JP2000029806A - LAN adapter load balancing method for computer system - Google Patents

Abstract

(57) [Problem] To provide a method capable of dynamically responding to a LAN system configuration change using an address resolution protocol when transmitting data to a terminal system. When a computer system transmits data to a terminal system, a logical address for communication is used as a source logical address, and a logical address for address resolution is used for address resolution for obtaining a physical address of the terminal system. By making the request, the load distribution to the LAN adapters for data reception from the terminal system can be continued, and the physical address of the terminal system can be dynamically obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a LAN adapter load distribution system in communication between a computer system and a terminal system connected to the same LAN via a plurality of LAN adapters.

[0002]

2. Description of the Related Art Conventionally, in data communication between a computer system and a terminal system connected to the same LAN via a plurality of LAN adapters, the terminal system does not need to be aware of the existence of a plurality of LAN adapters in the computer system. As a method of distributing the load to a plurality of LAN adapters, there is the following method as described in Japanese Patent Application Laid-Open No. 1-245619.

One logical address is provided for the computer system, and when the terminal system transmits data to the computer system, the destination logical address uses the logical address of the computer system, and the physical address is the address resolution transmitted by the terminal. In response to the request, a unique physical address is returned to the LAN adapter used based on the predefined information, and subsequent communication between the computer system and the terminal system uses the LAN adapter. Do.

[0004]

Conventionally, the physical addresses of a computer system and a terminal system may be changed by replacement of the computer system and the terminal system, replacement of a LAN adapter, and the like. ARP (Address Resolution Protocol)
ol). ARP broadcasts an address resolution request including the logical address of the communication partner on the LAN and
The computer system and the terminal system that have transmitted the request to all the computer systems and the terminal systems on N and received the request, if they are their own logical addresses, return their own physical addresses to obtain the physical addresses. It is a protocol that defines an address conversion method that can perform the address conversion. The ARP standard is RFC (Request For Commen
ts) 826.

In ARP, correspondence between a logical address and a physical address of a communication partner is stored in an address conversion table, and data is transmitted based on the contents of the table. Also, in order to immediately know that the physical address of the communication partner has changed, even if the address resolution request broadcast on the LAN is not addressed to itself, the address is translated based on the logical address and physical address of the transmission source. It is prescribed to store in a table.

For this reason, in the above-mentioned prior art, when the physical address of the terminal system is changed due to the configuration change of the LAN system, the LAN which transmitted the address solution request
Since the physical address of the adapter is stored in all terminal systems on the LAN, the load concentrates on a specific LAN adapter. To prevent this, the computer system must define the logical addresses and physical addresses of all terminal systems on the LAN so that the computer system does not need to send an address resolution request.

Further, in the above-mentioned prior art, since the LAN adapter to be used for each terminal system needs to be defined in advance, the maintainability of the computer system is poor.

An object of the present invention is to make a terminal system aware of the existence of a plurality of LAN adapters of a computer system in data communication between the computer system and the terminal system connected to the same LAN via a plurality of LAN adapters. In addition, the computer system can distribute the load of processing the received data from the terminal system to the LAN adapters, and can use the address resolution protocol to transmit the data to the terminal system to change the configuration of the LAN system. It is an object of the present invention to provide a method capable of coping with the problem.

[0009]

In order to achieve the above object, the present invention provides two types of logical addresses for a computer system: a logical address for communication and a logical address for address resolution.

[0010] The communication logical address is used in data communication with the terminal system. In other words, when the terminal system transmits data to the computer system, a logical address for communication is set to the destination logical address, and when the computer system transmits data to the terminal system, the logical address for communication is set to the source logical address. Set the address. Also, upon receiving an address resolution request from the terminal system, the computer system selects the LAN adapter with the lowest load among the plurality of LAN adapters, and responds with its physical address, thereby enabling communication with the subsequent terminal system. Data communication is via LAN
Via an adapter.

As a result, the terminal system does not need to be aware of the existence of a plurality of LAN adapters in the computer system.
Data communication can be performed via the LAN adapter selected by the computer system only by using the communication logical address.

The logical address for address resolution is used when the computer system sends an address resolution request. If the destination physical address of the terminal system is unknown in the address translation table, any one of the plurality of LAN adapters is selected, and an address resolution request in which an address resolution logical address is set is broadcast on the LAN. All terminal systems on the LAN receive the address resolution request. However, since a logical address for address resolution has been set, the correspondence between the logical address for address resolution and the physical address of the LAN adapter that transmitted the address resolution request has been established. Is merely stored. Therefore, the data communication with the terminal system using the communication logical address can be continued via the LAN adapter used so far.

[0013]

FIG. 1 shows a LAN to which the present invention is applied.
FIG. 1 is a configuration diagram illustrating an example of a system. 101 is a computer system such as a file server, 102 and 103 are terminal systems such as workstations, 104 is IEEE8
22.3 and the like. The computer system 101
As shown in FIG. 1, LAN adapters 111 to 113 corresponding to LAN interface lines, a computer 114 for executing a program, a communication management program 115 for performing a communication protocol process, an address conversion table 116, and an application for realizing a service to a terminal system Program 117, computer and LAN adapters 111 to 113
Are connected to each other.

