Computer networks that provide connection-oriented service are called Virtual Circuits while those providing connection-oriented services are called as Datagram networks. For prior knowledge, the Internet which we use is actually based on Datagram network (coonectionless) at network level as all packets from a source to a destination do not follow same path.
Let us see what are the highlighting differences between these two hot debated topics here:
Virtual Circuits-
- It is connection-oriented simply meaning that there is a reservation of resources like buffers, CPU, bandwidth,etc. for the time in which the newly setup VC is going to be used by a data transfer session.
- First packet goes and reserves resources for the subsequent packets which as a result follow the same path for the whole connection time.
- [ad type=”banner”]
- Since all the packets are going to follow the same path, a global header is required only for the first packet of the connection and other packets generally don’t require global headers.
- Since data follows a particular dedicated path, packets reach inorder to the destination.
- From above points, it can be concluded that Virtual Circuits are highly reliable means of transfer.
- Since each time a new connection has to be setup with reservation of resources and extra information handling at routers, its simply costly to implement Virtual Circuits.
Datagram Networks :
- It is connectionless service. There is no need of reservation of resources as there is no dedicated path for a connection session.
- All packets are free to go to any path on any intermediate router which is decided on the go by dynamically changing routing tables on routers.
- Since every packet is free to choose any path, all packets must be associated with a header with proper information about source and the upper layer data.
- The connectionless property makes data packets reach destination in any order, means they need not reach in the order in which they were sent.
- [ad type=”banner”]
- Datagram networks are not reliable as Virtual Circuits.
- But it is always easy and cost efficient to implement datagram networks as there is no extra headache of reserving resources and making a dedicated each time an application has to communicate.
- [ad type=”banner”]