JP3056348B2 - Bridge device and storage means management method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an inter-LAN bridge device that executes data transfer between Area Networks, and particularly to a method of managing a buffer memory that temporarily stores received data and transmitted data.

[0002]

2. Description of the Related Art As a conventional technique, for example, Japanese Unexamined Patent Publication No.
There is one described in -150536. In the prior art, in a bridge device for executing data transfer between networks, a buffer memory for storing received data, a read unit for generating a read address of the buffer memory, and a read unit for discarding the received data. And the address conversion means for converting the address value so as to indicate the received data, so that the access at the time of reading is continuous. Here, discarding the received data means a so-called filtering process in which when the transfer destination of the received data is a transfer source network, the data transfer is unnecessary because the data transfer is unnecessary.

[0003]

The above-mentioned conventional LAN
In the inter-bridge device, when there is an empty buffer generated by the filtering process, the access at the time of reading is configured to be continuous, but the address when storing the received data is sequentially indicated by the lower bits of the buffer address. Have been. Therefore, for example, when the throughput on the output side temporarily drops, the reception buffer is busy if the address for storing the received data matches the read address even though there is an empty buffer. I will judge. In other words, the filtering process causes the buffer memory to be in a discontinuous state in which a free buffer and received data (data that has not been read yet) are mixed. When the receiving buffer is busy, there is a disadvantage that the received frame is discarded before filtering.

[0004] An object of the present invention is to solve the above problems.
An object of the present invention is to provide a LAN-to-LAN bridge device that reduces reception frame discard due to reception buffer busy.

[0005]

In order to achieve the above object, according to the present invention, there is provided a bridge device for transferring information between a plurality of networks.
It provided corresponding to each of the plurality of networks, before
A controller for receiving information from each of the plurality of networks and storing the information in the storage unit, reading the information stored in the storage unit, and transmitting the information to a destination network; and information stored in the storage unit. Is filtering means for discarding transfer information from a transfer destination to a transfer source in the same network, and the storage means, for each predetermined area, by the controller
And a management unit for storing the received information and managing the area , wherein the management unit is configured to store the information by the controller.
At the time of receiving, in the area where the information is not stored,
The received information is stored, and the stored area is
The information is processed by the filtering, and the
Information that was not discarded due to
And sent by the controller
The area where the information was stored and the filtering
The area where the more discarded information was stored is
This area is not stored .

Also, in a bridge device for transferring information between a plurality of networks, a storage means for storing information, provided corresponding to the network, receiving information from the network and storing the information in the storage means, A controller for reading information stored in the storage means and transmitting the information to a destination network; and a controller for reading information stored in the storage means when the information is transfer information from a destination to a source in the same network. Filtering means for discarding information, reception management means indicating a storage position of the storage means for storing the information received by the controller in the storage means, and storage means for storing information to be transmitted by the controller. Transmission management means for indicating a read position of the storage means for reading from the storage means, and information stored in the storage means The controller stores the received information in the storage position indicated by the reception management means, reads the information from the read position indicated by the transmission management means, The transmission management means, as the information to be transmitted, the information not discarded by the filtering means, and sequentially indicates the storage position of the information indicated by the reception management means as the readout position according to the information readout by the controller, The reception management unit stores, in the storage unit, the storage position where the information discarded by the filtering unit has been stored and the position of the free space indicated by the free space management unit, the information received by the controller in the storage unit. For the information received by the controller as the storage location for After the information has been read out by the controller, the read position indicated by the transmission management means is defined as the position of the free area, and the position of the free area in the reception management means is determined. Can be sequentially shown according to the storage position.

Further, the transmission management means indicates a transmission management table having a plurality of entry areas capable of storing pointers as the read positions, a writable entry area of the transmission management table, and information to be transmitted. And a read entry that indicates an entry area to be read out of the transmission management table according to the information read by the controller and sequentially shifts the entry area according to the reading of information by the controller. The reception management means indicates a reception management table including a plurality of entry areas capable of storing a pointer as the storage location, a writable entry area of the reception management table, and sequentially stores the entry areas according to the storage of the reception information. Migrating write entries and A read entry which indicates an entry area to be read out of the reception management table, and sequentially shifts the entry area in accordance with the reading of information by the filtering means, wherein the free area management means sets a pointer as the position of the free area. A free area management table having a plurality of entry areas that can be stored, and a writable entry area of the free area management table are shown. A write entry and a read entry that indicates an entry area to be read from the free area management table, and sequentially shifts the entry area according to the free area as the storage location, can be provided.

