Siemens Information & Communication Networks, Inc.

Siemens Information and Communications Systems, Inc.

Charles Marcus White

Shmuel Shaffer

William Joseph Beyda

David Weiss

Harry Yen

A network node,capable of detecting how many parties have collided during attempts to transmit on a bus,If more than one party has been detected to collide, the node,selects a backoff window from a larger randomized group of possible backoff windows than if the node had collided with only one other party. In this way, delays due to multiple parties colliding are minimized.

System and method for improving CSMA/CD network performance during collisions

A network having a number of terminals connected by a hub includes managing data transmission collisions by distinguishing among the terminals following a transmission. In the preferred embodiment, the terminals are arranged in a star configuration and the hub is an Ethernet hub that forwards a data packet from a terminal to all of the remaining terminals. A data packet is stored in memory while it is transmitted to all of the other terminals in the collision domain. If a collision is detected in forwarding the data packet, the transmission is completed to the collision-free terminals, thereby isolating subsequent forwarding of the data packet to the one or more collision-inducing terminals. When a no-carrier condition is sensed, the data packet is retransmitted to the one or more collision-inducing terminals. Preferably, a back-off scheme provides priority to the hub-to-terminal transmissions over the terminal-to-hub transmissions, so that the probability of repeated collisions between the same packets is significantly reduced. After all of the terminals have received the transmission of the data packet, the packet is deleted from memory. A memory threshold may be established in order to prevent the storage of the data packets from reaching a condition in which packets are lost. A pseudo-collision condition may be generated within any incoming data packets when the memory threshold is exceeded or to provide a correction if one of the terminals has &ldquo;captured&rdquo; the network.

Growing community of inventors

San Jose, CA, United States of America

Charles Marcus White