JP5767146B2 - Packet relay device - Google Patents

Description

  The present invention relates to a packet relay device capable of preferentially relaying response packets corresponding to request packets received later.

  In a computer network, a technique called QoS exists as a method of ensuring important communication relay performance.

As one of the methods for realizing QoS, there is a method of setting priorities called TOS value and DSCP value in the IP header. However, in this method, since the priority is determined by the transmitting terminal, the priority cannot be determined on the relay device side. Another method for realizing QoS should be prioritized on the relay device side. There is a method of setting communication conditions (a transmission source address, a destination address, a transmission source port number, a destination port number, a protocol type, etc.) in advance. However, since the communications performed by the user are diverse, it is difficult to set all of them in advance.

JP 2011-259014 A

  For example, when considering HTTP communication, the user's expectation is compared with HTTP communication for a user to browse a homepage (HP browsing) and HTTP communication for performing an operating system update (OS update) or the like in the background. (The background processing should be no problem no matter how long it takes, and HP browsing should be resolved immediately).

  For example, in FIG. 11, the terminal 2 transmits an OS update request packet to the server 3 (S101). The server 3 sequentially transmits a plurality of response packets to the terminal 2 (S102). The terminal 2 also sequentially transmits a plurality of request packets to the server for HP browsing (S111). The server 3 transmits a response packet for each request packet to the terminal 2 (S112). In such a case, priority is given to the HP browsing response packet (S112) over the OS update response packet (S102).

  However, the existing QoS means requires prior preparation such as setting the priority on the transmission terminal side or setting communication to be prioritized in the relay apparatus in advance.

  To improve the user experience in Web browsing as described above, it is a problem to prioritize automatically.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a packet relay apparatus capable of preferentially relaying a response packet corresponding to a request packet received later.

  In order to solve the above problems, a packet relay device according to the present invention is a packet relay device that relays a packet between a terminal and a server, and each response transmitted from the server and received by the packet relay device. For the packet, the source address, destination address, source port number and destination port number set in the response packet, and the timing at which the packet relay device receives the request packet from the terminal corresponding to the response packet are shown. A priority information storage unit that stores timing information and priority information including a priority when transmitting a response packet from the packet relay apparatus to the terminal, and a request packet for a request from the terminal to the server is the packet If received by the relay device, the source address set in the response packet sent from the server , Destination address, source port number and destination port number, timing information indicating the timing at which the request packet is received, and an initial value of priority when the response packet is transmitted from the packet relay device to the terminal. If a response packet from a server is received by the packet relay device, a priority information registration unit that generates priority information including and stores the priority information in the priority information storage unit, and transmits in the response packet from the priority information storage unit Search for priority information including source address, destination address, source port number and destination port number that is the same as the source address, destination address, source port number, and destination port number. A priority control unit that controls transmission so that the higher the priority is, the priority information including the priority Timing elapsed time is long enough the priority from the corresponding timing information is characterized by comprising a priority information updating unit which updates the priority to be lower.

  For example, the packet relay device, for each request packet received by the packet relay device, a LAN-side source address that is a source address in the request packet, and a LAN-side destination address that is a destination address in the request packet The LAN side source port number, which is the source port number in the request packet, and the LAN side destination port number, which is the destination port number in the request packet, and the packet transmitted to the server are transmitted from the server. WAN side source address that is the source address set in the response packet, WAN side destination address that is the destination address set in the response packet, and WAN side that is the source port number set in the response packet Source port number and destination port number set in the response packet A connection tracking information storage unit that stores connection tracking information including a WAN destination port number, and the priority information registration unit receives a request packet for a request from a terminal to a server at the packet relay device If so, connection tracking information including the same LAN side source address, LAN side destination address and LAN side destination port number as the source address, destination address and destination port number in the request packet in the connection tracking information storage unit And the WAN side source address, WAN side destination address, WAN side source port number, and WAN side destination in the connection tracking information from the priority information storage unit for each one or more of the searched connection tracking information Priority information including the same source address, destination address, source port number, and destination port number as the port number Find and timing information in the priority information, to change the timing information indicating a timing of receiving the request packet by the packet relay apparatus.

  For example, the packet relay device includes a target information storage unit that stores target information indicating a target request packet corresponding to the priority information stored in the priority information storage unit, and the priority information registration unit is When a request packet for a request to the server is received by the packet relay device, it is determined whether the request packet corresponds to target information in the target information storage unit, and the request packet is If it corresponds to the target information, priority information is generated and stored in the priority information storage unit.

