Datagram switching
Datagram packet switching
Each packet, or datagram, is treated as a separate entity in this packet switching technique. Every packet is routed independently through the network. It is a service that is not connection-dependent. There is no requirement to reserve resources because there is no dedicated channel for a connection session. Consequently, packets have a header containing all of the destination’s data. A packet’s header is examined by the intermediate nodes, which then decide on an appropriate link to another node that is closer to the destination.
Virtual Circuit
Virtual packet switching
Virtual circuit switching is a method in which a path is created between the source and the intended destination through which all packets are routed during a call. This path is referred to as a virtual circuit because the connection appears to the user to be an enamoured physical circuit. On the other hand, other communications might be travelling some of the same path. The source and destination must agree on a virtual circuit path before data transmission can start. Each intermediate node that connects the two locations adds a routing entry to their routing database to reflect the choice. During call setup, the source and consequently the destination also exchange other parameters, such as the maximum packet size. After the information transfer is finished, the virtual circuit is cleared.
| Sr. No. | Key | Virtual Circuits | Datagram Networks |
|---|---|---|---|
| 1 | Definition | The connection-oriented service known as Virtual Circuit implements resources such as CPU, bandwidth, and buffers that are used by Virtual Circuit during a data transfer session. | In comparision, Datagram is a connection-less service that transmits data without the need for any such resources. |
| 2 | Path | In virtual circuits, all of the resources and bandwidth are reserved before the transmission, which fixes the path that the first data packet uses or follows and ensures that all subsequent data packets use the same path and use the same resources. | In contrast, the path is not fixed in a datagram network because data packets are free to choose the route on any intermediate router while they are in motion by dynamically changing routing tables on routers. |
| 3 | Header | A common and identical header is used by all data packets because they all travel along the same path. | However, in a datagram network, various headers containing information from other data packets are used. |
| 4 | Complexity | Comparing the complexity of the Virtual Circuit network to the Datagram network | However, compared to virtual circuit, datagram networks are more complex. |
| 5 | Reliability | Datagram networks are more complicated than virtual circuit networks, though. | On the other hand, datagram networks are less dependable than virtual circuits because they allocate resources dynamically and follow dynamic paths. |
| 6 | Example and Cost | Virtual circuits, which are frequently used by the ATM (Asynchronous Transfer Mode) Network, which is used for telephone calls, are more expensive to install and maintain. | In contrast, Datagram networks, which are primarily used by IP networks, which are used for Data services like the Internet, are less expensive than Virtual Circuits. |