[0008]

The controller is provided corresponding to each network, receives information from the network, stores the information in the storage means, reads out the information stored in the storage means, and transmits the information to the destination network. Further, the controller stores the received information in a storage position indicated by the reception management unit, and reads the information from a read position indicated by the transmission management unit. The filtering unit discards the information stored in the storage unit when the transfer destination included in the information is the transfer source network.

The reception management means indicates a storage position of the storage means for storing the information received by the controller in the storage means. The transmission management means indicates a read position of the storage means for reading out information to be transmitted by the controller from the storage means. Further, the free area management means indicates a position of a free area where no information is stored in the storage means. The free area management means indicates the area that has become a free area after transmission, thereby making the storage means that has become discontinuous due to a free area continuous.

In this case, the transmission management means sets information not discarded by the filtering means as information to be transmitted, a storage position of the information indicated by the reception management means as the readout position, and an information stored in the controller. The reception management means indicates the storage position where the information discarded by the filtering means is stored, and the position of the free space indicated by the free space management means, according to the information received by the controller. As the storage location for storing in the storage means in accordance with the storage of the received information in the controller, and the free space management means indicates in the transmission management means after the information is read out in the controller. The read position to be read As sequentially shown according to a storage position to a position of free space in the reception management means. Thereby, the management of the storage position of the storage means is shifted one after another, and the reception management means can always indicate the continuous storage position.

By performing the above processing, the discontinuity of the reception buffer due to the discard of the received information in the filtering means does not occur, and the reception frame discard due to the reception buffer busy can be reduced.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration diagram of a LAN-to-LAN bridge device of the present embodiment. FIG. 2 is a diagram illustrating a configuration of the reception management table and the transmission management table of the inter-LAN bridge device of the present embodiment. FIG. 3 shows a configuration diagram of an inter-LAN bridge device that connects two LAN systems.

In FIG. 1, a CPU 11 is a control unit of an inter-LAN bridge device.
Control is performed to transfer information from N to the destination LAN. The CPU 11 controls the filtering database (FDB) 12, the program memory 13, and the management tables 14-1 to 14- of the management unit by the internal bus 19.
n, buffer memory 15 and LAN controller 17
-1 to 17-n. The CPU 11
Through the internal bus 19, it can be freely accessed under the arbitration of the bus arbiter 16. Bus Abita 1
6 arbitrates upon receiving an access request to the internal bus 19 from each LAN controller and the CPU 11, and gives an access right to accessible ones. The LAN controllers 17-1 to 17-n communicate with the program memory 13 and the management table 14-1 under the arbitration of the bus arbiter 16.
14-n and the buffer memory 15 can be freely accessed. LAN controllers 17-1 to 17
-N are LAN1 system 18-1 to LAN N system1
8-n. The filtering database 12 holds addresses of information processing apparatuses connected to the LAN1 system 18-1 to the LANN system 18-n as an address list. The CPU 11 performs a filtering process by referring to an address list in the filtering database 12. CPU1
1 retrieves the destination address of the data stored in the reception buffer from the address list, and discards the data if it is an address connected to the transmission source LAN. If the data is connected to a LAN other than the transmission source, the data is transferred to the destination LAN.
The LAN controllers 17-1 to 17-n receive the data, store the received data in an area of the buffer memory indicated by the pointer of the reception management table described later, and, when transmitting, store the data in the buffer memory indicated by the pointer of the transmission management table. Data is read from the area and sent to the destination LAN. The program memory 13 stores programs processed by the CPU 11. Buffer memory 1
5 stores transmission data and reception data. The management tables 14-1 to 14-n are provided corresponding to the LAN system and manage the position of the buffer memory 15 storing the received data, the reception management table of the reception management means;
It has a transmission management table of the transmission management means for managing the position of the buffer memory 15 storing the transmission data, and a free buffer management table of the free area management means for managing the free area of the buffer memory 15.