  According to the packet relay device of the present invention, a response packet corresponding to a request packet received later can be relayed preferentially.

It is a block diagram which shows schematic structure of the packet relay apparatus which concerns on this Embodiment. It is a figure which shows an example of a structure and content (data) of the priority information storage part. It is a figure which shows an example of a structure and content (data) of the connection tracking information storage part. It is a figure for demonstrating the specific example of priority information and connection tracking information. It is a figure which shows an example of a structure and the content (data) of the target information storage part. It is a flowchart regarding the process at the time of receiving a packet. It is a flowchart which shows the process of step S9 in detail. It is a flowchart which shows the process of step S33 in detail. It is a flowchart regarding the process at the time of receiving a response packet. It is a figure which shows the specific example of the transition of a priority. It is a sequence diagram which shows the transmission timing of the request packet and response packet in the past.

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

FIG. 1 is a block diagram showing a schematic configuration of the packet relay apparatus according to the present embodiment.
The packet relay device 1 is connected to a terminal (such as a personal computer) 2 and a server 3 via a communication line. Although not shown, the packet relay device 1 is connected to a plurality of terminals 2 and a plurality of servers 3. The terminal 2 is used as a generic term for terminals and an individual terminal. The server 3 is used as a general term for servers and an individual server.

  The packet relay device 1 includes a packet relay unit 10 that relays a packet between the terminal 2 and the server 3, a priority information storage unit 11 that stores priority information for performing priority control of the packet, and priority information as priority information. Priority information registration unit 12 to be stored in the storage unit 11, priority information update unit 13 for updating the priority information in the priority information storage unit 11, and priority control for performing packet priority control based on the priority information in the priority information storage unit 11 Unit 14, a connection tracking information storage unit 15 in which information (connection tracking information) related to NAT conversion is stored, and a target information storage unit 16 in which target information indicating a target of priority control is stored.

FIG. 2 is a diagram illustrating an example of the configuration and contents (data) of the priority information storage unit 11.
In the priority information storage unit 11, for each response packet transmitted from the server 3 and received by the packet relay device 1, a source address 101, a destination address 102, a source port number 103 and a destination port set in the response packet Number 104, timing information 105 indicating the timing at which the packet relay device 1 received the request packet from the terminal 2 corresponding to the response packet, and priority when the response packet is transmitted from the packet relay device 1 to the terminal 2 Priority information including 106 is stored.

FIG. 3 is a diagram illustrating an example of the configuration and contents (data) of the connection tracking information storage unit 15.
For each request packet transmitted from the terminal 2 and received by the packet relay device 1, the connection tracking information storage unit 15 includes a LAN-side source address 201 that is a source address in the request packet, and a destination address in the request packet. LAN side destination address 202, LAN side source port number 203 that is the source port number in the request packet, LAN side destination port number 204 that is the destination port number in the request packet, and the request transmitted to the server A WAN side source address 301 that is a source address set in a response packet transmitted from the server to a packet or the like, a WAN side destination address 302 that is a destination address set in the response packet, and a response packet The WAN-side source port number 303, which is the source port number, and the response Connection tracking information including the WAN side destination port number 304 is the destination port number set in Tsu bets are stored.

FIG. 4 is a diagram for explaining a specific example of priority information and connection tracking information.
For example, from the terminal 2 (terminal 2A) to which the local address “192.168.1.2” is assigned, the source address “192.168.1.2”, which is the local address, and the server 3 (server 3A) To browse (HP browsing) a request packet including a destination address “301.302.303.304” which is an assigned global address, a transmission source port number “10000”, and a destination port number “80”, that is, a certain homepage. Is transmitted to the packet relay device 1, the connection tracking information storage unit 15 stores the LAN side source address “192.168.1.2” and the LAN side destination address “301.302.303.304”. , LAN side source port number “10000” and LAN side destination port number “80”, and WAN side Source address "301.302.303.304",
Connection tracking information including the WAN-side destination address “10.20.30.40”, the WAN-side source port number “80”, and the WAN-side destination port number “10001” is stored (see FIG. 3).

  The priority information storage unit 11 includes a priority including a transmission source address “301.302.303.304”, a destination address “10.20.30.40”, a transmission source port number “80”, and a destination port number “10001”. Information is stored (see FIG. 2).

