System and method for external resolution of packet transfer information

Abstract

When a packet transfer equipment receives a packet, it extracts several types of information contained in the received packet such as the destination IP address and the destination port number and, using the extracted information as the key, inquires of a packet transfer method resolution server about the information related to the packet transfer method. The server keeps the correspondences between several types of information contained in the packet and one or more type of information related to the packet transfer method in the database and, in response to the inquiry from the packet transfer equipment, replies one or more type of information related to the packet transfer method. The packet transfer equipment rewrites several types of information such as the destination IP address and the destination port number according to one or more type of information obtained and transfers the received packet.

1 - 53 . (canceled) 
   
   
       54 . A packet transferring system comprising:
 an external server; and   a plurality of switches transferring a packet under control of the external server through a network,   wherein the external server determines a route through which a packet is transferred in response to an inquiry made by at least one of the switches.   
   
   
       55 . The packet transferring system according to  claim 54 , wherein the external server determines a next hop of the packet. 
   
   
       56 . The packet transferring system according to  claim 54 , wherein the external server determines the route based on a plurality of header fields of the packet. 
   
   
       57 . The packet transferring system according to  claim 54 , wherein the external server determines the route based on a plurality of header fields of the packet, and wherein the header fields belong to different layers with respect to each other. 
   
   
       58 . The packet transfer system according to  claim 54 , wherein the external server determines the route relating to a plurality of header fields of the packet. 
   
   
       59 . The packet transfer system according to  claim 54 , wherein the external server determines the route relating to a plurality of header fields of the packet, and wherein the header fields belong to different layers with respect to each other. 
   
   
       60 . The packet transferring system according to  claim 54 , wherein the external server determines a destination of the packet from several destinations. 
   
   
       61 . The packet transferring system according to  claim 54 , wherein the external server determines how to process the packet. 
   
   
       62 . The packet transferring system according to  claim 61 , wherein the process comprises rewriting a header of the packet. 
   
   
       63 . The packet transferring system according to  claim 61 , wherein the process comprises dropping the packet. 
   
   
       64 . A server controlling a packet transfer, comprising:
 a first element which controls a plurality of switches through a network; and   a second element which accepts an inquiry made by at least one of the switches,   wherein the first element determines a route through which a packet is transferred in response to the inquiry.   
   
   
       65 . The server according to  claim 64 , wherein the first element determines a next hop of the packet. 
   
   
       66 . The server according to  claim 64 , wherein the first element determines the route based on a plurality of header fields of the packet. 
   
   
       67 . The server according to  claim 64 , wherein the first element determines the route based on a plurality of header fields of the packet, and wherein the header fields belong to different layers with respect to each other. 
   
   
       68 . The server according to  claim 64 , wherein the first element determines the route relating to a plurality of header fields of the packet. 
   
   
       69 . The server according to  claim 64 , wherein the first element determines the route relating to a plurality of header fields of the packet, and wherein the header fields belong to different layers with respect to each other. 
   
   
       70 . The server according to  claim 64 , wherein the first element determines a destination of the packet from several destinations. 
   
   
       71 . The server according to  claim 64 , wherein the server determines how to process the packet. 
   
   
       72 . The server according to  claim 71 , wherein the process comprises rewriting a header of the packet. 
   
   
       73 . The server according to  claim 71 , wherein the process comprises dropping the packet. 
   
   
       74 . A packet transferring switch, comprising:
 a first element which sends an inquiry about a route, through which a packet is transferred, to an external server controlling a plurality of the switches through a network; and   a second element which transfers the packet through the route determined by the external server in response to the inquiry made by at least one of the switches.   
   
   
       75 . The packet transferring switch according to  claim 74 , wherein the external server determines a next hop of the packet. 
   
   
       76 . The packet transferring switch according to  claim 74 , wherein the external server determines the route based on a plurality of header fields of the packet. 
   
   
       77 . The packet transferring switch according to  claim 74 , wherein the external server determines the route based on a plurality of header fields of the packet, and wherein the fields belong to different layers with respect to each other. 
   
   
       78 . The packet transferring switch according to  claim 74 , wherein the external server determines the route relating to a plurality of header fields of the packet. 
   
