ATM bridge device and method for detecting loop in ATM bridge transmission

A loop detecting method for detecting a loop formed in an ATM bridge device to which an ATM network and a layer 2 network are connected, said method comprising:

• a first learning step of learning a transmitter address of a packet input from said ATM network and information about a transmission path through which said packet had been transmitted and to judge a destination of said packet based on a result from the learning;
• a second learning step of learning a transmitter address of a packet input from said ATM network and information about a transmission path to which said packet is to be output;
• and
• a packet scrapping judging step of comparing said transmitter address of said packet input from said ATM network and information about said transmission path through which said packet had been transmitted with said transmitter address of said packet learnt in said second learning step and information about said transmission path to which said packet is to be output and, if said transmitter address of said packet input from said ATM network and information about said transmission path through which said packet had been transmitted are matched with said transmitter address of said packet learnt in said second learning step and information about said transmission path to which said packet is to be output, to scrap said packet.

An ATM (Asynchronous Transfer Mode) bridge device to which an ATM network and a layer 2 network are connected, comprising:

• a first learning means to learn a transmitter address of a packet input from said ATM network and information about a transmission path through which said packet had been transmitted and to judge a destination of said packet based on a result from the learning;
• a second learning means to learn a transmitter address of a packet input from said ATM network and information about a transmission path to which said packet is to be output;
• and
• a packet scrapping judging means to compare said transmitter address of said packet input from said ATM network and information about said transmission path through which said packet had been transmitted with said transmitter address of said packet learnt by said second learning means and information about said transmission path to which said packet is to be output and, if said transmitter address of said packet input from said ATM network and information about said transmission path through which said packet had been transmitted are matched with said transmitter address of said packet learnt by said second learning means and information about said transmission path to which said packet is to be output, to scrap said packet.