Communication apparatus and method for inter-as routing

A communication apparatus for connecting a stub network group consisting of one or more stub networks assigned a predetermined AS (Autonomous System) number respectively to an upstream network assigned an AS number, said communication apparatus having its own AS number, comprising:

• means for storing said own AS number;
• an interface for sending/receiving a routing message for controlling forwarding of information between autonomous systems (AS) in accordance with a predetermined protocol and an own AS number notification message to notify its own AS number to a communication apparatus deployed in said stub network group or said upstream network;
• notifying means for notifying said routing message and said own AS number notification message to said communication apparatus through said interface;
• a processor for processing said routing message;
• and
• storage means for storing a routing software program used for said routing,
• wherein said processor, when sending said own AS number notification message to said communication apparatus deployed in a stub network, notifies said upstream network AS number to said communication apparatus instead of its own AS number;
• and
• wherein said processor, when relaying a routing message received from a stub network to said upstream network, processes said routing message without discarding information ruled by said routing protocol so as to pass an AS and not to be relayed thereto, said not-to-be-relayed-information being included in information related to a preferential route of packet forwarding.

A communication method about inter-AS routing protocol, said method employed for a network for connecting a stub network group consisting of one or more stub networks, each having a predetermined AS number assigned to itself, to an upstream network assigned an AS number differently from any of said AS numbers assigned to said stub networks through a first router, said method comprising the steps of:

• enabling said first router to send a message to notify the AS number of said upstream network to a second router deployed in said stub network as its own AS number;
• enabling said first router to send a message for notifying a predetermined AS number different from said upstream network AS number and the AS number of any of said stub networks in said stub network group to a third router deployed in said upstream network as its own AS number;
• and
• enabling said first router to receive a routing message from said third router and send said message together with unmodified information ruled by said routing protocol so as to pass an AS and not to be relayed thereto to said second router, said not-to-be-relayed information being included in the information related to a packet forwarding preferential route set in said routing message received by said first router.

A communication method about inter-AS routing protocol, said method employed for a network for connecting a stub network group consisting of one or more stub networks, each having a predetermined AS number assigned to itself, to an upstream network assigned an AS number differently from any of said AS numbers assigned to said stub networks through a first router respectively, said method comprising the steps of:

• enabling said first router to send a message to notify the AS number of said upstream network to a second router deployed in said stub network as its own AS number;
• enabling said first router to send a message to notify a predetermined AS number different from any of said upstream network AS number and the AS numbers of said stub networks in said stub network group to a third router deployed in said upstream network as its own AS number;
• and
• enabling said first router to receive a routing message from said second router and send said message together with unmodified information ruled by said routing protocol so as to pass an AS and not to be relayed thereto to said third router, said not-to-be-relayed information being included in information related to a packet forwarding preferential route included in said routing message received by said first router.