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Abstract

A method and apparatus for coupling IP ECN with ATM congestion control is disclosed. The invention extends IP-ECN to ATM devices with minimal implementation complexity. Thus, the performance of IP data traffic over ATM is enhanced without requiring packet-reconstruction at the ATM layer. The method includes using AAL5 packet trailers in ATM cells to detect packet boundaries for identifying a first cell in an IP packet, determining whether an ATM cell capable of using explicit congestion notification to indicate congestion and setting a explicit congestion notification indicator in a capable ATM cell to indicated congestion to a source node. The use of the packet trailers further comprises monitoring a flag for indicating whether an ATM cell is an end of packet. The method further includes resetting the end of packet flag to an off state to so the next cell is recognized a first cell of a packet and transmitting the ATM cell. A determination is made as to whether a next ATM cell is a first ATM cell for a packet. The next ATM cell is transmitted when the ATM cell is not a first ATM cell for a packet. A determination is then made as to whether ATM congestion is associated with the next ATM cell. The next ATM cell is then transmitted when congestion is not associated with the next ATM cell.

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First Claim