FIG. 2 shows the structures of a reception management table, a transmission management table, and a free buffer management table. Since the structures of the reception management table, the transmission management table, and the empty buffer management table are the same, they will be described with reference to the same drawing as the management table. In the present embodiment, the management table is configured by a ring buffer. The management table 21 includes a pointer indicating the storage position of data in the buffer memory 24, a buffer length indicating the size of the storage area of the buffer memory 24, the presence / absence of data storage, and the LAN.
A plurality of statuses for storing error information during transmission / reception processed by the controller are provided as management information, and a ring buffer structure is provided. The management table includes entry areas to which entry numbers 1 to M are assigned. As management information relating to each data, a pointer, a buffer length, and a status for each data are stored in areas of entry numbers 1 to M. The management table write entry 22 indicates the next writable entry number when storing data in the buffer memory, and the management table read entry 23 indicates the entry number written earlier, that is, Indicates the entry number to be deleted. The management table write entry 22 and the management table read entry 23 are provided corresponding to the reception management table, the transmission management table, and the empty buffer management table, and may be provided in the program memory 13. It is referenced at the time of reading and writing, and the entry number is sequentially updated at the time of reference. Management table write entry 22 and management table read entry 2
3 may be constituted by a counter or the like. In addition, areas for storing data in the buffer memory are divided into areas in advance, and the start position of each area is indicated by a pointer in the reception management table and the empty buffer management table. That is, the pointers of the respective entry areas of the reception management table and the empty buffer management table are set in advance. For example, the number of entry areas in each management table is set to 64, and the address of the buffer is set in each entry area pointer. Alternatively, the number of entries in the free buffer management table may be smaller than the number of entries in the reception management table. The management table write entry 22 and the management table read entry 23 indicate the entry number sequentially from 1, reset when counting up to the respective entry number, and are further configured on the ring so as to indicate the entry number sequentially from 1. I have.

Next, the operation of the LAN bridge thus configured will be described. For the explanation of the operation, referring to FIG. 3, two LAs of the LAN1 system and the LAN2 system will be described.
The case where N connections are made is taken as an example. FIG. 3 is a configuration diagram of two LAN bridge devices of the present embodiment, and FIGS. 4 to 9 are explanatory diagrams illustrating the operation of the LAN bridge of the present embodiment. The configuration shown in FIG. 3 is the same as the configuration shown in FIG. 1, and connects the LAN1 system and the LAN2 system, and has a management table for the LAN1 system and the LAN2 system.

In FIG. 3, when data is received, the LAN controller 17-1 connected to the LAN1 system 18-1 stores the data in the buffer memory 15 based on the management information in the reception management table 114-1a. Then, the CPU 11 is notified that the data has been received. CPU11
Detects the transmission destination address from the reception data stored in the buffer memory 15 based on the management information of the reception management table 114-1a, and searches the filtering database 12 based on the transmission destination address. The CPU 11
If the transmission destination is connected to the LAN 1 system, the received data is discarded. If the transmission destination is connected to the LAN 2 system, the contents of the management table of the buffer storing the received data are transmitted to the transmission management table 214-2b. And inform the LAN controller 17-2. LAN controller 17
-2 transmits data based on the management information stored in the transmission management table 214-2b.

Next, the operation of this embodiment will be described in detail with reference to FIGS.

(1) Initial State FIG. 4 shows a state of each management table before the operation of the inter-LAN bridge device starts. In the initial state, no data is stored in the buffer memory 15. The arrow 56 indicates that the pointer of the table of the entry number 1 of the reception management table 114-1a indicates the address of the area of the buffer memory 15a. The pointer of the table of all entry numbers of the transmission management table 214-2b does not indicate any area of the buffer memory 15. In the reception management table 114-1a, data to be received is stored in the buffer memory 1
5, the pointer of the table of all entry numbers indicates the address of a certain area of the buffer memory 15. Empty buffer management table 1 14-
The pointer of the table of all entry numbers of 1c is
The address of a certain area of the buffer memory 15 is shown. In each management table, a buffer length indicating the size of each buffer is set. The entry number of the read entry and the write entry of each management table is set to 1 as an initial value.

