JPH0832608A - Network relay device - Google Patents

Abstract

PURPOSE:To provide a network repeater where a network management function is improved and repeating delay can be suppressed. CONSTITUTION:The network repeater where plural ports 105a and 105b are provided, LAN are connected to the respective ports to repeat frames between LAN is provided with a table storing the transmission source MAC addresses and transmission source IP addresses of frames, which are received for the respective ports, and with a response means 106 answering the content of the table to the network management station in accordance with a request from a network management station provided in LAN.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network relay device for interconnecting LANs, and more particularly to a network relay device capable of improving a network management function and suppressing relay delay.

[0002]

2. Description of the Related Art A network relay device such as a bridge is
It is equipped with multiple ports, and LAN is connected to each port to LA
Frame relay between N is performed. For example, MAC
The MAC bridge working at the (Medium Access Control) layer is
EE (American Institute of Electrical and Electronics Engineers or Institute of Electrical and Electronics Engineers)
Performs the operation specified by 802.1D. As shown in FIG. 12, a plurality of stations 1201a to 1201 are provided.
c, 1201d to 1201e two LANs 12
02a and 1202b are interconnected by a MAC bridge 1203. One LAN is provided with a management station 1204 that manages this network.

A conventional bridge using Ethernet (CSMA / CD) defined by IEEE802.3 as the MAC part of the MAC bridge 1203 is shown in FIG.
As shown in FIG.
02, memory 1303, Ethernet control unit 1304
a, 1305b, and ports 1305a, 1305b. The memory 1303 has a filtering table having a table structure. As shown in Table 1, the filtering table stores a plurality of filtering data for each port.

[0004]

[Table 1]

Station 1201a implementing Ethernet
As shown in FIG. 14, a frame transmission procedure inside 1201 to 1201e is as follows.
The transmission data 1402 that 1 is about to transmit is the IP
(Internet Protocol) It is passed to the control unit 1403. The IP control unit 1403 transmits the transmitted transmission data 1402.
Is added to the IP communication control information 1404 and passed to the Ethernet control unit 1405. The Ethernet control unit 1405
Further, Ethernet communication control information (MAC communication control information) 1406 is added and passed to the output unit 1407. The output unit 1407 converts the frame thus configured into a signal and outputs the signal to the transmission path. Therefore, as shown in FIG. 15A, the frame output to the transmission path has a structure in which the MAC communication control information 1406, the IP communication control information 1404, and the transmission data 1402 are sequentially arranged from the beginning. Details of the Ethernet communication control information are, as shown in FIG. 15B, when the head is 0 bit, 0 to 47 bits are the destination MAC address 1501, 48 to 95 bits are the source MAC address 1502, 96 to 111. The bit is of type 1503. Details of the IP communication control information are shown in FIG.
As shown in 5 (c), between 0 to 159 bits,
VERS, LEN, service type, frame length,
A frame identification number, a FLAG, a sequence number when divided, a maximum number of relays, an upper identification number, a checksum of control information, a source IP address, and a destination IP address are arranged in order.

A relay procedure in the bridge will be described.
The frame arriving at the port (1) 1305a is converted by the Ethernet control unit 1304a from a transmission signal into data that can be stored in a memory. Relay judgment circuit 1
The reference numeral 302 refers to the filtering table in the memory 1303, and determines (filters) whether or not to relay the frame. The filtering in the relay determination circuit 1302 is performed by extracting the destination MAC address from the received frame passed from the Ethernet control unit 1304a and checking whether the destination MAC address is registered in the port (1) column of the filtering table. Done. If it is registered, it will not be relayed. If not registered, the received frame is passed to the Ethernet control unit 1304b and relayed via the port (2) 1305b. Similarly, port (2) 13
If the destination MAC address of the frame arriving at 05b is not registered in the port (2) column of the filtering table, this frame will be relayed via port (1) 1305a.

