4 Design Features
Kingston Technology Company KNS800/WG User’s Guide – Rev.B01
Design Features
Switching Function
The Fast EtheRx Switch is basically designed to bridge Standard 10BASE-T
Ethernet networks to 100BASE-TX Fast Ethernet networks and to segment
10Mbps or 100Mbps network segments.
Auto-Negotiation
Auto-Negotiation provides the means of automatically establishing a link by
detecting the link capabilities of the connected device on the network to select
the best operational mode available (i.e. 100BASE-TX/10BASE-T selection,
half- / full-duplex mode operation, etc.)
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 flow 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 flow
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.