  Here, the address “10.20.30.40” is the global address of the packet relay device 1. The same applies to the following examples.

  The port number “10001” is a port number assigned to the set of the LAN side source address “192.168.1.2” and the LAN side source port number “10000”.

  Further, from the terminal 2A, a request packet including a source address “192.168.1.2”, a destination address “301.302.303.304”, a source port number “10001”, and a destination port number “80”, That is, when a second request packet for browsing the same homepage (HP browsing) is transmitted to the packet relay device 1, the LAN-side transmission source address “192.168.1.2” is stored in the connection tracking information storage unit 15. , LAN side destination address “301.302.303.304”, LAN side source port number “10001” and LAN side destination port number “80”, and WAN side source address “301.302.303.304” , WAN side destination address “10.20.30.40”, WAN side source port number “80” and WAN side destination port Connection tracking information including the port number "10002" is stored (see Figure 3).

  The priority information storage unit 11 includes a priority including a source address “301.302.303.304”, a destination address “10.20.30.40”, a source port number “80”, and a destination port number “10002”. Information is stored (see FIG. 2).

  For example, from the terminal 2A, the source address “192.168.1.2”, the destination address “401.402.403.404” which is a global address assigned to another server 3 (server 3B), the source port When a request packet including the number “20000” and the destination port number “12345” is transmitted to the packet relay device 1, the connection tracking information storage unit 15 stores the LAN-side source address “192.168.1.2”, the LAN Side destination address “401.402.403.404”, LAN side source port number “20000”, LAN side destination port number “12345”, WAN side source address “401.402.403.404”, WAN side Destination address “10.20.30.40”, WAN-side source port number “12345” and W Connection tracking information including N-side and destination port number "10004" is stored (see Figure 3).

  Further, from the terminal 2 (terminal 2B) to which the local address “192.168.1.3” is assigned, the source address “192.168.1.3”, which is the local address, and the server 3 (server 3C). A request packet including a destination address “101.102.103.104” that is an assigned global address, a transmission source port number “1000”, and a destination port number “8080”, that is, a different home page is browsed (HP browsing). When the request packet for transmission is transmitted to the packet relay device 1, the connection tracking information storage unit 15 stores the LAN side source address “192.168.1.3” and the LAN side destination address “101.102.103.104”. ”, LAN-side source port number“ 1000 ”, LAN-side destination port number“ 8080 ”, and WAN Connection tracking including source address “101.102.103.104”, WAN side destination address “10.20.30.40”, WAN side source port number “8080” and WAN side destination port number “10003” Information is stored (see FIG. 3).

  The priority information storage unit 11 includes a priority including a transmission source address “101.102.103.104”, a destination address “10.20.30.40”, a transmission source port number “8080”, and a destination port number “10003”. Information is stored (see FIG. 2).

  Here, the port number “10003” is a port number assigned to the set of the LAN side source address “192.168.1.3” and the LAN side source port number “1000”.

  Further, from the terminal 2 (terminal 2C) to which the global address “10.20.30.41” is assigned, to the source address “10.20.30.41” that is the global address and the server 3 (server 3D). When a request packet including a destination address “201.202.203.204” that is an assigned global address, a transmission source port number “10000”, and a destination port number “10080” is transmitted to the packet relay device 1, connection tracking information The storage unit 15 includes a LAN-side source address “10.20.30.41”, a LAN-side destination address “201.202.203.204”, a LAN-side source port number “10000”, and a LAN-side destination port number. “10080”, WAN-side source address “201.202.203.204”, W N-side destination address "10.20.30.41", connection tracking information including the WAN side transmission source port number "10080" and WAN side destination port number "10000" is stored (see Figure 3).

  The priority information storage unit 11 includes a priority including a source address “201.202.203.204”, a destination address “10.20.30.41”, a source port number “10080”, and a destination port number “10000”. Information is stored (see FIG. 2).

  Further, a request packet including a source address “10.20.30.41”, a destination address “201.202.203.204”, a source port number “10001”, and a destination port number “10080” from the terminal 2C, That is, when the second request packet for browsing the same homepage (HP browsing) is transmitted to the packet relay device 1, the connection tracking information storage unit 15 stores the LAN side source address “201.202.203.204”. LAN side destination address “10.20.30.41”, LAN side source port number “10001” and LAN side destination port number “10080”, WAN side source address “201.202.203.204”, WAN-side destination address “10.20.30.41”, WAN-side source port number “10080” and Connection tracking information including the WAN side destination port number "10001" is stored (see Figure 3).