The procedure of registration in the filtering table will be described. The frame arriving at the port (1) 1305a is converted by the Ethernet control unit 1304a from a transmission signal into data that can be stored in a memory. At this time, the CPU 1301 determines from the received frame that the source MAC
The address is extracted, and if the source MAC address is not registered in the port (1) column of the filtering table, it is registered. Similarly, port (2) 130
If the source MAC address of the frame arriving at 5b is not registered in the port (2) column of the filtering table, it is registered.

By the above registration and the determination of the relay,
The bridge is designed to prevent unnecessary relays, thus avoiding network congestion.

Next, in the conventional network of FIG. 16, a LAN having a plurality of stations 1601a to 1601c
1202a is connected to the remote bridge 1603a,
LAN 160 having a plurality of stations 1601a to 1601c
2b is connected to the remote bridge 1603b, and the remote bridge 1603a and the remote bridge 1603b are interconnected by a public line 1605 such as a telephone network. Remote bridges 1603a and 1603b are IEEE
Performs the operation specified by E802.1D. One L
The AN is provided with a management station 1604 that manages this network.

As shown in FIG. 17, the conventional remote bridge includes a CPU 1701, a relay determination circuit 1702,
Memory 1703, Ethernet control unit 1704, LAN
Port 1705, public line access control circuit 1706,
It is composed of a public line port 1707. Memory 1
A relay information database is stored in 703.

Station 1201a implementing Ethernet
The frame transmission procedure inside 1201e to 1201e is as already described in FIG. Therefore, the frame structure is as shown in FIGS. 15 (a) to 15 (c).

In the remote bridge shown in FIG. 17, a frame arriving at the public line port 1707 is converted by the public line access control circuit 1706 from a transmission signal into data which can be stored in a memory. Similarly, LAN
The frame arriving at the port 1705 is converted by the Ethernet control unit 1704 from a transmission signal into data that can be stored in a memory. The relay determination circuit 1702 refers to the relay information database and determines whether to relay the frame.

Next, details of the MAC bridge will be described.

The MAC bridge has a plurality of ports,
It has a function of transmitting or receiving a MAC frame via a port. Connect different LAN to each port,
A MAC frame received from a certain LAN via a port is transmitted to another LAN via another port. Such an operation is called frame relay. FIG. 18 shows MAC
An example of a network using a bridge is shown. A plurality of computers 1801a to 1801b, 1 respectively
Two LANs 1802 with 801c to 1801d
a and 1802b are interconnected by a MAC bridge 1803. Computers connected to the network communicate with each other by exchanging MAC frames 1804. Here, a MAC frame or a frame is a block of data configured for communication on a network. An Ethernet frame is shown in FIG. 19 as a configuration example of the MAC frame. As shown,
The MAC frame includes communication data such as a destination address 1901, a source address 1902, and a higher-level protocol 1903, and user data 1 including contents to be actually exchanged.
And 904.

In FIG. 18, the computer 1801d connected to the LAN 1802b is connected to the LAN 1802.
The relay operation of the MAC bridge will be described by taking as an example the case of transmitting data to the computer 1801a connected to a. First, the computer 1801d adds communication control information to the data to be transmitted, forms a frame 1804, and transmits the frame 1804 to the LAN 1802b. LAN1802
The computer 1801c and the MAC bridge 1803 connected to b receive this frame 1804. The computer 1801c discards the frame 1804 because the destination address is not its own station. MAC bridge 1803
Relays frame 1804 to LAN 1802a if it is not designated to discard this frame 1804. The relayed frame 1804 is the computer 1
It is received by the computer 801b and the computer 1801a. The computer 1801b discards the frame 1804 because the destination address is not its own station. Computer 1801a
Since the destination address is its own station, frame 180
The user data in 4 is taken out and received. Thus, when viewed from the computer 1804d, the transmitted data passes through the MAC bridge 1803 and the computer 1
Appears to reach 801a.

