JP3049028B1 - Multiplexing system and method for LAN connection device - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To switch to a spare LAN connection device in a short time without manual intervention for a failure of a LAN connection device,
In addition, the present invention provides a multiplexing method and a method of a LAN connection device which do not affect TCP / IP connections. SOLUTION: A TCP / IP protocol processing unit, a plurality of LAN connection devices, a plurality of LAN connection device control units for controlling the plurality of LAN connection devices, the TCP / IP protocol processing unit, and the plurality of LANs Intermediate with the connection device control unit, during the frame format and ARP (Add
ress Resolution Protocol) Rewrite the MAC address at a predetermined position in the packet format, and
An address translation unit that transmits an ARP reply packet for rewriting the RP cache table.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiplexing system for a LAN connection device.

[0002]

2. Description of the Related Art Hitherto, as a multiplexing method of a LAN connection device, Japanese Patent Laid-Open Nos. 4-365238 and 5-21
No. 0607, JP-A-8-335198 and JP-A-9-167128.

[0003] The technique described in Japanese Patent Application Laid-Open No. 4-365238 is intended to efficiently and quickly switch from a failed communication processing device to a standby communication process without manual intervention. When a failure occurs in the operating communication processing device and the operation of the communication processing device is stopped, the operation stop of the communication processing device is detected and the L of the operating communication processing device is determined.
The same address as the address on the AN is given to the standby communication processing device, and the general-purpose computer operates the standby communication processing device.

The technology described in Japanese Patent Laid-Open No. Hei 5-210607 automatically switches LAN connection devices when a failure occurs in redundant LAN connection measures, and recovers in a short time.
L that can improve operational efficiency as a network
A connection control unit that receives an individual address from a general-purpose computer and stores one of a communication processing state of an operation state and a standby state for the purpose of providing an AN connection device; and A report on whether the apparatus is in the standby state is received from the connection control unit, and the general-purpose computer is notified via the LAN connection device input / output control unit.
The connection device monitors the operation state of the operating LAN connection device in response to the connection command output by the general-purpose computer via the general-purpose computer, and when it detects that no response is made within a predetermined period of time, transmits a provisional operation start report to the LAN. And a LAN connection device control unit that notifies the general-purpose computer via the connection device input / output control unit.

The technique described in Japanese Patent Application Laid-Open No. 8-335198 is intended to improve the reliability of the system by switching the IP address at the time of constructing the redundant system of the LAN connection device of the general-purpose computer without manual operation. Things.
In this technology, a standby LAN connection device controls a device control unit for controlling the general-purpose computer interface protocol, an IP information replacement unit that replaces IP information of the active LAN connection device with IP information of the standby system, It has a flag indicating the active standby system, and has the active LAN from the LAN side.
An operating system check unit that performs a communication function check of the connection device; an IP information storage unit that stores the IP information of the own device and the IP information of the operation LAN connection device acquired by the IP information acquisition unit; It comprises an IP information acquisition unit for acquiring IP information, and a LAN interface control unit for controlling and activating and deactivating the LAN interface.

The technique described in Japanese Patent Application Laid-Open No. HEI 9-167128 aims at simplifying the recovery processing of a LAN controller failure and shortening the processing time in a communication system for controlling a TCP / IP protocol in a computer. It is an object of the present invention to make the MAC address of another LAN controller that does not cause a failure when the LAN controller fails, to correspond to the IP address corresponding to the LAN controller that failed.

[0007]

However, the prior art has the following problems.

In the technology described in JP-A-4-365238 and JP-A-5-210607, a mechanism capable of designating a MAC address of a LAN connection device from software other than a LAN connection device control unit,
A mechanism for stopping and starting the connection device is required. However, in a computer using a general-purpose OS such as a personal computer, a LAN connection device control unit generally called a driver reads a MAC address written on a ROM mounted on the LAN connection device. Since the setting is performed on the LAN connection device, the MAC address cannot be set freely unless the LAN connection device control unit is modified.
Also, regarding the stop and start of the LAN connection device,
The connection device control unit or the OS does not have such a function.

