High-availability computer system and method for switching servers having an imaginary address

A network computer system, comprising:

• a plurality of servers each of which has at least one corresponding actual addresses and all having an imaginary address in common;
• a client which transmits a first packet addressed to an imaginary address which contains a network trailer;
• and
• a gateway which extracts the network trailer from the first packet, generates a second packet which includes the network trailer, assigns one of the actual addresses to the second packet, and transmits the second packet to a server having the actual address;
• wherein the server extracts the network trailer from the second packet.

A method for transmitting a packet in a network computer system comprising a plurality of computers which have both their several actual addresses and an imaginary address in common, comprising:

• receiving a first packet addressed to the imaginary address, the packet including a network trailer;
• extracting the network trailer from the first packet;
• generating a second packet that includes the network trailer;
• assigning one of the actual addresses to the second packet;
• and
• transmitting the second packet to a computer having the actual address.

A method for processing a packet transmitted in a network computer system comprising a plurality of computers which have both their several actual addresses and an imaginary address in common, comprising:

• receiving a packet;
• determining whether a received packet is addressed to an actual address or an imaginary address;
• stripping the packet of every header section if the packet is addressed to the imaginary address;
• and
• processing the remainder of the packet as a network trailers.

A system for switching servers in a network computer system, the system which comprises a client, a plurality of servers which have both their several actual addresses and an imaginary address in common, and a gateway, comprising:

• means for transmitting a first packet addressed to the imaginary address, the packet including a network trailer;
• means for extracting the network trailer from the first packet;
• means for generating a second packet that includes the network trailer;
• means for assigning one of the actual addresses to the second packet;
• means for transmitting the second packet to a server having the actual address;
• and
• means for extracting the network trailer from the second packet.