Also, many MAC bridges are equipped with filter means. The function of the filter means is to prevent a frame received at one port of the MAC bridge from being transmitted to another port, and to avoid unnecessary frame relay to the network. The judgment as to whether the received frame is relayed or discarded is based on the information in the filter database. Here, FIG. 20 shows the internal configuration of the MAC bridge. The MAC bridge is a processor 2001, a frame storage memory 2002, a filter database 2003, a LAN connection circuit 2004.
a, 2004b, input / output ports 2005a, 2005b
Consists of Table 2 shows the contents of the filter database 2003.

[0017]

[Table 2]

Explaining Table 2, one filter information is the upper limit value and the lower limit value of the source MAC address, and the destination M.
The filter database 2003 is composed of eight pieces of information including the upper limit value and the lower limit value of the AC address, the upper limit value and the lower limit value of the upper protocol, the input port number, and the process. One piece of filter information is, regarding the port specified by the input port number, the received frame has a source address in the range of the lower limit value to the upper limit value, and a destination address in the range of the lower limit value to the upper limit value. And has a higher protocol in the range of the lower limit value to the upper limit value, the process of relaying or discarding is designated.

A specific operation of the filter processing will be described. In FIG. 20, taking the case where the input / output port 2005a connected to the LAN 2006a receives a frame as an example, the transmission signal of the frame received at the input / output port 2005a is transmitted to the processor 200 at the LAN connection circuit 2004a.
1 is converted into a data format that can be processed and stored in the frame storage memory 2002. The destination address, the source address, and the upper protocol value of the frame stored in the frame storage memory 2002 are compared with the destination address, the source address, and the upper protocol value held in the filter database 2003, and designated. If it is included in the range, relay or discard is decided according to the designated processing.

When the discard process is determined, the frame is deleted from the frame storage memory 2002. When the relay process is determined, the frame in the frame storage memory 2002 is sent to the LAN connection circuit 2004b. The frame is converted into a transmission signal by the LAN connection circuit 2004b, and is transmitted to the LAN 2006b via the input / output port 2005b.
Sent to.

[0021]

In the configuration of FIG. 12, the management station 1204 collects the MAC address and IP address of each station connected to the network as network configuration information. The conventional collection method is IAB
The management station 1204 makes inquiries to all stations individually using ARP (MAC address inquiry protocol) defined in the standard recommendation document RFC826 of the (Internet Architecture Committee). Therefore, when the number of stations to be managed increases, the number of times of communication by ARP increases, which leads to network congestion.

In the configuration of FIG. 16, the management station 1604
Performs network management using SNMP (simple network management protocol) defined in RFC1067. In network management using SNMP, the management station 1604 uses the application 14 to send transmission data for inquiring of the managed station about the status of the managed station.
The frame created in 01 and added with the IP communication control information 1404 and the MAC communication control information 1406 is output to the transmission path. The managed station passes the data excluding the communication control information to the upper application. The application of the managed station creates response contents to the inquiry, and the management station 1604
Sent as a response to. This network management is a very effective means for grasping the communication status of the network, but conventionally, the same transmission line is used for a frame containing network management information and a frame for sending data other than network management. If a failure occurs in the transmission line,
Since you can no longer send network management information,
It is difficult to find the cause of the disorder. In particular, in a network in which a remote LAN is connected using a public line, there is a problem that network management information cannot be transmitted / received when a failure occurs in the public line.

In the conventional filter processing described with reference to FIG. 20, it is necessary to compare the information of the received frame with all the information in the filter database. Therefore, if the number of information registered in the filter database is large, relay or discard is performed. It takes time to judge whether or not. If this determination takes a long time, the relay delay of the frame increases, and as a result, the performance of the network deteriorates. In recent years, in particular, the size of computers has increased, and the size of data exchanged between computers using networks has increased from several thousand bytes to several million bytes. On the other hand, in the case of Ethernet, which is the most popular as a small-scale network, the maximum frame size is specified as 1500 bytes. Therefore, when transferring large data as described above, the data is divided into pieces. Then, it is necessary to transmit each one as a frame. In this way, when a large amount of data is transferred between two computers, many MAC frames having the same communication control information section are generated. When the two computers are connected via the network relay device, the network relay device refers to the filter database every time a frame having the same communication control information section is received, and determines the process. When the filter database becomes huge, the time required for reference increases,
Relay delay becomes large.