(2) Receiving Operation FIG. 5 shows a case where a data receiving operation is performed in the LAN 1 system. FIG. 5 shows a case where four data have already been stored in the areas of the buffer memories 15a, 15b, 15c and 15d. In FIG. 3, LA
The N controller 17-1 refers to the write entry 53 of the reception management table 114-1 of the LAN1 system, reads the write entry number, and advances the entry number of the write entry 53 by one. At this time, when the write entry number matches the read entry number, it can be determined that the reception cannot be performed because all the reception buffers are in use. Next, LAN
The controller 17-1 receives the reception management table 114-
1a, referring to the pointer of the table of entry number 1;
An address of an area of the buffer memory 15a for storing received data is detected. LAN controller 17-1
Stores the data received in the area indicated by the pointer in the buffer memory 15a. At the time of storage, the status of the management information is set to “with data”. Further, the LAN controller 17-1 compares the buffer length of the management information with the received data length, and when the received data is large, determines that an error has occurred and indicates the presence of error information by the status. If an error occurs, the management table can discard the data in which the error has occurred. The same operation is repeated each time data is received. By performing the receiving operation in this manner, for example, as shown in FIG. 5, four data are stored in the areas of the buffer memories 15a, 15b, 15c, and 15d.

The receiving operation is summarized as follows.

(A) The LAN controller sends the L
The write entry number of the AN entry management table write entry is read, and the entry number of the write entry is incremented by one.

(B) The buffer memory address is detected from the pointer of the received entry number in the reception management table.

(C) Write the received data. At the time of storage, the status of the management information is set to “with data”. Thus, the received data is stored in the buffer memory.

(3) Filtering Processing FIG. 6 shows an example in which filtering processing is performed and data is transferred. The CPU 11 refers to the read entry 54 of the reception management table 1, reads a read entry number, and advances the entry number by one. The read entry number is retained. Next, CPU
Numeral 11 detects the address of the area of the buffer memory 15a from the pointer of the table of the entry number 1 of the reception management table 114-1a. The CPU 11 reads a destination address in the stored data from the address, searches a filtering database, and performs a filtering process. That is, if the destination address is an address connected to the source LAN, the data is discarded, and if the destination address is connected to a LAN other than the source, the data is transferred to the destination LAN. In this embodiment, if the transmission destination is the LAN2 system, the data is transferred.

In this case, the CPU 11 transmits the data to the destination LAN.
The entry number is read from the write entry 51 of the transmission management table 2 of the second system, the write entry number is read, and the entry number of the write entry 51 is advanced by one. Next, the CPU 11 copies the management information stored in the entry number 1 table held before the reception management table 11 14-1a into the entry number 1 management table of the transmission management table 214-2b. Next, the CPU 11 refers to the entry number of the read entry 57 of the free buffer management table 1, and
The read entry number is read, and the entry number of the read entry 57 is advanced by one. CPU
Numeral 11 transfers the management information of the table of entry number 1 of the free buffer management table 114-1c to the table of entry number 1 held at the end of the reception management table 114-1a. The state shown in FIG. 6 is obtained by performing the above processing.

Next, an example in which filtering processing is performed and data is discarded will be described with reference to FIG. CPU
Reference numeral 11 refers to the entry number from the read entry 54 of the reception management table 114-1-1a, reads the read entry number, and reads the read entry 54
Advance the entry number of. At present, the entry number of the read entry 54 is 2. Reception management table 1
The address of the area of the buffer memory 15b is detected from the pointer of the table of the entry number 2 of 14-1a.
The destination address of the stored data is read, a filtering database is searched, and a filtering process is performed. When discarding the data, the status of the management information stored in the table of the entry number 2 of the reception management table 114-1a is set to no data. The state shown in FIG. 7 is obtained by performing the above processing.