In the technique described in Japanese Patent Application Laid-Open No. 8-335198, in addition to the above-mentioned stop and start of the LAN connection device, a mechanism for changing the IP address assigned to the active LAN connection device to the standby LAN connection device. Is required. Some OSs operating on a personal computer require an IP address to be assigned to each LAN connection device before the OS starts. Moreover, each L
The same IP address cannot be set in the AN connection device. In such an OS, it is not possible to change the IP address to the standby system.

In the technique described in Japanese Patent Application Laid-Open No. 9-167128, the correspondence table of the IP address and the LAN connection device of the TCP / IP protocol processing unit is rewritten, and the ARP cache table is changed to the communication partner. Module is needed. Some of the TCP / IP protocol processing units operating on a personal computer cannot rewrite the correspondence table between the IP address and the LAN connection device, and the OS and the TCP capable of realizing the technology described in JP-A-9-167128 are disclosed. / IP protocol processing unit is limited. In addition, it is necessary to add software for rewriting the ARP cache table to all the communication partner computers.

The present invention provides a LAN which solves the above problems.
This is a multiplexing method for connecting devices.

[0012]

The multiplexing method of the LAN connection device according to the present invention is based on TCP / IP (Transmission Control).
rol Protocol / Internet Protocol) protocol processing unit, a plurality of LAN connection devices, a plurality of LAN connection device control units for controlling the plurality of LAN connection devices, and the TCP
/ IP protocol processing unit and the plurality of LAN connection device control units, and
AR for rewriting the MAC address of a predetermined value in the RP (Address Resolution Protocol) packet format and rewriting the ARP cache table of the communication partner
An address translator for transmitting a P reply packet.

The multiplexing method of the LAN connection device according to the present invention is the multiplexing method of the LAN connection device described above, wherein the address conversion unit transmits the plurality of LANs at the time of transmission.
One MAC address selected from the connection devices is written into a source MAC address, a sender MAC address, or a target MAC address, and is output to the selected LAN connection device.

Further, in the multiplexing method of the LAN connection device according to the present invention, in the above-mentioned multiplexing method, the address conversion unit transmits a MAC address of a predetermined value to the destination
The method is characterized in that the MAC address is written into the C address, and the MAC address having the predetermined value is written into the sender MAC address under predetermined conditions upon reception.

Further, the multiplexing method of the LAN connection devices according to the present invention is the multiplexing method of the LAN connection devices described above, further comprising a LAN monitoring unit for monitoring whether or not the plurality of LAN connection devices are abnormal. The address conversion unit operates based on a monitoring result of the LAN monitoring unit.

Further, the multiplexing method of the LAN connection device according to the present invention is the multiplexing method described above, wherein
It is characterized in that non-failure LAN connection devices among the N connection devices are operated simultaneously.

In the multiplexing method for LAN connection devices according to the present invention, a MAC address at a predetermined position in a frame format and an ARP packet format received from a plurality of LAN connection devices is rewritten to a MAC address of a predetermined value to transmit a TCP / TCP. Output to the IP protocol processing unit,
Rewriting the MAC address at a predetermined position in the frame format and the ARP packet format received from the CP / IP protocol into one MAC address selected from the plurality of LAN connection devices and outputting the MAC address to the LAN connection device. It is characterized by.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a TCP / IP (Transmission Control) between computers connected to a LAN.
Protocol / Internet Protocol) In a system that performs communication using a protocol, when a failure occurs in a LAN connection device, switching to a spare device is performed in a short time to improve reliability. In particular, software for processing the TCP / IP protocol (TCP / IP protocol processing unit 1)
7) and software for controlling the LAN connection device (LAN
It is characterized in that no special device is required for the connection device control units 14a and 14b), and that no software for switching is required in the computer on the communication partner side.

In FIG. 1, the LAN connection device 13a is a LAN connection device in an operation state, and the LAN connection device 13b is a LAN connection device in a standby state. Address converter 15
Is the LAN to the TCP / IP protocol processing unit 17
In order to make it appear that there is only one connection device, the MAC address in the transmission or reception frame is set to a fixed value vM.
Convert to a. Further, a LAN connection device specified by an instruction from the LAN monitoring unit 16 is used. Further, when an instruction to switch the LAN connection device is issued from the LAN monitoring unit 16, an ARP reply packet is transmitted to another computer, and the TCP / I of another computer is transmitted.
By causing the P-protocol processing unit to update the ARP cache table for performing the conversion between the IP address and the MAC address, other computers can transmit the packet to the switched LAN connection device without disconnecting the TCP / IP connection. Come to come.