FIG. 5 is a diagram illustrating an example of the configuration and contents (data) of the target information storage unit 16.
The target information storage unit 16 stores target information indicating a target request packet corresponding to the priority information stored in the priority information storage unit 11.

  Each target information is included in the request packet, source address information 401 indicating the condition of the source address to be included in the request packet, destination address information 402 indicating the condition of the destination address to be included in the request packet, and the request packet. It includes transmission source port number information 403 indicating the conditions of the transmission source port number to be processed, and destination port number information 404 indicating the conditions of the destination port number to be included in the request packet.

  As the source address information 401, the source address itself or the word “any” indicating unconditional is set.

  As the destination address information 402, the destination address itself or the word “any” indicating unconditional is set.

  As the source port number information 403, the source port number itself or the word “any” indicating unconditional is set.

  As the destination port number information 404, the destination port number itself or the word “any” indicating unconditional is set.

FIG. 6 is a flowchart relating to processing when a packet is received.
First, the priority information registration unit 12 determines whether the protocol set in the received packet is TCP (S1).

  Since the protocol of packets (request packets) for HP browsing and OS update is often TCP, a TCP packet is selected here.

  If the protocol is TCP (S1: YES), the same LAN side source address 201, LAN side destination address 202, LAN side source port as the source address, destination address, source port number and destination port number in the packet It is determined whether or not the connection tracking information including the number 203 and the LAN side destination port number 204 is in the connection tracking information storage unit 15 (S2).

  If there is no corresponding connection tracking information (S2: NO), the connection tracking information storage unit 15 is sent to the LAN side source address 201 that is the same as the source address, destination address, source port number, and destination port number in the packet. LAN-side destination address 202, LAN-side source port number 203 and LAN-side destination port number 204, and a source address in a response packet sent from the server to a packet that is NAT-converted from the packet and sent to the server , Destination tracking information including destination address, source port number and WAN side source address 301, WAN side destination address 302, WAN side source port number 303, and WAN side destination port number 304 are newly stored. (S3).

  If it is determined YES in step S2 or if the processing in step S3 is completed, the priority information registration unit 12 determines whether the packet size is equal to or larger than a preset threshold value (S4).

  Packets (request packets) for HP browsing and OS update are relatively large sized packets, and on the other hand, relatively small sized packets that are not such request packets also flow through the network. Then, the former packet (request packet) is selected.

  If the packet size is equal to or larger than the threshold (S4: YES), the priority information registration unit 12 sends the source address, the destination address, the source port number, and the source address corresponding to the destination port number in the packet (request packet). It is determined whether or not the target information including the information 401, the destination address information 402, the transmission source port number information 403, and the destination port number information 404 exists in the target information storage unit 16 (S5).

  When the target information storage unit 16 shown in FIG. 5 is used, the source address, destination address, source port number, and destination port number in the request packet are 192.168.1.2, 301.302.303.304. If it is 10,000, 80, since the first target information from the top corresponds, it is determined that there is the corresponding target information (S5: YES).

  If the source address, destination address, source port number and destination port number in the request packet are 192.168.1.2, 301.302.303.304, 10001, 80, the first from the top Since the target information is applicable, it is determined that the target information exists (S5: YES).

  If the source address, destination address, source port number, and destination port number in the request packet are 192.168.1.3, 101.102.103.104, 1000, 8080, the second from the top Since the target information is applicable, it is determined that the target information exists (S5: YES).

  If the source address, destination address, source port number and destination port number in the request packet are 10.20.30.401, 201.202.203.204, 10000, and 10080, the third from the top Since the target information is applicable, it is determined that the target information exists (S5: YES).

  On the other hand, if the source address, destination address, source port number, and destination port number in the request packet are 192.168.1.2, 401.402.403.404, 20000, 12345, any target information is applicable. Therefore, it is determined that there is no corresponding target information (S5: NO).

  In addition, if the source address, destination address, source port number, and destination port number in the request packet are 10.20.30.401, 201.202.203.204, 10001, 10080, any target information is applicable. Therefore, it is determined that there is no corresponding target information (S5: NO).

  The priority information registration unit 12 determines YES in step S5 and, if a predetermined condition is satisfied, generates new priority information, stores it in the priority information storage unit 11, and updates the priority information satisfying the predetermined condition. (S9).

