JPH11313101A - Acceleration method and system for reconnecting connection of duplex lan system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a system capable of immediately establishing communication with a host on the outside of a segment at the time of the system changeover of a duplex server system. SOLUTION: By sending out a packet for updating the address of an ARP (address resolution protocol) table provided in a router 5 to the router of the same network segment as a duplex LAN system 1 from a new active system side after completing the system changeover in the duplex LAN system 1, connection reconnection from the node of a different network through at least the router 5 is immediately performed after executing the system changeover in the duplex LAN system 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a duplex system, and more particularly, to a method and system for speeding up connection reconnection at the time of system switching in a redundant LAN (local area network) system.

[0002]

2. Description of the Related Art Servers on a computer network are required to have high reliability as a system. In order to cope with this demand, the server systems are switched to an active system (act system) and a standby system (standby system) on the network. In some cases, the configuration is duplicated. For example, referring to FIG. 1, a duplicated server system 1 includes servers 2 and 3. This server system 1 has one network address (for example, an IP address) in the duplicated system 1 and has a MAC ( There are two Media Access Control addresses for each of the server 2 and the server 3. Servers 2 and 3 are connected to LAN 4 and L
The AN 4 is connected to a router 5 as a network gateway. As shown in FIG. 2, the router 5 includes an ARP (Address Resolution Protocol) cache table 10 which is a correspondence table between a network address and a MAC address.
The MAC address holds the MAC address of the active server.

[0003]

However, this conventional duplex system has the following problems. In other words, if a failure occurs on the active server side in the redundant server system and system switching between the active system and the standby system is performed, the ARP cache table of the router on the same network segment (the IP address of the host on the network) Table holding the correspondence between the MAC address and the MAC address), for several minutes until the correspondence between the network address and the MAC address is automatically cut off by the ARP cache flush.
Since the MAC address of the old active system is retained, communication from the client (for example, 6 in FIG. 1) outside the segment to the new active system is completely interrupted.

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to establish communication with a new active system from a node of a network outside a segment immediately upon system switching of a redundant system. It is an object of the present invention to provide a method and a method that make it possible.

[0005]

In order to achieve the above-mentioned object, the present invention relates to a network having a system in which a server or a client is duplicated.
By transmitting a packet for updating an address of an ARP (Address Resolution Protocol) table provided in the router to a router connected to the duplex system and functioning as a gateway to another network, the duplex system is transmitted. After the execution of the failover, a connection reconnection from a node of another network at least via the router can be immediately performed.

[0006]

Embodiments of the present invention will be described below. The present invention, in a preferred embodiment thereof, executes a system switchover in a redundant system by transmitting a packet for updating an ARP (Address Resolution Protocol) cache in a router immediately after performing a system switchover in a redundant system. This makes it possible to immediately perform the connection reconnection later.

That is, according to a preferred embodiment of the present invention, in a duplex system comprising an active system and a standby system, after completion of system switching from the active system to the standby system,
The new active system has means for transmitting a packet for updating the address of an ARP (address resolution protocol) table provided in the router to a router in the same segment as the network to which the duplex system is connected. , The router receiving the packet,
The address of the duplex system in the RP table is
Updating based on the contents of the P-packet, and after the system switchover in the redundant system, the connection reconnection to the redundant system from a node (host) on another segment's network via at least the router can be performed immediately. Like that.

Referring to FIG. 1, an embodiment of the present invention will be described. A redundant LAN system 1 operates as a server, includes servers 2 and 3, and has a redundant system as an act standby system. I have. The redundant system 1 has one network address (for example, an IP address), and two MAC addresses for each of the server 2 and the server 3. Server 2
And the server 3 is a LAN (local area network)
The LAN 4 is connected to a router 5 which is a network gateway.

As shown in FIG. 2, the router 5 has an ARP cache table 10 which is a correspondence table between a network address and a MAC address. When the connection of the redundant LAN system 1 is established via the router 5, the contents of the ARP cache table 10 for the redundant LAN system 1 include the network address 11, the network address of the redundant LAN system 1, and the MAC address 12. Of the active (active) system of the server 2 or the server 3
The AC address is recorded.

When an event that causes system switchover occurs in the redundant LAN system 1 and a system switchover is performed between the server 2 and the server 3, immediately after completion of the operation processing, a new active system (act system) is established. The new server sends a packet to the router 5 for updating the MAC address 12 of the ARP cache table 10 in the router 5 to a new active system.

As a result, the client 6 on the network segment different from the LAN 4
When there is a communication request to the system 1, it is possible to immediately connect to the new active server in the redundant LAN system 1.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; FIG. 1 is a diagram illustrating an example of a system configuration according to an embodiment of the present invention.

Referring to FIG. 1, a redundant LAN system 1 is a server that is duplicated by an act-standby system, and includes a server 2 and a server 3, each of which is connected to a LAN 4. Redundant LAN system 1
When the system is operated, the server 2 or the server 3
Either one performs actual operation as an active system (act system), and the other is in a standby state as a standby system (standby system).

When a failure event occurs in the redundant LAN system 1, an act / standby system switching is performed between the server 2 and the server 3. The redundant LAN system 1 has a network address (eg, IP address)
Has one MAC address for the system and two MAC addresses for each of the server 2 and the server 3.

The router 5 is a network gateway connected to the LAN 4 and has an ARP cache table 10 which is a correspondence table between network addresses and MAC addresses, as shown in FIG.

