In the
world of network communication, we often confuse between hubs, switches and
routers. Fact is they all seem the same to a layman but are very much different
in their internal structure and their working. To clear the air of confusion
and also to have a good idea of what they are let us get a look:
The Definition
Hub – this is simply an electronic device that is
used to connect devices together in a network. In a LAN there are different
segments and a hub connects them all together. The hub receives a data packet
from a source and forwards it to all the other ports that it is connected to.
Switch – this is like a hub but it has intelligence
as it can filter the data packets that it receives and forwards them to only
the required destinations. A switch generally operates in the Data Link Layer
of the OSI model but also operates in the Network Layer. Those which operate in
the Network Layer are called as Layer 3 switches.
Router – while switches and hubs are present inside
a network, a router is present outside a network called a gateway. Actually it
is used to connect between networks and so at least two networks are needed to
set up a router. Routers are very intelligent as they follow an algorithm to
send data packets using headers, forwarding tables and protocols and send them
through the best path that is available.
The Difference
The
difference between a hub, a switch and a router lies in the way data is carried
in the form of frames.
Hub – the hub receives the frame from a source
and transmits it to all the other ports. As a result it creates a lot of
traffic unnecessarily and the bandwidth is eaten up. Also, since a hub shares
the bandwidth with all the other computers there will be a reduction in speed
and performance. There may occur a situation when many computers start sending
data packets to one another and there is a collision in between the data packets.
Switch – a switch works in the way that it keeps a
record of the addresses of the computers that it is connected to. This helps it
to identify the computer that the data frame is intended for. The frame has the
address of the destination computer and the switch sends the data to it. As a
result there is no collision or delay in delivery. Also, a switch can fully
allocate the bandwidth to each of the ports that it is connected to. Even different
ports can send data to one another without creating any form of collisions.
Router – a router is totally different from a hub or
a switch in that it is used for inter-networking. It uses the IP addresses and
connects the best ways to make a link between the sender and the receiver. All routers
consist of WAN port connecting to a DSL or cable modem.
