JPH09167128A - Dynamic lan controller switching method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten recovery time by simplifying recover processing by dynamically switching a LAN controller at the time of LAN controller fault by performing a TCP/IP protocol while using plural LAN controllers. SOLUTION: When a fault in a LAN controller 11 in a communication system 10 is detected, a fault report 20 is issued from a LAN controller control process 13. An IP control process 15 searches a LAN controller on the same network as the LAN controller 11 out of a local address table 30 and issues a MAC address change information 21. A LAN controller control process 14 sets the MAC address of LAN controller 12 to this information 21 and issues it onto the network. Receiving this information, a LAN controller process 13' of communication system 10' changes the MAC address of table coincident with the IP address informed by the MAC address change information 21 from an ARP cache table 31 according to this information and communicates it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication processing system for performing communication using TCP / IP protocol.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
After the communication system 10 'recognizes the failure of the control device 11 by disconnecting the TCP connection due to the timeout of the ACK response of the IP packet 26, the LA operation is performed by the operator.
The connection was made to the IP address 41 corresponding to another LAN control device 12 via the N control device 12, and the connection was recovered.

[0003]

Therefore, the recovery process due to a LAN controller failure has the following problems because there is no failure notification from the failure source.

1. The TCP connection is cut off.

[0005] 2. Since the failure of the LAN control device is not known until the TCP connection is cut off, it takes time to recover.

[0006] 3. Since the recovery process must be performed by the operator's operation, it is troublesome.

The present invention is to solve the above-mentioned problems in a communication processing system which carries out the TCP / IP protocol.

[0008]

In the event of a LAN controller failure, the MAC address of another LAN controller that is not a failure is made to correspond to the IP address that was associated with the failed LAN controller, and Since the MAC address is changed at this time, it has a function of notifying the changed MAC address.

With this function, the communication partner can perform communication immediately after the failure of the LAN control device without disconnecting the TCP connection.

The function of giving one LAN control device a plurality of IP addresses operates by having an address table for each IP address. As a result, the same IP address as before the failure can be used even after the switching due to the failure of the LAN control device.

Further, the function of notifying the changed MAC address creates a MAC address change notification when a failure of the LAN control device is detected and broadcasts the packet on the network. The communication system that has received the MAC address change notification updates the MAC address according to the contents of the MAC address change notification. As a result, a failure occurs in the LAN controller and the MA of the other party in communication is communicating.
Even if the C address is changed, communication can be performed without disconnecting the TCP connection.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an outline and a data flow diagram of a recovery process when a LAN controller failure occurs.

When a failure of the LAN control device 11 is detected by the LAN control device control process 13 of the communication system 10, the LAN
The LAN control device failure notification 20 is issued from the control device control process 13 to the IP control process 15. IP
The control process 15 uses the local IP address table 30.
To L on the same network as the LAN control device 11
It searches for the AN controller 12 and issues a MAC address change notification 21 to the LAN controller control process 14. L
The AN control device control process 14 sets the MAC address of the LAN control device 12 in the MAC address change notification 21 and issues it by broadcast on the network.

The LAN controller controlling process 13 'of the communication system 10' which has received the MAC address change notice 21
Searches the ARP cache table 31 for a table that matches the IP address notified by the MAC address change notification 21, and changes the MAC address of the table according to the MAC address change notification 21. The communication system 10 'thereafter uses this address for communication.

FIG. 2 shows the packet format of the MAC address change notification 21.

Destination MAC address 22 of the MAC header section
Sets a broadcast address, and sets the protocol type 23 to the protocol type of the MAC address change notification. The IP address 24 of the data section is set to the IP address corresponding to the MAC address of the LAN control device in trouble, and the MAC address 25 is set to the changed MAC address.

FIG. 5 is an outline of the IP address determination processing in the IP packet reception processing and a data flow chart.

The IP packet 26 received by the LAN control device control process 13 is passed to the IP control process 15.
After checking the IP header, the IP control process 15 determines whether the local IP address table 30 has an IP address that matches the destination IP address of the IP packet 26, and if there is, passes the IP packet 26 to the upper process 16. If not, the IP packet 26 is discarded.

FIG. 6 is an outline and data flow chart of the IP address determination processing in the ARP request packet reception processing.

The ARP request packet 27 received by the LAN control device control process 13 judges whether or not there is an IP address in the local IP address table 30 that matches the target IP address of the ARP request packet 27, and if there is, an ARP reply packet 28 is sent. If not returned, the ARP request packet 27 is discarded.

[0022]

In a system that supports a plurality of LAN control devices, failure recovery processing of the LAN control devices is performed by the LAN.
Since it can be performed immediately after the failure of the control device, the incommunicable time is eliminated, and the TCP connection is not disconnected. Therefore, the recovery process by the operator is also unnecessary.

[Brief description of the drawings]

FIG. 1 is an outline of a recovery process when a LAN controller failure occurs and a data flow chart.

FIG. 2 is a format of a MAC address change notification.

FIG. 3 is a format of a local IP address table.

FIG. 4 is a format of an ARP cache table.

FIG. 5 is an outline of an IP address determination process when an IP packet is received and a data flow chart.

FIG. 6 is an outline of an IP address determination process when an ARP request packet is received and a data flow chart.

FIG. 7 is an outline and a data flow chart of a conventional recovery process in the event of a LAN controller failure.

[Explanation of symbols]

10, 10 '... communication system, 11, 12, 11' ... L
AN controller, 13, 14, 14 '... LAN controller control process, 15 ... IP control process, 16 ...
Upper process, 20 ... LAN controller failure notification, 21
... MAC address change notification, 22 ... MAC header destination MAC address, 23 ... MAC header protocol type, 24 ... IP address that changed MAC address of MAC address change notification, 25 ... MAC address after change of MAC address change notification , 26 ... IP packet,
27 ... ARP request packet, 28 ... AR
P response packet, 30 ... Local IP address table, 31 ... ARP cache table, 40, 41
... IP address.

Claims (1)

[Claims] 1. A method of dynamically switching LAN control devices when a LAN control device fails in a communication processing system that performs TCP / IP protocol in a configuration using a plurality of LAN control devices.