| Virtual circuits are
connection-oriented, which means that there is a reservation of
resources like buffers, bandwidth, etc. for the time during which the
newly setup VC is going to be used by a data transfer session. | It
is connectionless service. There is no need for reservation of
resources as there is no dedicated path for a connection session. |
| A
virtual circuit network uses a fixed path for a particular session,
after which it breaks the connection and another path has to be set up
for the next the next session. | A Datagram based network is a true packet switched network. There is no fixed path for transmitting data. |
| All
the packets follow the same path and hence a global header is required
only for the first packet of connection and other packets will not
require it. | Every packet is free to choose any
path, and hence all the packets must be associated with a header
containing information about the source and the upper layer data. |
| Packets reach in order to the destination as data follows the same path. | Data packets reach the destination in random order, which means they need not reach in the order in which they were sent out. |
| Virtual Circuits are highly reliable. | Datagram networks are not as reliable as Virtual Circuits. |
| Implementation
of virtual circuits is costly as each time a new connection has to be
set up with reservation of resources and extra information handling at
routers. | But it is always easy and cost-efficient to
implement datagram networks as there is no need of reserving resources
and making a dedicated path each time an application has to communicate. |
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