JP2009081595A - Packet data relay apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the overflow of a reception buffer memory, to reduce the number of times of retransmission for packet discard in TCP communication, and to improve the speed performance of the TCP communication, with respect to a packet data relay apparatus. <P>SOLUTION: Packet data inputted from a reception port to which a server terminal or the like is connected are stored in the reception buffer memories 1-1, 1-2 and 1-3, and then the packet data are sent out from the reception buffer memories 1-1, 1-2 and 1-3 to a transmission port to which a client terminal or the like is connected. The reception rate of each reception port is monitored in a reception rate monitoring part 1-4, and the memory region of the reception buffer memory (reception buffer memory 1-2, for instance) of the reception port wherein the degree of congestion is low and the reception buffer memory (reception buffer memory 1-3, for instance) of an unused port is allocated to the reception buffer memory (reception buffer memory 1-1, for instance) of the reception port wherein the degree of the congestion is high. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a packet data relay device, and more specifically, after temporarily storing packet data received from an opposite device in a reception buffer memory corresponding to a reception port, the packet data is read from the reception buffer memory and another opposite data is received. The present invention relates to a relay device that relays to a device.

  FIG. 6 shows an example of a packet data relay sequence via a relay device used in the Internet or the like. As shown in the figure, a client terminal 6-1 such as a personal computer that receives a communication service such as the Internet sends a packet having a set window size to a server terminal 6-3 via a relay device 6-2 such as a router. Request transmission of data group.

  The server terminal 6-3 that has received the request transmits a packet data group having the requested setting window size to the client terminal 6-1 via the relay device 6-2. The client terminal 6-1 reports normal reception of the packet data group to the server terminal 6-3. Then, the server terminal 6-3 transmits the next packet data group to the client terminal 6-1 via the relay device 6-2. The above sequence is repeated, and the packet data group is transmitted from the server terminal 6-3 to the client terminal 6-1 via the relay device 6-2.

  In TCP (Transmission Control Protocol) communication represented by the Internet as described above, the size of the reception buffer memory provided in the relay device 6-2 such as a LAN (Local Area Network) device, and the client terminal 6-1 The TCP communication speed may decrease due to the relationship with the window size of the packet data group requested to be transmitted to the server terminal 6-3 side.

  The main cause is that the reception buffer memory overflows in the packet data group due to a mismatch between the window size used in the client terminal 6-1 and the size of the reception buffer memory of the relay device 6-2. 1 may not be able to normally receive the packet data group.

  In handshake type communication such as TCP communication, the server terminal 6-3 confirms that the client terminal 6-1 has successfully received the packet data transmitted by the server terminal 6-3, and then the next packet data group Since transmission is performed, when the normal packet reception at the client terminal 6-1 cannot be confirmed, the server terminal 6-3 retransmits the packet data group after a certain waiting time, A lot of time is spent until the packet data group is normally received.

  Therefore, it is desirable to prevent the reception buffer memory of the relay device 6-2 from overflowing and to improve so that the client terminal 6-1 can normally receive the packet data group.

As a prior art document related to the present invention, the following Patent Document 1 is provided with a buffer amount measuring means for measuring an intra-system communication buffer amount in each station in a network, and each subordinate terminal communicates with a partner terminal. A delay tolerance value setting means for setting a delay time tolerance value is provided to select a route satisfying the delay time tolerance value from a plurality of routes, and to select a route with a small amount of communication buffer in the system from the selected routes. The data exchange route selection method to be selected is described.
JP-A-9-191322

  As described above, in the conventional packet data relay device, the reception buffer memory overflows with the packet data group, and the client terminal may not be able to normally receive the packet data group. The present invention prevents the reception buffer memory from overflowing with received data in the relay device, reduces the number of retransmissions for packet discard in TCP communication, and improves the speed performance of TCP communication.

