System for reliably connecting a client computer to a server computer
First Claim
1. A network system, comprising:
- a first server computer;
a second server computer;
at least one client computer connected to a network;
a network supervising means for supervising operations of the first server computer, and for instructing a server switching means that the second server computer is executed in place of the first server computer;
the server switching means for setting an identification address, that is a network address of the first server computer, and a virtual address, that is a network address of the second server computer and corresponds to the identification address, in an address table of the second server computer in response to the server switching instruction;
packet converting means for setting an identification address and a virtual address in an address mapping table of the a packet converting means in response to the server switching instruction, and for transmitting a packet after executing the conversion of the packet of which transmitting destination is changed to the virtual address, when the destination address of the packet received from the at least one of client computer corresponds to the identification address to be set in the address mapping table; and
the second server computer for setting a source address of an answering packet to the identification address, when the second server computer transmits the answering packet to the at least one client computer in request to the packet.
1 Assignment
0 Petitions
Accused Products
Abstract
In order to realize server switching to a backup server from a working server without changing any setting on a client computer, a network system is provided having a network supervising means for supervising operations of a plurality of server computers connected to the network, a server switching means for realizing server switching in which the backup server computer alternatively executes the server function of the working server computer by virtually setting the address of the working server computer connected to the network as the address of the backup server computer. A packet converting means is provided for converting the packet transmitted and received between the working server computer and the client computer into the packet transmitted and received between the backup server computer and the client computer.
302 Citations
22 Claims
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1. A network system, comprising:
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a first server computer;
a second server computer;
at least one client computer connected to a network;
a network supervising means for supervising operations of the first server computer, and for instructing a server switching means that the second server computer is executed in place of the first server computer;
the server switching means for setting an identification address, that is a network address of the first server computer, and a virtual address, that is a network address of the second server computer and corresponds to the identification address, in an address table of the second server computer in response to the server switching instruction;
packet converting means for setting an identification address and a virtual address in an address mapping table of the a packet converting means in response to the server switching instruction, and for transmitting a packet after executing the conversion of the packet of which transmitting destination is changed to the virtual address, when the destination address of the packet received from the at least one of client computer corresponds to the identification address to be set in the address mapping table; and
the second server computer for setting a source address of an answering packet to the identification address, when the second server computer transmits the answering packet to the at least one client computer in request to the packet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A network system, comprising:
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a first server computer;
a second server computer;
at least one client computer connected to a network;
a network supervising apparatus for supervising operations of the first server computer, and for instructing a server switching means that the second server computer is executed in place of the first server computer;
a first router for setting an identification address, that is a network address of the first server computer, and a virtual address, that is a network address of the second server computer and corresponds to the identification address, in an address table of the second server computer in response to the server switching instruction;
a second router for setting an identification address and a virtual address in an address mapping table of a packet converting means in response to the server switching instruction, and for transmitting a packet after executing the conversion of the packet of which transmitting destination is changed to the virtual address, when the destination address of the packet received from the at least one client computer corresponds to the identification address to be set in the address mapping table; and
the second server computer for setting a source address of an answering packet to the identification address, when the second server computer transmits the answering packet to the at least one client computer in request to the packet. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method for processing a packet in a network system having a first server computer, a second server computer, at least one of client computer and a router which connected between the first server computer and the second server computer the method comprising the steps of:
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supervising operations of the first server computer;
instructing the second server computer to execute in place of the first server computer;
setting an identification address, that is a network address of the first server computer, and a virtual address, that is a network address of the second server computer and corresponds to the identification address, in an address table of the second server computer in response to the step of instructing;
setting an identification address and a virtual address in an address mapping table of the router in response to the step of instructing;
transmitting a packet after executing the conversion of the packet of which transmitting destination is changed to the virtual address, when the destination address of the packet received from the at least one client computer corresponds to the identification address is set in the address mapping table; and
setting a source address of an answering packet to the identification address, when the answering packet is transmitted to the at least one client computer in response to the packet. - View Dependent Claims (18)
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19. A server computer for being used in a network system comprising at least two of server computers and at least one client computer, the server computer comprising:
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a server switching means for setting an identification address, that is a network address of an other server computer which is defective, and a virtual address, that is a network address of the own server computer and corresponds to the identification address, in an address table of the own server computer in response to the defection of the other server computer; and
a packet processing means for setting a source address of an answering packet to the identification address, when the own server computer transmits the answering packet to the at least one of client computer in request to the packet destined to the other server computer. - View Dependent Claims (20)
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21. An internetworking apparatus to be used in a network system comprising at least two of server computers, at least one client computer and the internetworking apparatus, the internetworking apparatus comprising:
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a packet converting means for setting an identification address, that is a network address of one of the server computer which is defective, and a virtual address, that is a network address of the other server computer and corresponds to the identification address, in an address table of the other server computer in response to the defection of one of the server computer; and
a transmitting destination changing means for transmitting a packet after executing the conversion of the packet of which transmitting destination is changed to the virtual address, when the destination address of the packet destined to the one of the server computer corresponds to the identification address. - View Dependent Claims (22)
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Specification