The address configuration includes a communication logical address 121 of the computer system 101, an address solving logical address 122, a logical address 123 of the terminal system 102, and a logical address 124 of the terminal system 103.
The physical address is the physical address 1 of the LAN adapter 111
31, physical address 132 of LAN adapter 112, L
The physical address 133 of the AN adapter 113, the physical address 134 of the terminal system 102, and the terminal system 10
3 physical address 135. In FIG. 1, for example, L
Although the number of AN adapters is three and the number of terminal systems is two, these numbers are not limited in the principle of the present invention.

First, a case where data is transmitted from the terminal system 102 to the computer system 101 will be described.
The terminal system 102 broadcasts an address solution request on the LAN 104 to obtain a physical address corresponding to the communication logical address 121 of the destination computer system 101. Thereby, the computer system 101
Sends an address resolution request from the terminal system 102 to the LAN
The signals are received by the adapters 111, 112, and 113, respectively. Communication management program 115 for computer system
Selects the LAN adapter 112 with a small load from the LAN adapters 111 to 113, sets its physical address in the address resolution response, and transmits the response.

An example of a LAN adapter selection processing flow in the communication management program 115 at this time will be described with reference to FIG. First, it is checked whether or not the LAN adapter to be used for the terminal system 102 of the transmission source has already been selected by referring to the management table of the LAN adapter being used (step 201). This is to store the LAN adapter selected for each terminal system in order to respond from one LAN adapter to the address resolution request from the same terminal system received for each LAN adapter, and do not respond from other LAN adapters. That's why. As the management table, the LAN selected in the address conversion table
This can be done by storing the physical address of the adapter.

If it has not been selected yet, a LAN adapter with a low load is selected (step 202).
The selected LAN adapter is registered in the management table of the AN adapter (step 203). If the selection has already been made, the selection processes 202 and 203 are not performed.

Next, referring to the management table of the used LAN adapter, it is checked whether or not the selected LAN adapter is equal to the received LAN adapter (step 204). Send it (step 205).

The terminal system 102 that has received the address resolution response registers the physical address 132 of the LAN adapter 112 in the address conversion table and transmits the data to the computer system 101 via the LAN adapter 112.

Next, a case where data is transmitted from the computer system 101 to the terminal system 103 will be described. Application program 11 of computer system 101
7 to the terminal system 103, the communication management program 115 of the computer system 101 that has received the data transmission request
If the physical address of the terminal system 103 is not in the address conversion table 116, an address resolution request is sent to any one of the LAN adapters 111 to 113, for example, Select adapter 113, LAN
Broadcast transmission to 104. At this time, the address resolution logical address 122 is set as the transmission source logical address.

The broadcast data is transmitted to the LAN 10
4 is received by both the terminal systems 102 and 103, but the communication logical address 12 of the computer system 101 is received.
2 is not used, the physical address corresponding to the communication logical address 112 of the computer system 101 in the address conversion table of each of the terminal systems 102 and 103 is not changed. Therefore, the terminal system 102 can perform data communication via the LAN adapter 112. The communication management program 115 of the computer system that has received the address resolution response from the terminal system 103 transmits data in which the communication logical address 121 is set to the transmission source logical address to the terminal system 103. The above computer system 10
FIG. 3 shows a sequence of data communication from No. 1 to the terminal system 103.

As described above, the terminal system can communicate using the LAN adapter with a low load selected by the computer system only by using the communication logical address of the computer system. Also, the computer system can transmit and obtain an address resolution request and perform communication with the terminal system without defining the physical address of the terminal system. Can be communicated over.

[0023]

According to the present invention, the terminal system can reduce the load of processing data received from the terminal system by each LA without being aware of the existence of a plurality of LAN adapters in the computer system.
N data can be distributed to N adapters, and an address resolution protocol can be used at the time of data transmission to the terminal system to dynamically respond to a change in the configuration of the LAN system.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a LAN system to which the present invention is applied.

FIG. 2 is a diagram showing an example of a LAN adapter selection processing flow in a communication management program 115.

FIG. 3 shows a computer system 101 to a terminal system 103
FIG. 4 is a diagram showing an example of a data communication sequence to the computer.

[Explanation of symbols]

101: Computer system, 102, 103: Terminal system, 104: LAN, 111-113: LAN adapter, 114: Computer, 115: Communication management program,
116: Address conversion table, 117: Application program, 118: Channel, 121: Computer system communication logical address, 122: Computer system address solution logical address, 123, 124: Terminal system logical address, 131-133 ... Physical addresses of LAN adapters, 134, 135... Physical addresses of terminal systems.

Claims (1)

[Claims] 1. The same L through a plurality of LAN adapters.
In data communication between a computer system connected to an AN and a terminal system, the computer system is used to determine a logical address for communication used in data communication with the terminal system and a physical address of the terminal system. Two types of logical addresses for address resolution are assigned, and each time the computer system receives an address resolution request from the terminal system, the computer system responds with a physical address of a LAN adapter with a low load, so that the computer system responds to each of the terminal systems. A LAN adapter load balancing method for a computer system, wherein the load is distributed to each LAN adapter.