  The packet data relay device according to the present invention temporarily stores packet data received from the opposite device in the reception buffer memory corresponding to the reception port, and then reads the packet data from the reception buffer memory and relays it to another opposite device. In the apparatus, a reception rate monitoring unit that monitors the amount of packet data received per unit time for each reception port, and a buffer area allocation unit that variably allocates a reception buffer memory area corresponding to the reception port to a memory space; , Based on the amount of packet data per unit time monitored by the reception rate monitoring unit, calculate the estimated time that the reception buffer memory corresponding to each reception port overflows, and compare the estimated time with the threshold time, Allocate more space to the receive buffer memory of the receive port whose estimated time is shorter than the threshold time As a packet quantity estimating unit that requests a space allocation change in the buffer area allocation unit, those having a.

  A buffer area allocating unit that variably allocates a reception buffer memory area corresponding to the reception port to a memory space; and a reduction amount of an empty area of the reception buffer memory per unit time for each reception port; Based on the decrease amount, an estimated time when the reception buffer memory corresponding to each reception port overflows is calculated, the estimated time is compared with the threshold time, and the reception buffer memory of the reception port with the estimated time shorter than the threshold time. A buffer remaining capacity monitoring unit that requests the buffer area allocation unit to change the area allocation so as to allocate more areas.

  According to the present invention, a reception port of a line with a low line usage rate or a line that is not used and a reception port of a line with a high line usage rate are recognized, and the area of the reception buffer memory of the former reception port is set as the latter reception port. Dynamic allocation to the receive buffer memory area reduces the occurrence of packet overflow in the receive buffer memory, thereby reducing the number of retransmissions for packet discard in TCP communication and improving TCP communication speed performance. Can do.

  That is, in contrast to the conventional packet data relay device in which the size of the reception buffer memory is fixedly set, the packet data relay device of the present invention is based on the reception rate or the decrease in the free area of the reception buffer memory. By dynamically allocating the reception buffer memory area corresponding to each reception port, it is possible to reduce packet discard at the reception port that is congested.

  In addition, although the physical size of the reception buffer memory of the entire relay apparatus is constant, the use efficiency of the reception buffer memory of the entire relay apparatus increases by dynamically allocating the area of the reception buffer memory corresponding to each reception port. Therefore, it is possible to use a reception buffer memory having a smaller size than the conventional one.

  FIG. 1 is a diagram for explaining the operating principle of a relay apparatus according to the present invention. As shown in the figure, the relay device stores packet data input from a reception port to which a server terminal or the like is connected in reception buffer memories 1-1, 1-2, and 1-3, and then receives the reception buffer. The packet data is transmitted from the memory 1-1, 1-2, 1-3 to the transmission port to which the client terminal or the like is connected.

  The relay apparatus according to the present invention includes a reception rate monitoring unit 1-4 that monitors the reception rate of each reception port, and the reception rate monitoring unit 1-4 monitors the reception rate of each reception port, thereby The congestion state of the packet data input to the reception port is grasped, and the reception buffer memory (for example, reception buffer memory 1-2) of the reception port with a low degree of congestion and the reception buffer memory (for example, reception buffer memory 1) of the unused port are low. -3) is allocated to the reception buffer memory (for example, reception buffer memory 1-1) of the reception port having a high degree of congestion.

  FIG. 2 shows functional blocks of functions of the first embodiment of the relay apparatus of the present invention. The embodiment shown in the figure shows a configuration example in which there are two reception ports for receiving packet data and two transmission ports for transmitting packet data, but the relay apparatus of the present invention is limited to this configuration. Instead, the reception port and the transmission port may be any number beyond this.

  In FIG. 2, the reception rate monitoring unit 2-1 monitors the amount of packets input from each reception port. Specifically, the amount of input packets per unit time is monitored. The buffer area allocating unit 2-2 has a function of allocating a necessary reception buffer memory area for each reception port. Normally, the same memory capacity is assigned to the memory areas assigned to the reception buffer memories 2-4 and 2-5.