Therefore, an object of the present invention is to solve the above problems, to provide a network relay device capable of improving the network management function and suppressing the relay delay.

[0025]

In order to achieve the above object, the present invention provides a network relay device having a plurality of ports, each of which is connected to a LAN to relay a frame between the LANs. A table for storing the transmission source MAC address and the transmission source IP address of the frame is provided, and a response means for answering the contents of the table to the network management station in response to a request from the network management station provided in the LAN is provided. It is a thing.

In addition, a plurality of ports are provided, and at least one
Connect the public line to one port and L to the other port
In a network relay device that connects an AN and relays a frame between remote LANs via a public line, the public line connected to the port is monitored, and if the public line cannot communicate, the public line is connected to the LAN. The frame received at the specified port is an IP-defined frame, and
When the network management information of SNMP is included, another public line is connected to one port, and line switching means for relaying the frame to a remote LAN via this public line is provided.

Also, a plurality of ports are provided, and each port has an L
A network relay device for relaying a frame between LANs by connecting an AN, which has a database storing relay availability information for frame communication control information, and stores the database according to the communication control information of a frame received at a port. In the network relay device having the filter means for limiting the relay by referring to it, the record holding means for holding the communication control information of the frame received in the past and the availability information at that time is provided, and the database is referred to. Previously, the same communication control information in the above-mentioned record holding means is searched based on the communication control information of the received frame, and the record filter means is provided to limit the relay by using the held availability information. Is.

The track record holding means has a key information holding section for holding a part of the communication control information as key information, and the track record filtering means holds a part of the communication control information of the received frame in the key information holding section. The same communication control information in the above-mentioned record holding means may be retrieved only when they are compared with each other by comparing with the key information.

[0029]

With the above configuration, the bridge is IAB RFC
When a frame with the IP specified in 791 is received, the source MAC address of the frame and the source IP
The address and the address are stored together in the table. Thus, in the table, the source M of the frame received for each port
The AC address and the source IP address are stored together. Therefore, the table stores the MAC address and the source IP address of the station connected to the port. If there is a request from the network management station, the response means returns the contents of the table to the network management station. Therefore, the network management station can understand the network configuration only by making a request to the relay device.
Therefore, it is possible to prevent the network from being congested by the inquiry frame.

In the configuration of the remote bridge in which the public line is connected to the port, the public line connected to the port is monitored, and if the public line cannot communicate, the frame received by the port connected to the LAN Is a frame defined by IP and includes SNMP network management information, the line switching means connects another public line to one port, and the frame is connected to a remote LAN via this public line. Relay. Therefore, another public line is used instead of the public line that cannot communicate. This other public line is used only when the frame contains network management information. Therefore, according to the present invention, a frame including network management information and a frame for transmitting data other than network management use different transmission lines, and the network management information is transmitted even when a failure occurs in the transmission line. be able to.

In the network relay device having the filter means, the filter means refers to the database to limit the relay, and at this time, the communication control information of the frame received by the record holding means and the availability information at that time. Is also held. That is, the record holding means holds the record of the past filter means. After that, when the frame is received, before referring to the database, the same communication control information in the result holding means is searched based on the communication control information of the frame received by the result filter means, and is also held together. The relay is restricted using the availability information. Therefore, the record that has a record in the past can be immediately relayed or discarded without waiting for the reference of the database.

When the record holding unit has a key information holding unit that holds a part of the communication control information as key information, the record filtering unit uses a part of the communication control information of the received frame as the key information of the key information holding unit. Compare. If the comparison result with the key information does not match, it is unlikely that the entire communication control information will match, so the comparison with the whole is cancelled. Only when the comparison result with the key information is a match, the same communication control information in the record holding means is searched. This speeds up the search.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, the bridge of the present invention comprises a CPU 101, a relay decision circuit 102, and a memory 10.
3, Ethernet control units 104a and 104b, port 1
It is composed of 05a and 105b. The memory 103 has a filtering table having a table structure.
As shown in Table 3, the filtering table can store the source MAC address and the source IP address of the frame received for each port together.

