Difference between Datagram Switching and Virtual Circuit
Datagram Switching
It is a packet switching method that treats each packet(datagram) as an individual entity.
Each datagram or packet is routed through a network of its own. It does not require a connection as there is no specific channel for a connection session. The packets have headers with all the destination’s information. Intermediate nodes assess the packet’s header and select links depending on which node is closer to the destination.
Virtual Circuit
In virtual packet switching, there is a path built between the source and the final destination. All the packets are routed through a call known as virtual circuit switching. For the data communication to commence, the source and the destination must agree on a virtual circuit path.
For the decision to be made, all the intermediary nodes between the two places add a routing entry to their routing database. During the call setup, additional parameters like packet size are also exchanged between the source and the destination.
Differences:
| Virtual Circuits | Datagram Networks |
| They are connection-oriented. | They are connectionless services. |
| They use a fixed path for a particular session. | There is no fixed path for transmitting data. |
| They are highly reliable. | They are comparatively less reliable. |
| Implementation is costly as each time a new connection has to be set up. | It is easier and cheaper to set up as there is no need for reserving resources. |
| All the packets follow the same path, therefore there is a need for a global header for the first packet, while other packets won’t need it. | Every packet is free to choose any path and therefore all the packets need a header. |
Difference between Datagram Switching and Virtual Circuit