Kingston Technology Kingston Fast EtheRx KNS3250/R - Manual (Page 10)

KNS3250/R Users Guide - Rev. A00 Kingston Technology Company
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.