Switching techniques are used to connect the systems for making one-to-one communication.
History
The internet of today has its origins in the 1960’s with the development of packet switched networks. Up until that time computers were connected using telephone network technology call circuit switching
Circuit switching
Circuit switching involves creating a dedicated circuit from the sender to the receiver when a call is requested, the data is sent in a continuous stream over the same circuit for the duration of the call. The circuit is closed down when the data transfer is complete. There are three phases in circuit switching:
- Connection establishment
- Data transfer
- Connection disconnection
Advantages
- Low latency: Each data connection has reserved bandwidth and path and so constant delay for data flowing over the connection and no need to establish a connection for each packet.
Drawbacks
- Inefficient use of bandwidth: Reserved bandwidth is wasted if no data is being transmitted.
- High cost for recovering: An interruption to the circuit cannot be recovered from without making a new call.
Packet switching technique was invented to fix the drawbacks of circuit switching, but at a cost of giving up guaranteed bandwidth.
Packet switching
Instead of sending data as continuous stream over a fixed circuit, packet switching involves breaking the data up into small packets, sending them independently through the network and reassembling them into the correct order at the destination.
The packets don’t necessarily follow the same path or route through the network, so the can be rerouted around breaks or congestion in the network.
The most common network technology today involves packet switching.
Advantage
- Efficient use of bandwidth: Bandwidth is shared among multiple users, and resources are allocated only when data needs to be transmitted. Data from different connections can share a channel.
- High resilience: The packets can be rerouted to face faults and overloading in the network.
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