Multicast Control Technique Using MPLS

Abstract

In this invention, an idea of the reverse direction label switched path (RLP) in Multi-Protocol Label Switching (MPLS) is applied to the multicast transmission to improve the management transmission in the multicast transmission, and to easily carry out an additional connection and disconnection. Specifically, in the reverse direction symmetric routing Label switched Path (LP), a virtual label in addition to an input label and an output label is used for the reverse direction routing. However, in this invention, instead of the virtual label, a multicast address to which a client terminal, which is connected to a head of the path on the reverse direction routing, and corresponds to a leaf in the multicast tree, is connected, is registered, as a multicast index, in routers on the path. Then, when receiving a multicast packet including a label and a multicast address, an output label corresponding to the received label is identified, thereby a destination link is identified.

1 . An information processing method executed by a management server that manages paths in a specific network, comprising:
 upon receiving a multicast connection request relating to a specific multicast address from an edge router connected to a client terminal, identifying a path used for data transmission to said client terminal by referring to a multicast data storage storing data concerning labels of links constituting multicast paths from a source address of a multicast source server to an edge router connected to a client terminal, which is capable of receiving multicast data;   identifying, in said multicast data storage, a label that is not associated with said specific multicast address relating to said multicast connection request, among said labels of said links constituting the identified path, and registering said specific multicast address in association with the identified label in said multicast data storage; and   carrying out a setting for a router associated with said identified label to register said specific multicast address in association with said identified label.   
     
     
         2 . The information processing method as set forth in  claim 1 , wherein said multicast data storage stores data concerning labels of links constituting a plurality of multicast paths, a portion having a common label is aggregated with respect to said plurality of multicast paths from said source address of said multicast source server, and said label that is not associated with said multicast address is identified in said portion with respect to any of said plurality of multicast paths. 
     
     
         3 . An information processing method executed by a management server that manages paths in a specific network, comprising:
 upon receiving a multicast disconnection request relating to a specific multicast address from an edge router connected to a specific client terminal that is receiving multicast data of said specific multicast address, identifying a path being used for data transmission to said specific client terminal, by referring to a multicast data storage storing labels of links constituting multicast paths from a source address of a multicast source server to an edge router connected to a client terminal that receives multicast data, multicast addresses associated with said labels, and multicast addresses relating to said client terminals receiving said multicast data;   determining whether or not said multicast address relating to said multicast disconnection request is registered in said multicast data storage in association with any of said client terminals associated with a label to be processed in order from a lower label in the identified path;   upon detection that it is determined that said multicast address relating to said multicast disconnection request is not registered in association with any of said client terminals associated with said label to be processed, deleting, in said multicast data storage, said multicast address, which is registered in association with the label to be processed and relates to said multicast disconnection request, and causing to execute said determining for an upper label in the identified path;   upon detection that it is determined that said multicast address relating to said multicast disconnection request is registered in association with any of said client terminals associated with said label to be processed, deleting, in said multicast data storage, said multicast address, which is registered in association with said label to be processed and relates to said multicast disconnection request; and   transmitting a deletion instruction including said multicast address relating to said multicast disconnection request and a label for which the corresponding multicast address was deleted, to a router associated with said label for which said corresponding multicast address was deleted.   
     
     
         4 . A program embodied on a medium for causing a management server that manages paths in a specific network to execute an information processing, said program comprising:
 upon receiving a multicast connection request relating to a specific multicast address from an edge router connected to a client terminal, identifying a path used for data transmission to said client terminal by referring to a multicast data storage storing data concerning labels of links constituting multicast paths from a source address of a multicast source server to an edge router connected to a client terminal, which is capable of receiving multicast data;   identifying, in said multicast data storage, a label that is not associated with said specific multicast address relating to said multicast connection request, among said labels of said links constituting the identified path, and registering said specific multicast address in association with the identified label in said multicast data storage; and carrying out a setting for a router associated with said identified label to register said specific multicast address in association with said identified label.   
     
     
         5 . A program embodied on a medium for causing a management server that manages paths in a specific network to execute an information processing, said program comprising:
 upon receiving a multicast disconnection request relating to a specific multicast address from an edge router connected to a specific client terminal that is receiving multicast data of said specific multicast address, identifying a path being used for data transmission to said specific client terminal, by referring to a multicast data storage storing labels of links constituting multicast paths from a source address of a multicast source server to an edge router connected to a client terminal that receives multicast data, multicast addresses associated with said labels, and multicast addresses relating to said client terminals receiving said multicast data;   determining whether or not said multicast address relating to said multicast disconnection request is registered in said multicast data storage in association with any of said client terminals associated with a label to be processed in order from a lower label in the identified path;   upon detection that it is determined that said multicast address relating to said multicast disconnection request is not registered in association with any of said client terminals associated with said label to be processed, deleting, in said multicast data storage, said multicast address, which is registered in association with the label to be processed and relates to said multicast disconnection request, and causing to execute said determining for an upper label in the identified path;   upon detection that it is determined that said multicast address relating to said multicast disconnection request is registered in association with any of said client terminals associated with said label to be processed, deleting, in said multicast data storage, said multicast address, which is registered in association with said label to be processed and relates to said multicast disconnection request; and transmitting a deletion instruction including said multicast address relating to said multicast disconnection request and a label for which the corresponding multicast address was deleted, to a router associated with said label for which said corresponding multicast address was deleted.   
     