   
       79 . The packet transferring switch according to  claim 74 , wherein the external server determines the route relating to a plurality of header fields of the packet, and wherein the header fields belong to different layers with respect to each other. 
   
   
       80 . The packet transferring switch according to  claim 74 , wherein the external server determines a destination of the packet from several destinations. 
   
   
       81 . The packet transferring switch according to  claim 74 , wherein the external server determines how to process the packet. 
   
   
       82 . The packet transferring switch according to  claim 81 , wherein the process comprises rewriting a header of the packet. 
   
   
       83 . The packet transferring switch according to  claim 81 , wherein the process comprises dropping the packet. 
   
   
       84 . A method of transferring a packet through a network in a packet transferring system, which includes a plurality of switches and an external server, comprising:
 controlling the switches by the external server;   sending an inquiry about a route, through which the packet is transferred, to the external server;   determining the route in response to the inquiry made by at least one of the switches; and   transferring the packet through the route determined by the external server.   
   
   
       85 . The method according to  claim 84 , further comprising:
 determining, by the external server, a next hop of the packet.   
   
   
       86 . The method according to  claim 84 , further comprising:
 determining, by the external server, the route based on a plurality of header fields of the packet.   
   
   
       87 . The method according to  claim 84 , further comprising:
 determining, by the external server, the route based on a plurality of header fields of the packet,   wherein the header fields belong to different layers with respect to each other.   
   
   
       88 . The method according to  claim 84 , further comprising:
 determining, by the external server, the route relating to a plurality of header fields of the packet.   
   
   
       89 . The method according to  claim 84 , further comprising:
 determining, by the external server, the route relating to a plurality of header fields of the packet,   wherein the header fields belong to different layers with respect to each other.   
   
   
       90 . The method according to  claim 84 , further comprising:
 determining, by the external server, a destination of the packet from several destinations.   
   
   
       91 . The method according to  claim 84 , further comprising:
 determining, by the external server, how to process the packet.   
   
   
       92 . The method according to  claim 91 , wherein the process comprises rewriting a header of the packet. 
   
   
       93 . The method according to  claim 91 , wherein the process comprises dropping the packet. 
   
   
       94 . A computer readable medium storing a computer program for causing one or more computers to control transfer of a packet through a network in a packet transferring system, which includes a plurality of switches and an external server, the one or more computers, when executing the computer program, performing the steps of:
 controlling the switches by the external server;   sending an inquiry about a route, through which the packet is transferred, to the external server;   determining the route in response to the inquiry made by at least one of the switches; and   transferring the packet through the route determined by the external server.   
   
   
       95 . The computer readable medium according to  claim 94 , further causing the one or more computers to perform the step of:
 determining, by the external server, a next hop of the packet.   
   
   
       96 . The computer readable medium according to  claim 94 , further causing the one or more computers to perform the step of:
 determining, by the external server, the route based on a plurality of header fields of the packet.   
   
   
       97 . The computer readable medium according to  claim 94 , further causing the one or more computers to perform the step of:
 determining, by the external server, the route based on a plurality of header fields of the packet,   wherein the header fields belong to different layers with respect to each other.   
   
   
       98 . The computer readable medium according to  claim 94 , further causing the one or more computers to perform the step of:
 determining, by the external server, the route relating to a plurality of header fields of the packet.   
   
   
       99 . The computer readable medium according to  claim 94 , further causing the one or more computers to perform the step of:
 determining, by the external server, the route relating to a plurality of header fields of the packet,   wherein the header fields belong to different layers with respect to each other.   
   
   
       100 . The computer readable medium according to  claim 94 , further causing the one or more computers to perform the step of:
 determining, by the external server, a destination of the packet from several destinations.   
   
   
       101 . The computer readable medium according to  claim 94 , further causing the one or more computers to perform the step of:
 determining, by the external server, how to process the packet.   
   
   
       102 . The computer readable medium according to  claim 101 , wherein the process comprises rewriting a header of the packet. 
   
   
       103 . The computer readable medium according to  claim 101 , wherein the process comprises dropping the packet.