  On the other hand, if the packet relay unit 10 determines NO in any of steps S1, S4, and S5, or if the processing in step S9 is completed, the packet relay unit 10 sends the request packet, particularly from the terminal 2 to which the local address is assigned. For the request packet, the source address and the source port number are converted into the global address of the packet relay device 1 and the newly assigned source port number, and transmitted to the server 3 (S11), and the process ends.

FIG. 7 is a flowchart showing in detail the process of step S9.
First, the priority information registration unit 12 sends from the connection tracking information storage unit 15 the same LAN side source address 201 and LAN side destination address 202 as the source address, destination address, source port number and destination port number in the request packet. Then, connection tracking information (connection tracking information generated in step S3) including the LAN-side source port number 203 and the LAN-side destination port number 204 is retrieved, and the WAN-side source address 301 and the WAN-side destination address are searched from the connection tracking information. 302, WAN side transmission source port number 303 and WAN side destination port number 304 are read (S21).

  Next, the priority information registration unit 12 transmits the same source as the read WAN side source address 301, WAN side destination address 302, WAN side source port number 303, and WAN side destination port number 304 in the priority information storage unit 11. It is determined whether there is priority information including address 101, destination address 102, source port number 103, and destination port number 104 (S23).

  If it is determined NO in step S23, the priority information registration unit 12 has the same source as the read WAN side source address 301, WAN side destination address 302, WAN side source port number 303, and WAN side destination port number 304. Address 101, destination address 102, source port number 103 and destination port number 104, timing information indicating the timing of receiving the request packet (for example, a numerical value indicating the current time), and initial priority value (for example, a positive integer “10”) ”) Is generated and stored in the priority information storage unit 11 (S25).

  If it is determined YES in step S23, or if the processing of step S25 is completed, the priority information registration unit 12 causes the connection tracking information storage unit 15 to transmit the source address, the destination address, and the destination port number in the request packet. Connection tracking information including the same LAN-side source address 201, LAN-side destination address 202, and LAN-side destination port number 204 is searched (S27).

  Next, the priority information registration unit 12 sends the WAN side transmission source address 301, the WAN side destination address 302, and the WAN side transmission in the connection tracking information from the priority information storage unit 11 for each one or more of the retrieved connection tracking information. Priority information including the same source address 101, destination address 102, source port number 103, and destination port number 104 as the source port number 303 and WAN side destination port number 304 is searched (S29).

  Next, the priority information registration unit 12 uses the timing information 105 in the retrieved priority information as the timing information 105 (for example, the timing information 105 in the priority information generated in step S25) indicating the timing at which the request packet is received. The timing information is changed to the same timing information 105) (S31).

  Next, the priority information update part 13 updates the priority in each priority information of the priority information storage part 11 (S33), and finishes a process.

FIG. 8 is a flowchart showing in detail the process of step S33.
The priority information update unit 13 selects priority information that has not been updated from the priority information storage unit 11, and reads the timing information 105 (S41).

  Next, the priority information update unit 13 sets a time interval t between the timing indicated by the timing information 105 and the current time, and a quotient value obtained by dividing the time interval t by a predetermined time length T [ t / T] is calculated (S43).

  Next, the priority information update unit 13 subtracts the value [t / T] from the initial priority value (P in the figure) set in step S25 (S45).

  Next, the priority information updating unit 13 determines whether or not the value p after subtraction is greater than 0 (S47). If the value p is greater than 0 (S47: YES), the priority information update unit 13 includes the priority information selected in step S41. Is replaced with the same priority 106 as the value p (S49).

  For example, for the priority 106 in the priority information that is not priority information including the timing information 105 changed in step S31, the priority 106 after replacement is the same as the priority 106 before replacement or is higher than the priority 106 before replacement. Becomes smaller.

  On the other hand, for the priority 106 in the priority information including the timing information 105 changed in step S31, the time interval t is very short, so the priority 106 after replacement is the same value as the initial value of the priority 106. . Therefore, even if the priority 106 is in the priority information corresponding to the request packet received in the past, the priority information for which the timing information 105 has been updated in step S31 is greater than the priority 106 before replacement. There is. A specific example of this will be described with reference to FIG.

  On the other hand, if the value p is 0 or less (S47: NO), the priority information update unit 13 deletes the priority information selected in step S41 from the priority information storage unit 11 (S51).