Referring to FIG. 1, this embodiment comprises a computer 11, a LAN 12, and LAN connection devices 13a and 13b for connecting the computer and the LAN.

As software operating in the computer 11, a LAN 1 is connected by using a LAN connection device 13a.
2, a LAN connection device control unit 14a for sending a frame to the LAN 12 and receiving a frame from the LAN 12, and a LAN connection device control for sending a frame to the LAN 12 and receiving a frame from the LAN 12 using the LAN connection device 13b. Unit 14b and send to LAN 12 or LAN
And an address conversion unit 15 for rewriting the MAC address of the frame received from the LAN 12 and monitoring the abnormality of the LAN connection device and requesting the address conversion unit 15 to switch the LAN connection device to be used when there is an abnormality. LAN monitoring unit 16 that performs TCP / IP protocol processing
It comprises a P / IP protocol processing unit 17.

The MAC address portion rewritten by the address conversion unit 15 includes a destination MAC address 21, a source MAC address 22, and a destination MAC address 22 in the frame format shown in FIG.
The sender MAC address 32 and the target MAC address 34 in the ARP (Address Resolution Protocol) packet format of FIG. FIGS. 4 and 5 are flowcharts of this rewriting. FIG. 4 is a flowchart at the time of transmission, and FIG. 5 is a flowchart at the time of reception.

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

Now, the computer 11 communicates with other computers connected to the LAN 12 using the TCP / IP protocol, using the LAN connection device 13a. At this time, the computer 11 sends the LAN1
The flow of the frame until it is transmitted to TCP / IP is TCP / IP
The information is passed to the protocol processing unit 17, the address conversion unit 15, the LAN connection unit control unit 14a, and the LAN connection device 13a in this order. At this time, the address conversion unit 15 changes the MAC address Ma1 of the LAN connection device 13a into the source MAC address 22, the sender MAC address in accordance with the flowchart of FIG.
The data is written to the address 32 or the target MAC address 34 and passed to the LAN connection device control unit 14a. LAN
The connection device control unit 14a sends the received frame to the LAN 12 using the LAN connection device 13a.

The flow of a frame when the computer 11 receives data from the LAN 12 is based on the LAN connection devices 13a and L
AN connection device control unit 14a, address conversion unit 15, TC
The order is the P / IP protocol processing unit 17. At this time,
In the address conversion unit 15, according to the flowchart of FIG.
The vMa is written to the destination MAC address 21 or the sender MAC address 32 and passed to the TCP / IP protocol processing unit 17. The frame received through the LAN connection device 13b is discarded by the address conversion unit 15.

At this time, the ARP cache table for converting the IP address on the memory of the communication partner computer into the MAC address is stored in the LAN of FIG.
It is like the ARP cache table 61 when the connection device 13a is the partner, and Ma1 is registered for IP1. In this state, the LAN monitoring unit 16
Monitors the LAN connection device 13a through the LAN connection device control unit 14a for any abnormality, and when the abnormality is detected, instructs the address conversion unit 15 to switch the LAN connection device. Address conversion unit 15 receiving the instruction
Is the value indicating the reply in operation 31 as the packet format of the ARP in FIG.
A frame in which an ARP reply packet having Ma2 as the address 34 and IP1 as the target IP address 35 is set in the data 24 of FIG. 2 is created, and the communication partner is transmitted via the LAN connection device control unit 14b and the LAN connection device 13b. To your computer. The computer that has received the ARP reply packet changes the ARP cache table on the memory according to the specification of the ARP protocol. The result of this change is shown in FIG.
ARP cache table 6 when the connection unit 13b is the partner
2. As a result, the frame transmitted by this computer is transmitted to Ma2.

