| All (most) Ethernet Switches on the market are either cut-thru or
store and forward. Cut-thru has been made famous by Kalpanna.
They only look at the destination address and then decide whether
to filter or forward the packet irregardless of whether its CRC
errored or a runt. Their marketing says that because of this they
can get more throughput than store and forward bridges. But you
no longer confine bad packets to the segment they originated on
but can now pass them around the network. Real nice. 8^(
A discussion in the Ethernet notes covered in more detail just how
much faster such a device would be compared to a store and forward
device. The bottom line is the Kalpana will be only one packet
ahead of a store and forward bridge, even at the end of the day.
Our DB900MX is a store and forward device. I call it an Ethernet
Switch to customers. It will switch an in coming packet to only
the segment it needs to go to. A packet on Ethernet port 1,
going to port 3 will not go out onto the FDDI. We also support
rate limiting on the number of broadcast packets through the bridge
(switch) so a broadcast storm on one Ethernet will not flood the other
5 Ethernets but will allow only a percent through.
Hope this helps.
dave
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