[0035]

[Table 3]

The CPU 101 responds to the contents of the filtering table to the network management station in response to a request from the network management station provided on the LAN.
6. The bridge of the present invention, like the conventional,
It can be provided in the network of FIG.

The operation will be described. As shown in FIG. 15B, the Ethernet communication control information includes a 16-bit area that indicates the frame type, that is, a type 1503. If the frame includes IP communication control information, it is specified in this area. Bit pattern is written. In the bridge of the present invention, when registering the filtering table,
The CPU 101 registers the source address of the received frame, compares the bit pattern of the type 1503 of the received frame with a specific bit pattern indicating that the IP communication control information is included, and if they match, the reception is performed. The source IP address is extracted from the IP communication control information of the frame. As shown in FIG. 15C, the source IP address is written in bits 96 to 127 of the IP communication control information. The extracted source IP address is written in the filtering table in the memory 103.

When the management station connected to the network requests the bridge to inquire about the MAC address and the IP address, the response means 106 causes all the MAC addresses and I's stored in the filtering table.
The P address is sent to the management station as a response.

In the conventional bridge, only the MAC address is stored in the filtering table. For this reason,
When the network management station wants to collect the correspondence between the MAC address and the IP address as network configuration information, it is necessary to make an inquiry to all stations. When the bridge of the present invention is used, the inquiry is completed to the bridge at one time, so that it is possible to prevent the frame transmitted for the inquiry from causing the network congestion.

According to the IEEE802.1D standard, the registered MAC addresses are deleted in the order of oldness so that the memory used for the filtering table does not overflow. Therefore, also in the present invention, the MAC address and the IP address are deleted from the oldest, and the information of the station having a relatively high communication frequency tends to remain in the filtering table. The management station can collect only the information of stations with high communication frequency by making an inquiry to the bridge.

Next, another embodiment will be described.

As shown in FIG. 2, the remote bridge of the present invention comprises a CPU 201, a relay determination circuit 202, a memory 203, an Ethernet controller 204, and a LAN port 2.
05, public line access control circuits 206a, 206b,
It is composed of public line ports 207a and 207b and a higher-level protocol determination circuit 208. A relay information database is stored in the memory 203.

As shown in FIG. 3, the network configuration is a LAN 30 having a plurality of stations 301a to 301c.
2a is connected to the remote bridge 303a of the present invention,
A LAN 302b having a plurality of stations 301a to 301c is connected to a remote bridge 303b of the present invention, and the remote bridge 303a and the remote bridge 303b are doubly interconnected by one or both of public lines 305a and 305b such as a telephone network. can do. Here, the remote bridges 303a and 303b respectively connect the public line ports 207a and 207b to the public line 305.
a and 305b. The remote bridges 303a and 303b perform the operation specified by IEEE802.1D. One LAN is provided with a management station 304 that manages this network.

Station 301d or management station 304 to station 301
The case of transmitting a frame to b will be described. The frame transmitted from the station 301d or the management station 304 to the LAN 302b is received by the remote bridge 303b. In the remote bridge 303b, the frame is relay determination circuit 202 via the LAN port 205 and the Ethernet control circuit 204.
Sent to In the relay determination circuit 202, the destination station 3
If 01b is connected to the LAN port 205 in the relay information database in the memory 203, the frame is discarded. Destination station 301b is LAN
If the connection to the port 205 is not stored in the relay information database in the memory 203, it is decided to send this frame to the remote LAN through the public line. On the other hand, the relay determination circuit 202 is connected to the public line 305.
When a frame does not arrive from a for a predetermined time or more, it is determined that the public line 305a cannot communicate. Therefore, when the public line 305a cannot communicate when transmitting the frame, the frame is transmitted to the upper protocol determination circuit 20.
8 to the public line access control circuit 206a if communication is possible. The frame sent to the public line access control circuit 206a is transmitted to the public line 305a via the public line port 207a.