FIG. 8 shows an example in which a filtering process has been performed on all the data stored in the buffer memory.
In FIG. 8, the reception management table 1 read entry 5
The entry number of 4 indicates 5, indicating that the data of the reception management tables of entry numbers 1 to 4 have already been subjected to the filtering process. Reception management table 1
The management information is copied from 4-1a and stored in the buffer memory 15a.
The data of a, 15c and 15d are managed by the transmission management table 14-2b.

The filtering processing is summarized as follows.

(A) The CPU 11 reads the read entry number of the reception management table, reads the reception management table, and advances the entry number by one.

(B) The buffer memory address is detected from the pointer of the read entry number in the reception management table.

(C) A destination address is detected from received data stored in a corresponding area of the buffer memory.

(D) Filtering is performed based on the destination address.

(E) When transferring, the following processing is performed.

The CPU 11 reads the write entry number in the transmission management table, and advances the entry number of the write entry by one.

The management information in the reception management table of the entry number subjected to the filtering process is copied to the transmission management table of the read entry number.

The read entry number of the empty buffer management table is read, and the entry number of the read entry 57 is advanced by one.

The management information of the empty buffer management table of the read entry number is transferred to the management information of the reception management table of the entry number subjected to the filtering process.

(F) When discarding, the status of the management information stored in the reception management table is set to no data.

(4) Transmission Operation FIG. 9 shows a case where a data transmission operation is performed on the LAN2 system. In FIG. 9, the buffer memory 15a
Shows a state in which the data stored in is transmitted. The LAN controller 17-2 reads the entry number from the read entry 52 of the transmission management table 2 of the LAN system 2, and advances the entry number of the read entry 52 by one. In addition, the LAN controller 17-2
The read entry number is held. Next, L
The AN controller 17-2 transmits the transmission management table 14-
The address of the area of the buffer memory 15a is detected from the pointer of the table of the entry number 1 of 2b. The LAN controller 17-2 reads the data to be transmitted from the buffer memory 15a and performs a transmission process. Next, LA
The N controller 17-2 refers to the write entry 55 of the empty buffer management table 1, reads the write entry number, and advances the entry number of the write entry 55 by one. LAN controller 17
-2 transfers the management information stored in the table of entry number 1 held in the transmission management table 14-2b to the table of entry number 1 in the empty buffer management table 14-1c. The same operation is continued each time data is transmitted.

The transmission operation is summarized as follows.

(A) The LAN controller 17-2 reads the read entry number of the transmission management table and advances the entry number by one.

(B) The buffer memory address is detected from the pointer of the read entry number in the transmission management table.

(C) Data to be transmitted is read from the buffer memory and transmission processing is performed.

(D) The write entry number of the empty buffer management table is read, and the entry number of the write entry is advanced by one.

(E) The management information of the transmission management table after the transmission is transferred to the table of the entry number read from the free buffer management table.

Next, how the buffer memory is managed in the data transfer process will be described with reference to FIG.

FIG. 10 is a conceptual diagram showing how the buffer memory management is moved in this embodiment. In FIG. 10, the buffer memory management described above is based on the input buffer management table (reception management table) for managing the storage location of the received data and the output buffer management table (the aforementioned reception management table) for managing the storage location of the transmitted data. And a free buffer management table, and shows the state of the buffer memory area managed for each unit area using a predetermined storage area as a unit.

In FIG. 10, data transmitted from the LAN1 system 18-1 is received by the inter-LAN bridge device and stored in the buffer at the position indicated by the write address managed by the input buffer management table (arrow 114). ). Next, by the filtering process,
The management of the area of the buffer memory where the data to be transferred is stored moves to the output buffer (arrow 115).
The data stored in the buffer memory is sequentially read out with the read address specified from the output buffer management table, and is transmitted to the LAN2 system 18-2 (arrow 1).
17). Since the filtering process is faster than the receiving operation, the read address managed by the output buffer management table can quickly catch up with the write address managed by the input buffer management table. The buffer memory for which transmission has been completed becomes an empty buffer as it is, and the management is moved to the empty buffer management table (arrow 118). Further, when data is discarded by the filtering process, the buffer area storing the discarded data is managed as it is by the input buffer management table. In the input buffer management table, management of one area of the buffer memory that is a free buffer is moved from the free buffer management table (arrow 116).

