Packet
Switching:
ØIn packet-based networks, the message gets broken into small data
packets.
ØThese packets are sent out from the computer
and they travel around the network seeking out the most efficient route to
travel as circuits become available.
ØThis does not necessarily mean that they seek
out the shortest route.
ØEach packet may go a different route from the
others
Advantages:
- Security
- Bandwidth used to full potential
- Devices of different speeds can communicate
- Not affected by line failure (redirects signal)
- Availability – no waiting for a direct connection to become available
- During a crisis or disaster, when the public telephone network might stop working, e-mails and texts can still be sent via packet switching
Disadvantages
»Under heavy use there can be a delay
»Data packets can get lost or become corrupted
»Protocols are needed for a reliable transfer
»Not so good for some types data streams (e.g.
real-time video streams can lose frames due to the way packets arrive out of
sequence)
Circuit
Switching:
ØCircuit switching was designed in 1878 in order to send telephone
calls down a dedicated channel.
ØThis channel remains open and in use
throughout the whole call and cannot be used by any other data or phone calls.
Advantages
»Circuit is dedicated to the call
–
no interference, no sharing
»Guaranteed the full bandwidth
for
the duration of the call
»Guaranteed quality of service
Disadvantages
»Inefficient – the equipment may
be
unused for a lot of the call; if no data is
being sent, the dedicated line
still
remains open.
»It takes a relatively long time
to set up
the circuit.
»During a crisis or disaster, the
network
may become unstable or unavailable.
»It was primarily developed for
voice
traffic rather than data traffic.