  The packet amount estimation unit 2-3 calculates the input packet amount per unit time of each reception port and the estimated time when the reception buffer memories 2-4 and 2-5 corresponding to the reception ports overflow, and the calculation result is Then, it is determined whether or not a request for changing the allocation area of each of the reception buffer memories 2-4 and 2-5 is required for the buffer area allocation unit 2-2.

  The determination of the necessity of the area allocation change request for each of the reception buffer memories 2-4 and 2-5 is based on the estimated time that the reception buffer memories 2-4 and 2-5 overflow in the packet amount estimation unit 2-3. It is determined whether it is shorter than the threshold value of the determination setting time recorded in the packet, and if it is shorter, the area of the reception buffer memories 2-4 and 2-5 is transferred from the packet amount estimation unit 2-3 to the buffer area allocation unit 2-2. A reassignment request is made.

  FIG. 3 is a table showing a specific example of determining whether or not a buffer memory area allocation change request is necessary. Table 1 in the figure is an example when no change request is made. As shown in Table 1, for the first and second reception ports (# 1, # 2), when the packet amount per unit time is 10 kbit and 20 kbit, respectively, and the capacity of the reception buffer memory is 300 kbit, the reception buffer The estimated time that the memory overflows is 30 seconds for the first receiving port (# 1), 15 seconds for the second receiving port (# 2), and the threshold of the judgment setting time of each receiving buffer memory is 7 seconds. In this case, since the estimated time 30 seconds and 15 seconds of each receiving port that overflows is longer than the threshold value 7 seconds, it is determined that the change request is unnecessary.

  Table 2 in FIG. 3 is an example when a change request is made. As shown in Table 2, for the first and second receiving ports (# 1, # 2), when the packet amount per unit time is 50 kbit and 20 kbit, respectively, and the capacity of the receiving buffer memory is 300 kbit, respectively, the receiving buffer The estimated time when the memory overflows is 6 seconds for the first receiving port (# 1) and 15 seconds for the second receiving port (# 2), and the threshold of the judgment setting time of each receiving buffer memory is 7 seconds. In this case, since the estimated time 6 seconds of the overflowing first receiving port (# 1) is shorter than the threshold value 7 seconds, it is determined that a change request is required.

  Table 3 in FIG. 3 shows an example of determining whether a change request is required after changing the area allocation of the reception buffer memory. As shown in Table 3, regarding the first and second receiving ports (# 1, # 2), the packet amounts per unit time are 50 kbit and 20 kbit, respectively, and the first receiving port (# 1) after changing the area allocation ) Receive buffer memory capacity is 400 kbits and the second receive port (# 2) receive buffer memory capacity is 200 kbits, the estimated time that the receive buffer memory overflows is the first receive port (# 1). Is 8 seconds, and the second reception port (# 2) is 10 seconds. When the threshold value of the determination setting time of each reception buffer memory is 7 seconds, the overflow of the first reception port (# 1) is estimated. Since the time 8 seconds and the estimated time 10 seconds of the second receiving port (# 2) are longer than the threshold value 7 seconds, it is determined that the change request is unnecessary.

  It should be noted that the processing time for determining whether or not to change the reception buffer memory area allocation by the packet amount estimation unit 2-3 and the buffer area allocation unit 2-2 to reset the areas of the reception buffer memories 2-4 and 2-5 It is necessary that the sum of the processing time and the processing time is sufficiently shorter than the estimated time that the reception buffer memories 2-4 and 2-5 overflow.

  Further, after resetting the reception buffer memories 2-4 and 2-5 by the buffer area allocation unit 2-2, the setting may be continued as it is. However, after a certain period of time, the original reception buffer memory It is good also as a structure returned to the area | region of 2-4 and 2-5.

  FIG. 4 shows functional blocks of the second embodiment of the relay apparatus according to the present invention. The embodiment shown in the figure shows a configuration example in which there are two reception ports for receiving packet data and two transmission ports for transmitting packet data, but the relay apparatus of the present invention is limited to this configuration. Instead, the reception port and the transmission port may be any number beyond this.

