Nec Corporation

The Tokyo Electric Power Company, Incorporated

Fumiyasu Hayakawa

Ryota Motobayashi

Kazuhiko Azuma

Hayato Momma

Mayumi Hara

In an ANS used for a television conference between calling and destined conference room terminals accommodated in an ATM network, an address of each conference room terminal is stored in an address database as address resolution data which have no hierarchical structure and which therefore uniquely define each conference room terminal. A priority level of each conference room terminal is also stored in the address database and is referenced on occurrence of congestion so as to determine whether or not a connection is released during a conference. Reservation data may be stored in the ANS together with topology data and connection data.

ANS designed for a conference between conference room terminals and network system including the ANS

A monitor () receives a returned response message, and stores the state of the link directed to the NE that returned the message as a successful transmission, and then repeats the same operation at arbitrary intervals. When the monitor can not receive the response message after placing a certain interval, it stores the link as an unsuccessful transmission. At this point, if all the links for a particular NE are in the unsuccessful state, the monitor informs an NMS () of a fault in that NE. If the NE truly has the NE fault, other NEs that also have the links to that fault NE inform the NMS of the fault. Thereby the NMS itself does not need to do the monitoring. The NMS only collates fault information with topology information stored in a topology information storage () and can judge that a particular NE is out of communication and control.

Network system, detection method and monitoring method of network entity faults, and storage medium

In a packet switched communications system wherein each destination data terminal sends an acknowledgment packet signalling correct receipt of packets from a source terminal, a congestion detector is provided for detecting a traffic congestion in the system to enable a packet detector. The packet detector, when enabled, detects the receipt of an acknowledgment packet from the destination terminal and stores this packet in a buffer for a specified period of time. The stored packet is then forwarded toward the source terminal upon termination of the specified time period.

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Kanagawa, Japan

Fumiyasu Hayakawa