SMC EZ Connect -EZ6505TX Manuel D'installation page 9

SMC-EZ6505TX_UK/GE/FR/SP/IT.qxd
How a switch works
A Switch works very differently to a normal Hub. The main
difference is that a Switch looks at the network packet and only
sends it to the person that it was intended for. This reduces the
amount of traffic flying around on the network and improves your
performance. A standard Hub cannot do this and how it works is
simply to send any packet that it receives to everybody connected
to it. This means that there is a lot of information going to each
computer that did not need to be delivered.
The main factor that effects the performance, is that the Switch
supports Full Duplex. This means that it can send and receive
information at the same time, therefore doubling the speed at
which it works and doubling the amount of information that can
be sent than a normal hub.
A hub only works at Half Duplex. This means that it can only send
or receive a packet of information at one time. Only one computer
can talk at any one time when connected to a hub which reduces
the speed in which you can receive your information. When more
than one computer is requesting information at the same time,
you get what is called a collision. This is when two packets of
information collide on the same cable. This happens when the
Hub is sending a packet of information when the receiving
computer is sending a packet of information. The more people
that are connected to a hub means that there are more chances of
collisions and a greater chance of your network performance
slowing down.
You do not get collisions when you are connected to a switch as it
only sends network packets to the computer that requested the
information and it can also send and receive at the same time.
Bandwidth is very important on an Ethernet network and a switch
offers much more bandwidth than a hub can. The more bandwidth
you have on your network, the better your network will perform.
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• 5 port 10Mbps hub has a bandwidth of 10Mbps
• 5 port 10/100Mbps hub, has a bandwidth of 110Mbps
• 5 port 10/100Mbps Switch has a bandwidth of 1000Mbps.
Therefore, the performance of the Switch is 100 times better than
a 10Mbps hub and almost 10 times better than a 10/100Mbps hub.
"Network Design" section
A switch can be used in a number of different ways. You can
either connect computers directly into it, connect groups of hubs
into it or do both.
Switch
Computers
Fig A.
Connecting computers directly into the Switch
Computers
In this diagram, every computer is connected straight into the
Switch. This means that every user has their own dedicated
bandwidth of 200Mbps. The performance will be very fast and will
not slow down when the amount of network traffic increases. If
one of the users is downloading a very large file, the performance
of the other users will not be effected.
Server
Switch
Hub Hub
Computers Computers
Fig B.
Server
Hub
Computers
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