Method of load distribution for message processing in host system in local area network

• US 5,517,488 A
• Filed: 06/21/1993
• Issued: 05/14/1996
• Est. Priority Date: 06/23/1992
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Orioka, Kazuo, Yagyu, Kazuo, Takahashi, Makoto, Miyazaki, Satoshi
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): BLUM, RUSSELL
• Application Number:
  US08/080,801
• Time in Patent Office: 1,058 Days
• Field of Search: 370/16, 370/58.3, 370/60, 370/60.1, 370/94.1, 370/85.1, 379/2, 371/8.1, 371/8.2, 371/11.1, 371/11.2
• US Class Current: 370/225
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

An LAN system provided with a host system connected to an LAN through a plurality of LAN adapters, and a plurality of terminal systems for communicating with the host system through the LAN. A plurality of logical addresses for the host system are set correspondingly to physical addresses of the LAN adapters. One of the logical addresses is selected arbitrarily as a key (common) logical address. When the host system is to send a message to one of the terminal systems, the host system sets the key logical address of the host system as a source logical address included in the message, selects one of the LAN adapters and sends the message to the LAN through the selected LAN adapter. When one of the terminal systems is to send a message to the host system, the terminal system sets the key logical address of the host system as a destination logical address included in the message, sets the physical address of the LAN adapter corresponding to the key logical address as a destination physical address included in the message and sends the message to the LAN.

Claims

1. In an LAN system including a host system, a plurality of LAN adapters connected with the host system for providing a plurality of alternate communication paths to a local area network, and a plurality of terminal system connected with the local area network, a method of load distribution for message processing in the host system for facilitating communication of messages between the host system and the terminal systems, the LAN adapters providing a wait-before-transmit message capacity indicative of a delay before a next received message will be transmitted, the method comprising the steps of:

(a) setting a plurality of logical addresses for said host system in a one-to-one correspondence with physical addresses of said LAN adapters and selecting an arbitrary one of said logical addresses as a key logical address;

(b) setting said key logical address of said host system as a source logical address included in a message when said host system is to send said message to a selected one of said plurality of terminal systems; and

(c) each time said host system is to send said messages to the selected one of said plurality of terminal systems selecting a least loaded one of said LAN adapters and sending said message through said selected LAN adapter to the local area network and to said selected one of said plurality of terminal systems, said selection of the least loaded one of said LAN adaptors examines the wait-before-transmit message capacities of each of said LAN adapters to identify;

a one of the LAN adapters having a wait-before-transmit message capacity not larger than a predetermined value for selection as said selected LAN adapter when the LAN adapter having the wait-before-transmit message capacity not larger than the predetermined value exists, and

a one of the LAN adapters having the smallest wait-before-transmit message capacity for selection as said selected LAN adapter when none of the LAN adapters have a wait-before-transmit message capacity smaller than the predetermined value.

2. In an LAN system including a local area network, a host system, a plurality of LAN adapters connecting the host system with the local area network, and a plurality of terminal systems connected with the local area network each of said terminal systems having a first table in which a key logical address and a physical address of a one of the LAN adapters corresponding to said key logical address are set as a logical address of said host system and as a physical address of said host system, respective, a method of load distribution for message processing in the host system comprising:

(a) setting a plurality of logical addresses for said host system correspondingly to physical addresses of said LAN adapters and selecting an arbitary one of said logical addresses as the key logical address;

(b) setting said key logical address of said host system as a source logical address included in a message, selecting one of said LAN adapters and sending said message through said selected LAN adapter and the local area network to one of said plurality of terminal systems; and

,

(c) setting the key logical address and the physical address in said first table.

3. A method of load distribution for message processing in the host system according to claim 2, further comprising the steps of:

(d) relating said key logical address to another normal LAN adapter when any failure occurs in said LAN adapter corresponding to said key logical address; and

(e) prohibiting said host system from selecting a failed LAN adapter at the time of transmitting of message when any failure occurs in said LAN adapter not corresponding to said key logical address.

4. A method of load distribution for message processing in the host system according to claim 3, wherein

said step (d) includes the substep of informing said plurality of terminal systems that said key logical address is related to said another normal LAN adapter.

5. A method of load distribution for message processing in the host system according to claim 3, wherein:

said host system is provided with a second table in which a physical address and a logical address are set correspondingly to each of said LAN adapters;

the physical address and logical address of a failed LAN adapter are removed from said second table so that said key logical address is related to the physical address of said normal LAN adapter in said second table.

6. A method of load distribution for message processing in the host system according to claim 4, wherein

each of said terminal systems relates said key logical address to the physical address of said normal LAN adapter in said first table in response to the information.

7. A method of load distribution for message processing in the host system according to claim 3, further comprising the steps of:

(f) relating said key logical address to an LAN adapter recovering from failure when the LAN adapter corresponding to said key logical address recovers from failure; and

(g) informing said plurality of terminal systems that said key logical address is related to said LAN adapter recovering from failure.

8. A method of load distribution for message processing in the host system according to claim 7, wherein:

said host system is provided with a second table in which a physical address and a logical address are set correspondingly to each of said LAN adapters;

the physical address and logical address of said LAN adapter recovering from failure are registered in said second table so that said key logical address is related to the physical address of said LAN adapter recovering from failure in said second table.

9. A method of load distribution for message processing in the host system according to claim 7, wherein

each of said terminal systems relates said key logical address to the physical address of said LAN adapter recovering from failure in said first table in response to the information.

10. In an LAN system including a host system, a plurality of LAN adapters which connect the host system with a local area network, each of said LAN adapters performing protocol processing inclusive of a transport layer, and a plurality of terminal systems connected with the local area network, a method of load distribution for message processing in the host system comprising the steps of:

(a) setting a plurality of logical addresses for said host system corresponding to physical addresses of said LAN adapters and selecting an arbitrary one of said logical addresses as a key logical address; and

(b) each time said host system is to send said message to one of said plurality of terminal systems, setting said key logical address of said host system as a source logical address included in a message, selecting said LAN adapter corresponding to said key logical address as said selected LAN adapter and sends said message through said selected LAN adapter to the local area network when the communication mode of said message is connection-oriented.

11. In an LAN system including a host system, a plurality of LAN adapters which connect the host system with a local area network, each of said LAN adapters performing protocol processing inclusive of a transport layer, and plurality of terminal systems connected with the local area network, a method of load distribution for message processing in a host system comprising the steps of:

(a) setting a plurality of logical addresses for said host system corresponding to physical addresses of said LAN adapters and selecting an arbitrary one of said logical addresses as a key logical address; and

(b) each time said host system is to send said message to one of said plurality of terminal systems, setting said key logical address of said host system as a source logical address included in a message, selecting a least loaded LAN adapter as said selected LAN adapter from said plurality of LAN adapters and sends said message through said selected LAN adapter to the local area network when the communication mode of said message is connectionless.