Ethernet switches
- an overview of Ethernet switches used in Ethernet LAN applications.
There are many items that are used within local area networks
to enable connections to be made in various ways and to enable the network to be
extended or operate in the required manner. A variety of items including
Ethernet switches, routers, hubs and more may be seen mentioned in literature as
well as being seen installed in local area networks. Of these the Ethernet
switch is one of the most widely used and seen. These Ethernet switches are
available very cheaply from many manufacturers and suppliers.
What is an Ethernet Switch?
Ethernet switches are used to link multiple individual
networks. These switches can improve the network performance by eliminating
extraneous traffic on network segments.
Two varieties of Ethernet switch that are in common use:
- Cut through
- Store and forward
The "cut through" Ethernet switches use algorithms that read
the destination address on the frame header and immediately forward the frame to
the switch port attached to the destination MAC address. This is very fast
because once the header information is read, the rest of the frame is
transmitted without inspection.
The other form of Ethernet switch, the store-and-forward
variety acts more like a like a bridge. It holds the frame until the whole
packet is visible and can be inspected. The store and forward Ethernet switch
makes sure the frame is fit to travel before transmitting it.
Using the store and forward approach there is the possibility
that this would introduce a delay. However in practice it is found that this
form of Ethernet switch is nearly as fast as the cut through variety of
switches.
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