  The priority information update unit 13 ends the process of step S49 or S51. If priority information that has not been updated in this way is present in the priority information storage unit 11 (S53: YES), the priority information update unit 13 returns to step S41, and updates it. If there is no priority information in the priority information storage unit 11 (S53: NO), the process ends.

  In addition, the priority information update part 13 performs the process of FIG. 8 regularly, for example. As a result, the priority 106 decreases with time.

FIG. 9 is a flowchart relating to processing when a response packet is received.
The priority control unit 14 first determines whether or not the protocol set in the received response packet is TCP (S61).

  Since the protocol of the request packet is limited to TCP, here, the protocol of the response packet is also limited to TCP.

  If the protocol is not TCP (S61: NO), the packet relay unit 10 performs appropriate NAT conversion according to the protocol and transmits the response packet to the terminal 2 having the destination address in the response packet after NAT conversion. (S62), and the process ends.

  On the other hand, if the protocol is TCP (S61: YES), the priority control unit 14 in the priority information storage unit 11 has the same source address as the source address, destination address, source port number, and destination port number in the response packet. 101, it is determined whether there is priority information including the destination address 102, the source port number 103, and the destination port number 104 (S63).

  The priority control unit 14 gives the lowest priority (for example, 0) for a response packet without such priority information (S63: NO) (S65), while for a response packet with priority information (S63: YES). ), The same priority as the priority 106 in the priority information is given (S67).

  Next, when there are a plurality of response packets with the same priority, in particular, in order from the response packet with the highest priority from the buffer in which the response packet is once held, the packet relay unit 10 The response packet held in the buffer earliest is taken out, and the source address, destination address, source port number, and destination port number in the response packet are the same as the WAN side source address 301, WAN from the connection tracking information storage unit 15 Side connection address 302, WAN side source port number 303 and WAN side destination port number 304 are searched for connection tracking information, and the source address, destination address, source port number and destination port number in the response packet are traced. LAN-side destination address 202, LAN-side source address 201 in the information, LAN It replaced the same as the destination port number 204 and the LAN-side transmission source port number 203, and transmits a response packet to the terminal 2 with the address of the LAN side source address 201 (S69), thus ending the process.

FIG. 10 is a diagram illustrating a specific example of priority transition.
For example, at time t1 in FIG. 10A, an OS update request packet is transmitted from the terminal, and the packet relay apparatus 1 receives the request packet. At time t1, priority information is generated based on this request packet, and the priority 106 (referred to as priority T1) in the priority information decreases with time.

  For example, at time t2 after time t1, a request packet for browsing a certain homepage (HP browsing) is transmitted from the same terminal, and the packet relay apparatus 1 receives the request packet. At time t2, priority information is generated based on this request packet, and the priority level 106 (referred to as priority level T2) in the priority information decreases with time.

  For example, at time t3 after time t2, it is assumed that the response packet to the OS update request packet and the response packet to the HP browsing request packet are not yet transmitted to the terminal and are held in the packet relay device 1. . In this case, since the priority T2 is higher than the priority T1, a response packet to the request packet for browsing the HP is transmitted to the terminal, and then a response packet to the OS update request packet is transmitted.

  Further, request packets for HP browsing are sequentially received thereafter, but the priority corresponding to these request packets is always higher than the priority T1 corresponding to the OS update request packet. However, the response packet for the request packet for browsing the HP is transmitted to the terminal earlier than the response packet for the request packet for OS update.

  On the other hand, as shown in FIG. 10B, when the time t1 is later than the time t2, the priority T1 is initially higher than the priority T2. However, at time t2 ′ after time t1, the second request packet for browsing the same HP (the same source address, destination address and destination address as the source address, destination address and destination port number in the first request packet) (Including the destination port number) is received, the timing information in the priority information including the priority T2 corresponding to the first request packet is changed to timing information indicating the reception timing of the second request packet ( FIG. 7: Step S31), thereby returning the priority T2 corresponding to the first request packet to the initial value (FIG. 8: Step S49).

  That is, the priority T2 corresponding to the first request packet and the priority T2 'corresponding to the second request packet match each other, and decrease with time.

  Thus, for example, when a response packet for the OS update request packet and a response packet for the first request packet for HP browsing are held at time t3 after time t2 ′, the priority is higher than the priority T1. Since T2 is higher, the response packet for the first request packet for HP browsing is transmitted to the terminal earlier than the response packet for the OS update request packet.

