Circuit switching is where there is a
dedicated, physical path between two
points. Data is broken up but it is
transmitted down a dedicated pathway.
An example of this is telephones: data is
transmitted in real time. The data packets is sent
in a continuous stream of bits.
There is no interference between any other
paths, as this path is dedicated to this
transmission.
Packet switching
Packet switching is transmitting broken
pieces of the data independently over
many networks to get to its destination. It
gets assembled once it has reached its
destination.
There is no dedicated path-the
packets can take any pathway
as long as they get to their
destination.
The router works out the fastest
way to reach the destination.
The packet will travel through
many routers.
This is very efficient because if one
path is broken or busy, the packet
will take another route.
Advantages and
Disadvantages of Circuit
switching
Advantages
Sending data down a circuit
switching network is more
reliable because there is one
dedicated path to send the
data down. This means that
there is a continuous stream
of data.
Once the circuit is established,
data is transmitted without any
delay as there is no waiting time at
each switch.
The data is received in the same order it
was sent in.
No loss of data because the
data is sent down on
dedicated pathway
Disadvantages
The connection is not instantaneous.
This means that there is no
communication until a connection
has been established
Dedicated channels require more bandwidth.
This means that traffic will be created, as there
is an idle connection.
Connection refused
when resources are not
sufficient
As there is only one path, if it
gets broken, then you cannot
communicate with the other
person.
Advantages and
disadvantages of Packet
switching
Advantages
Packet switching is more
reliable because it can reroute
the data onto another path if
one of the paths of broken or
damaged. This ensures that
all the data will reach the
destination
Many users can share the same channel
simultaneously. Hence packet switching
makes use of available bandwidth
efficiently.
Packet-switching allows each packet to find its
own path to the destination, with no
dedicated connection needed. This means
that multiple users can use the network.
Disadvantages
If the network becomes
overloaded, packets are delayed or
discarded or dropped. This leads
to retransmission of lost packets
by the sender. This often leads to
loss of critical information if errors
are not recovered.
Packet switching network can not be
used in applications requiring very
little delay and higher quality of
service e.g. reliable voice calls.
Ethernet frame contains: source
address, destination address, data
and a checksum
Ethernet-layer 2 protocol
Layer 2= mac address-machine address
having an id in a machine-unique id
Frames are used to package
data in a network, allowing
it to be sent from A to B.
Frames use MAC addesses