When the public line 305a is incommunicable, the upper layer protocol determination circuit 208 causes the top 16 of the communication data 1402 following the IP communication control information 1404 of this frame.
Based on the bit, it is determined that this frame is a frame including SNMP network management information.

Here, according to the regulation of IAB RFC1060, the bit patterns of some applications are assigned to the leading 16 bits of communication data, and the upper protocol identification bit pattern indicating SNMP is "0000000010100001" ( 1
The hexadecimal notation “00A1”) is assigned. Therefore, the data structure of the network management information in SNMP is as shown in FIG. Upper protocol determination circuit 208
Determines whether or not the SNMP network management information is included, depending on whether the leading 16 bits of the communication data 1402 of the frame sent from the relay determination circuit 202 match "00A1".

When it is determined that the frame contains the SNMP network management information, this frame is sent to the public line access control circuit 206b and then to the public line 305b via the public line port 207b. If it is determined that the frame is a frame that sends data other than network management, the frame is discarded.

On the other hand, in the remote bridge 303a, the frame received from any of the public line ports 207a and 207b is passed through the Ethernet control circuit 204 and the LAN port 205 without the determination of the upper layer protocol.
It relays to AN302a. Therefore, the station 301b can receive all types of frames transmitted by the stations 301d and 301e or the management station 304 when the public line 305a is healthy, and the management station 304 or the like transmits when the public line 305a cannot communicate. It is possible to receive only the frames for network management.

In the conventional remote bridge, since there is only one line connecting the bridges, if a communication failure occurs, network management information cannot be exchanged, and the network management information cannot be used for investigating the cause of the failure. , It is difficult to isolate the failure, whether the station has a failure or the transmission path has a failure. However, by using the remote bridge of the present invention, the line connecting the bridges fails. Even in this case, the network management information can be exchanged by using another line, and the state of the remote station can be confirmed, so that the fault can be easily isolated.

Next, another embodiment will be described.

As shown in FIG. 5, the MAC bridge of the present invention comprises a processor 501 and a frame storage memory 50.
2, filter database 503, LAN connection circuit 50
4a and 504b, input / output ports 505a and 505b, and a temporary storage memory 507. Temporary storage memory 5
Reference numeral 07 denotes a record holding unit 508 that holds together the communication control information of the frame received in the past and the availability information at that time.
Is. The processor 501 executes the processing of FIG. 6, and part of the flow is to search the same communication control information in the record holding means 508 based on the communication control information of the received frame before referring to the database. In addition, the result filter means 509 for limiting the relay is configured by using the availability information that is also stored. Filter database 5
The contents of 03 are as shown in Table 2 as in the conventional case.
The contents of the temporary storage memory 507 are as shown in Table 4, for example.

[0052]

[Table 4]

As shown in Table 4, one piece of record information is composed of the communication control information of the frame received in the past, the determination result (property information), and the reference count.

In FIG. 5, when the input / output port 505a connected to the LAN 506a receives a frame as an example, the transmission signal of the frame received by the input / output port 505a is transmitted to the processor 50 by the LAN connection circuit 504a.
1 is converted into a data format that can be processed and stored in the frame storage memory 502. In the present invention, the temporary storage memory 507 is referred to before the filter database 503 is referred to.

In step 601 of FIG. 6, it is determined whether or not there is a registration in the temporary storage memory 507. If there is no registration, or if there is no corresponding registration even if the temporary storage memory 507 is sequentially referred to as described later, step 602
Thus, the relay is restricted by referring to the filter database 503 as usual. In this case, since the communication control information, the determination result, and the reference count = 1 are newly registered in the temporary storage memory 507, a frame having the same communication control information will be searched for in the temporary storage memory 507 from the next time onward. .

If there is a registration in the temporary storage memory 507,
At step 603, the communication control information column of the temporary storage memory 507 is sequentially referred to as to whether or not the communication control information of the received frame is registered.
The reference count is incremented by 1 and the determination result is referenced. In this way, the actual results can be immediately relayed or discarded by the actual results filter means without waiting for the reference of the filter database.