  Further, the request packets for HP browsing are received thereafter, but the priority corresponding to these request packets is always higher than the priority T1 corresponding to the OS update request packet. The response packet for the request packet for browsing the HP is transmitted to the terminal earlier than the response packet for the request packet for OS update.

  As described above, the packet relay device 1 according to the present embodiment is a packet relay device that relays packets between the terminal 2 and the server 3, and is transmitted from the server and received by the packet relay device 1. For the response packet, the packet relay apparatus 1 transmits the source address 101, the destination address 102, the source port number 103 and the destination port number 104 set in the response packet, and the request packet from the terminal 2 corresponding to the response packet. Timing information 105 indicating the received timing, priority information storage unit 11 storing priority information including priority 106 when transmitting a response packet from the packet relay apparatus 1 to the terminal 2, and the terminal 2 to the server 3 If the packet relay device 1 receives a request packet for requesting a response, a response packet transmitted from the server 3 Source address 101, destination address 102, source port number 103 and destination port number 104, timing information 105 indicating the timing of receiving the request packet, and response packet from the packet relay device 1 to the terminal 2 Priority information including the initial value of the priority 106 when transmitting the message is generated and stored in the priority information storage unit 11 (FIG. 7: S25), and the priority information registration unit 12 and the packet relay apparatus 1 receive from the server 3 If the response packet is received, the source information 101, the destination address 102, and the source port number 103 that are the same as the source address, destination address, source port number, and destination port number in the response packet are received from the priority information storage unit 11. And priority information including the destination port number 104 is searched (FIG. 9: S63), and the terminal 2 is responded. Control is performed so that the packet is transmitted earlier as the priority 106 in the priority information is higher (FIG. 9: S69), and the time elapses from the timing corresponding to the timing information 105 in the priority information including the priority 106. By adding the priority information updating unit 13 that updates the priority 106 so that the priority 106 becomes lower as the time spent increases (FIG. 8: S49), the priority of the request packet received later becomes higher, Accordingly, it is possible to preferentially relay a response packet corresponding to a request packet received later.

  For example, for the purpose of giving priority to HTTP communication for HP browsing over OS update, the most direct solution is to analyze the contents of the response packet and give priority to HTTP communication triggered by the user. "Yes" is considered. In this embodiment, the indirect method of “monitoring the request packet and giving priority to the response packet” is selected without using the direct method. The reason is that when the response packet is analyzed, the response packet relay speed is reduced by the analysis process itself. On the other hand, the request packet monitored in the present embodiment is an upstream stream, and the relay performance of the upstream stream does not have a significant influence on the user. This is the reason why the uplink request is monitored as a problem solving method.

  The packet relay device 1 also transmits, for each request packet received by the packet relay device 1, a LAN-side source address 201 that is a source address in the request packet, and a LAN-side destination that is a destination address in the request packet. Address 202, LAN-side source port number 203 that is a source port number in the request packet, LAN-side destination port number 204 that is a destination port number in the request packet, and a packet transmitted to the server WAN side source address 301 which is a source address set in the response packet transmitted from the server, WAN side destination address 302 which is a destination address set in the response packet, source set in the response packet WAN side transmission source port number 303 which is a port number and A connection tracking information storage unit 15 that stores connection tracking information including the WAN side destination port number 304 that is a destination port number set in the answer packet is provided. The priority information registration unit 12 receives the request packet from the packet relay device 1. In the connection tracking information storage unit 15, the same LAN side source address 201, LAN side destination address 202 and LAN side destination port number 204 as the source address, destination address and destination port number in the request packet are received. (FIG. 7: S27), and for each one or more of the searched connection tracking information, the WAN side transmission source address 301 and the WAN side destination address in the connection tracking information are retrieved from the priority information storage unit 11. 302, the same source address as the WAN side source port number 303 and the WAN side destination port number 304 101, the priority information including the destination address 102, the source port number 103 and the destination port number 104 is searched (FIG. 7: S29), and the packet relay apparatus 1 receives the request packet for the timing information 105 in the priority information. Since the timing information 105 is changed to the timing information 105 (FIG. 7: S31), the response packet corresponding to the request packet received earlier (at time t2) is the same as shown in FIG. 10B. When a request packet including the same destination port number for the same server 3 is received from the terminal 2 (at time t2 ′), the priority T2 corresponding to the previously received request packet returns to the initial value, so the priority T2 Becomes higher than the priority T1 corresponding to the request packet received later (at time t1). Therefore, the response packet corresponding to the request packet including the same destination port number from the same terminal 2 to the same server 3 is transmitted to the terminal 2 earlier than the response packet corresponding to the request packet received later (at time t1). (Time t3). As a result, when many request packets including the same destination port number for the same server 3 are transmitted from the same terminal 2 such as HP browsing, all response packets corresponding to these request packets are preferentially transmitted. be able to.