  In FIG. 4, the buffer area allocation unit 4-1 has a function of allocating areas of the reception buffer memories 4-3 and 4-4 for each reception port. Usually, the areas of the reception buffer memories 4-3 and 4-4 are allocated with areas having the same memory capacity.

  The buffer remaining capacity monitoring unit 4-2 monitors the decrease amount of the free area per unit time of each reception buffer memory 4-3, 4-4, and based on the decrease amount, each reception buffer memory 4-3, 4 -4 is estimated to overflow, and based on the calculation result, it is determined whether the buffer area allocation unit 4-1 needs to change the allocation area of the reception buffer memories 4-3 and 4-4.

  Whether the allocation area change request of the reception buffer memories 4-3 and 4-4 is required is determined based on the estimated time when the reception buffer memories 4-3 and 4-4 overflow in advance in the buffer remaining capacity monitoring unit 4-2. It is determined whether or not it is shorter than the threshold of the recorded determination setting time, and if it is shorter than the threshold, the buffer remaining capacity monitoring unit 4-2 sends the reception buffer memory 4- to the buffer area allocation unit 4-1. A request for reallocation of the area 3, 4-4 is sent out.

  FIG. 5 is a table showing a specific example of determining whether or not a request for changing the allocation of the buffer memory area is necessary. Table 1 in the figure is an example when no change request is made. As shown in Table 1, with respect to the first and second reception ports (# 1, # 2), the reduction values of the free capacity of the reception buffer memory per unit time are 10 kbit and 20 kbit, respectively, and the capacity of the reception buffer memory is respectively In the case of 300 kbit, the estimated time that the reception buffer memory overflows is 30 seconds for the first reception port (# 1) and 15 seconds for the second reception port (# 2). When the threshold of the set time is 7 seconds, it is determined that the change request is unnecessary because the estimated times 30 seconds and 15 seconds of each receiving port that overflows are longer than the threshold 7 seconds.

  Table 2 in FIG. 5 is an example when a change request is made. As shown in Table 2, with respect to the first and second reception ports (# 1, # 2), the reduction values of the free capacity of the reception buffer memory per unit time are 50 kbit and 20 kbit, respectively, and the capacity of the reception buffer memory is respectively In the case of 300 kbit, the estimated time that the reception buffer memory overflows is 6 seconds for the first reception port (# 1) and 15 seconds for the second reception port (# 2). When the threshold value of the set time is 7 seconds, the estimated time 6 seconds of the overflowing first reception port (# 1) is shorter than the threshold value 7 seconds, so it is determined that a change request is required.

  Table 3 in FIG. 5 shows an example of determining whether or not a further change request is required after changing the area of the reception buffer memory. As shown in Table 3, with respect to the first and second reception ports (# 1, # 2), the decrease values of the free capacity of the reception buffer memory per unit time are 50 kbit and 20 kbit, respectively, When the capacity of the reception buffer memory of the first reception port (# 1) is 400 kbit and the capacity of the reception buffer memory of the second reception port (# 2) is 200 kbit, the estimated time when the reception buffer memory overflows is the first time The first reception port (# 1) is 8 seconds, the second reception port (# 2) is 10 seconds, and the threshold of the determination setting time of each reception buffer memory is 7 seconds. Since the estimated time of the port (# 1) 8 seconds and the estimated time 10 seconds of the second receiving port (# 2) are longer than the threshold value 7 seconds, it is determined that the change request is unnecessary.

  It should be noted that the processing time for determining whether or not the area allocation change request of the reception buffer memories 4-3 and 4-4 is required by the buffer remaining capacity monitoring unit 4-2, and the buffer area allocation unit 4-1 is the reception buffer memory 4-3. The total of the processing time for resetting the area 4-4 needs to be sufficiently shorter than the estimated time when the reception buffer memories 4-3 and 4-4 overflow.