On the other hand, after transmitting the ARP reply packet, the address translator 15 makes the transmission to the LAN connection device controller 14b, discards the frame received from the LAN connection device controller 14a, and The frame received from the device control unit 14b is passed to the TCP / IP protocol processing unit. At this time, in the same way as when the LAN connection device 13a is used, the destination MAC address 2 is transmitted according to the flowchart of FIG. 4 for transmission and according to the flowchart of FIG. 5 for reception.
1. Rewrite the source MAC address 22, the sender MAC address 32, and the target MAC address 34.

As described above, L of the standby system is
Switching to the AN connection device 13b can be performed in a short time without disconnecting the TCP / IP connection.

Next, another embodiment of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 7, this embodiment differs from FIG. 4 in that if there is no failure in either of the two LAN connection devices, the MAC address is set to use both of the two LAN connection devices. This is different in that if a failure occurs in one of the LAN connection devices, the MAC address is changed to use only the other.

Now, it is assumed that both the LAN connection devices 13a and 13b are in a normal state. At this time, the flow of the frame from the computer 11 to the transmission to the LAN 12 is T
CP / IP protocol processing unit 17 to address conversion unit 1
5, the address conversion unit 15 determines which LAN connection device to use based on the destination MAC address 21 by a predetermined method, and rewrites the MAC address in the frame according to the flowchart of FIG. 7. , L to use
The frame is passed to the AN connection device control unit 14a or 14b, and the passed frame is sent to the LAN connection device 13a or 1b.
It is sent to the LAN 12 through 3b.

Among them, there are several methods for determining which LAN connection device to use. One is the destination MA
If the C address 21 is an odd number, the LAN connection device 13a
In the case of an even number, the LAN connection device 13b is used. Otherwise, L for the first sender
Use the AN connection device 13a, use the LAN connection device 13b when it is necessary to transmit to a partner other than this transmission partner, and use 13a when the next transmission must be performed to a new partner. There is a method of using the LAN connection device alternately for a new transmission destination, such as using the next 13b. In addition, when a new transmission partner is generated, there is a method in which the number of times of transmission / reception is small during a certain period in recent years.

On the other hand, when the computer 11 receives the frame from the LAN 12, the flow of the frame is the MAC address corresponding to the destination MAC address 21 of the frame flowing on the LAN 12.
Received by the LAN connection device having the address and the corresponding LA
The address is passed to the address conversion unit 15 through the N connection device control unit. The address translator 15 rewrites the MAC address in the frame according to the flow chart of FIG.
It is passed to the P protocol processing unit 17.

Next, a case where a failure occurs in the LAN control unit 13a or 13b will be described. Since the flow of operation does not change when a failure occurs in the LAN connection device 13a or when it occurs in the LAN connection device 13b, only the case where a failure occurs in the LAN connection device 13a will be described here.

When a failure occurs in the LAN connection device 13a, the LAN monitoring unit 16 detects this failure and notifies the address conversion unit 15 not to use the LAN connection device 13a. The address translator 15 having received this notification converts the ARP packet format shown in FIG.
A value indicating a reply to 1 and a target MAC address 34
A2, a frame in which an ARP reply packet whose target IP address 35 is IP1 is set as the data 24 in FIG. 2, and the LAN connection device control unit 14b
And to the communication partner computer via the LAN connection device 13b. The computer receiving this frame stores the ARP table in the memory in the ARP cache table 62 when the LAN connection device 13b in FIG.
Change to As a result, all computers communicating with the computer 11
b.

However, since the LAN connection device 13a is not stopped, the frames transmitted until all the computers are switched to the transmission to the LAN connection device 13b or the broadcast frames are not connected to the LAN connection device 13a. Because it is received through the device 13a,
The address management unit 15 discards the frame passed from the LAN connection device control unit 14a.

As described above, when an abnormality occurs in one of the LAN connection devices, only the other one can be used.

Although the above embodiment is a duplex system, it can be extended to two or more multiplex systems.

As is apparent from the above description, the method performed by the address conversion unit 15 and the LAN monitoring unit 16 is based on a method in which a computer stores a recording medium such as a CD-ROM in which a program for executing the method is executed. It can also be realized by reading and executing.

[0040]

The advantages of the present invention are as follows. In the event of a failure of a LAN connection device, a spare LAN
The switching to the connection device does not affect the TCP / IP connection, so that the reliability of the computer network system is improved.