The dual LAN system 1 via the router 5
Is established, the contents of the ARP cache table 10 for the duplicated LAN system 1 are as follows: the network address 11 is the network address of the duplicated LAN system 1; The MAC address is recorded.

The client 6 is a LAN system operating as a client, and is connected to a LAN 7 on a different network segment from the LAN 4. LAN
7 is connected to a router 8 as a network gateway. When the router 5 and the router 8 are interconnected via the Internet 9, the redundant LAN system 1 and the client 6 are in a physically communicable state.

Duplicated LAN system 1 and client 6
When communicating with the router, the router 6, the Internet 9, and the router 5 sequentially pass through the redundant LA
Communication with the active server of the N server system 1 is performed.

The operation at the time of system switching in one embodiment of the present invention will be described.

The redundant LAN system 1 and the client 6
In a state where communication with the server is established, an event that causes system switchover of the redundant LAN system 1 occurs, and a system switchover is performed between the server 2 and the server 3. The active server sends an ARP request packet to the router 5.

FIG. 3 is a diagram showing an example of the ARP request packet format. The ARP request packet is a packet constituting the ARP protocol. A
The RP (Address Resolution Protocol) protocol is a protocol used for obtaining an unknown destination MAC address using the broadcast property of a MAC address.

In this embodiment, an ARP request packet is used as a packet sent from the redundant LAN system 1 to the router 5. The reason for using the ARP request packet is to update the ARP cache table in the system with the contents of the received ARP request packet in the network system that has received the ARP packet.

The contents of the source and destination addresses of the ARP request packet sent to the router 5
The AC address 21 is the broadcast address, the source MAC address 22 is the MAC address of the new act system of the server 2 or server 3, the destination network address 23 is the network address of the router 5, and the source network address 24 is the duplicated LAN. The network address of the system 1 is set.

When the router 5 receives the ARP request packet, the router 5 refers to the source network address and the source MAC address and checks the ARP cache table 1
MA corresponding to network address 11 in 0
For the C address 12, the MAC address of the old active server is updated to the MAC address of the new active server.

As a result, the ARP cache table 10 in the router 5 is associated with the MAC of the new act server in accordance with the execution of the failover of the redundant LAN system 1.

In the above embodiment, in the redundant LAN system, the act / standby system in the server system has been described as an example.
Of course, the present invention can be applied as it is to a redundant LAN system using a standby system.

[0027]

As described above, according to the present invention,
At the time of system switching of the redundant LAN system, the correspondence between the network address and the MAC address in the router is automatically cut off without waiting for the cache flush time (2 to 3 minutes in general) of the ARP cache table. This has the effect that communication with clients outside the segment can be established.

The reason is that, in the present invention, the double L
This is because an ARP request packet is sent to a router on the same network segment to update the ARP cache table at the same time as the failover of the AN system is completed.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a network system for explaining an embodiment of the present invention.

FIG. 2 is a diagram for explaining one embodiment of the present invention;
FIG. 4 is a diagram illustrating an example of an ARP cache table.

FIG. 3 is a diagram for explaining one embodiment of the present invention;
FIG. 3 is a diagram illustrating a format of an ARP packet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dual server system 2, 3 server 4, 7 LAN 5, 8 Router 9 Internet 10 ARP cache table 11 Network address 12 MAC address 20 ARP format 21 Destination MAC address 22 Source MAC address 23 Source network address 24 Destination network address

Claims (5)

[Claims] In a network having a system in which a server and / or a client are duplicated, after completion of system switching in the duplicated system, another network is connected from a new active system to a network to which the duplicated system is connected. ARP provided for the router acting as a gateway to the router
(Address Resolution Protocol) sends out a packet containing information for updating the address of the table,
After the system switchover in the redundant system, a connection reconnection to the redundant system from a node of another network segment via at least the router can be performed immediately.
A method for speeding up connection reconnection of the N system. 2. A network having a system in which a server and / or a client are duplicated, wherein after completion of system switching in the duplicated system, a network address of the duplicated system and a new MAC of the current active system are sent from a new active system side. AR containing address information
P (address resolution protocol) request packet is transmitted, and a router in the same network segment as the network to which the duplex system is connected receives the ARP request packet and manages the AR held by the router.
The registered contents of the P table are updated, and after performing the system switchover in the redundant system, a connection reconnection from the node of another network segment via at least the router to the redundant system can be immediately performed. Duplicate LA
A method for speeding up connection reconnection of the N system. 3. A redundant system in which at least one of a server and a client includes an active system and a standby system, wherein after the system switching from the active system to the standby system is completed, a new active system is connected to the redundant system. Means for transmitting a packet containing information for updating an address of an ARP (Address Resolution Protocol) table provided in the router to a router connected to the network and functioning as a gateway to another network, The received router updates the address of the duplex system in the ARP table based on the contents of the packet, and thereby, after executing system switching in the duplex system, from a node of another network segment that has passed at least the router. Connection to the redundant system Connection reconnect accelerated method of duplicated LAN system characterized by Deployment was allow reconnect immediately. 4. The duplex LAN according to claim 3, wherein said packet is an ARP request packet.
High-speed system for reconnecting system connections. 5. A redundant system in which at least one of a server and a client includes an active system and a standby system, after completion of system switching from the active system to the standby system, a new active system is connected to the redundant system. Means for transmitting a packet containing information for updating an address of an ARP (Address Resolution Protocol) table provided in the router to a router connected to the network and functioning as a gateway to another network, A recording medium on which a program for functioning on a constituent server computer or client computer is recorded.