  In addition, after resetting the areas of the reception buffer memories 4-3 and 4-4 by the buffer area allocating unit 4-1, the setting may be continued as it is. It is good also as a structure which returns to the area | region of receiving buffer memory 4-3 and 4-4.

  The allocation of the areas of the reception buffer memories 4-3 and 4-4 is performed by assigning an allocation address table for storing the upper limit value and the lower limit value of addresses in the memory space of the areas of the reception buffer memories 4-3 and 4-4. By preparing and referring to the buffer allocation table, it is possible to recognize a usable area of each reception buffer memory 4-3 and 4-4 and store packet data.

  In the above configuration, the allocation change of the areas of the reception buffer memories 4-3 and 4-4 is performed by changing the upper limit value or lower limit of the addresses of the reception buffer memories 4-3 and 4-4 stored in the allocation address table. This can be done by changing the value.

  Alternatively, allocation buffer information indicating which address of the common memory used for each reception buffer memory 4-3, 4-4 is allocated to each reception buffer memory 4-3, 4-4 is stored. An allocation buffer table is prepared, and by referring to the allocation buffer table, a usable area of each of the reception buffer memories 4-3 and 4-4 can be recognized to store packet data.

  In the above configuration, the allocation of the areas of the reception buffer memories 4-3 and 4-4 can be changed by changing the allocation buffer information corresponding to each address of the common memory stored in the allocation buffer table. .

  In any of the above configurations, the areas of the reception buffer memories 4-3 and 4-4 are allocated not only to one continuous address space but also to a plurality of discontinuous address spaces. Can do.

It is explanatory drawing of the operation principle of the relay apparatus by this invention. It is a figure which shows the functional block of 1st Embodiment function of the relay apparatus of this invention. It is a figure which shows the specific example of judgment of the necessity of the change request | requirement of the area allocation of the buffer memory of 1st Embodiment function. It is a figure which shows the functional block of 2nd Embodiment function of the relay apparatus of this invention. It is a figure which shows the specific example of judgment of the necessity of the change request | requirement of the area allocation of the buffer memory of the function of 2nd Embodiment. It is a figure which shows the example of the relay sequence of packet data.

Explanation of symbols

1-1, 1-2, 1-3 Reception buffer memory 1-4 Reception rate monitoring unit 2-1 Reception rate monitoring unit 2-2 Buffer area allocation unit 2-3 Packet amount estimation unit 2-4, 2-5 Reception buffer memory 4-1 Buffer area allocation unit 4-2 Buffer remaining capacity monitoring unit 4-3, 4-4 Reception buffer memory

Claims (2)

In the relay device that temporarily stores the packet data received from the opposite device in the reception buffer memory corresponding to the reception port, then reads the packet data from the reception buffer memory and relays it to the other opposite device.
A reception rate monitoring unit that monitors the amount of packet data received per unit time for each reception port;
A buffer area allocation unit that variably allocates an area of the reception buffer memory corresponding to the reception port to a memory space;
Based on the amount of packet data per unit time monitored by the reception rate monitoring unit, an estimated time when the reception buffer memory corresponding to each reception port overflows is calculated, and the estimated time is compared with a threshold time, A packet amount estimator that requests the buffer area allocator to change area allocation so as to allocate more area to the reception buffer memory of the reception port whose estimation time is shorter than the threshold time;
A packet data relay device. In the relay device that temporarily stores the packet data received from the opposite device in the reception buffer memory corresponding to the reception port, then reads the packet data from the reception buffer memory and relays it to the other opposite device.
A buffer area allocation unit that variably allocates an area of the reception buffer memory corresponding to the reception port to a memory space;
The amount of decrease in the free area of the reception buffer memory per unit time is monitored for each reception port, and based on the amount of decrease, an estimated time when the reception buffer memory corresponding to each reception port overflows is calculated, and the estimated time A buffer remaining capacity monitoring unit that requests the buffer area allocation unit to change area allocation so that more areas are allocated to the reception buffer memory of the reception port whose estimated time is shorter than the threshold time. ,
A packet data relay device.

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