Further, when the capacity of the temporary storage memory 507 is limited, by deleting the registration from the one with the smallest number of references, it is possible to preferentially leave the record information having a high appearance frequency.

Next, an embodiment in which the form of holding the record information is modified will be described.

In the MAC bridge shown in FIG. 5, the temporary storage memory 507 has a structure in which 32 bits are one word. The first list block shown in FIG. 7, the second list block shown in FIG. 8, and the registration shown in FIG. Holds performance information using blocks. The first list block consists of three words, and each word stores the memory address 701 of the next first list block, the key 702, and the memory address 703 of the second list block in order. The key 702 is a key extracted from the leading 32 bits of the communication control information. That is, the first list block constitutes a key information holding unit. The second list block in FIG. 8 has a memory address 801 of the next second list block and a memory address 8 of the registration block.
02 and 2 are stored. The registration block in FIG. 9 includes a 4-word communication control information section 901 for storing communication control information and a 1-word result section 902 for storing determination results and reference times. Here, the determination result “1” means relaying, and “0” means discarding.

As shown in FIG. 10, these blocks are distributed and stored in arbitrary locations in the temporary storage memory 507. In order to read the record information of the registered block, the memory address of the second list block is fetched from the first list block and the memory address of the registered block is fetched from the second list block according to the flow of the broken line with an arrow in the figure. Become. Also, since the first list block has the memory address of the next first list block,
Using this information, the first list block can be traced in sequence, and although the plurality of first list blocks are actually stored in the temporary storage memory 507 in an arbitrary location in a distributed manner, the plurality of first list blocks are as if they were stored. It can be treated like a continuous array. Similarly, the plurality of second list blocks can be treated as if they are continuous arrays. In addition,
At the end of the array of the first list block or the second list block, 0 is stored in the memory address of the next list block to indicate the end. The memory address of the first list block, which is the head of the array of the first list block, is stored in the word of the specific memory address. In the example of FIG. 10, the memory address of the first list block at the beginning of the array = “20” is stored at address 0, and the memory address of the next first list block 1002 = at the first list block 1001 at address 20 = “60”, a key corresponding to the first 32 bits of the communication control information = “012
30000 "and the memory address of the second list block 1003 =" 120 "are stored.

The performance filter means corresponding to the performance holding means shown in FIG. 10 executes the processing of FIG.
The operation will be described below with reference to FIGS.

In step 1101, when the first list block exists, the leading 32 bits of the communication control information of the received frame and the leading first list block 10
The key included in 01 is compared with the key included in 01 (step 1102). If they match, the second list block 1003 is referred to by using the memory address of the second list block included in the first list block 1001, and the second list block 1003
The registration block 1006 is referred to by using the memory address of the registration block included in. The communication control information of the frame received here is compared with the communication control information included in the registration block 1006 (step 1103). If they match, it is determined that the frame is registered, and the reference count is set to 1
Increase by one and refer to the judgment result.

Top 3 of communication control information of received frame
If the two bits do not match the key contained in the first list block, the next first list block is referenced. Also,
When the keys match but the communication control information does not match, the next second list block is referred to. If the first list block does not exist, or if there is no registration block having the same communication control information, the relay is restricted by referring to the filter database 503 as in step 1104, and a new first list block, 2 Create a list block and a registration block with the reference count = 1. A frame having the same communication control information will be searched in the temporary storage memory 507 from the next time onward.

As described above, the result filter means immediately decides the relay or the discard of the item having a past result without waiting for the reference of the filter database. Also, when searching, the first list block
Since only words are compared in advance, processor 5
The minimum instruction operation of 01 enables sieving and speeds up the search.

When a large amount of data is cut into small pieces and transmitted in a network system in which the frame length is restricted, the network relay device frequently receives frames having the same communication control information portion in a short time. According to the present invention, the relay delay can be suppressed because the record filter means immediately determines whether the frame having the same communication control information portion is relayed or discarded without waiting for the reference of the filter database.