According to the present embodiment, a discontinuous state in which empty buffers and data coexist does not occur in the input buffer management table. In general, information transferred between networks can be considered less than information transferred within the same network. For this reason, since the information to be discarded in the bridge device is larger than the information to be transferred, by making the reception buffer continuous, the buffer busy can be further reduced. Also, the filtering process is faster than the receiving operation, and the management of the buffer memory in which the data is stored by the filtering process is moved to the output buffer management table, so that even if the transmission side throughput temporarily drops, No input buffer busy occurs and no received frame discard occurs.

As described above, the buffer memory is managed by the reception management table, the transmission management table, and the empty buffer management table, and when transferring data by the filtering process, the data to be transferred from the reception data management table is stored. Means for transferring the management information of the allocated area to the transmission data management table, and instead transferring the management information of the free buffer from the free buffer management table to the reception buffer management table, and transmitting the data from the transmission data management table when transmitting data. Means for transferring the management information of the buffer memory for which the processing has been completed to the free buffer management table is provided, so that the discontinuity of the reception buffer does not occur due to the filtering process, and the discard of the reception frame due to the reception buffer busy can be prevented.

[0051]

According to the present invention, it is possible to prevent the reception frame from being discarded due to the reception buffer being busy in the LAN-to-LAN bridge device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a LAN-to-LAN bridge device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the structures of a transmission management table, a reception management table, and a free buffer management table according to the embodiment of the present invention.

FIG. 3 is a diagram showing an inter-LAN bridge device for connecting two LAN systems for explaining the operation of the embodiment of the present invention;

FIG. 4 is a diagram showing an initial state of a management table and a buffer memory for explaining the operation of the embodiment of the present invention.

FIG. 5 is a diagram showing a state of a management table and a buffer memory for explaining a receiving process according to the embodiment of the present invention.

FIG. 6 is a diagram showing a state of a management table and a buffer memory for explaining transfer processing at the time of filtering processing according to the embodiment of the present invention.

FIG. 7 is a diagram showing a state of a management table and a buffer memory for explaining a discarding process at the time of a filtering process according to the embodiment of the present invention.

FIG. 8 is a diagram showing a state of a management table and a buffer memory for explaining a filtering process according to the embodiment of the present invention.

FIG. 9 is a diagram illustrating a state of a management table and a buffer memory for explaining transmission processing according to the embodiment of the present invention.

FIG. 10 is a diagram showing the concept of processing according to the embodiment of the present invention.

[Explanation of symbols]

11 CPU, 12 filtering database, 1
3: Program memory, 14-1 to n: Reception / transmission / empty buffer management table, 15: Buffer memory, 16
... Bus arbiter, 17-1 to n ... LAN controller, 18-1 to n ... LAN system, 21 ... Reception / transmission management table, 22 # Reception / transmission management table write entry, 23 ... Reception / transmission management table read entry ,
24: buffer memory managed by the reception / transmission management table, 31: free buffer management table, 32: free buffer management table entry, 33: buffer memory managed by the free buffer management table, 51:
Transmission management table 2 write entry, 52 ... transmission management table 2 read entry, 53 ... reception management table 1 write entry, 54 ... reception management table 1 read entry, 55 ... empty buffer management table 1 write entry, 56 ... management table Arrow indicating that the pointer holds the address of the buffer memory, 5
7... Free buffer management table 1 read entry, 1
11 input buffer 112 output buffer 113
Empty buffers, 114 to 118... Arrows indicating data flow.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Hiroshi Tomizawa 5-2-1 Omikacho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Omika Plant (56) References JP-A-60-91745 (JP, A) JP-A-63-5564 (JP, A) JP-A-4-150536 (JP, A) JP-A-4-290150 (JP, A) JP-A-6-78000 (JP, A) JP-A-6-132975 ( JP, A) IEICE Technical Report, Vol. 91 No. 270, IN91-113, Masato Tsukagoshi, et al., "FDDI high-speed connection method in multimedia high-speed core LAN @ -600", pages. 1-6 (58) Fields surveyed (Int. Cl. ⁷ , DB name) H04L 12/46 H04L 12/28 H04L 13/08 JICST file (JOIS)

