Abstract: A path management device of the present invention manages information about communication paths in a communication network, the communication network including a plurality of routers mutually connected by means of a communication line, link states between the plurality of routers being shared among each of the plurality of routers by means of link state advertisement messages that are announced from each of the plurality of routers, and routing tables being created in each of the plurality of routers based on shortest path trees, and the path management device includes: a receiving unit that receives the link state advertisement messages; a routing table creation unit that reproduces the shortest path trees and the routing tables of each of the plurality of routers based on the link state advertisement messages; and a routing table recording unit that records the reproduced routing tables of each of the plurality of routers.

Abstract: The present invention provides a BGP route evaluation device and method. A message receiving section 101 receives a BGP Update message. A status detecting section 102 detects the active/inactive status of each BGP route on the basis of a pair of prefix and next hop registered in “Announce” and “Withdraw” of the BGP Update message. In a management table 104, the active/inactive status of each BGP route is managed. An update section 103 updates the registration contents of the management table 104 on the basis of the detection result of the active/inactive status. An evaluation section 105 evaluates each BGP route on the basis of the registration contents of the management table 104.

Abstract: In order to provide the routing information of both the present time and the past, provide the latest routing information very quickly and improve searching speed of the routing information, a routing information management apparatus includes: a routing information receiving portion receiving routing information which broadly notifies a change/withdrawal of a communication route and which is received from an observation apparatus of communication routes; and a routing state table generation portion which generates a routing state table of each of the communication routes including both a route existing time based on a received time of the routing information and a range of an address space obtained by digitizing a prefix involved in the routing information, and which stores the routing state table in a routing information database.

Abstract: The present invention provides a BGP route evaluation device and method. A message receiving section 101 receives a BGP Update message. A status detecting section 102 detects the active/inactive status of each BGP route on the basis of a pair of prefix and next hop registered in “Announce” and “Withdraw” of the BGP Update message. In a management table 104, the active/inactive status of each BGP route is managed. An update section 103 updates the registration contents of the management table 104 on the basis of the detection result of the active/inactive status. An evaluation section 105 evaluates each BGP route on the basis of the registration contents of the management table 104.

Abstract: A path management device of the present invention manages information about communication paths in a communication network, the communication network including a plurality of routers mutually connected by means of a communication line, link states between the plurality of routers being shared among each of the plurality of routers by means of link state advertisement messages that are announced from each of the plurality of routers, and routing tables being created in each of the plurality of routers based on shortest path trees, and the path management device includes: a receiving unit that receives the link state advertisement messages; a routing table creation unit that reproduces the shortest path trees and the routing tables of each of the plurality of routers based on the link state advertisement messages; and a routing table recording unit that records the reproduced routing tables of each of the plurality of routers.

Abstract: In order to provide the routing information of both the present time and the past, provide the latest routing information very quickly and improve searching speed of the routing information, a routing information management apparatus includes: a routing information receiving portion receiving routing information which broadly notifies a change/withdrawal of a communication route and which is received from an observation apparatus of communication routes; and a routing state table generation portion which generates a routing state table of each of the communication routes including both a route existing time based on a received time of the routing information and a range of an address space obtained by digitizing a prefix involved in the routing information, and which stores the routing state table in a routing information database.

Abstract: As shown in FIG. 2, when the SYN segment is detected, the amount of transmitted segment from the side which sent the detected SYN segment is obtained by counting the continuously detected DATA segments for collecting the traffic in a certain direction where it is impossible to directly capture the traffic. Further, the amount [ini_sdt] of the transmitted bytes from the side which sent the detected SYN segment is obtained by calculating the equation [ini_sdt]=[SEQn+LENn]?[SEQ1]. Wherein, [SEQ1] is the sequence number of the first detected DATA segment, [SEQn] is the sequence number of the last detected DATA segment and [LENn] is the user data length of the last detected DATA segment.

Abstract: As shown in FIG. 2, when the SYN segment is detected, the amount of transmitted segment from the side which sent the detected SYN segment is obtained by counting the continuously detected DATA segments for collecting the traffic in a certain direction where it is impossible to directly capture the traffic. Further, the amount [ini_sdt] of the transmitted bytes from the side which sent the detected SYN segment is obtained by calculating the equation [ini_sdt]=[SEQn+LENn]−[SEQ1]. Wherein, [SEQ1] is the sequence number of the first detected DATA segment, [SEQn] is the sequence number of the last detected DATA segment and [LENn] is the user data length of the last detected DATA segment.

Abstract: A method and apparatus for monitoring a communication link based on TCP/IP protocol obtains a protocol data unit (PDU) between communication systems. A emulation log is produced by analyzing the PDU in a PDU analysis part. An event sequence log is produced by estimating an event sequence of both communication systems based the emulation log in an event sequence estimation part. The behavior and the internal procedure of TCP is emulated by using the specific TCP state transition specification, internal variables of TCP, internal variables indicating the status and internal procedures in the TCP emulation part.