RFConnection-Oriented vs. Connectionless Routing
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This page explains the difference between connection-oriented routing (virtual circuit routing) and connectionless routing (datagram services). There are two main traffic types: one requiring urgent delivery and the other not needing real-time delivery. The network determines routing services, protocols, and call handling techniques based on these needs.
In connection-oriented routing, the communication path between the message source and destination is fixed for the entire duration of the message transfer.
In connectionless routing, no connection is established initially between the source and destination. Instead, the data/message is broken up into packets, and each packet travels through different routes to reach the destination. The table below further describes the differences.
| Feature | Connection-Oriented (Virtual Circuit Routing) | Connectionless (Datagram Routing) |
|---|---|---|
| Link Establishment | A dedicated link is established at the start to deliver the entire message, making it more reliable. | No link is established initially, and packets are routed independently, making it generally less reliable. |
| Transmission Path | The entire information is transmitted over a single channel. | Different packets are transmitted over different routes/channels. |
| Data Re-ordering | Due to the direct connection, no re-ordering of data is required at the receiver end. | Re-ordering of data is needed and is done using sequence numbers embedded at the transmit side for each fragmented segment (packet). |
| Recovery From Disconnection | If the call gets cut, the full message needs to be re-transmitted. | When the connection gets disconnected, only that particular packet is re-transmitted. |
| Call Setup | To establish the call, a call setup procedure is required at the beginning. | No such procedures are needed. |
| Overhead Information | Less overhead information is needed due to the dedicated connection. | More overhead information is needed to ensure proper delivery. |
