Design Features

5

Full-Duplex

Full-Duplex transmission means that dedicated inbound and outbound channels are established for bi-directional transmission of data. This allows the collision detection mechanism (CSMA/CD) to be by-passed, thus decreasing transmission delay normally caused by listening, collisions, and packet resends when operating in half-duplex mode.

Store-and-Forward Switching

The Fast EtheRx Switch uses a packet-forwarding method called Store-and- Forward, which minimizes the re-transmission of faulty data packets. This means that the Fast EtheRx Switch can store the incoming frame in an internal buffer and check the packet for errors before sending it out to the destination port. If the frame does contain errors, it will be discarded and then retransmitted.

Flow Control

In half-duplex mode the Fast EtheRx Switch implements a collision-based backpressure ow control mechanism that reduces the risk of data loss at congested ports. This is accomplished by forcing a collision with the data frames on all ports once the free-buffer queue has reached the pre-set minimum.

In full-duplex mode the Fast EtheRx Switch implements the IEEE 802.3x ow control mechanism. This is accomplished by sending a PAUSE packet on a port when the number of buffers allocated to this port exceeds the pre-set minimum.

KNS3250/R Users Guide - Rev. A00

Kingston Technology Company

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Kingston Technology KNS2450/R, KNS3250/R, KNS1650/R manual Full-Duplex, Store-and-Forward Switching, Flow Control