compatible protocol processing circuit 405 IP network compatible interface circuit 406 IP network compatible protocol processing circuit 407 Internal switch circuit 408 Device control circuit 409 Setting terminal 501 CPU 502 Memory 503 Line interface receive buffer 504 Line interface transmit buffer 505 Internal switch transmit buffer 506 Internal switch receive buffer 507 CP U-to-U communication interface circuit 508 Program 509 User terminal information management table 510 ISP information management table 601 Data 602 PPP connection ID header 701 Data 702 PPP connection ID header 703 Internal switch transfer destination information header 1801 HTTP request message management table

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Akinori Honda 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture F-term in Hitachi, Ltd. Communications Division 5K030 HA08 HC01 HD03 KA01 KA06

Claims (4)

[Claims] 1. A first network to which a user terminal is connected is connected via a second network to one of a plurality of third networks each accommodating an information providing terminal for providing information. A gateway device for connecting the first network and the second network, wherein the gateway device is connected to a cache terminal for storing data acquired from the information providing terminal. Determining means for determining a request content of a packet transmitted from the user terminal to the information providing terminal; and, if the result of the determination is that the data requested by the packet is in the cache terminal, the data is stored in the cache terminal. The data that was being sent to the user terminal, if not in the cache terminal, the A transfer unit configured to set a connection to the information providing terminal from the gateway device in the network of the second device and transfer information included in a packet from the user terminal through the connection, based on a request content from the user terminal. Data acquisition means for acquiring data from the information providing terminal and sending the acquired data to the cache terminal. 2. The user terminal sets the cache terminal as a proxy, and the determining unit determines destination information of a packet transmitted from the user terminal,
The gateway device according to claim 1, wherein the packet is transmitted to the cache terminal based on the destination information. 3. The gateway according to claim 1, wherein the determination unit rewrites destination information of a packet sent from a user terminal to the cache terminal and transmits the packet to the cache terminal. apparatus. 4. The connection set in the second network is a layer 2 tunneling protocol.
4. The gateway device according to claim 1, wherein the gateway device is a connection.