  The packet relay device 1 further includes a target information storage unit 16 in which target information indicating a target request packet corresponding to the priority information stored in the priority information storage unit 11 is stored. It is determined whether or not the packet corresponds to the target information in the target information storage unit 16 (FIG. 6: S5). If the request packet corresponds to the target information (S5: YES), the priority information is set. Since it is generated and stored in the priority information storage unit 11 (FIG. 7: S25), priority control can be performed only for the response packet corresponding to the target request packet.

DESCRIPTION OF SYMBOLS 1 Packet relay apparatus 2, 2A, 2B, 2C terminal 3, 3A, 3C, 3D server 10 Packet relay part 11 Priority information storage part 12 Priority information registration part 13 Priority information update part 14 Priority control part 15 Connection tracking information storage part 16 Target information storage unit 101 Source address 102 Destination address 103 Source port number 104 Destination port number 105 Destination port number 105 Timing information 106 Priority 201 LAN side source address 202 LAN side destination address 203 LAN side source port number 204 LAN side destination port number 301 WAN side source address 302 WAN side destination address 303 WAN side source port number 304 WAN side destination port number 401 Source address information 402 Destination address information 403 Source port number information 404 Destination port number information

Claims (3)

A packet relay device that relays packets between a terminal and a server,
For each response packet transmitted from the server and received by the packet relay device, a source address, a destination address, a source port number and a destination port number set in the response packet, and a terminal corresponding to the response packet A priority information storage unit for storing timing information indicating a timing at which the packet relay apparatus receives a request packet from the packet, and priority information including a priority when a response packet is transmitted from the packet relay apparatus to the terminal; ,
If a request packet for a request from a terminal to a server is received by the packet relay device, a source address, a destination address, a source port number, and a destination port number set in a response packet transmitted from the server Generating priority information including timing information indicating the timing at which the request packet is received and an initial value of priority when the response packet is transmitted from the packet relay apparatus to the terminal, and storing the priority information in the priority information storage unit A priority information registration unit to be stored;
When a response packet from the server is received by the packet relay device, the same source address, destination as the source address, destination address, source port number, and destination port number in the response packet from the priority information storage unit A priority control unit that searches for priority information including an address, a source port number, and a destination port number, and controls the terminal to transmit a response packet earlier as the priority in the priority information is higher;
A priority information updating unit that updates the priority so that the priority decreases as the time elapsed from the timing corresponding to the timing information in the priority information including the priority increases. . For each request packet received by the packet relay device, a LAN-side source address that is a source address in the request packet, a LAN-side destination address that is a destination address in the request packet, and a source in the request packet The LAN side source port number that is the port number, the LAN side destination port number that is the destination port number in the request packet, and the response packet sent from the server to the packet sent to the server WAN-side source address that is a source address, WAN-side destination address that is a destination address set in the response packet, WAN-side source port number that is a source port number set in the response packet, and the response packet WAN-side destination port number that is the destination port number set in Connection tracking information including comprises a connection tracking information storage unit to be stored,
The priority information registration unit
If a request packet for a request from a terminal to a server is received by the packet relay device, the connection tracking information storage unit transmits the same LAN side as the source address, destination address, and destination port number in the request packet. Search connection tracking information including original address, LAN side destination address and LAN side destination port number,
For one or more pieces of retrieved connection tracking information, the same as the WAN side source address, WAN side destination address, WAN side source port number and WAN side destination port number in the connection tracking information from the priority information storage unit Search for priority information including source address, destination address, source port number and destination port number, and change timing information in the priority information to timing information indicating the timing at which the packet relay device received the request packet. The packet relay device according to claim 1, wherein: A target information storage unit that stores target information indicating a target request packet corresponding to the priority information stored in the priority information storage unit;
The priority information registration unit
If a request packet for a request from the terminal to the server is received by the packet relay device, it is determined whether the request packet corresponds to the target information in the target information storage unit, and the request packet The packet relay apparatus according to claim 1 or 2, wherein priority information is generated and stored in the priority information storage unit if the information corresponds to the target information.

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