Further, since it is only necessary to add software for the address conversion unit and the LAN monitoring unit, the present invention can be applied to a system in which the TCP / IP protocol processing unit and the LAN connection device control unit cannot be modified.

Further, when multiplexing a LAN connection device with an already operating computer, it is only necessary to add the LAN connection device and the software to only the computer to be multiplexed. The work is simple.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a multiplexing system of a LAN connection device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a frame format.

FIG. 3 is a diagram showing an ARP (Address Resolution Protocol) packet format.

FIG. 4 is a flowchart showing an operation at the time of transmitting a packet according to the embodiment of the address translation unit of FIG. 1;

FIG. 5 is a flowchart showing the operation of the address translation unit of FIG. 1 when receiving a packet.

FIG. 6 is an example of the contents of an ARP cache table according to the embodiment of the present invention.

FIG. 7 is a flowchart illustrating an operation at the time of transmitting a packet according to another embodiment of the address conversion unit of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Computer 12 LAN 13a, 13b LAN connection device 14a, 14b LAN connection device control part 15 Address conversion part 16 LAN monitoring part 17 TCP / IP protocol processing part

Continuation of front page (56) References JP-A-10-320327 (JP, A) JP-A-10-320323 (JP, A) JP-A 8-32599 (JP, A) JP-A-4-328660 (JP) JP-A-3-110942 (JP, A) JP-A-9-167128 (JP, A) RFC (Request For Comments) 826, David C. Plummer, "An Ethernet et Address Resolution Protocol", ( (November 1982) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/28 G06F 13/00 353

Claims (7)

(57) [Claims] [Claim 1] TCP / IP (Transmission Control Pr
otocol / Internet Protocol) protocol processing unit, a plurality of LAN connection devices, a plurality of LAN connection device control units for controlling the plurality of LAN connection devices, the TCP / IP protocol processing unit, and the plurality of LAs
Transmits an ARP reply packet for rewriting the MAC address at a predetermined position in the frame format and the ARP (Address Resolution Protocol) packet format, and rewriting the ARP cache table of the communication partner, interposed between the N connection device control unit. A multiplexing method for a LAN connection device, comprising: 2. The multiplexing method for a LAN connection device according to claim 1, wherein the address conversion unit transmits one MAC address selected from the plurality of LAN connection devices at the time of transmission to a transmission source MAC address and a transmission destination MAC address. A multiplexing method for a LAN connection device, wherein the multiplexing method is to write to a user MAC address or a target MAC address and output to the selected LAN connection device. 3. The multiplexing method for a LAN connection device according to claim 1, wherein the address conversion unit writes a MAC address of a predetermined value into a destination MAC address at the time of reception, and writes the MAC address under a predetermined condition at the time of reception. A multiplexing method for a LAN connection device, wherein a MAC address having a predetermined value is written in a sender MAC address. 4. The multiplexing system for a LAN connection device according to claim 1, wherein the plurality of LAs are used.
The LA monitoring device further includes a LAN monitoring unit that monitors whether there is an abnormality in the N connection device, wherein the address conversion unit operates based on a monitoring result of the LAN monitoring unit.
Multiplexing method of N connection device. 5. The multiplexing method for a LAN connection device according to claim 4, wherein, among the plurality of LAN connection devices, LAN connection devices that do not fail are simultaneously operated. . 6. A step of rewriting a MAC address at a predetermined position in a frame format and an ARP packet format received from a plurality of LAN connection devices to a MAC address of a predetermined value, and outputting the MAC address to a TCP / IP protocol processing unit; The MAC address at a predetermined position in the frame format and the ARP packet format received from the TCP / IP protocol is rewritten to one MAC address selected from the plurality of LAN connection devices and output to the LAN connection device. And a multiplexing method of the LAN connection device. 7. A step of rewriting a MAC address at a predetermined position in a frame format and an ARP packet format received from a plurality of LAN connection devices to a MAC address of a predetermined value and outputting the MAC address to a TCP / IP protocol processing unit; The MAC address at a predetermined position in the frame format and the ARP packet format received from the TCP / IP protocol is rewritten to one MAC address selected from the plurality of LAN connection devices and output to the LAN connection device. Steps and
A computer-readable recording medium on which a program for causing a computer to execute the program is recorded.