Packet switching system, packet switching method, routing apparatus, structure of packet, and packet generating method

Abstract

The packet switching system for transmitting and receiving a packet via a packet switching network 100, which comprises a plurality of routing tables (# 0, #1, #2 . . . ), each of which has been generated by a unique routing policy, stored in the routing apparatuses deployed at the border, at the origin or at the end of the respective routing domains, an identifier (RTI) inserted in the packet to specify the routing tables, and an identifier changer to change a value of the identifier on the packet switching network 100. The routing apparatus selects one of the routing tables (# 0, #1, #2 . . . ) according to the RTI in the received packet and transfers the packet to a destination that is specified by the selected routing table.

What is claimed is:  
     
         1 . A packet switching system for transmitting and receiving a packet via a packet switching network that is configured by interconnecting a plurality of routing apparatuses, comprising: 
 a plurality of routing tables stored in the respective routing apparatuses, each of the routing tables being generated by a unique routing policy;    an identifier inserted in the packet, configured to specify the routing tables; and    an identifier changer configured to change a value of the identifier within the packet switching network, wherein 
 the routing apparatus is configured, to select a routing table in accordance with the value of the identifier inserted in the packet received, and to transfer the packet to a destination that is specified by the selected routing table.  
   
     
     
         2 . A packet switching system according to  claim 1 , wherein the packet switching network is configured by interconnecting a plurality of routing domains formed in a prescribed area, 
 a plurality of routing tables, each of which has been generated by a unique routing policy, are utilized in each of the routing domains,    the routing apparatus is deployed at a border with an adjacent routing domain, at the origin or at the end of the routing domain, and    the identifier changer is configured to change the value of the identifier in view of a routing policy utilized in the routing domain to which the packet is to be transferred.    
     
     
         3 . A packet switching system according to  claim 1 , wherein the identifier changer is configured to perform the same process to change the value of the identifier for a prescribed block of the packets in accordance with a type of packet.  
     
     
         4 . A packet switching system according to  claim 1 , further comprising, a monitor configured to monitor a status of communication on the packet switching network, and to instruct the identifier changer to change the value of the identifier in accordance with variation in a status of communication.  
     
     
         5 . A packet switching system according to  claim 4 , wherein the monitor is implemented independently from the routing apparatus.  
     
     
         6 . A packet switching system according to  claim 4 , wherein the monitor is implemented in the routing apparatus.  
     
     
         7 . A packet switching method for transmitting and receiving a packet via a packet switching network that is configured by interconnecting a plurality of routing appparatuses comprising the steps of: 
 (1) storing a plurality of routing tables, each of which has been generated by a unique routing policy, in the routing apparatuses;    (2) inserting an identifier in the packet to specify a routing table;    (3) transferring the packet to a destination that is specified by the routing table selected in accordance with a value of the identifier inserted in the packet that is received at the routing apparatus; and    (4) changing the value of the identifier within the packet switching network.    
     
     
         8 . A packet switching method according to  claim 7 , wherein the packet switching network is configured by interconnecting a plurality of routing domains formed in a prescribed area, 
 a plurality of routing tables, each of which has been generated by a unique routing policy, are utilized in each of the routing domains,    the routing apparatus is deployed at a border with an adjacent routing domain, at the origin or at the end of the routing domain, and    at step (4), the value of the identifier is changed in view of a routing policy utilized in the routing domain to which the packet is to be transferred.    
     
     
         9 . A packet switching method according to  claim 7 , wherein at step (4), the same process is performed to change the value of the identifier for a prescribed block of the packets in accordance with a type of packet.  
     
     
         10 . A packet switching method according to  claim 7 , further comprising, the step of: 
 (5) instructing an applicable routing apparatus to change the value of the identifier in accordance with variation in a status of communication by monitoring the status of the packet switching network.    
     
     
         11 . A packet switching method according to  claim 10 , where in step (5) is performed at a controlling apparatus which is independent from the routing apparatus.  
     
     
         12 . A packet switching method according to  claim 10 , where in step (5) is performed in the routing apparatus.  
     
     
         13 . A routing apparatus for configuring a packet switching network for transmitting and receiving a packet comprising: 
 a storing unit configured to store a plurality of routing tables, each of which has been generated by a unique routing policy;    a routing table searcher configured to select a routing table in accordance with a value of an identifier inserted in the packet for specifying a routing table;    a transferor configured to transfer the packet to a destination that is specified by the selected routing table; and    a identifier changer configured to change the value of the identifier.    
     
     
         14 . A routing apparatus according to  claim 13 , wherein the packet switching network is configured by interconnecting a plurality of routing domains formed in a prescribed area, 
 a plurality of routing tables, each of which has been generated by a unique routing policy, are utilized in each of the routing domains, and    the identifier changer is configured to change the value of the identifier in view of a routing policy utilized in the routing domain to which the packet is to be transferred.    
     
     
         15 . A routing apparatus according to  claim 13 , wherein the identifier changer is configured to perform the same process to change the value of the identifier for a prescribed block of the packets in accordance with a type of packet.  
     
     
         16 . A routing apparatus according to  claim 13 , further comprising, a monitor configured to monitor the status of communication on the packet switching network, and to instruct the identifier changer to change the value of the identifier in accordance with variation in a status of communication.  
     
     
         17 . A packet generating method for generating a packet that is transmitted and received on a packet switching network configured by interconnecting a plurality of routing apparatuses comprising the steps of: 
 (1) storing a plurality of routing tables, each of which has been generated by a unique routing policy, in the routing apparatuses; and    (2) inserting an identifier, which is able to be changed on the packet switching network, in the received packet to specify a routing table.    
     
     
         18 . A packet generating method according to  claim 17 , wherein the packet switching network is configured by interconnecting a plurality of routing domains formed in a prescribed area, 
 a plurality of routing tables, each of which has been generated by a unique routing policy, are utilized in each of the routing domains,    the routing apparatus is deployed at a border with an adjacent routing domain, at the origin or at the end of the routing domain, and    a value of the identifier is able to be changed in view of a routing policy utilized in the routing domain to which the packet is to be transferred.    
     
     
         19 . A packet generating method according to  claim 17 , wherein the identifier is inserted to allow performing the same process of changing the value of the identifier for a prescribed block of the packets in accordance with a type of packet.  
     
     
         20 . A packet generating method according to  claim 17 , wherein the value of the identifier is able to be changed in accordance with variation in a status of communication by monitoring the status of the packet switching network.  
     
     
         21 . A structure of packet transmitted and received on a packet switching network configured by interconnecting a plurality of routing apparatuses comprising an identifier, to specify a plurality of routing tables stored in the routing apparatuses, each of which has been generated by a unique routing policy, and is able to be changed on the packet switching network.  
     
     
         22 . A structure of packet according to  claim 21 , wherein the packet switching network is configured by interconnecting a plurality of routing domains formed in a prescribed area, 
 a plurality of routing tables, each of which has been generated by a unique routing policy, are utilized in each of the routing domains,    the routing apparatus is deployed at a border with an adjacent routing domain, at the origin or at the end of the routing domain, and    a value of the identifier is able to be changed in view of a routing policy utilized in the routing domain to which the packet to be transferred.    
     
     
         23 . A structure of packet according to  claim 21 , wherein the identifier is inserted to allow performing the same process of changing the value of the identifier for a prescribed block of the packets in accordance with a type of packet.  
     
     
         24 . A structure of packet according to  claim 21 , wherein the value of the identifier is able to be changed in accordance with variation in a status of communication by monitoring the status of the packet switching network.