     
         6 . A router for carrying out routing according to an instruction of a management server for managing a path between arbitrary nodes in a specific network, comprising:
 a data storage storing a pair of labels for an input link and an output link which are directly connected to said router, among links constituting paths passing through said router, and correspondence between labels and links; and   a routing unit that identifies an output link and an output label corresponding to an input label included in a received packet, by referring to said data storage, and carries out routing of the received packet based on the identified output link and output label, and wherein said data storage stores a multicast address in addition to said input label and said output label, which relate to an uplink, and upon receiving a downlink packet including said output label and said multicast address, said routing unit searches data stored in said data storage by using said multicast address and said output label, which are included in said downlink packet, to identify an output link of said downlink packet.   
     
     
         7 . The router as set forth in  claim 6 , further comprising:
 a confirmation unit that confirms, upon receiving a multicast connection request including a specific multicast address from a client terminal, which is capable of receiving multicast data and is connected to said router, whether or not said specific multicast address included in said multicast connection request is registered in said data storage; and   a connection controller that registers said specific multicast address in said data storage in association with an output label associated with said client terminal upon detection that said specific multicast address is registered in said data storage.   
     
     
         8 . The router as set forth in  claim 7 , further comprising:
 a unit that transmits a second multicast connection request including said specific multicast address to a billing server that carries out a billing processing for multicast, and wherein said connection controller operates upon receiving a connection allowance from said billing server.   
     
     
         9 . The router as set forth in  claim 7 , further comprising:
 a unit that transmits a third multicast connection request including said specific multicast address and an address of said client terminal from which said multicast connection request was received to said management server, upon detection that said specific multicast address is registered in said data storage.   
     
     
         10 . The router as set forth in  claim 6 , further comprising:
 a unit that deletes, upon receiving a first multicast disconnection request including a specific multicast address from a specific client terminal receiving multicast data and connected to said router, said specific multicast address registered in association with a label associated with said specific client terminal in said data storage;   a unit that confirms whether or not said specific multicast address is registered in association with a label other than said label associated with said specific client terminal in said data storage; and   a unit that transmits, upon detection that said specific multicast address is not registered in association with a label other than said label associated with said specific client terminal, a second multicast disconnection request including an address of said specific client terminal and said specific multicast address to said management server.   
     
     
         11 . The router as set forth in  claim 6 , further comprising:
 a unit that deletes, upon receiving a disconnection instruction including an input label and a multicast address from said management server, said multicast address, which is included in said disconnection instruction and is associated with said input label included in said disconnection instruction, in said data storage.   
     
     
         12 . A management server that manages paths in a specific network, comprising:
 a unit that identifies, upon receiving a multicast connection request relating to a specific multicast address from an edge router connected to a client terminal, a path used for data transmission to said client terminal by referring to a multicast data storage storing data concerning labels of links constituting multicast paths from a source address of a multicast source server to an edge router connected to a client terminal, which is capable of receiving multicast data;   a unit that identifies, in said multicast data storage, a label that is not associated with said specific multicast address relating to said multicast connection request, among said labels of said links constituting the identified path, and registers said specific multicast address in association with the identified label in said multicast data storage; and   a unit that carries out a setting for a router associated with said identified label to register said specific multicast address in association with said identified label.   
     
     
         13 . A management server that manages paths in a specific network, comprising:
 an identification unit that identifies, upon receiving a multicast disconnection request relating to a specific multicast address from an edge router connected to a specific client terminal that is receiving multicast data of said specific multicast address, a path being used for data transmission to said specific client terminal, by referring to a multicast data storage storing labels of links constituting multicast paths from a source address of a multicast source server to an edge router connected to a client terminal that receives multicast data, multicast addresses associated with said labels, and multicast addresses relating to said client terminals receiving said multicast data;   a unit that determines whether or not said multicast address relating to said multicast disconnection request is registered in said multicast data storage in association with any of said client terminals associated with a label to be processed in order from a lower label in the identified path;   a unit that deletes, upon detection that it is determined that said multicast address relating to said multicast disconnection request is not registered in association with any of said client terminals associated with said label to be processed, said multicast address, which is registered in association with the label to be processed and relates to said multicast disconnection request, in said multicast data storage, and operates said identification unit for an upper label in the identified path;   a unit that deletes, upon detection that it is determined that said multicast address relating to said multicast disconnection request is registered in association with any of said client terminals associated with said label to be processed, said multicast address, which is registered in association with said label to be processed and relates to said multicast disconnection request, in said multicast data storage;   and a unit that transmits a deletion instruction including said multicast address relating to said multicast disconnection request and a label for which the corresponding multicast address was deleted, to a router associated with said label for which said corresponding multicast address was deleted.