Claims (4)

(57) [Claims] 1. A bridge apparatus for transferring information between a plurality of networks, and storage means for storing information, provided corresponding to each of the plurality of networks, before
A controller that receives information from each of the plurality of networks, stores the information in the storage unit, reads out the information stored in the storage unit, and transmits the information to a destination network; , Transfer information from the transfer destination to the transfer source in the same network,
Filtering means for discarding the information, and the storage means for each of predetermined areas.
Store the information received by the
And a management unit for receiving information by the controller.
In the area where the information is not stored,
Information stored in the storage area, and
Processing by filtering
Information that was not discarded by the controller
And the information sent by the controller
Discarded by the stored area and the above filtering
The area where the information was stored is stored in the area where the information is stored.
A bridge device characterized in that it is an area that is not covered. 2. A bridge device for transferring information between a plurality of networks, comprising: storage means for storing information; provided in correspondence with the network; receiving information from the network and storing the information in the storage means; A controller for reading the information stored in the storage means and transmitting the information to the destination network; and a controller for reading the information stored in the storage means when the information is transfer information from the destination to the source in the same network. Filtering means for discarding information, reception management means indicating a storage position of the storage means for storing the information received by the controller in the storage means, and storage means for storing information to be transmitted by the controller. Transmission management means indicating a read position of the storage means for reading from the storage means, and information is stored in the storage means. The controller stores the received information in a storage position indicated by the reception management unit, and reads information from a read position indicated by the transmission management unit. The transmission management means, as the information to be transmitted, the information not discarded by the filtering means, and sequentially indicates the storage position of the information indicated by the reception management means as the read position in accordance with the reading of the information by the controller. The reception management unit stores, in the storage unit, the storage position where the information discarded by the filtering unit has been stored and the position of the free space indicated by the free space management unit, the information received by the controller in the storage unit. For the information received by the controller as the storage location for After the information has been read out by the controller, the read position indicated by the transmission management means is taken as the position of the free area, and the position of the free area in the reception management means is displayed. Are sequentially displayed according to the storage position. 3. The transmission management means according to claim 2, wherein:
A transmission management table including a plurality of entry areas capable of storing pointers as the readout positions, and a writable entry area of the transmission management table are shown, and the entry areas are sequentially shifted according to storage of information to be transmitted. A write entry, and a read entry indicating an entry area to be read from the transmission management table, and sequentially shifting the entry area in accordance with the reading of information by the controller, wherein the reception management means includes a pointer as the storage position. A reception management table provided with a plurality of entry areas capable of storing the reception management table, a write entry indicating a writable entry area of the reception management table, and sequentially shifting the entry area according to the storage of the reception information; Ent to read table And a read entry that sequentially shifts the entry area in accordance with the reading of information by the filtering means. The free area management means sets an entry area in which a pointer can be stored as a position of the free area. A plurality of free space management tables, a writable entry area of the free space management table, a write entry that sequentially shifts the entry area by setting the read position to a free area position, and a free space management table. A read entry that indicates an entry area to be read from the table, and sequentially shifts the entry area according to the empty area as the storage position. 4. A storage means for storing information, receiving information from a network and storing the information in the storage means, reading the information stored in the storage means and transmitting the information to a destination network, When the information stored in the storage unit is transfer information from a transfer destination to a transfer source in the same network, the storage unit management method in a bridge device that discards the information, wherein the storage unit should be transmitted. A transmission area for storing information, a reception area for storing received information and having a predetermined size, and a free area for not storing information are divided into unit areas using a predetermined storage area as a unit. Performs management, causes the controller to store the information in a unit area of the reception area when the information is received, and discards the information after processing in the filtering. The unit area of the receiving area storing the never been information and the transmission region, the receiving area
The when the transmission region, the a unit area of the free area and the receiving area, the storage means, wherein the unit area of the transmission region after being transmitted after the transmission of information in the controller to said free area Management method.