Nortel Networks Corporation

Avaya Inc.

Jamal Hadi Salim

Biswajit Nandy

Nabil Seddigh

Joseph Fook-Kong Thoo

A packet processing apparatus comprises a programmable hardware discriminator for receiving incoming packets, and selecting bits from any part of the incoming packets, a decision table for storing information relating to how the packets are to be processed, programmable hardware searching logic for accessing the information in the table according to the selected bits, and a packet handler for processing the packets according to the result of the access. Since many networking processing tasks can be broken down into bit selection and table searching, this generic type of arrangement will suit a wide variety of applications. It facilitates developing logic directly in hardware which can reduce the effort needed to convert a working prototype into a product ready for use in the field, e.g. for handling new protocol components.

Programmable packet switching device

A system and method for transmitting data in a data communications network, using a transmission control protocol, to provide reduced acknowledgment control traffic, error recovery and congestion control. A communications link is established between a transmitter and a receiver. Setting the communications link includes setting a network congestion window to an initial length. A sequence, or stream, of data packets is sent from the transmitter to the receiver. The receiver detects any missing packets, by examining the sequence numbers of the incoming packets, and sends negative acknowledgments, generally no more than four, to the transmitter identifying the missing data packet. When the transmitter receives a negative acknowledgment, it decreases the length of the congestion window, and re-transmits the missing packet. Detection and use of round-trip time, re-transmission time-out are provided.

System and method for a negative acknowledgement-based transmission control protocol

In a packet network, on receiving a packet a receiving host determines if the packet has been marked by any of the nodes through which it passed, to indicate congestion at that node, e.g. by checking the CE bit in an IP header. A packet flow control parameter is generated at the receiving side, and sent to the source using an Internet Protocol, as part of the packet acknowledgment, to control the flow of packets from the source, according to the packet flow control parameter. This can reduce control loop delays caused by waiting at the source for a number of acknowledgments to arrive before the congestion level can be calculated. Conditions at the receiver which may be different to those at the source can now be taken into account in the flow control.

Receiver based congestion control

In a router in a network comprising a source node, and a receiver node, and other nodes, a congestion monitor determines a degree of congestion, which is sent back to the source node, using an OSI network layer protocol. This enables the flow of packets from the source to be controlled more accurately to maintain high throughput with reduced probability of congestion. Using the network layer rather than lower layers can ensure the indication can be carried across the entire network, and not be lost at boundaries between data links making up the network.

Growing community of inventors

Nepean, Canada

Jamal Hadi Salim