[0066]

The present invention exhibits the following excellent effects.

(1) In response to a request from the network management station, the network relay device replies the source MAC address and source IP address of the frame received for each port. Congestion is prevented.

(2) Even if the public line is incommunicable, the network management information can be sent by using another public line, so that the fault can be easily isolated.

(3) Since relays or discards of those having a past record are not immediately waited for reference to the database but are directly determined by the record filter means, relay delay can be suppressed.

[Brief description of drawings]

FIG. 1 is an internal configuration diagram of a bridge of the present invention.

FIG. 2 is an internal configuration diagram of a remote bridge of the present invention.

FIG. 3 is a configuration diagram of a network using a remote bridge of the present invention.

FIG. 4 is a data configuration diagram of network management information in SNMP.

FIG. 5 is an internal configuration diagram of a MAC bridge of the present invention.

FIG. 6 is a processing flow chart of the performance filter means of the present invention.

FIG. 7 is a word configuration diagram of a first list block in the achievement holding means of the present invention.

FIG. 8 is a word configuration diagram of a second list block in the achievement holding means of the present invention.

FIG. 9 is a word configuration diagram of a registration block in the achievement holding means of the present invention.

FIG. 10 is a memory map diagram of the record holding means of the present invention.

FIG. 11 is a process flow chart of the performance filter means of the present invention.

FIG. 12 is a configuration diagram of a network using a bridge.

FIG. 13 is an internal configuration diagram of a conventional bridge.

FIG. 14 is a flow chart showing a frame transmission procedure inside a station implementing Ethernet.

FIG. 15 is a structural diagram of a frame.

FIG. 16 is a configuration diagram of a network using a conventional remote bridge.

FIG. 17 is an internal block diagram of a conventional remote bridge.

FIG. 18 is a configuration diagram of a network using a MAC bridge.

FIG. 19 is a structural diagram of an Ethernet frame.

FIG. 20 is an internal configuration diagram of a conventional MAC bridge.

[Explanation of symbols]

 101 CPU 103 Memory 105a, 105b Port 106 Response Unit 205 LAN Ports 207a, 207b Public Line Port 208 Higher Protocol Judgment Circuit 305a, 305b Public Line 503 Filter Database 507 Temporary Storage Memory 508 Actual Result Means 509 Actual Result Filter Means

Claims (4)

[Claims] 1. A plurality of ports, each port being a LAN
In a network relay device for connecting a LAN and relaying a frame between LANs, a table for storing the source MAC address and the source IP address of the frame received for each port is provided, and a network management station provided in the LAN is provided. A network relay device comprising a response means for responding to the network management station in response to a request from the network management station. 2. A plurality of ports are provided, a public line is connected to at least one port, and a LAN is connected to other ports.
In the network relay device that connects the LAN and relays a frame between remote LANs via the public line, the public line connected to the port is monitored, and when the public line cannot communicate, the public line is connected to the LAN. The frame received at the port is a frame defined by IP and the SN
When the network management information of MP is included, another public line is connected to one port, and line switching means for relaying the frame to a remote LAN via this public line is provided. . 3. A plurality of ports are provided, and each port is a LAN
Is a network relay device that relays frames between LANs by connecting to each other, and has a database that stores whether or not to relay frame communication control information, and refers to the above database according to the communication control information of the frame received at the port. In a network relay device having a filter means for restricting relaying, before providing the record holding means for holding together the communication control information of the frame received in the past and the availability information at that time, before referring to the database. In addition, the same communication control information in the above-mentioned record holding means is searched based on the communication control information of the received frame, and the record filter means for limiting the relay by using the held availability information is also provided. Characteristic network relay device. 4. The achievement holding means has a key information holding portion for holding a part of the communication control information as key information, and the achievement filter means holds a part of the communication control information of the received frame as the key information. 4. The network relay device according to claim 3, wherein the same communication control information in the record holding means is retrieved only when the key information is compared with the key information of the copy.